Tagged: NASA Goddard Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 12:29 pm on October 21, 2016 Permalink | Reply
    Tags: , , NASA Goddard,   

    From Goddard: “Photonics Dawning as the Communications Light For Evolving NASA Missions” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    Oct. 21, 2016
    Ashley Hume
    ashley.l.morrow@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    A largely unrecognized field called photonics may provide solutions to some of NASA’s most pressing challenges in future spaceflight.

    Photonics explores the many applications of generating, detecting and manipulating photons, or particles of light that, among other things, make up laser beams. On this day in 1983, the General Conference of Weights and Measures adopted the accepted value for the speed of light, an important photonics milestone. Oct. 21, 2016, is Day of Photonics, a biennial event to raise awareness of photonics to the general public. The study has multiple applications across NASA missions, from space communications to reducing the size of mission payloads to performing altitude measurements from orbit.


    Access mp4 video here .
    NASA is using photonics to solve some of the most pressing upcoming challenges in spaceflight, such as better data communications from space to Earth.
    Credits: NASA’s Goddard Space Flight Center/Amber Jacobson, producer.

    One major NASA priority is to use lasers to make space communications for both near-Earth and deep-space missions more efficient. NASA’s communications systems have matured over the decades, but they still use the same radio-frequency (RF) system developed in the earliest days of the agency. After more than 50 years of using solely RF, NASA is investing in new ways to increase data rates while also finding more efficient communications systems.

    Photonics may provide the solution. Several centers across NASA are experimenting with laser communications, which has the potential to provide data rates at least 10 to 100 times better than RF. These higher speeds would support increasingly sophisticated instruments and the transmission of live video from anywhere in the solar system. They would also increase the bandwidth for communications from human exploration missions in deep space, such as those associated with Journey to Mars.

    2
    Conceptual animation depicting a satellite using lasers to relay data from Mars to Earth.
    Credits: NASA’s Goddard Space Flight Center

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, launched the first laser communications pathfinder mission in 2013. The Lunar Laser Communications Demonstration (LLCD) proved that a space-based laser communications system was viable and that the system could survive both launch and the space environment. But the mission was short-lived by design, as the host payload crashed into the lunar surface in a planned maneuver a few months after launch.

    The Goddard team is now planning a follow-on mission called the Laser Communications Relay Demonstration (LCRD) to prove the proposed system’s longevity. It will also provide engineers more opportunity to learn the best way to operate it for near-Earth missions.

    “We have been using RF since the beginning, 50 to 60 years, so we’ve learned a lot about how it works in different weather conditions and all the little things to allow us to make the most out of the technology, but we don’t have that experience with laser comm,” said Dave Israel, Exploration and Space Communications architect at Goddard and principal investigator on LCRD. “LCRD will allow us to test the performance over all different weather conditions and times of day and learn how to make the most of laser comm.”

    Scheduled to launch in 2019, LCRD will simulate real communications support, practicing for two years with a test payload on the International Space Station and two dedicated ground stations in California and Hawaii. The mission could be the last hurdle to implementing a constellation of laser communications relay satellites similar to the Space Network’s Tracking and Data Relay Satellites.

    NASA’s Jet Propulsion Laboratory in Pasadena, California, and Glenn Research Center in Cleveland are also following up on LLCD’s success. But both will focus on how laser communications could be implemented in deep-space missions.

    Missions to deep space impose special communication challenges because of their distance from Earth. The data return on these missions slowly trickle back to the ground a little at a time using radio frequency. Laser communications could significantly improve data rates in all space regions, from low-Earth orbit to interplanetary.

    JPL’s concept, called Deep Space Optical Communications (DSOC), focuses on laser communications’ benefits to data rates and to space and power constraints on missions. The data-rate benefits of laser communications for deep-space missions are clear, but less recognized is that laser communications can also save mass, space and/or power requirements on missions. That could be monumental on missions like the James Webb Space Telescope, which is so large that, even folded, it will barely fit in the largest rocket currently available. Although Webb is an extreme example, many missions today face size constraints as they become more complex. The Lunar Reconnaissance Orbiter mission carried both types of communications systems, and the laser system was half the mass, required 25 percent less power and transferred data at six times the rate of the RF system. Laser communications could also benefit a class of missions called CubeSats, which are about the size of a shoebox. These missions are becoming more popular and require miniaturized parts, including communications and power systems.

