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  • richardmitnick 4:50 pm on May 26, 2021 Permalink | Reply
    Tags: "NASA Laser Communications Innovations- A Timeline", , , NASA Goddard Space Flight Center, NASA will test a variety of laser communications applications.   

    From NASA Goddard Space Flight Center: “NASA Laser Communications Innovations- A Timeline” 

    NASA Goddard Banner

    From NASA Goddard Space Flight Center

    May 26, 2021

    Katherine Schauer
    katherine.s.schauer@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    1
    A conceptualization of NASA’s Laser Communications Relay Demonstration (LCRD) communicating data over infrared laser links between the International Space Station and a ground station on Earth. Credit: NASA/Dave Ryan.

    Laser communications will revolutionize the way NASA sends and receives information to and from space. Leveraging the advantages of infrared light, laser systems will provide missions with extraordinary data capabilities, leading NASA into the next era of space communications. This summer, NASA will launch the Laser Communications Relay Demonstration (LCRD) to test the validity of laser systems. However, LCRD is just one laser communications mission on the road to operational laser communications with both predecessors and follow-on missions.

    2
    An info-graphic detailing NASA’s laser communications technology roadmap.
    Credits: NASA/Dave Ryan.

    Previous Laser Communications Missions:

    In 2013, NASA launched the Lunar Laser Communications Demonstration (LLCD), which sent laser communications signals from the Moon at 600 megabits per second, proving this cutting-edge technology 238,000 miles from Earth. This mission set the stage for future laser communications research and development.

    Other previous laser missions include the 2014 Optical Payload for Lasercomm Science (OPALS) experiment – a four-month laser communications demonstration onboard the International Space Station. As well as the 2017 Optical Communications and Sensor Demonstration (OCSD), which conducted the first-ever high-speed laser communications downlink from a CubeSat to a ground station.

    Current Laser Communications Missions:

    Building upon the success of these missions, NASA will test a variety of laser communications applications.

    Launching in summer 2021, NASA’s LCRD mission will be the agency’s first technology demonstration of a two-way laser relay system. The mission will test laser capabilities with experiments, one of which will study atmospheric impacts like clouds, which can block or damage laser signals. Similar to how if you block a television remote, you block the signal. Humans already use the concept behind laser communications with their televisions. Using infrared light, remotes send signals to control a television.

    NASA is testing laser communications in both large and small satellites. Although just the size of a shoebox, in late 2021 the Terabyte Infrared Delivery (TBIRD) mission will demonstrate a burst-like laser downlink of 200 gigabits-per-second (Gbps) – a new record for data rates. With multiple passes a day, TBIRD will send back terabytes of data – roughly 250, 120-minute movies – and give NASA more insight into the capabilities of lasers on small satellites.

    Laser terminals are ideal for spacecraft like the International Space Station because they require less size, weight, and power – a key benefit when designing new mission concepts. In 2022, LCRD’s first orbiting experimental user will be the Integrated LCRD Low Earth Orbit User Modem and Amplifier Terminal (ILLUMA-T) aboard the space station. ILLUMA-T will provide 1.2 Gbps data rates to communicate high-resolution images and videos of ongoing experiments down to Earth for investigation and discovery.

    These missions will give NASA increased knowledge about laser communications systems near Earth. As NASA journeys further into space than ever before, missions at the Moon and in deep space will also benefit from advanced communications capabilities.

    NASA’s Artemis II will leverage laser communications, sending back critical data to increase our knowledge of the Moon for when the agency lands the first woman and next man on the surface and establishes a sustainable presence.

    The Orion Artemis II Optical Communications System (O2O) terminal will enable an ultra-high-definition video feed between Artemis II and Earth.

    NASA’s laser communications endeavors extend into deep space as well. Launching in 2022, the Psyche mission will embark on a three and a half year journey to reach its destination at its namesake asteroid, over 150 million miles away from Earth.

    During the first year of its voyage, the onboard Deep Space Optical Communications (DSOC) payload will test laser communications against the distinctive challenges presented by deep space exploration – extreme distance pointing. DSOC will give NASA insight into laser communications capabilities farther than ever before, proving these systems are viable for deep space exploration.

    With all of these laser missions in development, one might think the night sky will be filled with a colorful laser light show. However, the infrared light used for laser communications is invisible to human eyes.

    As use of laser communications systems becomes frequent, the importance of standardization increases. Following common standards for laser communications will eliminate the need for missions to design their systems from the ground up, resulting in cost savings and interoperability between spacecraft.

    Through NASA missions, the aerospace community is garnering extensive knowledge about the capabilities and challenges of laser communications in different environments. LCRD, launching no earlier than June 23, 2021, is one of the first steps in showcasing laser communications systems, setting the stage for future science and exploration missions to embrace and standardize this technology.

    For more background information on LCRD, please visit:

    Laser Communications: Empowering More Data Than Ever Before | NASA

    What is the Laser Communications Relay Demonstration? | NASA

    See the full article here.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.


    Stem Education Coalition


    NASA/Goddard Campus

    NASA’s Goddard Space Flight Center, Greenbelt, MD (US) is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    GSFC also operates two spaceflight tracking and data acquisition networks (the NASA Deep Space Network(US) and the Near Earth Network); develops and maintains advanced space and Earth science data information systems, and develops satellite systems for the National Oceanic and Atmospheric Administration(US) .

    GSFC manages operations for many NASA and international missions including the NASA/ESA Hubble Space Telescope; the Explorers Program; the Discovery Program; the Earth Observing System; INTEGRAL; MAVEN; OSIRIS-REx; the Solar and Heliospheric Observatory ; the Solar Dynamics Observatory; Tracking and Data Relay Satellite System ; Fermi; and Swift. Past missions managed by GSFC include the Rossi X-ray Timing Explorer (RXTE), Compton Gamma Ray Observatory, SMM, COBE, IUE, and ROSAT. Typically, unmanned Earth observation missions and observatories in Earth orbit are managed by GSFC, while unmanned planetary missions are managed by the Jet Propulsion Laboratory (JPL) in Pasadena, California(US).

    Goddard is one of four centers built by NASA since its founding on July 29, 1958. It is NASA’s first, and oldest, space center. Its original charter was to perform five major functions on behalf of NASA: technology development and fabrication; planning; scientific research; technical operations; and project management. The center is organized into several directorates, each charged with one of these key functions.

    Until May 1, 1959, NASA’s presence in Greenbelt, MD was known as the Beltsville Space Center. It was then renamed the Goddard Space Flight Center (GSFC), after Robert H. Goddard. Its first 157 employees transferred from the United States Navy’s Project Vanguard missile program, but continued their work at the Naval Research Laboratory in Washington, D.C., while the center was under construction.

    Goddard Space Flight Center contributed to Project Mercury, America’s first manned space flight program. The Center assumed a lead role for the project in its early days and managed the first 250 employees involved in the effort, who were stationed at Langley Research Center in Hampton, Virginia. However, the size and scope of Project Mercury soon prompted NASA to build a new Manned Spacecraft Center, now the Johnson Space Center, in Houston, Texas. Project Mercury’s personnel and activities were transferred there in 1961.

    The Goddard network tracked many early manned and unmanned spacecraft.

    Goddard Space Flight Center remained involved in the manned space flight program, providing computer support and radar tracking of flights through a worldwide network of ground stations called the Spacecraft Tracking and Data Acquisition Network (STDN). However, the Center focused primarily on designing unmanned satellites and spacecraft for scientific research missions. Goddard pioneered several fields of spacecraft development, including modular spacecraft design, which reduced costs and made it possible to repair satellites in orbit. Goddard’s Solar Max satellite, launched in 1980, was repaired by astronauts on the Space Shuttle Challenger in 1984. The Hubble Space Telescope, launched in 1990, remains in service and continues to grow in capability thanks to its modular design and multiple servicing missions by the Space Shuttle.

    Today, the center remains involved in each of NASA’s key programs. Goddard has developed more instruments for planetary exploration than any other organization, among them scientific instruments sent to every planet in the Solar System. The center’s contribution to the Earth Science Enterprise includes several spacecraft in the Earth Observing System fleet as well as EOSDIS, a science data collection, processing, and distribution system. For the manned space flight program, Goddard develops tools for use by astronauts during extra-vehicular activity, and operates the Lunar Reconnaissance Orbiter, a spacecraft designed to study the Moon in preparation for future manned exploration.

     
  • richardmitnick 1:02 pm on May 26, 2021 Permalink | Reply
    Tags: "Binary Black Hole Simulations Provide Blueprint for Future Observations", , , , NASA Goddard Space Flight Center, Scientists did not capture the first radio image of a black hole until 2019.   

    From NASA Goddard Space Flight Center: “Binary Black Hole Simulations Provide Blueprint for Future Observations” 

    NASA Goddard Banner

    From NASA Goddard Space Flight Center

    May 26, 2021
    Emma Edmund
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    Astronomers continue to develop computer simulations to help future observatories better home in on black holes, the most elusive inhabitants of the universe.

    Though black holes likely exist abundantly in the universe, they are notoriously hard to see. Scientists did not capture the first radio image of a black hole until 2019.

    Only about four dozen black hole mergers have been detected through their signature gravitational ripples since the first detection in 2015.

    That is not a lot of data to work with. So scientists look to black hole simulations to gain crucial insight that will help find more mergers with future missions. Some of these simulations, created by scientists like astrophysicist Scott Noble, track supermassive black hole binary systems. That is where two monster black holes like those found in the centers of galaxies orbit closely around each other until they eventually merge.


    Simulation Reveals Spiraling Supermassive Black Holes.
    Gas glows brightly in this computer simulation of supermassive black holes only 40 orbits from merging. Models like this may eventually help scientists pinpoint real examples of these powerful binary systems. Credit: NASA’s Goddard Space Flight Center.

    The simulations, created by computers working through sets of equations too complicated to solve by hand, illustrate how matter interacts in merger environments. Scientists can use what they learn about black hole mergers to identify some telltale characteristics that let them distinguish black hole mergers from stellar events. Astronomers can then look for these telltale signs and spot real-life black hole mergers.

    Noble, who works at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said these binary systems emit gravitational waves and influence surrounding gases, leading to unique light shows detectable with conventional telescopes. This allows scientists to learn about different aspects of the same system. Multimessenger observations that combine different forms of light or gravitational waves could allow scientists to refine their models of black hole binary systems.

    “We’ve been relying on light to see everything out there,” Noble said. “But not everything emits light, so the only way to directly ‘see’ two black holes is through the gravitational waves they generate. Gravitational waves and the light from surrounding gas are independent ways of learning about the system, and the hope is that they will meet up at the same point.”

    Binary black hole simulations can also help the Laser Interferometer Space Antenna (LISA) mission.

    This space-based gravitational wave observatory, led by the European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU) with significant contributions from NASA, is expected to launch in 2034. If simulations determine what electromagnetic characteristics distinguish a binary black hole system from other events, scientists could detect these systems before LISA flies, Noble said. These observations could then be confirmed through additional detections once LISA launches.

    That would allow scientists to verify that LISA is working, observe systems for a longer period before they merge, predict what is going to happen, and test those predictions.

    “We’ve never been able to do that before,” Noble said. “That’s really exciting.”

    The simulations rely on code which describes how the density and pressure of plasma changes in strong-gravity regions near a single black hole or neutron star, Noble said. He modified the code to allow for two black holes to evolve.

    Noble is working with Goddard and university partners, including Bernard Kelly at the University of Maryland, Manuela Campanelli leading a team of researchers at the Rochester Institute of Technology, and Julian Krolik leading a Johns Hopkins University research team.

    Kelly creates simulations using a special approach called a moving puncture simulation.

    These simulations allow scientists to avoid representing a singularity inside the event horizon — the part of the black hole from which nothing can escape, Kelly said. Everything outside of that event horizon evolves, while the objects inside remain frozen from earlier in the simulation. This allows scientists to overlook the fact that they do not know what happens within an event horizon.

    To mimic real-life situations, where black holes accumulate accretion disks of gas, dust, and diffuse matter, scientists have to incorporate additional code to track how the ionized material interacts with magnetic fields.

    “We’re trying to seamlessly and correctly glue together different codes and simulation methods to produce one coherent picture,” Kelly said.

    In 2018, the team published an analysis of a new simulation in The Astrophysical Journal that fully incorporated the physical effects of Einstein’s general theory of relativity to show a merger’s effects on the environment around it. The simulation established that the gas in binary black hole systems will glow predominantly in ultraviolet and X-ray light.

    3
    This visualization of supercomputer data shows the X-ray glow of the inner accretion disc of a black hole.
    Credit: Jeremy Schnittman/Scott Noble /NASA Goddard.

    Simulations also showed that accretion disks in these systems are not completely smooth. A dense clump forms orbiting the binary, and every time a black hole sweeps close, it pulls off matter from the clump. That collision heats up the matter, producing a bright signal and creating an observable fluctuation of light.

    In addition to improving their confidence in the accuracy of the simulations, Goddard astrophysicist Jeremy Schnittman said they also need to be able to apply the same simulation code to a single black hole or a binary and show the similarities and also the differences between the two systems.

    “The simulation are going to tell us what the systems should look like,” Schnittman said. “LISA works more like a radio antenna as opposed to an optical telescope. We’re going to hear something in the universe and get its basic direction, but nothing very precise. What we have to do is take other telescopes and look in that part of the sky, and the simulations are going to tell us what to look for to find a merging black hole.”

    Kelly said LISA will be more sensitive to lower gravitational wave frequencies than the current ground-based gravitational wave observer, the Laser Interferometer Gravitational-Wave Observatory (LIGO). That means LISA will be able to sense smaller-mass binary systems much earlier and will likely detect merging systems in time to alert electromagnetic telescopes.

    For Schnittman, these simulations are key to understanding the real-life data LISA and other spacecraft collect. The case for models may be even stronger for binary black holes, Schnittman said, because the scientific community has little data.

    “We probably will never find a binary black hole with a telescope until we simulate them to the point we know exactly what we’re looking for, because they’re so far away, they’re so tiny, you’re going to see just one speck of light,” Schnittman said. “We need to be able to look for that smoking gun.”

    See the full article here.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.


    Stem Education Coalition


    NASA/Goddard Campus

    NASA’s Goddard Space Flight Center, Greenbelt, MD (US) is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    GSFC also operates two spaceflight tracking and data acquisition networks (the NASA Deep Space Network(US) and the Near Earth Network); develops and maintains advanced space and Earth science data information systems, and develops satellite systems for the National Oceanic and Atmospheric Administration(US) .

    GSFC manages operations for many NASA and international missions including the NASA/ESA Hubble Space Telescope; the Explorers Program; the Discovery Program; the Earth Observing System; INTEGRAL; MAVEN; OSIRIS-REx; the Solar and Heliospheric Observatory ; the Solar Dynamics Observatory; Tracking and Data Relay Satellite System ; Fermi; and Swift. Past missions managed by GSFC include the Rossi X-ray Timing Explorer (RXTE), Compton Gamma Ray Observatory, SMM, COBE, IUE, and ROSAT. Typically, unmanned Earth observation missions and observatories in Earth orbit are managed by GSFC, while unmanned planetary missions are managed by the Jet Propulsion Laboratory (JPL) in Pasadena, California(US).

    Goddard is one of four centers built by NASA since its founding on July 29, 1958. It is NASA’s first, and oldest, space center. Its original charter was to perform five major functions on behalf of NASA: technology development and fabrication; planning; scientific research; technical operations; and project management. The center is organized into several directorates, each charged with one of these key functions.

    Until May 1, 1959, NASA’s presence in Greenbelt, MD was known as the Beltsville Space Center. It was then renamed the Goddard Space Flight Center (GSFC), after Robert H. Goddard. Its first 157 employees transferred from the United States Navy’s Project Vanguard missile program, but continued their work at the Naval Research Laboratory in Washington, D.C., while the center was under construction.

    Goddard Space Flight Center contributed to Project Mercury, America’s first manned space flight program. The Center assumed a lead role for the project in its early days and managed the first 250 employees involved in the effort, who were stationed at Langley Research Center in Hampton, Virginia. However, the size and scope of Project Mercury soon prompted NASA to build a new Manned Spacecraft Center, now the Johnson Space Center, in Houston, Texas. Project Mercury’s personnel and activities were transferred there in 1961.

    The Goddard network tracked many early manned and unmanned spacecraft.