    Power requirements can become a major challenge on missions to the outer solar system. As spacecraft move away from the sun, solar power becomes less viable, so the less power a payload requires, the smaller the spacecraft battery, saving space, and the easier spacecraft components can be recharged.

    Laser communications could help to solve all of these challenges.

    The team at Glenn is developing an idea called Integrated Radio and Optical Communications (iROC) to put a laser communications relay satellite in orbit around Mars that could receive data from distant spacecraft and relay their signal back to Earth. The system would use both RF and laser communications, promoting interoperability amongst all of NASA’s assets in space. By integrating both communications systems, iROC could provide services both for new spacecraft using laser communications systems and older spacecraft like Voyager 1 that use RF.

    But laser communications is not NASA’s only foray into photonics, nor is it the first. In fact, NASA began using lasers shortly after they were invented. Goddard successfully demonstrated satellite laser ranging, a technique to measure distances, in 1964.

    Satellite Laser Ranging is still managed at Goddard. The system uses laser stations worldwide to bounce short pulses of light off of special reflectors installed on satellites. There are also reflectors on the moon that were placed there during the Apollo and Soviet rover programs. By timing the bounce of the pulses, engineers can compute distances and orbits. Measurements are accurate up to a few millimeters. This application is used on numerous NASA missions, such as ICESat-2, which will measure the altitude of the ice surface in the Antarctic and Greenland regions. It will provide important information regarding climate and the health of Earth’s polar regions.

    NASA’s Satellite Laser Ranging system consists of eight stations covering North America, the west coast of South America, the Pacific, South Africa and western Australia. NASA and its partners and associated universities operate the stations. SLR is part of the larger International Laser Ranging Service, and NASA’s contribution comprises more than a third of the organization’s total data volume.

    From communications to altimetry and navigation, photonics’ importance to NASA missions cannot be understated. As technology continues to evolve, many photonics applications may come to fruition over the next several decades. Others may also be discovered, especially as humanity pushes further out into the universe than ever before.

    To find out more, visit http://day-of-photonics.org/.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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
    NASA/Goddard Campus
    NASA image

     
  • richardmitnick 7:48 am on October 18, 2016 Permalink | Reply
    Tags: NASA Goddard, , NASA's MAVEN Mission Gives Unprecedented Ultraviolet View of Mars   

    From Goddard: “NASA’s MAVEN Mission Gives Unprecedented Ultraviolet View of Mars” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    Oct. 17, 2016
    Nancy Jones
    nancy.n.jones@nasa.gov

    Bill Steigerwald
    william.a.steigerwald@nasa.gov

    NASA Goddard Space Flight Center, Greenbelt, Maryland
    301-286-0039 / x-5017

    New global images of Mars from the MAVEN mission show the ultraviolet glow from the Martian atmosphere in unprecedented detail, revealing dynamic, previously invisible behavior. They include the first images of “nightglow” that can be used to show how winds circulate at high altitudes. Additionally, dayside ultraviolet imagery from the spacecraft shows how ozone amounts change over the seasons and how afternoon clouds form over giant Martian volcanoes. The images were taken by the Imaging UltraViolet Spectrograph (IUVS) on the Mars Atmosphere and Volatile Evolution mission (MAVEN).

    NASA/Mars MAVEN
    NASA/Mars MAVEN


    Access mp4 video here .
    Images from MAVEN’s Imaging UltraViolet Spectrograph were used to make this movie of rapid cloud formation on Mars on July 9-10, 2016. The ultraviolet colors of the planet have been rendered in false color, to show what we would see with ultraviolet-sensitive eyes. The movie uses four MAVEN images to show about 7 hours of Mars rotation during this period, and interleaves simulated views that would be seen between the four images. Mars’ day is similar to Earth’s, so the movie shows just over a quarter day. The left part of the planet is in morning and the right side in afternoon. Mars’ prominent volcanoes, topped with white clouds, can be seen moving across the disk. Mars’ tallest volcano, Olympus Mons, appears as a prominent dark region near the top of the images, with a small white cloud at the summit that grows during the day. Olympus Mons appears dark because the volcano rises up above much of the hazy atmosphere which makes the rest of the planet appear lighter. Three more volcanoes appear in a diagonal row, with their cloud cover merging to span up to a thousand miles by the end of the day. These images are particularly interesting because they show how rapidly and extensively the clouds topping the volcanoes form in the afternoon. Similar processes occur at Earth, with the flow of winds over mountains creating clouds. Afternoon cloud formation is a common occurrence in the American West, especially during the summer. Credits: NASA/MAVEN/University of Colorado

    “MAVEN obtained hundreds of such images in recent months, giving some of the best high-resolution ultraviolet coverage of Mars ever obtained,” said Nick Schneider of the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder. Schneider is presenting these results Oct. 19 at the American Astronomical Society Division for Planetary Sciences meeting in Pasadena, California, which is being held jointly with the European Planetary Science Congress.

    Nightside images show ultraviolet (UV) “nightglow” emission from nitric oxide (abbreviated NO). Nightglow is a common planetary phenomenon in which the sky faintly glows even in the complete absence of external light. Mars’ nightside atmosphere emits light in the ultraviolet due to chemical reactions that start on Mars’ dayside. Ultraviolet light from the sun breaks down molecules of carbon dioxide and nitrogen, and the resulting atoms are carried around the planet by high-altitude wind patterns that encircle the planet. On the nightside, these winds bring the atoms down to lower altitudes where nitrogen and oxygen atoms collide to form nitric oxide molecules. The recombination releases extra energy, which comes out as ultraviolet light.

    1
    This image of the Mars night side shows ultraviolet emission from nitric oxide (abbreviated NO). The emission is shown in false color with black as low values, green as medium, and white as high. These emissions track the recombination of atomic nitrogen and oxygen produced on the dayside, and reveal the circulation patterns of the atmosphere. The splotches, streaks and other irregularities in the image are indications that atmospheric patterns are extremely variable on Mars’ nightside. The inset shows the viewing geometry on the planet. MAVEN’s Imaging UltraViolet Spectrograph obtained this image of Mars on May 4, 2016 during late winter in Mars Southern Hemisphere. Credits: NASA/MAVEN/University of Colorado.

    Scientists predicted NO nightglow at Mars, and prior missions detected its presence, but MAVEN has returned the first images of this phenomenon in the Martian atmosphere. Splotches and streaks appearing in these images occur where NO recombination is enhanced by winds. Such concentrations are clear evidence of strong irregularities in Mars’ high altitude winds and circulation patterns. These winds control how Mars’ atmosphere responds to its very strong seasonal cycles. These first images will lead to an improved determination of the circulation patterns that control the behavior of the atmosphere from approximately 37 to 62 miles (about 60 to 100 kilometers) high.

    Dayside images show the atmosphere and surface near Mars’ south pole in unprecedented ultraviolet detail. They were obtained as spring comes to the southern hemisphere. Ozone is destroyed when water vapor is present, so ozone accumulates in the winter polar region where the water vapor has frozen out of the atmosphere. The images show ozone lasting into spring, indicating that global winds are inhibiting the spread of water vapor from the rest of the planet into winter polar regions. Wave patterns in the images, revealed by UV absorption from ozone concentrations, are critical to understanding the wind patterns, giving scientists an additional means to study the chemistry and global circulation of the atmosphere.

    2
    This ultraviolet image near Mars’ South Pole was taken by MAVEN on July 10 2016 and shows the atmosphere and surface during southern spring. The ultraviolet colors of the planet have been rendered in false color, to show what we would see with ultraviolet-sensitive eyes. Darker regions show the planet’s rocky surface and brighter regions are due to clouds, dust and haze. The white region centered on the pole is frozen carbon dioxide (dry ice) on the surface. Pockets of ice are left inside craters as the polar cap recedes in the spring, giving its edge a rough appearance. High concentrations of atmospheric ozone appear magenta in color, and the wavy edge of the enhanced ozone region highlights wind patterns around the pole. Credits: NASA/MAVEN/University of Colorado.