    Goddard Space Flight Center remained involved in the manned space flight program, providing computer support and radar tracking of flights through a worldwide network of ground stations called the Spacecraft Tracking and Data Acquisition Network (STDN). However, the Center focused primarily on designing unmanned satellites and spacecraft for scientific research missions. Goddard pioneered several fields of spacecraft development, including modular spacecraft design, which reduced costs and made it possible to repair satellites in orbit. Goddard’s Solar Max satellite, launched in 1980, was repaired by astronauts on the Space Shuttle Challenger in 1984. The Hubble Space Telescope, launched in 1990, remains in service and continues to grow in capability thanks to its modular design and multiple servicing missions by the Space Shuttle.

    Today, the center remains involved in each of NASA’s key programs. Goddard has developed more instruments for planetary exploration than any other organization, among them scientific instruments sent to every planet in the Solar System. The center’s contribution to the Earth Science Enterprise includes several spacecraft in the Earth Observing System fleet as well as EOSDIS, a science data collection, processing, and distribution system. For the manned space flight program, Goddard develops tools for use by astronauts during extra-vehicular activity, and operates the Lunar Reconnaissance Orbiter, a spacecraft designed to study the Moon in preparation for future manned exploration.

     
  • richardmitnick 9:55 pm on May 12, 2021 Permalink | Reply
    Tags: "Laser Communications- Empowering More Data Than Ever Before", , NASA Goddard Space Flight Center   

    From NASA Goddard Space Flight Center: “Laser Communications- Empowering More Data Than Ever Before” 

    NASA Goddard Banner

    From NASA Goddard Space Flight Center

    May 12, 2021

    Katherine Schauer
    katherine.s.schauer@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    1
    Illustration of the U.S. Department of Defense’s Space Test Program Satellite-6 (STPSat-6) with the Laser Communications Relay Demonstration (LCRD) payload communicating data over infrared links. Credit: NASA.

    Launching this summer, NASA’s Laser Communications Relay Demonstration (LCRD) will showcase the dynamic powers of laser communications technologies. With NASA’s ever-increasing human and robotic presence in space, missions can benefit from a new way of “talking” with Earth.

    Since the beginning of spaceflight in the 1950s, NASA missions have leveraged radio frequency communications to send data to and from space. Laser communications, also known as optical communications, will further empower missions with unprecedented data capabilities.

    1
    Graphic representation of the difference in data rates between radio and laser communications. Credit: NASA.

    Why Lasers?

    As science instruments evolve to capture high-definition data like 4K video, missions will need expedited ways to transmit information to Earth. With laser communications, NASA can significantly accelerate the data transfer process and empower more discoveries.

    Laser communications will enable 10 to 100 times more data transmitted back to Earth than current radio frequency systems. It would take roughly nine weeks to transmit a complete map of Mars back to Earth with current radio frequency systems. With lasers, it would take about nine days.

    Additionally, laser communications systems are ideal for missions because they need less volume, weight, and power. Less mass means more room for science instruments, and less power means less of a drain of spacecraft power systems. These are all critically important considerations for NASA when designing and developing mission concepts.

    “LCRD will demonstrate all of the advantages of using laser systems and allow us to learn how to use them best operationally,” said Principal Investigator David Israel at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “With this capability further proven, we can start to implement laser communications on more missions, making it a standardized way to send and receive data.”

    How it Works

    Both radio waves and infrared light are electromagnetic radiation with wavelengths at different points on the electromagnetic spectrum. Like radio waves, infrared light is invisible to the human eye, but we encounter it every day with things like television remotes and heat lamps.

    Missions modulate their data onto the electromagnetic signals to traverse the distances between spacecraft and ground stations on Earth. As the communication travels, the waves spread out.

    The infrared light used for laser communications differs from radio waves because the infrared light packs the data into significantly tighter waves, meaning ground stations can receive more data at once. While laser communications aren’t necessarily faster, more data can be transmitted in one downlink.

    Laser communications terminals in space use narrower beam widths than radio frequency systems, providing smaller “footprints” that can minimize interference or improve security by drastically reducing the geographic area where someone could intercept a communications link. However, a laser communications telescope pointing to a ground station must be exact when broadcasting from thousands or millions of miles away. A deviation of even a fraction of a degree can result in the laser missing its target entirely. Like a quarterback throwing a football to a receiver, the quarterback needs to know where to send the football, i.e. the signal, so that the receiver can catch the ball in stride. NASA’s laser communications engineers have intricately designed laser missions to ensure this connection can happen.

    Laser Communications Relay Demonstration

    Located in geosynchronous orbit, about 22,000 miles above Earth, LCRD will be able to support missions in the near-Earth region. LCRD will spend its first two years testing laser communications capabilities with numerous experiments to refine laser technologies further, increasing our knowledge about potential future applications.

    LCRD’s initial experiment phase will leverage the mission’s ground stations in California and Hawaii, Optical Ground Station 1 and 2, as simulated users. This will allow NASA to evaluate atmospheric disturbances on lasers and practice switching support from one user to the next. After the experiment phase, LCRD will transition to supporting space missions, sending and receiving data to and from satellites over infrared lasers to demonstrate the benefits of a laser communications relay system.

    The first in-space user of LCRD will be NASA’s Integrated LCRD Low-Earth Orbit User Modem and Amplifier Terminal (ILLUMA-T), which is set to launch to the International Space Station in 2022. The terminal will receive high-quality science data from experiments and instruments onboard the space station and then transfer this data to LCRD at 1.2 gigabits per second. LCRD will then transmit it to ground stations at the same rate.

    LCRD and ILLUMA-T follow the groundbreaking 2013 Lunar Laser Communications Demonstration, which downlinked data over a laser signal at 622 megabits-per-second, proving the capabilities of laser systems at the Moon. NASA has many other laser communications missions currently in different stages of development. Each of these missions will increase our knowledge about the benefits and challenges of laser communications and further standardize the technology.

    LCRD is slated to launch as a payload on a Department of Defense spacecraft on June 23, 2021.

    LCRD is a NASA payload aboard the Department of Defense’s Space Test Program Satellite-6 (STPSat-6). STPSat-6, part of the third Space Test Program (STP-3) mission, will launch on a United Launch Alliance Atlas V 551 rocket from the Cape Canaveral Space Force Station in Florida. STP is operated by the United States Space Force’s Space and Missile Systems Center.

    LCRD is led by Goddard and in partnership with NASA’s Jet Propulsion Laboratory in Southern California and the MIT (US) Lincoln Laboratory. LCRD is funded through NASA’s Technology Demonstration Missions program, part of the Space Technology Mission Directorate, and the Space Communications and Navigation (SCaN) program, within the Human Exploration and Operations Mission Directorate.

    See the full article here.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.


    Stem Education Coalition


    NASA/Goddard Campus

    NASA’s Goddard Space Flight Center, Greenbelt, MD (US) is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    GSFC also operates two spaceflight tracking and data acquisition networks (the NASA Deep Space Network(US) and the Near Earth Network); develops and maintains advanced space and Earth science data information systems, and develops satellite systems for the National Oceanic and Atmospheric Administration(US) .

    GSFC manages operations for many NASA and international missions including the NASA/ESA Hubble Space Telescope; the Explorers Program; the Discovery Program; the Earth Observing System; INTEGRAL; MAVEN; OSIRIS-REx; the Solar and Heliospheric Observatory ; the Solar Dynamics Observatory; Tracking and Data Relay Satellite System ; Fermi; and Swift. Past missions managed by GSFC include the Rossi X-ray Timing Explorer (RXTE), Compton Gamma Ray Observatory, SMM, COBE, IUE, and ROSAT. Typically, unmanned Earth observation missions and observatories in Earth orbit are managed by GSFC, while unmanned planetary missions are managed by the Jet Propulsion Laboratory (JPL) in Pasadena, California(US).

    Goddard is one of four centers built by NASA since its founding on July 29, 1958. It is NASA’s first, and oldest, space center. Its original charter was to perform five major functions on behalf of NASA: technology development and fabrication; planning; scientific research; technical operations; and project management. The center is organized into several directorates, each charged with one of these key functions.

    Until May 1, 1959, NASA’s presence in Greenbelt, MD was known as the Beltsville Space Center. It was then renamed the Goddard Space Flight Center (GSFC), after Robert H. Goddard. Its first 157 employees transferred from the United States Navy’s Project Vanguard missile program, but continued their work at the Naval Research Laboratory in Washington, D.C., while the center was under construction.

    Goddard Space Flight Center contributed to Project Mercury, America’s first manned space flight program. The Center assumed a lead role for the project in its early days and managed the first 250 employees involved in the effort, who were stationed at Langley Research Center in Hampton, Virginia. However, the size and scope of Project Mercury soon prompted NASA to build a new Manned Spacecraft Center, now the Johnson Space Center, in Houston, Texas. Project Mercury’s personnel and activities were transferred there in 1961.

    The Goddard network tracked many early manned and unmanned spacecraft.

    Goddard Space Flight Center remained involved in the manned space flight program, providing computer support and radar tracking of flights through a worldwide network of ground stations called the Spacecraft Tracking and Data Acquisition Network (STDN). However, the Center focused primarily on designing unmanned satellites and spacecraft for scientific research missions. Goddard pioneered several fields of spacecraft development, including modular spacecraft design, which reduced costs and made it possible to repair satellites in orbit. Goddard’s Solar Max satellite, launched in 1980, was repaired by astronauts on the Space Shuttle Challenger in 1984. The Hubble Space Telescope, launched in 1990, remains in service and continues to grow in capability thanks to its modular design and multiple servicing missions by the Space Shuttle.

    Today, the center remains involved in each of NASA’s key programs. Goddard has developed more instruments for planetary exploration than any other organization, among them scientific instruments sent to every planet in the Solar System. The center’s contribution to the Earth Science Enterprise includes several spacecraft in the Earth Observing System fleet as well as EOSDIS, a science data collection, processing, and distribution system. For the manned space flight program, Goddard develops tools for use by astronauts during extra-vehicular activity, and operates the Lunar Reconnaissance Orbiter, a spacecraft designed to study the Moon in preparation for future manned exploration.

     
  • richardmitnick 1:12 pm on May 9, 2021 Permalink | Reply
    Tags: "Natural radio signal buzzes in Venus’ atmosphere", , , NASA Goddard Space Flight Center,   

    From NASA Goddard Space Flight Center via EarthSky : “Natural radio signal buzzes in Venus’ atmosphere” 

    NASA Goddard Banner

    From NASA Goddard Space Flight Center

    via

    1

    EarthSky

    May 9, 2021
    Paul Scott Anderson


    NASA’s Parker Solar Probe Discovers Natural Radio Emission in Venus’ Atmosphere. NASA Goddard

    Venus has been in the news a lot since last September, when researchers announced the possible detection of phosphine, a possible life sign, in its atmosphere. On May 3, 2021, NASA’s Parker Solar Probe announced another discovery: a never-before-seen natural low-frequency radio signal in the atmosphere of Venus.

    The probe, designed primarily to study the sun, came close to Venus to use it as a gravity slingshot, needed to propel the probe sunward. Parker Solar Probe was at its closest to Venus yet – only about 500 miles (800 km) above Venus’ surface on July 11, 2020 – when it found the surprising signal.

    The researchers published their new peer-reviewed findings on May 3 in AGU’s Geophysical Research Letters.

    Glyn Collinson of NASA’s Goddard Space Flight Center and lead author exclaimed:

    “I was just so excited to have new data from Venus.”

    The measurements from Parker Solar Probe are the first new direct measurements of Venus’ atmosphere in nearly 30 years. The results also show that the atmosphere undergoes changes during the sun’s 11-year solar cycle, and that it is now quite different from what it was in the past.

    1
    Parker Solar Probe captured this stunning view of Venus’ nightside during its flyby on July 11, 2020. The streaks are cosmic rays and dust particles. Image via Guillermo Stenborg and Brendan Gallagher/ National Aeronautics Space Agency (US)/ Johns Hopkins Applied Physics Lab (US)/ Naval Research Laboratory (US).

    How did the spacecraft detect the radio signal?

    It did so using its FIELDS instrument, which measures electrical and magnetic fields in the atmosphere. The signal was detected when the spacecraft was closest to the planet, for a period of only seven minutes.

    Collinson saw it in the data and recognized it, saying:

    “Then the next day, I woke up. And I thought, ‘Oh my god, I know what this is!’”

    He had seen the exact same kind of radio signal before from the Galileo orbiter, which had explored Jupiter and its moons.

    That mission ended in 2003. In this case, the signal, which looked like a thin “frown” in the data, was found in the ionospheres of some of the moons. The similarity of the signal meant that Parker Solar Probe had unexpectedly skimmed through the upper atmosphere of Venus, or more specifically, its ionosphere.

    The ionosphere is a region of charged gases or plasma in the upper atmosphere that emits natural radio waves. Galileo had detected those radio waves at Jupiter’s moons, and now Parker Solar Probe had also found them in Venus’ atmosphere. The last time Venus’ ionosphere was measured directly was in 1992 by the Pioneer Venus Orbiter. The sun also happened to be at the peak of its solar cycle at the time.

    3
    Parker Solar Probe also took the first-ever complete image of the dust ring that circles the sun along Venus’ orbit. The 4 frames of the image were first captured on August 25, 2019. Image via Guillermo Stenborg and Brendan Gallagher/ National Aeronautics Space Agency (US)/Johns Hopkins Applied Physics Lab (US)/ Naval Research Laboratory (US)/.

    For a long time afterward, however, there were no more Venus missions that could take new measurements. Instead, scientists relied on Earth-based telescopes, which showed that the ionosphere was changing while the sun’s solar cycle started to wane again and become calmer. During solar minimum, the ionosphere on Venus was at its thinnest.

    Now, the new measurements from Parker Solar Probe support the previous findings. The close flyby occurred six months after solar minimum – the least active period on the sun – and the data showed that again, the ionosphere was significantly thinner than it was during solar maximum, the most active period. This confirms that the density of Venus’ ionosphere is directly correlated to the strength of the solar cycle. According to co-author Robin Ramstad:

    “When multiple missions are confirming the same result, one after the other, that gives you a lot of confidence that the thinning is real.”

    As outlined in the paper:

    “On July 11, 2020, NASA’s Parker Solar Probe made a close flyby of Venus. During the 7 minutes around the closest approach, one of its scientific instruments detected low-frequency radio emission of a type naturally generated by planetary ionospheres. By measuring the frequency of this emission, we can directly calculate the density of the ionosphere around Parker, finding it to be far less dense than previous missions have encountered. This supports the theory that the ionosphere of Venus varies substantially over the 11-year solar cycle.”

    Why is this important?

    Scientists want to better understand how Venus changed from a former habitable world, according to the latest research, to the inhospitable inferno we see today. The fact that the planet’s ionosphere thins at solar minimum can provide valuable clues as to how the sun affects Venus’ atmosphere. It is also known that the planet’s ionosphere can “leak” into space. Changes like that can tell scientists how the atmosphere has evolved over time.

    The discovery of the radio signal is a fortuitous development, since Parker Solar Probe’s main mission is to study the sun, not Venus. As Parker Solar Probe project scientist Nour Raouafi commented:

    “The goal of flying by Venus is to slow down the spacecraft so that Parker Solar Probe can dive closer to the sun. But we would not miss the opportunity to gather science data and provide unique insights into a mysterious planet such as Venus.’

    Parker Solar Probe took some stunning images of Venus during its flyby, which NASA released on February 24, 2021. It also imaged the entire dust ring that orbits the sun along Venus’ orbit, the first time that has ever been accomplished by any spacecraft.

    There are no current U.S. missions at Venus, so these close flybys provide a great opportunity to gather more data. As Collinson noted:

    “To see Venus now, it’s all about these little glimpses.”

    4
    False-color view of Venus (to bring out details) from Japan’s Akatsuki orbiter.

    The radio signal was detected in Venus’ ionosphere in the upper atmosphere by Parker Solar Probe. Image via Japan Aerospace Exploration Agency [ (国立研究開発法人宇宙航空研究開発機構] (JP)/ Institute of Space and Astronautical Science [宇宙科学研究所] (JP)/ JAXA Venus Climate Orbiter AKATSUKI [あかつき](JP) Project Team/ Royal Astronomical Society (UK)/ CC BY 4.0.

    See the full article here.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.


    Stem Education Coalition


    NASA/Goddard Campus

    NASA’s Goddard Space Flight Center, Greenbelt, MD (US) is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    GSFC also operates two spaceflight tracking and data acquisition networks (the NASA Deep Space Network(US) and the Near Earth Network); develops and maintains advanced space and Earth science data information systems, and develops satellite systems for the National Oceanic and Atmospheric Administration(US) .