    MAVEN observations also show afternoon cloud formation over the four giant volcanoes on Mars, much as clouds form over mountain ranges on Earth. IUVS images of cloud formation are among the best ever taken showing the development of clouds throughout the day. Clouds are a key to understanding a planet’s energy balance and water vapor inventory, so these observations will be valuable in understanding the daily and seasonal behavior of the atmosphere.

    3
    MAVEN’s Imaging UltraViolet Spectrograph obtained these images of rapid cloud formation on Mars on July 9-10, 2016. The ultraviolet colors of the planet have been rendered in false color, to show what we would see with ultraviolet-sensitive eyes. The series interleaves MAVEN images to show about 7 hours of Mars rotation during this period, just over a quarter of Mars’ day. The left part of the planet is in morning and the right side is in afternoon. Mars’ prominent volcanoes, topped with white clouds, can be seen moving across the disk. Mars’ tallest volcano, Olympus Mons, appears as a prominent dark region near the top of the images, with a small white cloud at the summit that grows during the day. Olympus Mons appears dark because the volcano rises up above much of the hazy atmosphere which makes the rest of the planet appear lighter. Three more volcanoes appear in a diagonal row, with their cloud cover merging to span up to a thousand miles by the end of the day. These images are particularly interesting because they show how rapidly and extensively the clouds topping the volcanoes form in the afternoon. Similar processes occur at Earth, with the flow of winds over mountains creating clouds. Afternoon cloud formation is a common occurrence in the American West, especially during the summer. Credits: NASA/MAVEN/University of Colorado.

    “MAVEN’s elliptical orbit is just right,” said Justin Deighan of the University of Colorado, Boulder, who led the observations. “It rises high enough to take a global picture, but still orbits fast enough to get multiple views as Mars rotates over the course of a day.”

    4
    MAVEN’s Imaging UltraViolet Spectrograph obtained images of rapid cloud formation on Mars on July 9-10, 2016. The ultraviolet colors of the planet have been rendered in false color, to show what we would see with ultraviolet-sensitive eyes. Mars’ tallest volcano, Olympus Mons, appears as a prominent dark region near the top of the image, with a small white cloud at the summit that grows during the day. Three more volcanoes appear in a diagonal row, with their cloud cover (white areas near center) merging to span up to a thousand miles by the end of the day. Credits: NASA/MAVEN/University of Colorado.

    MAVEN’s principal investigator is based at the University of Colorado’s Laboratory for Atmospheric and Space Physics, Boulder. The university provided two science instruments and leads science operations, as well as education and public outreach, for the mission. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the MAVEN project and provided two science instruments for the mission. The University of California at Berkeley’s Space Sciences Laboratory also provided four science instruments for the mission. Lockheed Martin built the spacecraft and is responsible for mission operations. NASA’s Jet Propulsion Laboratory in Pasadena, California, provides navigation and Deep Space Network support, as well as the Electra telecommunications relay hardware and operations.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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
    NASA/Goddard Campus
    NASA image

     
  • richardmitnick 7:28 am on October 18, 2016 Permalink | Reply
    Tags: , NASA Goddard, ,   

    From Goddard: “Wayward Field Lines Challenge Solar Radiation Models” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    Oct. 17, 2016
    Lina Tran
    kathalina.k.tran@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    In addition to the constant emission of warmth and light, our sun sends out occasional bursts of solar radiation that propel high-energy particles toward Earth. These solar energetic particles, or SEPs, can impact astronauts or satellites. To fully understand these particles, scientists must look to their source: the bursts of solar radiation.

    But scientists aren’t exactly sure which of the two main features of solar eruptions –narrow solar flares or wide coronal mass ejections – causes the SEPs during different bursts. Scientists try to distinguish between the two possibilities by using observations, and computer models based on those observations, to map out where the particles could be found as they spread out and traveled away from the sun. NASA missions STEREO and SOHO collect the data upon which these models are built.