    GSFC manages operations for many NASA and international missions including the NASA/ESA Hubble Space Telescope; the Explorers Program; the Discovery Program; the Earth Observing System; INTEGRAL; MAVEN; OSIRIS-REx; the Solar and Heliospheric Observatory ; the Solar Dynamics Observatory; Tracking and Data Relay Satellite System ; Fermi; and Swift. Past missions managed by GSFC include the Rossi X-ray Timing Explorer (RXTE), Compton Gamma Ray Observatory, SMM, COBE, IUE, and ROSAT. Typically, unmanned Earth observation missions and observatories in Earth orbit are managed by GSFC, while unmanned planetary missions are managed by the Jet Propulsion Laboratory (JPL) in Pasadena, California(US).

    Goddard is one of four centers built by NASA since its founding on July 29, 1958. It is NASA’s first, and oldest, space center. Its original charter was to perform five major functions on behalf of NASA: technology development and fabrication; planning; scientific research; technical operations; and project management. The center is organized into several directorates, each charged with one of these key functions.

    Until May 1, 1959, NASA’s presence in Greenbelt, MD was known as the Beltsville Space Center. It was then renamed the Goddard Space Flight Center (GSFC), after Robert H. Goddard. Its first 157 employees transferred from the United States Navy’s Project Vanguard missile program, but continued their work at the Naval Research Laboratory in Washington, D.C., while the center was under construction.

    Goddard Space Flight Center contributed to Project Mercury, America’s first manned space flight program. The Center assumed a lead role for the project in its early days and managed the first 250 employees involved in the effort, who were stationed at Langley Research Center in Hampton, Virginia. However, the size and scope of Project Mercury soon prompted NASA to build a new Manned Spacecraft Center, now the Johnson Space Center, in Houston, Texas. Project Mercury’s personnel and activities were transferred there in 1961.

    The Goddard network tracked many early manned and unmanned spacecraft.

    Goddard Space Flight Center remained involved in the manned space flight program, providing computer support and radar tracking of flights through a worldwide network of ground stations called the Spacecraft Tracking and Data Acquisition Network (STDN). However, the Center focused primarily on designing unmanned satellites and spacecraft for scientific research missions. Goddard pioneered several fields of spacecraft development, including modular spacecraft design, which reduced costs and made it possible to repair satellites in orbit. Goddard’s Solar Max satellite, launched in 1980, was repaired by astronauts on the Space Shuttle Challenger in 1984. The Hubble Space Telescope, launched in 1990, remains in service and continues to grow in capability thanks to its modular design and multiple servicing missions by the Space Shuttle.

    Today, the center remains involved in each of NASA’s key programs. Goddard has developed more instruments for planetary exploration than any other organization, among them scientific instruments sent to every planet in the Solar System. The center’s contribution to the Earth Science Enterprise includes several spacecraft in the Earth Observing System fleet as well as EOSDIS, a science data collection, processing, and distribution system. For the manned space flight program, Goddard develops tools for use by astronauts during extra-vehicular activity, and operates the Lunar Reconnaissance Orbiter, a spacecraft designed to study the Moon in preparation for future manned exploration.

     
  • richardmitnick 1:58 pm on May 3, 2021 Permalink | Reply
    Tags: "NASA’s Parker Solar Probe Discovers Natural Radio Emission in Venus’ Atmosphere", NASA Goddard Space Flight Center,   

    From NASA Goddard Space Flight Center: “NASA’s Parker Solar Probe Discovers Natural Radio Emission in Venus’ Atmosphere” 

    NASA Goddard Banner

    From NASA Goddard Space Flight Center

    May 3, 2021
    Lina Tran
    lina.tran@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    During a brief swing by Venus, NASA’s Parker Solar Probe detected a natural radio signal that revealed the spacecraft had flown through the planet’s upper atmosphere.

    This was the first direct measurement of the Venusian atmosphere in nearly 30 years — and it looks quite different from Venus past. A study published today confirms that Venus’ upper atmosphere undergoes puzzling changes over a solar cycle, the Sun’s 11-year activity cycle. This marks the latest clue to untangling how and why Venus and Earth are so different.

    Born of similar processes, Earth and Venus are twins: both rocky, and of similar size and structure. But their paths diverged from birth. Venus lacks a magnetic field, and its surface broils at temperatures hot enough to melt lead. At most, spacecraft have only ever survived a couple hours there. Studying Venus, inhospitable as it is, helps scientists understand how these twins have evolved, and what makes Earth-like planets habitable or not.

    On July 11, 2020, Parker Solar Probe swung by Venus in its third flyby. Each flyby is designed to leverage the planet’s gravity to fly the spacecraft closer and closer to the Sun. The mission — managed by Johns Hopkins Applied Physics Laboratory (US) in Laurel, Maryland — made its closest flyby of Venus yet, passing just 517 miles (833 km) above the surface.


    NASA’s Parker Solar Probe Discovers Natural Radio Emission in Venus’ Atmosphere.
    The data sonification in the video translates data from Parker Solar Probe’s FIELDS instrument into sound. FIELDS detected a natural, low-frequency radio emission as it moved through Venus’ atmosphere that helped scientists calculate the density of the planet’s electrically charged upper atmosphere, called the ionosphere.
    Credits: NASA’s Scientific Visualization Studio/Mark SubbaRao/Glyn Collinson.

    “I was just so excited to have new data from Venus,” said Glyn Collison of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, the lead scientist on the study, published today in Geophysical Research Letters. A Venus expert, Collinson has pored over all the Venus data available — from past missions like NASA’s Pioneer Venus Orbiter and European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU) Venus Express — several times.

    One of Parker Solar Probe’s instruments is FIELDS, named for the electric and magnetic fields it measures in the Sun’s atmosphere. For just seven minutes — when Parker Solar Probe was closest to Venus — FIELDS detected a natural, low-frequency radio signal. The thin frown in the data caught Collinson’s attention. The shape and strength of the signal seemed familiar, but he could not place it. “Then the next day, I woke up,” he said. “And I thought, ‘Oh my god, I know what this is!’”

    Collinson recognized the signal from his previous work with NASA’s Galileo orbiter, which explored Jupiter and its moons before the mission ended in 2003. A similar frown appeared whenever the spacecraft passed through the ionospheres of Jupiter’s moons.

    National Aeronautics and Space Administration(US)Galileo 1989-2003

    Like Earth, Venus sports an electrically charged layer of gas at the upper edge of its atmosphere, called the ionosphere. This sea of charged gases, or plasma, naturally emits radio waves that can be detected by instruments like FIELDS. When Collinson and his team identified that signal, they realized Parker Solar Probe had skimmed Venus’ upper atmosphere — a pleasant surprise, though one they might have expected based on previous data, he said.

    The researchers used this radio emission to calculate the density of the ionosphere that Parker Solar Probe flew through. Researchers last obtained direct measurements of Venus’ ionosphere from Pioneer Venus Orbiter in 1992. Then, the Sun was near solar maximum, the stormy peak of the solar cycle.

    In the years that followed, data from ground-based telescopes suggested big changes were taking place as the Sun settled into its calm phase, solar minimum. While the bulk of the atmosphere remained the same, the ionosphere — which is at the top, where gases can escape to space — was much thinner during solar minimum.

    Without direct measurements, it was impossible to confirm.

    The observations from Parker Solar Probe’s recent flyby, which occurred six months after the latest solar minimum, verify the puzzle in Venus’ ionosphere. Indeed, Venus’ ionosphere is much thinner compared to previous measurements taken during solar maximum.

    “When multiple missions are confirming the same result, one after the other, that gives you a lot of confidence that the thinning is real,” said Robin Ramstad, a study co-author and post-doctoral researcher at the Laboratory of Atmospheric and Space Physics at the University of Colorado, Boulder.

    Understanding why Venus’ ionosphere thins near solar minimum is one part of unraveling how Venus responds to the Sun — which will help researchers determine how Venus, once so similar to Earth, became the world of scorching, toxic air it is today. For example, Venus’ ionosphere is prone to leaking, meaning the escape of energized gases into space. Gathering data on this and other changes in the ionosphere is key to understanding how Venus’ atmosphere has evolved over time.

    This study was some 30 years in the making. It took a mission to Venus, and decades later, a state-of-the-art mission to the Sun. “The goal of flying by Venus is to slow down the spacecraft so that Parker Solar Probe can dive closer to the Sun,” said Nour E. Raouafi, Parker Solar Probe project scientist at the Applied Physics Laboratory. “But we would not miss the opportunity to gather science data and provide unique insights into a mysterious planet such as Venus.”

    Collinson likened the research to hitchhiking. Venus scientists were eager to piggyback off Parker Solar Probe’s flyby for new data and views of Earth’s twin planet. “To see Venus now, it’s all about these little glimpses,” he said.

    See the full article here.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.


    Stem Education Coalition


    NASA/Goddard Campus

    NASA’s Goddard Space Flight Center, Greenbelt, MD (US) is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    GSFC also operates two spaceflight tracking and data acquisition networks (the NASA Deep Space Network(US) and the Near Earth Network); develops and maintains advanced space and Earth science data information systems, and develops satellite systems for the National Oceanic and Atmospheric Administration(US) .

    GSFC manages operations for many NASA and international missions including the NASA/ESA Hubble Space Telescope; the Explorers Program; the Discovery Program; the Earth Observing System; INTEGRAL; MAVEN; OSIRIS-REx; the Solar and Heliospheric Observatory ; the Solar Dynamics Observatory; Tracking and Data Relay Satellite System ; Fermi; and Swift. Past missions managed by GSFC include the Rossi X-ray Timing Explorer (RXTE), Compton Gamma Ray Observatory, SMM, COBE, IUE, and ROSAT. Typically, unmanned Earth observation missions and observatories in Earth orbit are managed by GSFC, while unmanned planetary missions are managed by the Jet Propulsion Laboratory (JPL) in Pasadena, California(US).

    Goddard is one of four centers built by NASA since its founding on July 29, 1958. It is NASA’s first, and oldest, space center. Its original charter was to perform five major functions on behalf of NASA: technology development and fabrication; planning; scientific research; technical operations; and project management. The center is organized into several directorates, each charged with one of these key functions.

    Until May 1, 1959, NASA’s presence in Greenbelt, MD was known as the Beltsville Space Center. It was then renamed the Goddard Space Flight Center (GSFC), after Robert H. Goddard. Its first 157 employees transferred from the United States Navy’s Project Vanguard missile program, but continued their work at the Naval Research Laboratory in Washington, D.C., while the center was under construction.

    Goddard Space Flight Center contributed to Project Mercury, America’s first manned space flight program. The Center assumed a lead role for the project in its early days and managed the first 250 employees involved in the effort, who were stationed at Langley Research Center in Hampton, Virginia. However, the size and scope of Project Mercury soon prompted NASA to build a new Manned Spacecraft Center, now the Johnson Space Center, in Houston, Texas. Project Mercury’s personnel and activities were transferred there in 1961.

    The Goddard network tracked many early manned and unmanned spacecraft.

    Goddard Space Flight Center remained involved in the manned space flight program, providing computer support and radar tracking of flights through a worldwide network of ground stations called the Spacecraft Tracking and Data Acquisition Network (STDN). However, the Center focused primarily on designing unmanned satellites and spacecraft for scientific research missions. Goddard pioneered several fields of spacecraft development, including modular spacecraft design, which reduced costs and made it possible to repair satellites in orbit. Goddard’s Solar Max satellite, launched in 1980, was repaired by astronauts on the Space Shuttle Challenger in 1984. The Hubble Space Telescope, launched in 1990, remains in service and continues to grow in capability thanks to its modular design and multiple servicing missions by the Space Shuttle.

    Today, the center remains involved in each of NASA’s key programs. Goddard has developed more instruments for planetary exploration than any other organization, among them scientific instruments sent to every planet in the Solar System. The center’s contribution to the Earth Science Enterprise includes several spacecraft in the Earth Observing System fleet as well as EOSDIS, a science data collection, processing, and distribution system. For the manned space flight program, Goddard develops tools for use by astronauts during extra-vehicular activity, and operates the Lunar Reconnaissance Orbiter, a spacecraft designed to study the Moon in preparation for future manned exploration.

     
  • richardmitnick 9:44 pm on April 30, 2021 Permalink | Reply
    Tags: "Hubble Views a Dazzling Cosmic Necklace", , , , NASA Goddard Space Flight Center, , , the “Necklace Nebula" [PN G054.2-03.4]   

    From NASA Goddard Space Flight Center and From NASA/ESA Hubble Telescope: “Hubble Views a Dazzling Cosmic Necklace” 

    NASA Goddard Banner

    From NASA Goddard Space Flight Center

    and

    From NASA/ESA Hubble Telescope

    Apr 30, 2021

    Claire Andreoli
    NASA’s Goddard Space Flight Center
    claire.andreoli@nasa.gov

    1

    The interaction of two doomed stars has created this spectacular ring adorned with bright clumps of gas ­– a diamond necklace of cosmic proportions. Fittingly known as the “Necklace Nebula,” [PN G054.2-03.4] this planetary nebula is located 15,000 light-years away from Earth in the small, dim constellation of Sagitta (the Arrow).

    A pair of tightly orbiting Sun-like stars produced the Necklace Nebula, which also goes by the less glamorous name of PN G054.203.4. Roughly 10,000 years ago, one of the aging stars expanded and engulfed its smaller companion, creating something astronomers call a “common envelope.” The smaller star continued to orbit inside its larger companion, increasing the bloated giant’s rotation rate until large parts of it spun outwards into space. This escaping ring of debris formed the Necklace Nebula, with particularly dense clumps of gas forming the bright “diamonds” around the ring.

    The pair of stars which created the Necklace Nebula remain so close together – separated by only several million miles – that they appear as a single bright dot in the center of this image. Despite their close encounter, the stars are still furiously whirling around each other, completing an orbit in just over a day.

    Hubble previously released an image of the Necklace Nebula, but this new image uses advanced processing techniques to create an improved and fresh view of this intriguing object. The composite image includes several exposures from Hubble’s Wide Field Camera 3.

    See the full article here.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The NASA/ESA Hubble Space Telescope is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versatile, renowned both as a vital research tool and as a public relations boon for astronomy. The Hubble telescope is named after astronomer Edwin Hubble and is one of NASA’s Great Observatories, along with the NASA Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the NASA Spitzer Infared Space Telescope.



    Edwin Hubble at Caltech Palomar Samuel Oschin 48 inch Telescope(US). Credit: Emilio Segre Visual Archives/AIP/SPL).

    Hubble features a 2.4-meter (7.9 ft) mirror, and its four main instruments observe in the ultraviolet, visible, and near-infrared regions of the electromagnetic spectrum. Hubble’s orbit outside the distortion of Earth’s atmosphere allows it to capture extremely high-resolution images with substantially lower background light than ground-based telescopes. It has recorded some of the most detailed visible light images, allowing a deep view into space. Many Hubble observations have led to breakthroughs in astrophysics, such as determining the rate of expansion of the universe.

    The Hubble telescope was built by the United States space agency National Aeronautics Space Agency(US) with contributions from the European Space Agency [Agence spatiale européenne](EU). The Space Telescope Science Institute (STScI) selects Hubble’s targets and processes the resulting data, while the NASA Goddard Space Flight Center(US) controls the spacecraft. Space telescopes were proposed as early as 1923. Hubble was funded in the 1970s with a proposed launch in 1983, but the project was beset by technical delays, budget problems, and the 1986 Challenger disaster. It was finally launched by Space Shuttle Discovery in 1990, but its main mirror had been ground incorrectly, resulting in spherical aberration that compromised the telescope’s capabilities. The optics were corrected to their intended quality by a servicing mission in 1993.

    Hubble is the only telescope designed to be maintained in space by astronauts. Five Space Shuttle missions have repaired, upgraded, and replaced systems on the telescope, including all five of the main instruments. The fifth mission was initially canceled on safety grounds following the Columbia disaster (2003), but NASA administrator Michael D. Griffin approved the fifth servicing mission which was completed in 2009. The telescope was still operating as of April 24, 2020, its 30th anniversary, and could last until 2030–2040. One successor to the Hubble telescope is the National Aeronautics Space Agency(USA)/European Space Agency [Agence spatiale européenne](EU)/Canadian Space Agency(CA) Webb Infrared Space Telescope scheduled for launch in October 2021.

    Proposals and precursors

    In 1923, Hermann Oberth—considered a father of modern rocketry, along with Robert H. Goddard and Konstantin Tsiolkovsky—published Die Rakete zu den Planetenräumen (“The Rocket into Planetary Space“), which mentioned how a telescope could be propelled into Earth orbit by a rocket.

    The history of the Hubble Space Telescope can be traced back as far as 1946, to astronomer Lyman Spitzer’s paper entitled Astronomical advantages of an extraterrestrial observatory. In it, he discussed the two main advantages that a space-based observatory would have over ground-based telescopes. First, the angular resolution (the smallest separation at which objects can be clearly distinguished) would be limited only by diffraction, rather than by the turbulence in the atmosphere, which causes stars to twinkle, known to astronomers as seeing. At that time ground-based telescopes were limited to resolutions of 0.5–1.0 arcseconds, compared to a theoretical diffraction-limited resolution of about 0.05 arcsec for an optical telescope with a mirror 2.5 m (8.2 ft) in diameter. Second, a space-based telescope could observe infrared and ultraviolet light, which are strongly absorbed by the atmosphere.

    Spitzer devoted much of his career to pushing for the development of a space telescope. In 1962, a report by the U.S. National Academy of Sciences recommended development of a space telescope as part of the space program, and in 1965 Spitzer was appointed as head of a committee given the task of defining scientific objectives for a large space telescope.

    Space-based astronomy had begun on a very small scale following World War II, as scientists made use of developments that had taken place in rocket technology. The first ultraviolet spectrum of the Sun was obtained in 1946, and the National Aeronautics and Space Administration (US) launched the Orbiting Solar Observatory (OSO) to obtain UV, X-ray, and gamma-ray spectra in 1962.

    An orbiting solar telescope was launched in 1962 by the United Kingdom as part of the Ariel space program, and in 1966 NASA launched the first Orbiting Astronomical Observatory (OAO) mission. OAO-1’s battery failed after three days, terminating the mission. It was followed by OAO-2, which carried out ultraviolet observations of stars and galaxies from its launch in 1968 until 1972, well beyond its original planned lifetime of one year.

    The OSO and OAO missions demonstrated the important role space-based observations could play in astronomy. In 1968, NASA developed firm plans for a space-based reflecting telescope with a mirror 3 m (9.8 ft) in diameter, known provisionally as the Large Orbiting Telescope or Large Space Telescope (LST), with a launch slated for 1979. These plans emphasized the need for crewed maintenance missions to the telescope to ensure such a costly program had a lengthy working life, and the concurrent development of plans for the reusable Space Shuttle indicated that the technology to allow this was soon to become available.

    Quest for funding

    The continuing success of the OAO program encouraged increasingly strong consensus within the astronomical community that the LST should be a major goal. In 1970, NASA established two committees, one to plan the engineering side of the space telescope project, and the other to determine the scientific goals of the mission. Once these had been established, the next hurdle for NASA was to obtain funding for the instrument, which would be far more costly than any Earth-based telescope. The U.S. Congress questioned many aspects of the proposed budget for the telescope and forced cuts in the budget for the planning stages, which at the time consisted of very detailed studies of potential instruments and hardware for the telescope. In 1974, public spending cuts led to Congress deleting all funding for the telescope project.
    In response a nationwide lobbying effort was coordinated among astronomers. Many astronomers met congressmen and senators in person, and large scale letter-writing campaigns were organized. The National Academy of Sciences published a report emphasizing the need for a space telescope, and eventually the Senate agreed to half the budget that had originally been approved by Congress.

    The funding issues led to something of a reduction in the scale of the project, with the proposed mirror diameter reduced from 3 m to 2.4 m, both to cut costs and to allow a more compact and effective configuration for the telescope hardware. A proposed precursor 1.5 m (4.9 ft) space telescope to test the systems to be used on the main satellite was dropped, and budgetary concerns also prompted collaboration with the European Space Agency. ESA agreed to provide funding and supply one of the first generation instruments for the telescope, as well as the solar cells that would power it, and staff to work on the telescope in the United States, in return for European astronomers being guaranteed at least 15% of the observing time on the telescope. Congress eventually approved funding of US$36 million for 1978, and the design of the LST began in earnest, aiming for a launch date of 1983. In 1983 the telescope was named after Edwin Hubble, who confirmed one of the greatest scientific discoveries of the 20th century, made by Georges Lemaître, that the universe is expanding.

    Construction and engineering

    Once the Space Telescope project had been given the go-ahead, work on the program was divided among many institutions. NASA Marshall Space Flight Center (MSFC) was given responsibility for the design, development, and construction of the telescope, while Goddard Space Flight Center was given overall control of the scientific instruments and ground-control center for the mission. MSFC commissioned the optics company Perkin-Elmer to design and build the Optical Telescope Assembly (OTA) and Fine Guidance Sensors for the space telescope. Lockheed was commissioned to construct and integrate the spacecraft in which the telescope would be housed.

    Optical Telescope Assembly

    Optically, the HST is a Cassegrain reflector of Ritchey–Chrétien design, as are most large professional telescopes. This design, with two hyperbolic mirrors, is known for good imaging performance over a wide field of view, with the disadvantage that the mirrors have shapes that are hard to fabricate and test. The mirror and optical systems of the telescope determine the final performance, and they were designed to exacting specifications. Optical telescopes typically have mirrors polished to an accuracy of about a tenth of the wavelength of visible light, but the Space Telescope was to be used for observations from the visible through the ultraviolet (shorter wavelengths) and was specified to be diffraction limited to take full advantage of the space environment. Therefore, its mirror needed to be polished to an accuracy of 10 nanometers, or about 1/65 of the wavelength of red light. On the long wavelength end, the OTA was not designed with optimum IR performance in mind—for example, the mirrors are kept at stable (and warm, about 15 °C) temperatures by heaters. This limits Hubble’s performance as an infrared telescope.

    Perkin-Elmer intended to use custom-built and extremely sophisticated computer-controlled polishing machines to grind the mirror to the required shape. However, in case their cutting-edge technology ran into difficulties, NASA demanded that PE sub-contract to Kodak to construct a back-up mirror using traditional mirror-polishing techniques. (The team of Kodak and Itek also bid on the original mirror polishing work. Their bid called for the two companies to double-check each other’s work, which would have almost certainly caught the polishing error that later caused such problems.) The Kodak mirror is now on permanent display at the National Air and Space Museum. An Itek mirror built as part of the effort is now used in the 2.4 m telescope at the Magdalena Ridge Observatory.

    Construction of the Perkin-Elmer mirror began in 1979, starting with a blank manufactured by Corning from their ultra-low expansion glass. To keep the mirror’s weight to a minimum it consisted of top and bottom plates, each one inch (25 mm) thick, sandwiching a honeycomb lattice. Perkin-Elmer simulated microgravity by supporting the mirror from the back with 130 rods that exerted varying amounts of force. This ensured the mirror’s final shape would be correct and to specification when finally deployed. Mirror polishing continued until May 1981. NASA reports at the time questioned Perkin-Elmer’s managerial structure, and the polishing began to slip behind schedule and over budget. To save money, NASA halted work on the back-up mirror and put the launch date of the telescope back to October 1984. The mirror was completed by the end of 1981; it was washed using 2,400 US gallons (9,100 L) of hot, deionized water and then received a reflective coating of 65 nm-thick aluminum and a protective coating of 25 nm-thick magnesium fluoride.

    Doubts continued to be expressed about Perkin-Elmer’s competence on a project of this importance, as their budget and timescale for producing the rest of the OTA continued to inflate. In response to a schedule described as “unsettled and changing daily”, NASA postponed the launch date of the telescope until April 1985. Perkin-Elmer’s schedules continued to slip at a rate of about one month per quarter, and at times delays reached one day for each day of work. NASA was forced to postpone the launch date until March and then September 1986. By this time, the total project budget had risen to US$1.175 billion.

    Spacecraft systems

    The spacecraft in which the telescope and instruments were to be housed was another major engineering challenge. It would have to withstand frequent passages from direct sunlight into the darkness of Earth’s shadow, which would cause major changes in temperature, while being stable enough to allow extremely accurate pointing of the telescope. A shroud of multi-layer insulation keeps the temperature within the telescope stable and surrounds a light aluminum shell in which the telescope and instruments sit. Within the shell, a graphite-epoxy frame keeps the working parts of the telescope firmly aligned. Because graphite composites are hygroscopic, there was a risk that water vapor absorbed by the truss while in Lockheed’s clean room would later be expressed in the vacuum of space; resulting in the telescope’s instruments being covered by ice. To reduce that risk, a nitrogen gas purge was performed before launching the telescope into space.

    While construction of the spacecraft in which the telescope and instruments would be housed proceeded somewhat more smoothly than the construction of the OTA, Lockheed still experienced some budget and schedule slippage, and by the summer of 1985, construction of the spacecraft was 30% over budget and three months behind schedule. An MSFC report said Lockheed tended to rely on NASA directions rather than take their own initiative in the construction.

    Computer systems and data processing

    The two initial, primary computers on the HST were the 1.25 MHz DF-224 system, built by Rockwell Autonetics, which contained three redundant CPUs, and two redundant NSSC-1 (NASA Standard Spacecraft Computer, Model 1) systems, developed by Westinghouse and GSFC using diode–transistor logic (DTL). A co-processor for the DF-224 was added during Servicing Mission 1 in 1993, which consisted of two redundant strings of an Intel-based 80386 processor with an 80387 math co-processor. The DF-224 and its 386 co-processor were replaced by a 25 MHz Intel-based 80486 processor system during Servicing Mission 3A in 1999. The new computer is 20 times faster, with six times more memory, than the DF-224 it replaced. It increases throughput by moving some computing tasks from the ground to the spacecraft and saves money by allowing the use of modern programming languages.

    Additionally, some of the science instruments and components had their own embedded microprocessor-based control systems. The MATs (Multiple Access Transponder) components, MAT-1 and MAT-2, utilize Hughes Aircraft CDP1802CD microprocessors. The Wide Field and Planetary Camera (WFPC) also utilized an RCA 1802 microprocessor (or possibly the older 1801 version). The WFPC-1 was replaced by the WFPC-2 [below] during Servicing Mission 1 in 1993, which was then replaced by the Wide Field Camera 3 (WFC3) [below] during Servicing Mission 4 in 2009.

    Initial instruments

    When launched, the HST carried five scientific instruments: the Wide Field and Planetary Camera (WF/PC), Goddard High Resolution Spectrograph (GHRS), High Speed Photometer (HSP), Faint Object Camera (FOC) and the Faint Object Spectrograph (FOS). WF/PC was a high-resolution imaging device primarily intended for optical observations. It was built by NASA JPL-Caltech(US), and incorporated a set of 48 filters isolating spectral lines of particular astrophysical interest. The instrument contained eight charge-coupled device (CCD) chips divided between two cameras, each using four CCDs. Each CCD has a resolution of 0.64 megapixels. The wide field camera (WFC) covered a large angular field at the expense of resolution, while the planetary camera (PC) took images at a longer effective focal length than the WF chips, giving it a greater magnification.

    The GHRS was a spectrograph designed to operate in the ultraviolet. It was built by the Goddard Space Flight Center and could achieve a spectral resolution of 90,000. Also optimized for ultraviolet observations were the FOC and FOS, which were capable of the highest spatial resolution of any instruments on Hubble. Rather than CCDs these three instruments used photon-counting digicons as their detectors. The FOC was constructed by ESA, while the University of California, San Diego(US), and Martin Marietta Corporation built the FOS.

    The final instrument was the HSP, designed and built at the University of Wisconsin–Madison(US). It was optimized for visible and ultraviolet light observations of variable stars and other astronomical objects varying in brightness. It could take up to 100,000 measurements per second with a photometric accuracy of about 2% or better.

    HST’s guidance system can also be used as a scientific instrument. Its three Fine Guidance Sensors (FGS) are primarily used to keep the telescope accurately pointed during an observation, but can also be used to carry out extremely accurate astrometry; measurements accurate to within 0.0003 arcseconds have been achieved.

    Ground support

    The Space Telescope Science Institute (STScI) is responsible for the scientific operation of the telescope and the delivery of data products to astronomers. STScI is operated by the Association of Universities for Research in Astronomy(US) (AURA) and is physically located in Baltimore, Maryland on the Homewood campus of Johns Hopkins University(US), one of the 39 U.S. universities and seven international affiliates that make up the AURA consortium. STScI was established in 1981 after something of a power struggle between NASA and the scientific community at large. NASA had wanted to keep this function in-house, but scientists wanted it to be based in an academic establishment. The Space Telescope European Coordinating Facility (ST-ECF), established at Garching bei München near Munich in 1984, provided similar support for European astronomers until 2011, when these activities were moved to the European Space Astronomy Centre.

    One rather complex task that falls to STScI is scheduling observations for the telescope. Hubble is in a low-Earth orbit to enable servicing missions, but this means most astronomical targets are occulted by the Earth for slightly less than half of each orbit. Observations cannot take place when the telescope passes through the South Atlantic Anomaly due to elevated radiation levels, and there are also sizable exclusion zones around the Sun (precluding observations of Mercury), Moon and Earth. The solar avoidance angle is about 50°, to keep sunlight from illuminating any part of the OTA. Earth and Moon avoidance keeps bright light out of the FGSs, and keeps scattered light from entering the instruments. If the FGSs are turned off, the Moon and Earth can be observed. Earth observations were used very early in the program to generate flat-fields for the WFPC1 instrument. There is a so-called continuous viewing zone (CVZ), at roughly 90° to the plane of Hubble’s orbit, in which targets are not occulted for long periods.

    Challenger disaster, delays, and eventual launch

    By January 1986, the planned launch date of October looked feasible, but the Challenger explosion brought the U.S. space program to a halt, grounding the Shuttle fleet and forcing the launch of Hubble to be postponed for several years. The telescope had to be kept in a clean room, powered up and purged with nitrogen, until a launch could be rescheduled. This costly situation (about US$6 million per month) pushed the overall costs of the project even higher. This delay did allow time for engineers to perform extensive tests, swap out a possibly failure-prone battery, and make other improvements. Furthermore, the ground software needed to control Hubble was not ready in 1986, and was barely ready by the 1990 launch.

    Eventually, following the resumption of shuttle flights in 1988, the launch of the telescope was scheduled for 1990. On April 24, 1990, Space Shuttle Discovery successfully launched it during the STS-31 mission.

    From its original total cost estimate of about US$400 million, the telescope cost about US$4.7 billion by the time of its launch. Hubble’s cumulative costs were estimated to be about US$10 billion in 2010, twenty years after launch.

    List of Hubble instruments

    Hubble accommodates five science instruments at a given time, plus the Fine Guidance Sensors, which are mainly used for aiming the telescope but are occasionally used for scientific astrometry measurements. Early instruments were replaced with more advanced ones during the Shuttle servicing missions. COSTAR was a corrective optics device rather than a science instrument, but occupied one of the five instrument bays.
    Since the final servicing mission in 2009, the four active instruments have been ACS, COS, STIS and WFC3. NICMOS is kept in hibernation, but may be revived if WFC3 were to fail in the future.

    Advanced Camera for Surveys (ACS; 2002–present)
    Cosmic Origins Spectrograph (COS; 2009–present)
    Corrective Optics Space Telescope Axial Replacement (COSTAR; 1993–2009)
    Faint Object Camera (FOC; 1990–2002)
    Faint Object Spectrograph (FOS; 1990–1997)
    Fine Guidance Sensor (FGS; 1990–present)
    Goddard High Resolution Spectrograph (GHRS/HRS; 1990–1997)
    High Speed Photometer (HSP; 1990–1993)
    Near Infrared Camera and Multi-Object Spectrometer (NICMOS; 1997–present, hibernating since 2008)
    Space Telescope Imaging Spectrograph (STIS; 1997–present (non-operative 2004–2009))
    Wide Field and Planetary Camera (WFPC; 1990–1993)
    Wide Field and Planetary Camera 2 (WFPC2; 1993–2009)
    Wide Field Camera 3 (WFC3; 2009–present)

    Of the former instruments, three (COSTAR, FOS and WFPC2) are displayed in the Smithsonian National Air and Space Museum. The FOC is in the Dornier museum, Germany. The HSP is in the Space Place at the University of Wisconsin–Madison. The first WFPC was dismantled, and some components were then re-used in WFC3.