    NASA/STEREO spacecraft
    NASA/STEREO spacecraft

    ESA/NASA SOHO
    ESA/NASA SOHO

    Sometimes, these solar observatories saw SEPs on the opposite side of the sun than where the eruption took place. What kind of explosion on the sun could send the particles so far they ended up behind where they started?


    Access mp4 video here .
    This video compares the two models for particle distribution over the course of just three hours after an SEP event. The white line represents a magnetic field line, the general path that the SEPs follow. The line starts at an SEP event at the sun, and leads the particles in a spiral around the sun. The animation of the updated model, on the right, depicts a static field line, but as the SEPs travel farther in space, turbulent solar material causes wandering field lines. In turn, wandering field lines cause the particles to spread much more efficiently than the traditional model, on the left, predicted. Credits: NASA’s Goddard Space Flight Center/UCLan/Stanford/ULB/Joy Ng, producer

    Now a new model has been developed by an international team of scientists, led by the University of Central Lancashire and funded in part by NASA. The new model shows how particles could travel to the back of the sun no matter what type of event first propelled them. Previous models assumed the particles mainly follow the average of magnetic field lines in space on their way from the sun to Earth, and slowly spread across the average over time. The average field line forms a steady path following a distinct spiral because of the sun’s rotation. But the new model takes into consideration that magnetic fields lines can wander – a result of turbulence in solar material as it travels away from the sun.

    With this added information, models now show SEPs spiraling out much wider and farther than previous models predicted – explaining how SEPs find their way to even the far side of the sun. Understanding the nature of SEP distribution helps scientists as they continue to map out the origins of these high-energy particles. A paper published in Astronomy and Astrophysics on June 6, 2016, summarizes the research, a result of collaboration between the University of Central Lancashire, Université Libre de Bruxelles, University of Waikato and Stanford University.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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
    NASA/Goddard Campus
    NASA image

     
  • richardmitnick 11:24 am on October 13, 2016 Permalink | Reply
    Tags: , , , NASA Goddard, NASA/Lunar Reconnaissance Orbiter   

    From Goddard: “Earth’s Moon Hit by Surprising Number of Meteoroids” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    Oct. 13, 2016
    Nancy Jones
    nancy.n.jones@nasa.gov

    Bill Steigerwald
    william.a.steigerwald@nasa.gov

    NASA Goddard Space Flight Center, Greenbelt, Maryland
    301-286-0039 / x-5017

    Last Updated: Oct. 13, 2016
    Editor: Bill Steigerwald

    The moon experiences a heavier bombardment by small meteoroids than models had predicted, according to new observations from NASA’s Lunar Reconnaissance Orbiter (LRO) spacecraft.

    NASA/Lunar Reconna
    NASA/Lunar Reconnaissance Orbiter

    The result implies that lunar surface features thought to be young because they have relatively few impact craters may be even younger than previous estimates.

    The finding also implies that equipment placed on the moon for long durations — such as a lunar base — may have to be made sturdier. While a direct hit from a meteoroid is still unlikely, a more intense rain of secondary debris thrown out by nearby impacts may pose a risk to surface assets.


    Access mp4 video here .
    After simulating the distant view of a new impact, the camera zooms up to the surface to show actual before/after images of a new 12-meter crater taken by the Lunar Reconnaissance Orbiter narrow-angle camera. Credits: NASA/GSFC/Ernie Wright

    “Before the launch of the Lunar Reconnaissance Orbiter, it was thought that churning of the lunar regolith (soil) from meteoroid impacts typically took millions of years to overturn the surface down to 2 centimeters (about 0.8 inches),” said Emerson Speyerer of Arizona State University, Tempe. “New images from the Lunar Reconnaissance Orbiter Camera (LROC) are revealing small surface changes that are transforming the surface much faster than previously thought.” Speyerer is lead author of a paper about this research in the Oct. 13 issue of the journal Nature.