    Flawed mirror

    Within weeks of the launch of the telescope, the returned images indicated a serious problem with the optical system. Although the first images appeared to be sharper than those of ground-based telescopes, Hubble failed to achieve a final sharp focus and the best image quality obtained was drastically lower than expected. Images of point sources spread out over a radius of more than one arcsecond, instead of having a point spread function (PSF) concentrated within a circle 0.1 arcseconds (485 nrad) in diameter, as had been specified in the design criteria.

    Analysis of the flawed images revealed that the primary mirror had been polished to the wrong shape. Although it was believed to be one of the most precisely figured optical mirrors ever made, smooth to about 10 nanometers, the outer perimeter was too flat by about 2200 nanometers (about 1⁄450 mm or 1⁄11000 inch). This difference was catastrophic, introducing severe spherical aberration, a flaw in which light reflecting off the edge of a mirror focuses on a different point from the light reflecting off its center.

    The effect of the mirror flaw on scientific observations depended on the particular observation—the core of the aberrated PSF was sharp enough to permit high-resolution observations of bright objects, and spectroscopy of point sources was affected only through a sensitivity loss. However, the loss of light to the large, out-of-focus halo severely reduced the usefulness of the telescope for faint objects or high-contrast imaging. This meant nearly all the cosmological programs were essentially impossible, since they required observation of exceptionally faint objects. This led politicians to question NASA’s competence, scientists to rue the cost which could have gone to more productive endeavors, and comedians to make jokes about NASA and the telescope − in the 1991 comedy The Naked Gun 2½: The Smell of Fear, in a scene where historical disasters are displayed, Hubble is pictured with RMS Titanic and LZ 129 Hindenburg. Nonetheless, during the first three years of the Hubble mission, before the optical corrections, the telescope still carried out a large number of productive observations of less demanding targets. The error was well characterized and stable, enabling astronomers to partially compensate for the defective mirror by using sophisticated image processing techniques such as deconvolution.

    Origin of the problem

    A commission headed by Lew Allen, director of the Jet Propulsion Laboratory, was established to determine how the error could have arisen. The Allen Commission found that a reflective null corrector, a testing device used to achieve a properly shaped non-spherical mirror, had been incorrectly assembled—one lens was out of position by 1.3 mm (0.051 in). During the initial grinding and polishing of the mirror, Perkin-Elmer analyzed its surface with two conventional refractive null correctors. However, for the final manufacturing step (figuring), they switched to the custom-built reflective null corrector, designed explicitly to meet very strict tolerances. The incorrect assembly of this device resulted in the mirror being ground very precisely but to the wrong shape. A few final tests, using the conventional null correctors, correctly reported spherical aberration. But these results were dismissed, thus missing the opportunity to catch the error, because the reflective null corrector was considered more accurate.

    The commission blamed the failings primarily on Perkin-Elmer. Relations between NASA and the optics company had been severely strained during the telescope construction, due to frequent schedule slippage and cost overruns. NASA found that Perkin-Elmer did not review or supervise the mirror construction adequately, did not assign its best optical scientists to the project (as it had for the prototype), and in particular did not involve the optical designers in the construction and verification of the mirror. While the commission heavily criticized Perkin-Elmer for these managerial failings, NASA was also criticized for not picking up on the quality control shortcomings, such as relying totally on test results from a single instrument.

    Design of a solution

    Many feared that Hubble would be abandoned. The design of the telescope had always incorporated servicing missions, and astronomers immediately began to seek potential solutions to the problem that could be applied at the first servicing mission, scheduled for 1993. While Kodak had ground a back-up mirror for Hubble, it would have been impossible to replace the mirror in orbit, and too expensive and time-consuming to bring the telescope back to Earth for a refit. Instead, the fact that the mirror had been ground so precisely to the wrong shape led to the design of new optical components with exactly the same error but in the opposite sense, to be added to the telescope at the servicing mission, effectively acting as “spectacles” to correct the spherical aberration.

    The first step was a precise characterization of the error in the main mirror. Working backwards from images of point sources, astronomers determined that the conic constant of the mirror as built was −1.01390±0.0002, instead of the intended −1.00230. The same number was also derived by analyzing the null corrector used by Perkin-Elmer to figure the mirror, as well as by analyzing interferograms obtained during ground testing of the mirror.

    Because of the way the HST’s instruments were designed, two different sets of correctors were required. The design of the Wide Field and Planetary Camera 2, already planned to replace the existing WF/PC, included relay mirrors to direct light onto the four separate charge-coupled device (CCD) chips making up its two cameras. An inverse error built into their surfaces could completely cancel the aberration of the primary. However, the other instruments lacked any intermediate surfaces that could be figured in this way, and so required an external correction device.

    The Corrective Optics Space Telescope Axial Replacement (COSTAR) system was designed to correct the spherical aberration for light focused at the FOC, FOS, and GHRS. It consists of two mirrors in the light path with one ground to correct the aberration. To fit the COSTAR system onto the telescope, one of the other instruments had to be removed, and astronomers selected the High Speed Photometer to be sacrificed. By 2002, all the original instruments requiring COSTAR had been replaced by instruments with their own corrective optics. COSTAR was removed and returned to Earth in 2009 where it is exhibited at the National Air and Space Museum. The area previously used by COSTAR is now occupied by the Cosmic Origins Spectrograph.

    Servicing missions and new instruments

    Servicing Mission 1

    The first Hubble serving mission was scheduled for 1993 before the mirror problem was discovered. It assumed greater importance, as the astronauts would need to do extensive work to install corrective optics; failure would have resulted in either abandoning Hubble or accepting its permanent disability. Other components failed before the mission, causing the repair cost to rise to $500 million (not including the cost of the shuttle flight). A successful repair would help demonstrate the viability of building Space Station Alpha, however.

    STS-49 in 1992 demonstrated the difficulty of space work. While its rescue of Intelsat 603 received praise, the astronauts had taken possibly reckless risks in doing so. Neither the rescue nor the unrelated assembly of prototype space station components occurred as the astronauts had trained, causing NASA to reassess planning and training, including for the Hubble repair. The agency assigned to the mission Story Musgrave—who had worked on satellite repair procedures since 1976—and six other experienced astronauts, including two from STS-49. The first mission director since Project Apollo would coordinate a crew with 16 previous shuttle flights. The astronauts were trained to use about a hundred specialized tools.

    Heat had been the problem on prior spacewalks, which occurred in sunlight. Hubble needed to be repaired out of sunlight. Musgrave discovered during vacuum training, seven months before the mission, that spacesuit gloves did not sufficiently protect against the cold of space. After STS-57 confirmed the issue in orbit, NASA quickly changed equipment, procedures, and flight plan. Seven total mission simulations occurred before launch, the most thorough preparation in shuttle history. No complete Hubble mockup existed, so the astronauts studied many separate models (including one at the Smithsonian) and mentally combined their varying and contradictory details. Service Mission 1 flew aboard Endeavour in December 1993, and involved installation of several instruments and other equipment over ten days.

    Most importantly, the High Speed Photometer was replaced with the COSTAR corrective optics package, and WFPC was replaced with the Wide Field and Planetary Camera 2 (WFPC2) with an internal optical correction system. The solar arrays and their drive electronics were also replaced, as well as four gyroscopes in the telescope pointing system, two electrical control units and other electrical components, and two magnetometers. The onboard computers were upgraded with added coprocessors, and Hubble’s orbit was boosted.

    On January 13, 1994, NASA declared the mission a complete success and showed the first sharper images. The mission was one of the most complex performed up until that date, involving five long extra-vehicular activity periods. Its success was a boon for NASA, as well as for the astronomers who now had a more capable space telescope.

    Servicing Mission 2

    Servicing Mission 2, flown by Discovery in February 1997, replaced the GHRS and the FOS with the Space Telescope Imaging Spectrograph (STIS) and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS), replaced an Engineering and Science Tape Recorder with a new Solid State Recorder, and repaired thermal insulation. NICMOS contained a heat sink of solid nitrogen to reduce the thermal noise from the instrument, but shortly after it was installed, an unexpected thermal expansion resulted in part of the heat sink coming into contact with an optical baffle. This led to an increased warming rate for the instrument and reduced its original expected lifetime of 4.5 years to about two years.

    Servicing Mission 3A

    Servicing Mission 3A, flown by Discovery, took place in December 1999, and was a split-off from Servicing Mission 3 after three of the six onboard gyroscopes had failed. The fourth failed a few weeks before the mission, rendering the telescope incapable of performing scientific observations. The mission replaced all six gyroscopes, replaced a Fine Guidance Sensor and the computer, installed a Voltage/temperature Improvement Kit (VIK) to prevent battery overcharging, and replaced thermal insulation blankets.

    Servicing Mission 3B

    Servicing Mission 3B flown by Columbia in March 2002 saw the installation of a new instrument, with the FOC (which, except for the Fine Guidance Sensors when used for astrometry, was the last of the original instruments) being replaced by the Advanced Camera for Surveys (ACS). This meant COSTAR was no longer required, since all new instruments had built-in correction for the main mirror aberration. The mission also revived NICMOS by installing a closed-cycle cooler and replaced the solar arrays for the second time, providing 30 percent more power.

    Servicing Mission 4

    Plans called for Hubble to be serviced in February 2005, but the Columbia disaster in 2003, in which the orbiter disintegrated on re-entry into the atmosphere, had wide-ranging effects on the Hubble program. NASA Administrator Sean O’Keefe decided all future shuttle missions had to be able to reach the safe haven of the International Space Station should in-flight problems develop. As no shuttles were capable of reaching both HST and the space station during the same mission, future crewed service missions were canceled. This decision was criticised by numerous astronomers who felt Hubble was valuable enough to merit the human risk. HST’s planned successor, the James Webb Telescope (JWST), as of 2004 was not expected to launch until at least 2011. A gap in space-observing capabilities between a decommissioning of Hubble and the commissioning of a successor was of major concern to many astronomers, given the significant scientific impact of HST. The consideration that JWST will not be located in low Earth orbit, and therefore cannot be easily upgraded or repaired in the event of an early failure, only made concerns more acute. On the other hand, many astronomers felt strongly that servicing Hubble should not take place if the expense were to come from the JWST budget.

    In January 2004, O’Keefe said he would review his decision to cancel the final servicing mission to HST, due to public outcry and requests from Congress for NASA to look for a way to save it. The National Academy of Sciences convened an official panel, which recommended in July 2004 that the HST should be preserved despite the apparent risks. Their report urged “NASA should take no actions that would preclude a space shuttle servicing mission to the Hubble Space Telescope”. In August 2004, O’Keefe asked Goddard Space Flight Center to prepare a detailed proposal for a robotic service mission. These plans were later canceled, the robotic mission being described as “not feasible”. In late 2004, several Congressional members, led by Senator Barbara Mikulski, held public hearings and carried on a fight with much public support (including thousands of letters from school children across the U.S.) to get the Bush Administration and NASA to reconsider the decision to drop plans for a Hubble rescue mission.

    The nomination in April 2005 of a new NASA Administrator, Michael D. Griffin, changed the situation, as Griffin stated he would consider a crewed servicing mission. Soon after his appointment Griffin authorized Goddard to proceed with preparations for a crewed Hubble maintenance flight, saying he would make the final decision after the next two shuttle missions. In October 2006 Griffin gave the final go-ahead, and the 11-day mission by Atlantis was scheduled for October 2008. Hubble’s main data-handling unit failed in September 2008, halting all reporting of scientific data until its back-up was brought online on October 25, 2008. Since a failure of the backup unit would leave the HST helpless, the service mission was postponed to incorporate a replacement for the primary unit.

    Servicing Mission 4 (SM4), flown by Atlantis in May 2009, was the last scheduled shuttle mission for HST. SM4 installed the replacement data-handling unit, repaired the ACS and STIS systems, installed improved nickel hydrogen batteries, and replaced other components including all six gyroscopes. SM4 also installed two new observation instruments—Wide Field Camera 3 (WFC3) and the Cosmic Origins Spectrograph (COS)—and the Soft Capture and Rendezvous System, which will enable the future rendezvous, capture, and safe disposal of Hubble by either a crewed or robotic mission. Except for the ACS’s High Resolution Channel, which could not be repaired and was disabled, the work accomplished during SM4 rendered the telescope fully functional.

    Major projects

    Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey [CANDELS]

    The survey “aims to explore galactic evolution in the early Universe, and the very first seeds of cosmic structure at less than one billion years after the Big Bang.” The CANDELS project site describes the survey’s goals as the following:

    The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey is designed to document the first third of galactic evolution from z = 8 to 1.5 via deep imaging of more than 250,000 galaxies with WFC3/IR and ACS. It will also find the first Type Ia SNe beyond z > 1.5 and establish their accuracy as standard candles for cosmology. Five premier multi-wavelength sky regions are selected; each has multi-wavelength data from Spitzer and other facilities, and has extensive spectroscopy of the brighter galaxies. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to 109 solar masses out to z ~ 8.

    Frontier Fields program

    The program, officially named Hubble Deep Fields Initiative 2012, is aimed to advance the knowledge of early galaxy formation by studying high-redshift galaxies in blank fields with the help of gravitational lensing to see the “faintest galaxies in the distant universe”. The Frontier Fields web page describes the goals of the program being:

    To reveal hitherto inaccessible populations of z = 5–10 galaxies that are ten to fifty times fainter intrinsically than any presently known
    To solidify our understanding of the stellar masses and star formation histories of sub-L* galaxies at the earliest times
    To provide the first statistically meaningful morphological characterization of star forming galaxies at z > 5
    To find z > 8 galaxies stretched out enough by cluster lensing to discern internal structure and/or magnified enough by cluster lensing for spectroscopic follow-up.

    Cosmic Evolution Survey (COSMOS)

    The Cosmic Evolution Survey (COSMOS) is an astronomical survey designed to probe the formation and evolution of galaxies as a function of both cosmic time (redshift) and the local galaxy environment. The survey covers a two square degree equatorial field with spectroscopy and X-ray to radio imaging by most of the major space-based telescopes and a number of large ground based telescopes, making it a key focus region of extragalactic astrophysics. COSMOS was launched in 2006 as the largest project pursued by the Hubble Space Telescope at the time, and still is the largest continuous area of sky covered for the purposes of mapping deep space in blank fields, 2.5 times the area of the moon on the sky and 17 times larger than the largest of the CANDELS regions. The COSMOS scientific collaboration that was forged from the initial COSMOS survey is the largest and longest-running extragalactic collaboration, known for its collegiality and openness. The study of galaxies in their environment can be done only with large areas of the sky, larger than a half square degree. More than two million galaxies are detected, spanning 90% of the age of the Universe. The COSMOS collaboration is led by Caitlin Casey, Jeyhan Kartaltepe, and Vernesa Smolcic and involves more than 200 scientists in a dozen countries.

    Important discoveries

    Hubble has helped resolve some long-standing problems in astronomy, while also raising new questions. Some results have required new theories to explain them.

    Age of the universe

    Among its primary mission targets was to measure distances to Cepheid variable stars more accurately than ever before, and thus constrain the value of the Hubble constant, the measure of the rate at which the universe is expanding, which is also related to its age. Before the launch of HST, estimates of the Hubble constant typically had errors of up to 50%, but Hubble measurements of Cepheid variables in the Virgo Cluster and other distant galaxy clusters provided a measured value with an accuracy of ±10%, which is consistent with other more accurate measurements made since Hubble’s launch using other techniques. The estimated age is now about 13.7 billion years, but before the Hubble Telescope, scientists predicted an age ranging from 10 to 20 billion years.

    Expansion of the universe

    While Hubble helped to refine estimates of the age of the universe, it also cast doubt on theories about its future. Astronomers from the High-z Supernova Search Team and the Supernova Cosmology Project used ground-based telescopes and HST to observe distant supernovae and uncovered evidence that, far from decelerating under the influence of gravity, the expansion of the universe may in fact be accelerating. Three members of these two groups have subsequently been awarded Nobel Prizes for their discovery.

    Saul Perlmutter [The Supernova Cosmology Project] shared the 2006 Shaw Prize in Astronomy, the 2011 Nobel Prize in Physics, and the 2015 Breakthrough Prize in Fundamental Physics with Brian P. Schmidt and Adam Riess [The High-z Supernova Search Team] for providing evidence that the expansion of the universe is accelerating.

    The cause of this acceleration remains poorly understood; the most common cause attributed is Dark Energy.

    Black holes

    The high-resolution spectra and images provided by the HST have been especially well-suited to establishing the prevalence of black holes in the center of nearby galaxies. While it had been hypothesized in the early 1960s that black holes would be found at the centers of some galaxies, and astronomers in the 1980s identified a number of good black hole candidates, work conducted with Hubble shows that black holes are probably common to the centers of all galaxies. The Hubble programs further established that the masses of the nuclear black holes and properties of the galaxies are closely related. The legacy of the Hubble programs on black holes in galaxies is thus to demonstrate a deep connection between galaxies and their central black holes.

    Extending visible wavelength images

    A unique window on the Universe enabled by Hubble are the Hubble Deep Field, Hubble Ultra-Deep Field, and Hubble Extreme Deep Field images, which used Hubble’s unmatched sensitivity at visible wavelengths to create images of small patches of sky that are the deepest ever obtained at optical wavelengths. The images reveal galaxies billions of light years away, and have generated a wealth of scientific papers, providing a new window on the early Universe. The Wide Field Camera 3 improved the view of these fields in the infrared and ultraviolet, supporting the discovery of some of the most distant objects yet discovered, such as MACS0647-JD.

    The non-standard object SCP 06F6 was discovered by the Hubble Space Telescope in February 2006.

    On March 3, 2016, researchers using Hubble data announced the discovery of the farthest known galaxy to date: GN-z11. The Hubble observations occurred on February 11, 2015, and April 3, 2015, as part of the CANDELS/GOODS-North surveys.

    Solar System discoveries

    HST has also been used to study objects in the outer reaches of the Solar System, including the dwarf planets Pluto and Eris.

    The collision of Comet Shoemaker-Levy 9 with Jupiter in 1994 was fortuitously timed for astronomers, coming just a few months after Servicing Mission 1 had restored Hubble’s optical performance. Hubble images of the planet were sharper than any taken since the passage of Voyager 2 in 1979, and were crucial in studying the dynamics of the collision of a comet with Jupiter, an event believed to occur once every few centuries.

    During June and July 2012, U.S. astronomers using Hubble discovered Styx, a tiny fifth moon orbiting Pluto.

    In March 2015, researchers announced that measurements of aurorae around Ganymede, one of Jupiter’s moons, revealed that it has a subsurface ocean. Using Hubble to study the motion of its aurorae, the researchers determined that a large saltwater ocean was helping to suppress the interaction between Jupiter’s magnetic field and that of Ganymede. The ocean is estimated to be 100 km (60 mi) deep, trapped beneath a 150 km (90 mi) ice crust.

    From June to August 2015, Hubble was used to search for a Kuiper belt object (KBO) target for the New Horizons Kuiper Belt Extended Mission (KEM) when similar searches with ground telescopes failed to find a suitable target.

    This resulted in the discovery of at least five new KBOs, including the eventual KEM target, 486958 Arrokoth, that New Horizons performed a close fly-by of on January 1, 2019.

    In August 2020, taking advantage of a total lunar eclipse, astronomers using NASA’s Hubble Space Telescope have detected Earth’s own brand of sunscreen – ozone – in our atmosphere. This method simulates how astronomers and astrobiology researchers will search for evidence of life beyond Earth by observing potential “biosignatures” on exoplanets (planets around other stars).
    Hubble and ALMA image of MACS J1149.5+2223.

    Supernova reappearance

    On December 11, 2015, Hubble captured an image of the first-ever predicted reappearance of a supernova, dubbed “Refsdal”, which was calculated using different mass models of a galaxy cluster whose gravity is warping the supernova’s light. The supernova was previously seen in November 2014 behind galaxy cluster MACS J1149.5+2223 as part of Hubble’s Frontier Fields program. Astronomers spotted four separate images of the supernova in an arrangement known as an “Einstein Cross”.

    The light from the cluster has taken about five billion years to reach Earth, though the supernova exploded some 10 billion years ago. Based on early lens models, a fifth image was predicted to reappear by the end of 2015. The detection of Refsdal’s reappearance in December 2015 served as a unique opportunity for astronomers to test their models of how mass, especially dark matter, is distributed within this galaxy cluster.

    Impact on astronomy

    Many objective measures show the positive impact of Hubble data on astronomy. Over 15,000 papers based on Hubble data have been published in peer-reviewed journals, and countless more have appeared in conference proceedings. Looking at papers several years after their publication, about one-third of all astronomy papers have no citations, while only two percent of papers based on Hubble data have no citations. On average, a paper based on Hubble data receives about twice as many citations as papers based on non-Hubble data. Of the 200 papers published each year that receive the most citations, about 10% are based on Hubble data.

    Although the HST has clearly helped astronomical research, its financial cost has been large. A study on the relative astronomical benefits of different sizes of telescopes found that while papers based on HST data generate 15 times as many citations as a 4 m (13 ft) ground-based telescope such as the William Herschel Telescope, the HST costs about 100 times as much to build and maintain.

    Deciding between building ground- versus space-based telescopes is complex. Even before Hubble was launched, specialized ground-based techniques such as aperture masking interferometry had obtained higher-resolution optical and infrared images than Hubble would achieve, though restricted to targets about 108 times brighter than the faintest targets observed by Hubble. Since then, advances in “adaptive optics” have extended the high-resolution imaging capabilities of ground-based telescopes to the infrared imaging of faint objects.

    The usefulness of adaptive optics versus HST observations depends strongly on the particular details of the research questions being asked. In the visible bands, adaptive optics can correct only a relatively small field of view, whereas HST can conduct high-resolution optical imaging over a wide field. Only a small fraction of astronomical objects are accessible to high-resolution ground-based imaging; in contrast Hubble can perform high-resolution observations of any part of the night sky, and on objects that are extremely faint.

    Impact on aerospace engineering

    In addition to its scientific results, Hubble has also made significant contributions to aerospace engineering, in particular the performance of systems in low Earth orbit. These insights result from Hubble’s long lifetime on orbit, extensive instrumentation, and return of assemblies to the Earth where they can be studied in detail. In particular, Hubble has contributed to studies of the behavior of graphite composite structures in vacuum, optical contamination from residual gas and human servicing, radiation damage to electronics and sensors, and the long term behavior of multi-layer insulation. One lesson learned was that gyroscopes assembled using pressurized oxygen to deliver suspension fluid were prone to failure due to electric wire corrosion. Gyroscopes are now assembled using pressurized nitrogen. Another is that optical surfaces in LEO can have surprisingly long lifetimes; Hubble was only expected to last 15 years before the mirror became unusable, but after 14 years there was no measureable degradation. Finally, Hubble servicing missions, particularly those that serviced components not designed for in-space maintenance, have contributed towards the development of new tools and techniques for on-orbit repair.

    Archives

    All Hubble data is eventually made available via the Mikulski Archive for Space Telescopes at STScI, CADC and ESA/ESAC. Data is usually proprietary—available only to the principal investigator (PI) and astronomers designated by the PI—for twelve months after being taken. The PI can apply to the director of the STScI to extend or reduce the proprietary period in some circumstances.

    Observations made on Director’s Discretionary Time are exempt from the proprietary period, and are released to the public immediately. Calibration data such as flat fields and dark frames are also publicly available straight away. All data in the archive is in the FITS format, which is suitable for astronomical analysis but not for public use. The Hubble Heritage Project processes and releases to the public a small selection of the most striking images in JPEG and TIFF formats.

    Outreach activities

    It has always been important for the Space Telescope to capture the public’s imagination, given the considerable contribution of taxpayers to its construction and operational costs. After the difficult early years when the faulty mirror severely dented Hubble’s reputation with the public, the first servicing mission allowed its rehabilitation as the corrected optics produced numerous remarkable images.

    Several initiatives have helped to keep the public informed about Hubble activities. In the United States, outreach efforts are coordinated by the Space Telescope Science Institute (STScI) Office for Public Outreach, which was established in 2000 to ensure that U.S. taxpayers saw the benefits of their investment in the space telescope program. To that end, STScI operates the HubbleSite.org website. The Hubble Heritage Project, operating out of the STScI, provides the public with high-quality images of the most interesting and striking objects observed. The Heritage team is composed of amateur and professional astronomers, as well as people with backgrounds outside astronomy, and emphasizes the aesthetic nature of Hubble images. The Heritage Project is granted a small amount of time to observe objects which, for scientific reasons, may not have images taken at enough wavelengths to construct a full-color image.

    Since 1999, the leading Hubble outreach group in Europe has been the Hubble European Space Agency Information Centre (HEIC). This office was established at the Space Telescope European Coordinating Facility in Munich, Germany. HEIC’s mission is to fulfill HST outreach and education tasks for the European Space Agency. The work is centered on the production of news and photo releases that highlight interesting Hubble results and images. These are often European in origin, and so increase awareness of both ESA’s Hubble share (15%) and the contribution of European scientists to the observatory. ESA produces educational material, including a videocast series called Hubblecast designed to share world-class scientific news with the public.

    The Hubble Space Telescope has won two Space Achievement Awards from the Space Foundation, for its outreach activities, in 2001 and 2010.

    A replica of the Hubble Space Telescope is on the courthouse lawn in Marshfield, Missouri, the hometown of namesake Edwin P. Hubble.

    Major Instrumentation

    Hubble WFPC2 no longer in service.

    Wide Field Camera 3 [WFC3]

    Advanced Camera for Surveys [ACS]

    Cosmic Origins Spectrograph [COS]

    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

    ESA50 Logo large


    NASA/Goddard Campus

    NASA’s Goddard Space Flight Center, Greenbelt, MD (US) is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    GSFC also operates two spaceflight tracking and data acquisition networks (the NASA Deep Space Network(US) and the Near Earth Network); develops and maintains advanced space and Earth science data information systems, and develops satellite systems for the National Oceanic and Atmospheric Administration(US) .

    GSFC manages operations for many NASA and international missions including the NASA/ESA Hubble Space Telescope; the Explorers Program; the Discovery Program; the Earth Observing System; INTEGRAL; MAVEN; OSIRIS-REx; the Solar and Heliospheric Observatory ; the Solar Dynamics Observatory; Tracking and Data Relay Satellite System ; Fermi; and Swift. Past missions managed by GSFC include the Rossi X-ray Timing Explorer (RXTE), Compton Gamma Ray Observatory, SMM, COBE, IUE, and ROSAT. Typically, unmanned Earth observation missions and observatories in Earth orbit are managed by GSFC, while unmanned planetary missions are managed by the Jet Propulsion Laboratory (JPL) in Pasadena, California(US).

    Goddard is one of four centers built by NASA since its founding on July 29, 1958. It is NASA’s first, and oldest, space center. Its original charter was to perform five major functions on behalf of NASA: technology development and fabrication; planning; scientific research; technical operations; and project management. The center is organized into several directorates, each charged with one of these key functions.

    Until May 1, 1959, NASA’s presence in Greenbelt, MD was known as the Beltsville Space Center. It was then renamed the Goddard Space Flight Center (GSFC), after Robert H. Goddard. Its first 157 employees transferred from the United States Navy’s Project Vanguard missile program, but continued their work at the Naval Research Laboratory in Washington, D.C., while the center was under construction.

    Goddard Space Flight Center contributed to Project Mercury, America’s first manned space flight program. The Center assumed a lead role for the project in its early days and managed the first 250 employees involved in the effort, who were stationed at Langley Research Center in Hampton, Virginia. However, the size and scope of Project Mercury soon prompted NASA to build a new Manned Spacecraft Center, now the Johnson Space Center, in Houston, Texas. Project Mercury’s personnel and activities were transferred there in 1961.

    The Goddard network tracked many early manned and unmanned spacecraft.

    Goddard Space Flight Center remained involved in the manned space flight program, providing computer support and radar tracking of flights through a worldwide network of ground stations called the Spacecraft Tracking and Data Acquisition Network (STDN). However, the Center focused primarily on designing unmanned satellites and spacecraft for scientific research missions. Goddard pioneered several fields of spacecraft development, including modular spacecraft design, which reduced costs and made it possible to repair satellites in orbit. Goddard’s Solar Max satellite, launched in 1980, was repaired by astronauts on the Space Shuttle Challenger in 1984. The Hubble Space Telescope, launched in 1990, remains in service and continues to grow in capability thanks to its modular design and multiple servicing missions by the Space Shuttle.

    Today, the center remains involved in each of NASA’s key programs. Goddard has developed more instruments for planetary exploration than any other organization, among them scientific instruments sent to every planet in the Solar System. The center’s contribution to the Earth Science Enterprise includes several spacecraft in the Earth Observing System fleet as well as EOSDIS, a science data collection, processing, and distribution system. For the manned space flight program, Goddard develops tools for use by astronauts during extra-vehicular activity, and operates the Lunar Reconnaissance Orbiter, a spacecraft designed to study the Moon in preparation for future manned exploration.

     
  • richardmitnick 1:44 pm on April 17, 2021 Permalink | Reply
    Tags: "NASA’s NICER Probes the Squeezability of Neutron Stars", , , , By measuring the sizes and masses of neutron stars with NICER we are exploring matter on the verge of imploding into a black hole., , J0740 is in a binary star system with a white dwarf., NASA Goddard Space Flight Center, NICER observes rapidly rotating neutron stars called pulsars., , PSR J0740+6620-the most massive known neutron star   

    From NASA Goddard Space Flight Center: “NASA’s NICER Probes the Squeezability of Neutron Stars” 

    NASA Goddard Banner


    Apr 17, 2021

    Jeanette Kazmierczak
    jeanette.a.kazmierczak@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    Media contacts:
    Claire Andreoli
    claire.andreoli@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.
    (301) 286-1940

    Elizabeth Landau
    elizabeth.r.landau@nasa.gov
    NASA Headquarters, Washington
    (202) 358-0845

    From NASA Goddard Space Flight Center

    Matter in the hearts of neutron stars ­– dense remnants of exploded massive stars – takes the most extreme form we can measure. Now, thanks to data from NASA’s Neutron star Interior Composition Explorer (NICER), an X-ray telescope on the International Space Station, scientists have discovered that this mysterious matter is less squeezable than some physicists predicted.

    The finding is based on NICER’s observations of PSR J0740+6620 (J0740 for short), the most massive known neutron star, which lies over 3,600 light-years away in the northern constellation Camelopardalis. J0740 is in a binary star system with a white dwarf, the cooling remnant of a Sun-like star, and rotates 346 times per second. Previous observations place the neutron star’s mass at about 2.1 times the Sun’s.

    “We’re surrounded by normal matter, the stuff of our everyday experience, but there’s much we don’t know about how matter behaves, and how it is transformed, under extreme conditions,” said Zaven Arzoumanian, the NICER science lead at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “By measuring the sizes and masses of neutron stars with NICER we are exploring matter on the verge of imploding into a black hole. Once that happens, we can no longer study matter because it’s hidden by the black hole’s event horizon.”

    Arzoumanian and members of the NICER team presented their findings on Saturday, April 17, at a virtual meeting of the American Physical Society, and papers describing the findings and their implications are now undergoing scientific review.


    NASA’s NICER Tests Matter’s Limits.
    Watch how NASA’s Neutron star Interior Composition Explorer (NICER) is helping physicists peer into the hearts of neutron stars, the remains of massive stars that exploded in supernovae. Scientists want to explore the nature of matter inside these objects, where it exists on the verge of collapsing into black holes. To do so, scientists need precise measurements of neutron stars’ masses and sizes, which NICER and other efforts are now making possible. Credit: NASA’s Goddard Space Flight Center.

    At the end of its life, a star many times heavier than the Sun runs out of fuel in its core, collapses under its own weight, and bursts into a supernova. The heaviest of these exploding stars leave behind black holes. Lighter ones birth neutron stars, which pack more mass than the Sun into a sphere about as wide as New York City’s Manhattan Island is long.

    1
    Scientists think neutron stars are layered. As shown in this illustration, the state of matter in their inner cores remains mysterious. Credit: NASA’s Goddard Space Flight Center/Conceptual Image Lab.

    Scientists think neutron stars are layered. At the surface, a thin atmosphere of hydrogen or helium atoms rests on a solid crust of heavier atoms. In the crust, the rapid increase in pressure strips electrons from atomic nuclei. Deeper down, in the outer core, the nuclei split into neutrons and protons. The immense pressure crushes together protons and electrons to form a sea of mostly neutrons that are eventually packed together at up to twice the density of an atomic nucleus.

    But what form does matter take in the inner core? Is it neutrons all the way down, or do the neutrons break into their own constituent parts, called quarks?

    Physicists have been asking this question since Walter Baade and Fritz Zwicky proposed the existence of neutron stars in 1934. To answer it, astronomers need precise measurements of both the sizes and masses of these objects. This allows them to calculate the relationship between pressure and density in the star’s inner core and evaluate matter’s ultimate squeezability.