    “The newly determined churning rate means that the Apollo astronaut tracks will be gone in tens of thousands of years rather than millions,” said Mark Robinson of Arizona State University, a co-author.

    2
    One of the first steps taken on the Moon, this is an image of Buzz Aldrin’s bootprint from the Apollo 11 mission. Neil Armstrong and Buzz Aldrin walked on the Moon on July 20, 1969. Credits: NASA

    LRO went into lunar orbit in June of 2009 and has acquired an extensive set of high-resolution images of the surface, including pairs of images of the same areas taken at different times. Using these before-and-after images (temporal pairs) acquired by the LROC Narrow Angle Camera (NAC), the team identified over 200 impact craters that formed during the LRO mission, ranging in size from about 10 to 140 feet (approximately 3 to 43 meters) in diameter.

    3
    Temporal ratio image formed from two LROC Narrow Angle Camera images (after image divided by the before image) revealing a new 12 meter (~40 foot) diameter impact crater (Latitude: 36.536°N; Longitude: 12.379°E) formed between 25 October 2012 and 21 April 2013, scene is 1300 meters (~4200 feet) wide. New crater and its continuous ejecta are seen as the small bright area in the center, dark areas are the result of material blasted out of the crater to distances much further than previously thought. Credits: NASA/GSFC/Arizona State University

    Since impact craters accumulate over time, a heavily cratered surface is older than a region with fewer craters. Knowing the number of craters that form each year is important when estimating absolute ages of the youngest regions. By analyzing the number, size distribution, and the time between each NAC temporal pair, the team estimated the contemporary cratering rate on the moon. During the search, they identified about 30 percent more new craters than anticipated by previous cratering models.

    “With this potentially higher impact rate, features with young model ages derived using crater counts and the standard rate may in fact be even younger than previously thought,” said Speyerer. “However, to be certain, we need several more years of observations and new crater discoveries.”

    In addition to discovering new impact craters, the team observed over 47,000 small surface changes, which they call splotches. They are most likely caused by small impacts, according to Speyerer. There are dense clusters of these splotches around new impact sites suggesting that many splotches may be secondary surface changes caused by material thrown out from the primary impact event.

    The team estimated their accumulation over time and from measuring their size they inferred how deeply each splotch dug up the surface and thus how long it takes to effectively churn the upper few centimeters (approximately an inch) of the regolith. The team found that 99 percent of the surface would be overturned by splotch formation after about 81,000 years. This rate is over 100 times faster than previous models that considered overturn from micrometeorite impacts alone, and ignored the effects of secondary impacts.

    “The increased churning rate will be important information for future designers of moon bases, said Speyerer. “Surface assets will have to be designed to withstand impacts from small particles moving at up to 500 meters per second (about 1,600 feet per second or 1,100 miles per hour).”

    The team also found that the new impact craters are surrounded by complex reflectance patterns related to material ejected during crater formation. Many of the larger impact craters — those greater than 10 meters in diameter — exhibit up to four distinct bright or dark reflectance zones.

    The research was funded by the LRO project. The Lunar Reconnaissance Orbiter Camera was developed at Arizona State University in Tempe. LRO is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, as a project under NASA’s Discovery Program. The Discovery Program is managed by NASA’s Marshall Spaceflight Center in Huntsville, Alabama, for the Science Mission Directorate at NASA Headquarters in Washington.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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
    NASA/Goddard Campus
    NASA image

     
  • richardmitnick 4:17 pm on September 29, 2016 Permalink | Reply
    Tags: , , LMC P3, , NASA Goddard, Record-breaking Binary in Galaxy Next Door   

    From NASA Goddard and Fermi: “NASA’s Fermi Finds Record-breaking Binary in Galaxy Next Door” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    NASA Fermi Banner


    Fermi

    Sept. 29, 2016
    Francis Reddy
    francis.j.reddy@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    Using data from NASA’s Fermi Gamma-ray Space Telescope and other facilities, an international team of scientists has found the first gamma-ray binary in another galaxy and the most luminous one ever seen. The dual-star system, dubbed LMC P3, contains a massive star and a crushed stellar core that interact to produce a cyclic flood of gamma rays, the highest-energy form of light.