    In traditional models of a typical neutron star, one with about 1.4 times the Sun’s mass, physicists expect the inner core to be mostly filled with neutrons. The lower density ensures that neutrons remain far enough apart to stay intact, and this inner stiffness results in a larger star.

    In more massive neutron stars like J0740, the inner core’s density is much higher, crushing the neutrons closer together. It’s unclear whether neutrons can remain intact under these conditions or if they instead break down into quarks. Theorists suspect they shatter under the pressure, but many questions about the details remain. To get answers, scientists need a precise size measurement for a massive neutron star. A smaller star would favor scenarios where quarks roam freely at the innermost depths because the tinier particles can be packed more closely. A larger star would suggest the presence of more complex forms of matter.

    To get the precise measurements needed, NICER observes rapidly rotating neutron stars called pulsars, discovered in 1967 by Jocelyn Bell Burnell.

    Dame Susan Jocelyn Bell Burnell, discovered pulsars with radio astronomy. Jocelyn Bell at the Mullard Radio Astronomy Observatory, University of Cambridge(UK), taken for the Daily Herald newspaper in 1968. Denied the Nobel.

    Bright, X-ray-emitting hot spots form on the surfaces of these objects. As pulsars rotate, their spots spin in and out of view like the beams of a lighthouse, producing regular variations in their X-ray brightness.

    But pulsars are also so dense that their gravity warps nearby space-time, like a bowling ball resting on a trampoline. This distortion is strong enough that it causes light from the star’s far side – light we otherwise could not detect – to be redirected toward us, which makes the pulsar look bigger than it really is. The same mass in a smaller package produces greater distortion. This effect can be so intense that it may prevent the hot spots from disappearing completely as they rotate around the pulsar.

    2
    A neutron star’s gravity warps nearby space-time, like a bowling ball resting on a trampoline. The distortion is strong enough that it redirects light from the star’s far side toward us, which makes the star look bigger than it really is. Credit: NASA’s Goddard Space Flight Center/Chris Smith (Universities Space Research Association/NASA GESTAR [Goddard Earth Science Technology and Research].

    Scientists can take advantage of these effects because NICER measures the arrival of each X-ray to better than 100 nanoseconds. By tracking how the pulsar’s X-ray brightness varies as it spins, scientists can reconstruct how much it distorts space-time. Since they know its mass, they can translate this distortion into a size.

    Two teams used different approaches to model J0740’s size. A group led by Thomas Riley and Anna Watts – a postdoctoral researcher and a professor of astrophysics at the University of Amsterdam [Universiteit van Amsterdam] (NL), respectively – estimate that the pulsar is around 15.4 miles (24.8 kilometers) across. A team led by Cole Miller, a professor of astronomy at the University of Maryland College Park (US), found J0740 to be around 17 miles (27.4 kilometers) wide. The two results overlap significantly within their uncertainties, ranging from 14.2 to 17 miles (22.8 to 27.4 kilometers) and 15.2 to 20.2 miles (24.4 to 32.6 kilometers), respectively.

    In addition to NICER data, both groups also included X-ray observations from the European Space Agency’s XMM-Newton satellite that were helpful in accounting for background noise.

    J0740’s mass was previously determined by radio measurements made by scientists from the North American Nanohertz Observatory for Gravitational Waves (US) and Canadian Hydrogen Intensity Mapping Experiment collaborations (CA).

    In 2019, Riley and Miller’s teams used NICER data to estimate both the size and mass of pulsar J0030+0451 (or J0030). They determined the object was about 1.4 times the Sun’s mass and 16 miles (26 kilometers) across.

    “Our new measurements of J0740 show that even though it’s almost 50% more massive than J0030, it’s essentially the same size,” Watts said. “That challenges some of the more squeezable models of neutron star cores, including versions where the interior is just a sea of quarks. J0740’s size and mass also pose problems for some less squeezable models containing only neutrons and protons.”

    Recent theoretical models propose some alternatives, such as inner cores containing a mix of neutrons, protons, and exotic matter made of quarks or new combinations of quarks. But all possibilities will need to be reevaluated in the context of this new information from NICER.

    “J0740’s size has us theorists baffled and excited,” said Sanjay Reddy, a professor of physics at the University of Washington (US) who studies matter under extreme conditions but was not involved in the finding. “NICER’s measurements, combined with other multimessenger observations, seem to support the idea that pressure increases rapidly in massive neutron star cores. While this disfavors transitions to more squeezable forms of matter in the core, its implications are yet to be fully understood.”

    Miller’s team also determined how well scientists can estimate the size of a pulsar, using NICER’s J0740 and J0030 measurements to supplement existing information from other heavy pulsars and gravitational wave events, space-time ripples generated by the collisions of massive objects like neutron stars and black holes.

    “We now know the radius of a standard neutron star, with 1.4 times the Sun’s mass, within an uncertainty of 5%,” Miller said. “That’s like knowing the size of Washington, D.C., to within about a quarter mile. NICER is not only rewriting the textbooks on neutron stars, but also revolutionizing our confidence in our measurements of objects that are both very distant and very small.”

    In addition to testing matter’s limits, neutron stars also offer a new means of exploring the vast reaches of space. In 2018, a team of scientists and NASA engineers used NICER to demonstrate, for the first time, fully autonomous navigation in space using pulsars, which could revolutionize our ability to pilot robotic spacecraft to the far reaches of the solar system and beyond.

    “NICER was a great crewmate,” said NASA astronaut Christina Koch, who served as a flight engineer on the space station from March 2019 to February 2020, setting the record for the longest single spaceflight by a woman. “The mission exemplifies all the best aspects of station research. It’s groundbreaking fundamental science, space science, and technological innovation, all enabled by the unique environment and platform of an orbiting laboratory.”

    NICER is an Astrophysics Mission of Opportunity within NASA’s Explorers program, which provides frequent flight opportunities for world-class scientific investigations from space utilizing innovative, streamlined and efficient management approaches within the heliophysics and astrophysics science areas. NASA’s Space Technology Mission Directorate supports the SEXTANT component of the mission, demonstrating pulsar-based spacecraft navigation.

    See the full article here.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.


    Stem Education Coalition

    NASA’s Goddard Space Flight Center, Greenbelt, MD (US) is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    GSFC also operates two spaceflight tracking and data acquisition networks (the NASA Deep Space Network(US) and the Near Earth Network); develops and maintains advanced space and Earth science data information systems, and develops satellite systems for the National Oceanic and Atmospheric Administration(US) .

    GSFC manages operations for many NASA and international missions including the NASA/ESA Hubble Space Telescope; the Explorers Program; the Discovery Program; the Earth Observing System; INTEGRAL; MAVEN; OSIRIS-REx; the Solar and Heliospheric Observatory ; the Solar Dynamics Observatory; Tracking and Data Relay Satellite System ; Fermi; and Swift. Past missions managed by GSFC include the Rossi X-ray Timing Explorer (RXTE), Compton Gamma Ray Observatory, SMM, COBE, IUE, and ROSAT. Typically, unmanned Earth observation missions and observatories in Earth orbit are managed by GSFC, while unmanned planetary missions are managed by the Jet Propulsion Laboratory (JPL) in Pasadena, California(US).

    Goddard is one of four centers built by NASA since its founding on July 29, 1958. It is NASA’s first, and oldest, space center. Its original charter was to perform five major functions on behalf of NASA: technology development and fabrication; planning; scientific research; technical operations; and project management. The center is organized into several directorates, each charged with one of these key functions.

    Until May 1, 1959, NASA’s presence in Greenbelt, MD was known as the Beltsville Space Center. It was then renamed the Goddard Space Flight Center (GSFC), after Robert H. Goddard. Its first 157 employees transferred from the United States Navy’s Project Vanguard missile program, but continued their work at the Naval Research Laboratory in Washington, D.C., while the center was under construction.

    Goddard Space Flight Center contributed to Project Mercury, America’s first manned space flight program. The Center assumed a lead role for the project in its early days and managed the first 250 employees involved in the effort, who were stationed at Langley Research Center in Hampton, Virginia. However, the size and scope of Project Mercury soon prompted NASA to build a new Manned Spacecraft Center, now the Johnson Space Center, in Houston, Texas. Project Mercury’s personnel and activities were transferred there in 1961.

    The Goddard network tracked many early manned and unmanned spacecraft.

    Goddard Space Flight Center remained involved in the manned space flight program, providing computer support and radar tracking of flights through a worldwide network of ground stations called the Spacecraft Tracking and Data Acquisition Network (STDN). However, the Center focused primarily on designing unmanned satellites and spacecraft for scientific research missions. Goddard pioneered several fields of spacecraft development, including modular spacecraft design, which reduced costs and made it possible to repair satellites in orbit. Goddard’s Solar Max satellite, launched in 1980, was repaired by astronauts on the Space Shuttle Challenger in 1984. The Hubble Space Telescope, launched in 1990, remains in service and continues to grow in capability thanks to its modular design and multiple servicing missions by the Space Shuttle.

    Today, the center remains involved in each of NASA’s key programs. Goddard has developed more instruments for planetary exploration than any other organization, among them scientific instruments sent to every planet in the Solar System. The center’s contribution to the Earth Science Enterprise includes several spacecraft in the Earth Observing System fleet as well as EOSDIS, a science data collection, processing, and distribution system. For the manned space flight program, Goddard develops tools for use by astronauts during extra-vehicular activity, and operates the Lunar Reconnaissance Orbiter, a spacecraft designed to study the Moon in preparation for future manned exploration.


    NASA/Goddard Campus

     
  • richardmitnick 3:10 pm on April 15, 2021 Permalink | Reply
    Tags: "New NASA Visualization Probes the Light-bending Dance of Binary Black Holes", , , , , NASA Goddard Space Flight Center   

    From NASA Goddard Space Flight Center: “New NASA Visualization Probes the Light-bending Dance of Binary Black Holes” 

    NASA Goddard Banner

    From NASA Goddard Space Flight Center

    Apr 15, 2021

    By Francis Reddy
    francis.j.reddy@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    Media contact:
    Claire Andreoli
    claire.andreoli@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.
    (301) 286-1940

    1
    In this frame from the new visualization, a supermassive black hole weighing 200 million solar masses lies in the foreground. Its gravity distorts light from the accretion disk of a smaller companion black hole almost directly behind it, creating this surreal view. Different colors for the accretion disks make it easier to track the contributions of each one. Credit: /Jeremy Schnittman and Brian P. Powell/NASA’s Goddard Space Flight Center.

    A pair of orbiting black holes millions of times the Sun’s mass perform a hypnotic pas de deux in a new NASA visualization. The movie traces how the black holes distort and redirect light emanating from the maelstrom of hot gas – called an accretion disk – that surrounds each one.

    Viewed from near the orbital plane, each accretion disk takes on a characteristic double-humped look. But as one passes in front of the other, the gravity of the foreground black hole transforms its partner into a rapidly changing sequence of arcs. These distortions play out as light from both disks navigates the tangled fabric of space and time near the black holes.


    Explore how the extreme gravity of two orbiting supermassive black holes distorts our view. In this visualization, disks of bright, hot, churning gas encircle both black holes, shown in red and blue to better track the light source. The red disk orbits the larger black hole, which weighs 200 million times the mass of our Sun, while its smaller blue companion weighs half as much. Zooming into each black hole reveals multiple, increasingly warped images of its partner. Watch to learn more.
    Credit: Jeremy Schnittman and Brian P. Powell/ NASA’s Goddard Space Flight Center.

    “We’re seeing two supermassive black holes, a larger one with 200 million solar masses and a smaller companion weighing half as much,” said Jeremy Schnittman, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who created the visualization. “These are the kinds of black hole binary systems where we think both members could maintain accretion disks lasting millions of years.”

    The accretion disks have different colors, red and blue, to make it easier to track the light sources, but the choice also reflects reality. Hotter gas gives off light closer to the blue end of the spectrum, and material orbiting smaller black holes experiences stronger gravitational effects that produce higher temperatures. For these masses, both accretion disks would actually emit most of their light in the UV, with the blue disk reaching a slightly higher temperature.

    Visualizations like this help scientists picture the fascinating consequences of extreme gravity’s funhouse mirror. The new video doubles down on an earlier one Schnittman produced showing a solitary black hole from various angles.

    Seen nearly edgewise, the accretion disks look noticeably brighter on one side. Gravitational distortion alters the paths of light coming from different parts of the disks, producing the warped image. The rapid motion of gas near the black hole modifies the disk’s luminosity through a phenomenon called Doppler boosting – an effect of Einstein’s relativity theory that brightens the side rotating toward the viewer and dims the side spinning away.

    The visualization also shows a more subtle phenomenon called relativistic aberration. The black holes appear smaller as they approach the viewer and larger when moving away.

    These effects disappear when viewing the system from above, but new features emerge. Both black holes produce small images of their partners that circle around them each orbit. Looking closer, it’s clear that these images are actually edge-on views. To produce them, light from the black holes must be redirected by 90 degrees, which means we’re observing the black holes from two different perspectives – face on and edge on – at the same time.

    2
    A face-on view of the system highlights the smaller black hole’s distorted image (inset) of its bigger companion. To reach the camera, the smaller black hole must bend light from its red companion by 90 degrees. The accretion disk of this secondary image appears as a line, which means we’re seeing an edge-on view of the red companion – while also simultaneously seeing it from above. A secondary image of the blue disk also forms just outside the bright ring of light nearest the larger black hole, too.
    Credits: Jeremy Schnittman and Brian P. Powell/ NASA’s Goddard Space Flight Center.

    “A striking aspect of this new visualization is the self-similar nature of the images produced by gravitational lensing,” Schnittman explained. “Zooming into each black hole reveals multiple, increasingly distorted images of its partner.”

    Schnittman created the visualization by computing the path taken by light rays from the accretion disks as they made their way through the warped space-time around the black holes. On a modern desktop computer, the calculations needed to make the movie frames would have taken about a decade. So Schnittman teamed up with Goddard data scientist Brian P. Powell to use the Discover supercomputer at the NASA Center for Climate Simulation. Using just 2% of Discover’s 129,000 processors, these computations took about a day.

    National Aeronautics and Space Administration(US) Discover SGI Supercomputer- NASA’s Center for Climate Simulation Primary Computing Platform.

    Astronomers expect that, in the not-too-distant future, they’ll be able to detect gravitational waves – ripples in space-time – produced when two supermassive black holes in a system much like the one Schnittman depicted spiral together and merge.

    See the full article here.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASA’s Goddard Space Flight Center, Greenbelt, MD (US) is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    GSFC also operates two spaceflight tracking and data acquisition networks (the NASA Deep Space Network(US) and the Near Earth Network); develops and maintains advanced space and Earth science data information systems, and develops satellite systems for the National Oceanic and Atmospheric Administration(US) .

    GSFC manages operations for many NASA and international missions including the NASA/ESA Hubble Space Telescope; the Explorers Program; the Discovery Program; the Earth Observing System; INTEGRAL; MAVEN; OSIRIS-REx; the Solar and Heliospheric Observatory ; the Solar Dynamics Observatory; Tracking and Data Relay Satellite System ; Fermi; and Swift. Past missions managed by GSFC include the Rossi X-ray Timing Explorer (RXTE), Compton Gamma Ray Observatory, SMM, COBE, IUE, and ROSAT. Typically, unmanned Earth observation missions and observatories in Earth orbit are managed by GSFC, while unmanned planetary missions are managed by the Jet Propulsion Laboratory (JPL) in Pasadena, California(US).

    Goddard is one of four centers built by NASA since its founding on July 29, 1958. It is NASA’s first, and oldest, space center. Its original charter was to perform five major functions on behalf of NASA: technology development and fabrication; planning; scientific research; technical operations; and project management. The center is organized into several directorates, each charged with one of these key functions.

    Until May 1, 1959, NASA’s presence in Greenbelt, MD was known as the Beltsville Space Center. It was then renamed the Goddard Space Flight Center (GSFC), after Robert H. Goddard. Its first 157 employees transferred from the United States Navy’s Project Vanguard missile program, but continued their work at the Naval Research Laboratory in Washington, D.C., while the center was under construction.

    Goddard Space Flight Center contributed to Project Mercury, America’s first manned space flight program. The Center assumed a lead role for the project in its early days and managed the first 250 employees involved in the effort, who were stationed at Langley Research Center in Hampton, Virginia. However, the size and scope of Project Mercury soon prompted NASA to build a new Manned Spacecraft Center, now the Johnson Space Center, in Houston, Texas. Project Mercury’s personnel and activities were transferred there in 1961.

    The Goddard network tracked many early manned and unmanned spacecraft.

    Goddard Space Flight Center remained involved in the manned space flight program, providing computer support and radar tracking of flights through a worldwide network of ground stations called the Spacecraft Tracking and Data Acquisition Network (STDN). However, the Center focused primarily on designing unmanned satellites and spacecraft for scientific research missions. Goddard pioneered several fields of spacecraft development, including modular spacecraft design, which reduced costs and made it possible to repair satellites in orbit. Goddard’s Solar Max satellite, launched in 1980, was repaired by astronauts on the Space Shuttle Challenger in 1984. The Hubble Space Telescope, launched in 1990, remains in service and continues to grow in capability thanks to its modular design and multiple servicing missions by the Space Shuttle.

    Today, the center remains involved in each of NASA’s key programs. Goddard has developed more instruments for planetary exploration than any other organization, among them scientific instruments sent to every planet in the Solar System. The center’s contribution to the Earth Science Enterprise includes several spacecraft in the Earth Observing System fleet as well as EOSDIS, a science data collection, processing, and distribution system. For the manned space flight program, Goddard develops tools for use by astronauts during extra-vehicular activity, and operates the Lunar Reconnaissance Orbiter, a spacecraft designed to study the Moon in preparation for future manned exploration.


    NASA/Goddard Campus

     
  • richardmitnick 9:32 pm on March 22, 2021 Permalink
    Tags: "Hubble captures re-energized planetary nebula", , , , , , NASA Goddard Space Flight Center, Planetary Nebula Abell 78   

    From NASA Goddard Space Flight Center via phys.org: “Hubble captures re-energized planetary nebula” 

    NASA Goddard Banner

    From NASA Goddard Space Flight Center

    via


    phys.org

    March 22, 2021

    1
    Planetary Nebula Abell 78. Credit: NASA/ESA Hubble Space Telescope, M. Guerrero; Acknowledgment: Judy Schmidt

    After exhausting the nuclear fuel in their cores, stars with a mass of around 0.8 to eight times the mass of our Sun collapse to form dense and hot white dwarf stars. As this process occurs, the dying star will throw off its outer layers of material, forming an elaborate cloud of gas and dust known as a planetary nebula. This phenomenon is not uncommon, and planetary nebulae are a popular focus for astrophotographers because of their often beautiful and complex shapes. However, a few like Abell 78 are the result of a so-called “born again” star.

    Although the core of the star has stopped burning hydrogen and helium, a thermonuclear runaway at its surface ejects material at high speeds. This ejecta shocks and sweeps up the material of the old nebula, producing the filaments and irregular shell around the central star seen in this image, which features data from Hubble’s Wide Field Camera 3 and the Panoramic Survey Telescope and Rapid Response System.

    Pan-STARRS1 (PS1) [Panoramic Survey Telescope and Rapid Response System] is a 1.8-meter diameter telescope located near the summit of Haleakala, altitude 10,023 ft (3,055 m) on the Island of Maui. It is equipped with the world’s largest digital camera, with almost 1.4 billion pixels.

    NASA’s Goddard Space Flight Center, Greenbelt, MD (US) is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    GSFC also operates two spaceflight tracking and data acquisition networks (the NASA Deep Space Network(US) and the Near Earth Network); develops and maintains advanced space and Earth science data information systems, and develops satellite systems for the National Oceanic and Atmospheric Administration(US) .

    GSFC manages operations for many NASA and international missions including the NASA/ESA Hubble Space Telescope; the Explorers Program; the Discovery Program; the Earth Observing System; INTEGRAL; MAVEN; OSIRIS-REx; the Solar and Heliospheric Observatory ; the Solar Dynamics Observatory; Tracking and Data Relay Satellite System ; Fermi; and Swift. Past missions managed by GSFC include the Rossi X-ray Timing Explorer (RXTE), Compton Gamma Ray Observatory, SMM, COBE, IUE, and ROSAT. Typically, unmanned Earth observation missions and observatories in Earth orbit are managed by GSFC, while unmanned planetary missions are managed by the Jet Propulsion Laboratory (JPL) in Pasadena, California(US).

    Goddard is one of four centers built by NASA since its founding on July 29, 1958. It is NASA’s first, and oldest, space center. Its original charter was to perform five major functions on behalf of NASA: technology development and fabrication; planning; scientific research; technical operations; and project management. The center is organized into several directorates, each charged with one of these key functions.

    Until May 1, 1959, NASA’s presence in Greenbelt, MD was known as the Beltsville Space Center. It was then renamed the Goddard Space Flight Center (GSFC), after Robert H. Goddard. Its first 157 employees transferred from the United States Navy’s Project Vanguard missile program, but continued their work at the Naval Research Laboratory in Washington, D.C., while the center was under construction.

    Goddard Space Flight Center contributed to Project Mercury, America’s first manned space flight program. The Center assumed a lead role for the project in its early days and managed the first 250 employees involved in the effort, who were stationed at Langley Research Center in Hampton, Virginia. However, the size and scope of Project Mercury soon prompted NASA to build a new Manned Spacecraft Center, now the Johnson Space Center, in Houston, Texas. Project Mercury’s personnel and activities were transferred there in 1961.

    The Goddard network tracked many early manned and unmanned spacecraft.

    Goddard Space Flight Center remained involved in the manned space flight program, providing computer support and radar tracking of flights through a worldwide network of ground stations called the Spacecraft Tracking and Data Acquisition Network (STDN). However, the Center focused primarily on designing unmanned satellites and spacecraft for scientific research missions. Goddard pioneered several fields of spacecraft development, including modular spacecraft design, which reduced costs and made it possible to repair satellites in orbit. Goddard’s Solar Max satellite, launched in 1980, was repaired by astronauts on the Space Shuttle Challenger in 1984. The Hubble Space Telescope, launched in 1990, remains in service and continues to grow in capability thanks to its modular design and multiple servicing missions by the Space Shuttle.

    Today, the center remains involved in each of NASA’s key programs. Goddard has developed more instruments for planetary exploration than any other organization, among them scientific instruments sent to every planet in the Solar System. The center’s contribution to the Earth Science Enterprise includes several spacecraft in the Earth Observing System fleet as well as EOSDIS, a science data collection, processing, and distribution system. For the manned space flight program, Goddard develops tools for use by astronauts during extra-vehicular activity, and operates the Lunar Reconnaissance Orbiter, a spacecraft designed to study the Moon in preparation for future manned exploration.

    See the full article here.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.


    NASA/Goddard Campus

     
  • richardmitnick 6:04 pm on March 12, 2021 Permalink | Reply
    Tags: "Scientists Sketch Aged Star System Using Over a Century of Observations", Astronomers have painted their best picture yet of an RV Tauri variable-a rare type of stellar binary where two stars-one approaching the end of its life orbit within a sprawling disk of dust., , , , , NASA Goddard Space Flight Center, RV Tauri variable named "U Monocerotis"   

    From NASA Goddard Space Flight Center: “Scientists Sketch Aged Star System Using Over a Century of Observations” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    Mar 12, 2021

    By Jeanette Kazmierczak
    jeanette.a.kazmierczak@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    Media contact:
    Claire Andreoli
    claire.andreoli@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.
    (301) 286-1940

    1
    U Mon’s primary star, an elderly yellow supergiant, has around twice the Sun’s mass but has billowed to 100 times the Sun’s size. Scientists know less about the companion, the blue star in the background of this illustration, but they think it’s of similar mass and much younger than the primary. Credit: NASA’s Goddard Space Flight Center/Chris Smith (USRA/GESTAR).

    Astronomers have painted their best picture yet of an RV Tauri variable, a rare type of stellar binary where two stars – one approaching the end of its life – orbit within a sprawling disk of dust. Their 130-year dataset spans the widest range of light yet collected for one of these systems, from radio to X-rays.

    “There are only about 300 known RV Tauri variables in the Milky Way galaxy,” said Laura Vega, a recent doctoral recipient at Vanderbilt University in Nashville, Tennessee. “We focused our study on the second brightest, named U Monocerotis, which is now the first of these systems from which X-rays have been detected.”

    A paper describing the findings, led by Vega, was published in The Astrophysical Journal.


    Scientists Build a Detailed Image of U Mon Binary.
    Two stars orbit each other within an enormous dusty disk in the U Monocerotis system, illustrated here. When the stars are farthest from each other, they funnel material from the disk’s inner edge. At this time, the primary star is slightly obscured by the disk from our perspective. The primary star, a yellow supergiant, expands and contracts. The smaller secondary star is thought to maintain its own disk of material, which likely powers an outflow of gas that emits X-rays. Credit: NASA’s Goddard Space Flight Center/Chris Smith (USRA/GESTAR).

    The system, called “U Mon” for short, lies around 3,600 light-years away in the constellation Monoceros. Its two stars circle each other about every six and a half years on an orbit tipped about 75 degrees from our perspective.

    The primary star, an elderly yellow supergiant, has around twice the Sun’s mass but has billowed to 100 times the Sun’s size. A tug of war between pressure and temperature in its atmosphere causes it to regularly expand and contract, and these pulsations create predictable brightness changes with alternating deep and shallow dips in light – a hallmark of RV Tauri systems. Scientists know less about the companion star, but they think it’s of similar mass and much younger than the primary.

    The cool disk around both stars is composed of gas and dust ejected by the primary star as it evolved. Using radio observations from the Submillimeter Array on Maunakea, Hawai’i, Vega’s team estimated that the disk is around 51 billion miles (82 billion kilometers) across.

    CfA Submillimeter Array Mauna Kea, Hawaii, USA, Altitude 4,080 m (13,390 ft).

    The binary orbits inside a central gap that the scientists think is comparable to the distance between the two stars at their maximum separation, when they’re about 540 million miles (870 million kilometers) apart.

    2
    This infographic shows U Mon’s components to scale.
    Credit: NASA’s Goddard Space Flight Center/Chris Smith (USRA/GESTAR).

    When the stars are farthest from each other, they’re roughly aligned with our line of sight. The disk partially obscures the primary and creates another predictable fluctuation in the system’s light. Vega and her colleagues think this is when one or both stars interact with the disk’s inner edge, siphoning off streams of gas and dust. They suggest that the companion star funnels the gas into its own disk, which heats up and generates an X-ray-emitting outflow of gas. This model could explain X-rays detected in 2016 by the European Space Agency’s XMM-Newton satellite.

    ESA/XMM Newton X-ray telescope (EU).

    “The XMM observations make U Mon the first RV Tauri variable detected in X-rays,” said Kim Weaver, the XMM U.S. project scientist and an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It’s exciting to see ground- and space-based multiwavelength measurements come together to give us new insights into a long-studied system.”

    In their analysis of U Mon, Vega’s team also incorporated 130 years of visible light observations.

    The earliest available measurement of the system, collected on Dec. 25, 1888, came from the archives of the American Association of Variable Star Observers (AAVSO), an international network of amateur and professional astronomers headquartered in Cambridge, Massachusetts. AAVSO provided additional historical measurements ranging from the mid-1940s to the present.

    The researchers also used archived images cataloged by the Digital Access to a Sky Century @ Harvard (DASCH), a program at the Harvard College Observatory in Cambridge dedicated to digitizing astronomical images from glass photographic plates made by ground-based telescopes between the 1880s and 1990s.

    3
    On May 12, 1948, astronomers at Boyden Observatory in Bloemfontein, South Africa, captured a portion of the sky containing U Monocerotis (left, circled) on a glass photographic plate. The logbook entry (right) for the observation reads: Gusty S wind. H.A. [Hour Angle] should be 2 02 W.
    Credits: Harvard College Observatory, Photographic Glass Plate Collection. Used with permission.

    U Mon’s light varies both because the primary star pulsates and because the disk partially obscures it every 6.5 years or so. The combined AAVSO and DASCH data allowed Vega and her colleagues to spot an even longer cycle, where the system’s brightness rises and falls about every 60 years. They think a warp or clump in the disk, located about as far from the binary as Neptune is from the Sun, causes this extra variation as it orbits.

    Vega completed her analysis of the U Mon system as a NASA Harriett G. Jenkins Predoctoral Fellow, a program funded by the NASA Office of STEM Engagement’s Minority University Research and Education Project.

    “For her doctoral dissertation, Laura used this historical dataset to detect a characteristic that would otherwise appear only once in an astronomer’s career,” said co-author Rodolfo Montez Jr., an astrophysicist at the Center for Astrophysics | Harvard & Smithsonian, also in Cambridge. “It’s a testament to how our knowledge of the universe builds over time.”

    Co-author Keivan Stassun, an expert in star formation and Vega’s doctoral advisor at Vanderbilt, notes that this evolved system has many features and behaviors in common with newly formed binaries. Both are embedded in disks of gas and dust, pull material from those disks, and produce outflows of gas. And in both cases, the disks can form warps or clumps. In young binaries, those might signal the beginnings of planet formation.

    “We still have questions about the feature in U Mon’s disk, which may be answered by future radio observations,” Stassun said. “But otherwise, many of the same characteristics are there. It’s fascinating how closely these two binary life stages mirror each other.”

    See the full article here.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASA’s Goddard Space Flight Center, Greenbelt, MD (US) is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    GSFC also operates two spaceflight tracking and data acquisition networks (the NASA Deep Space Network(US) and the Near Earth Network); develops and maintains advanced space and Earth science data information systems, and develops satellite systems for the National Oceanic and Atmospheric Administration(US) .

    GSFC manages operations for many NASA and international missions including the NASA/ESA Hubble Space Telescope; the Explorers Program; the Discovery Program; the Earth Observing System; INTEGRAL; MAVEN; OSIRIS-REx; the Solar and Heliospheric Observatory ; the Solar Dynamics Observatory; Tracking and Data Relay Satellite System ; Fermi; and Swift. Past missions managed by GSFC include the Rossi X-ray Timing Explorer (RXTE), Compton Gamma Ray Observatory, SMM, COBE, IUE, and ROSAT. Typically, unmanned Earth observation missions and observatories in Earth orbit are managed by GSFC, while unmanned planetary missions are managed by the Jet Propulsion Laboratory (JPL) in Pasadena, California(US).

    Goddard is one of four centers built by NASA since its founding on July 29, 1958. It is NASA’s first, and oldest, space center. Its original charter was to perform five major functions on behalf of NASA: technology development and fabrication; planning; scientific research; technical operations; and project management. The center is organized into several directorates, each charged with one of these key functions.

    Until May 1, 1959, NASA’s presence in Greenbelt, MD was known as the Beltsville Space Center. It was then renamed the Goddard Space Flight Center (GSFC), after Robert H. Goddard. Its first 157 employees transferred from the United States Navy’s Project Vanguard missile program, but continued their work at the Naval Research Laboratory in Washington, D.C., while the center was under construction.

    Goddard Space Flight Center contributed to Project Mercury, America’s first manned space flight program. The Center assumed a lead role for the project in its early days and managed the first 250 employees involved in the effort, who were stationed at Langley Research Center in Hampton, Virginia. However, the size and scope of Project Mercury soon prompted NASA to build a new Manned Spacecraft Center, now the Johnson Space Center, in Houston, Texas. Project Mercury’s personnel and activities were transferred there in 1961.

    The Goddard network tracked many early manned and unmanned spacecraft.

    Goddard Space Flight Center remained involved in the manned space flight program, providing computer support and radar tracking of flights through a worldwide network of ground stations called the Spacecraft Tracking and Data Acquisition Network (STDN). However, the Center focused primarily on designing unmanned satellites and spacecraft for scientific research missions. Goddard pioneered several fields of spacecraft development, including modular spacecraft design, which reduced costs and made it possible to repair satellites in orbit. Goddard’s Solar Max satellite, launched in 1980, was repaired by astronauts on the Space Shuttle Challenger in 1984. The Hubble Space Telescope, launched in 1990, remains in service and continues to grow in capability thanks to its modular design and multiple servicing missions by the Space Shuttle.

    Today, the center remains involved in each of NASA’s key programs. Goddard has developed more instruments for planetary exploration than any other organization, among them scientific instruments sent to every planet in the Solar System. The center’s contribution to the Earth Science Enterprise includes several spacecraft in the Earth Observing System fleet as well as EOSDIS, a science data collection, processing, and distribution system. For the manned space flight program, Goddard develops tools for use by astronauts during extra-vehicular activity, and operates the Lunar Reconnaissance Orbiter, a spacecraft designed to study the Moon in preparation for future manned exploration.


    NASA/Goddard Campus

     
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