    “Fermi has detected only five of these systems in our own galaxy, so finding one so luminous and distant is quite exciting,” said lead researcher Robin Corbet at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Gamma-ray binaries are prized because the gamma-ray output changes significantly during each orbit and sometimes over longer time scales. This variation lets us study many of the emission processes common to other gamma-ray sources in unique detail.”

    These rare systems contain either a neutron star or a black hole and radiate most of their energy in the form of gamma rays. Remarkably, LMC P3 is the most luminous such system known in gamma rays, X-rays, radio waves and visible light, and it’s only the second one discovered with Fermi.


    Access mp4 video here .
    Dive into the Large Magellanic Cloud and see a visualization of LMC P3, an extraordinary gamma-ray binary system discovered by NASA’s Fermi Gamma-ray Space Telescope. Credits: NASA’s Goddard Space Flight Center/Scott Wiessinger, producer

    A paper describing the discovery will appear in the Oct. 1 issue of The Astrophysical Journal and is now available online, and you an see the full science team.

    LMC P3 lies within the expanding debris of a supernova explosion located in the Large Magellanic Cloud (LMC), a small nearby galaxy about 163,000 light-years away.

    Large Magellanic Cloud. Adrian Pingstone  December 2003
    Large Magellanic Cloud. Adrian Pingstone December 2003

    In 2012, scientists using NASA’s Chandra X-ray Observatory found a strong X-ray source within the supernova remnant and showed that it was orbiting a hot, young star many times the sun’s mass.

    NASA/Chandra Telescope
    NASA/Chandra Telescope

    The researchers concluded the compact object was either a neutron star or a black hole and classified the system as a high-mass X-ray binary (HMXB).

    In 2015, Corbet’s team began looking for new gamma-ray binaries in Fermi data by searching for the periodic changes characteristic of these systems. The scientists discovered a 10.3-day cyclic change centered near one of several gamma-ray point sources recently identified in the LMC. One of them, called P3, was not linked to objects seen at any other wavelengths but was located near the HMXB. Were they the same object?

    3
    Observations from Fermi’s Large Area Telescope (magenta line) show that gamma rays from LMC P3 rise and fall over the course of 10.3 days. The companion is thought to be a neutron star. Illustrations across the top show how the changing position of the neutron star relates to the gamma-ray cycle. Credits: NASA’s Goddard Space Flight Center

    To find out, Corbet’s team observed the binary in X-rays using NASA’s Swift satellite, at radio wavelengths with the Australia Telescope Compact Array near Narrabri and in visible light using the 4.1-meter Southern Astrophysical Research Telescope on Cerro Pachón in Chile and the 1.9-meter telescope at the South African Astronomical Observatory near Cape Town.

    NASA/SWIFT Telescope
    NASA/SWIFT Telescope

    CSIRO Australian Telescope Compact Array at the Paul Wild Observatory, about 25 km west of the town of Narrabri in rural NSW about 500 km north-west of Sydney
    CSIRO Australian Telescope Compact Array at the Paul Wild Observatory, about 25 km west of the town of Narrabri in rural NSW about 500 km north-west of Sydney, AU

    NOAO/ Southern Astrophysical Research Telescope (SOAR)telescope situated on Cerro Pachón - IV Región - Chile, at 2,700 meters (8,775 feet)
    NOAO/ Southern Astrophysical Research Telescope (SOAR)telescope situated on Cerro Pachón – IV Región – Chile

    4
    1.9-meter Radcliffe telescope at the South African Astronomical Observatory near Cape Town

    The Swift observations clearly reveal the same 10.3-day emission cycle seen in gamma rays by Fermi. They also indicate that the brightest X-ray emission occurs opposite the gamma-ray peak, so when one reaches maximum the other is at minimum. Radio data exhibit the same period and out-of-phase relationship with the gamma-ray peak, confirming that LMC P3 is indeed the same system investigated by Chandra.

    “The optical observations show changes due to binary orbital motion, but because we don’t know how the orbit is tilted into our line of sight, we can only estimate the individual masses,” said team member Jay Strader, an astrophysicist at Michigan State University in East Lansing. “The star is between 25 and 40 times the sun’s mass, and if we’re viewing the system at an angle midway between face-on and edge-on, which seems most likely, its companion is a neutron star about twice the sun’s mass.” If, however, we view the binary nearly face-on, then the companion must be significantly more massive and a black hole.

    5
    LMC P3 (circled) is located in a supernova remnant called DEM L241 in the Large Magellanic Cloud, a small galaxy about 163,000 light-years away. The system is the first gamma-ray binary discovered in another galaxy and is the most luminous known in gamma rays, X-rays, radio waves and visible light.

    Both objects form when a massive star runs out of fuel, collapses under its own weight and explodes as a supernova. The star’s crushed core may become a neutron star, with the mass of half a million Earths squeezed into a ball no larger than Washington, D.C. Or it may be further compacted into a black hole, with a gravitational field so strong not even light can escape it.

    The surface of the star at the heart of LMC P3 has a temperature exceeding 60,000 degrees Fahrenheit (33,000 degrees Celsius), or more than six times hotter than the sun’s. The star is so luminous that pressure from the light it emits actually drives material from the surface, creating particle outflows with speeds of several million miles an hour.

    In gamma-ray binaries, the compact companion is thought to produce a “wind” of its own, one consisting of electrons accelerated to near the speed of light. The interacting outflows produce X-rays and radio waves throughout the orbit, but these emissions are detected most strongly when the compact companion travels along the part of its orbit closest to Earth.

    Through a different mechanism, the electron wind also emits gamma rays. When light from the star collides with high-energy electrons, it receives a boost to gamma-ray levels. Called inverse Compton scattering, this process produces more gamma rays when the compact companion passes near the star on the far side of its orbit as seen from our perspective.

    Prior to Fermi’s launch, gamma-ray binaries were expected to be more numerous than they’ve turned out to be. Hundreds of HMXBs are cataloged, and these systems are thought to have originated as gamma-ray binaries following the supernova that formed the compact object.

    “It is certainly a surprise to detect a gamma-ray binary in another galaxy before we find more of them in our own,” said Guillaume Dubus, a team member at the Institute of Planetology and Astrophysics of Grenoble in France. “One possibility is that the gamma-ray binaries Fermi has found are rare cases where a supernova formed a neutron star with exceptionally rapid spin, which would enhance how it produces accelerated particles and gamma rays.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy and with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

    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
    NASA/Goddard Campus

    NASA image

     
  • richardmitnick 6:33 am on September 28, 2016 Permalink | Reply
    Tags: , , Local Hot Bubble, NASA DXL sounding rocket, NASA Goddard, Solar wind charge exchange   

    From Goddard: “NASA-Funded Sounding Rocket Solves One Cosmic Mystery, Reveals Another” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    Sept. 23, 2016
    Editor: Rob Garner

    1
    NASA/JPL-Caltech/GSFC. Science Alert

    In the last century, humans realized that space is filled with types of light we can’t see – from infrared signals released by hot stars and galaxies, to the cosmic microwave background that comes from every corner of the universe. Some of this invisible light that fills space takes the form of X-rays, the source of which has been hotly contended over the past few decades.

    It wasn’t until the flight of the DXL sounding rocket, short for Diffuse X-ray emission from the Local galaxy, that scientists had concrete answers about the X-rays’ sources. In a new study, published Sept. 23, 2016, in the Astrophysical Journal, DXL’s data confirms some of our ideas about where these X-rays come from, in turn strengthening our understanding of our solar neighborhood’s early history. But it also reveals a new mystery – an entire group of X-rays that don’t come from any known source.

    2
    NASA-funded researchers sent a sounding rocket through the sun’s dense helium wake, called the helium-focusing cone, to understand the origin of certain X-rays in space. (Conceptual graphic not to scale.) Credits: NASA Goddard’s Conceptual Image Lab/Lisa Poje

    The two known sources of X-ray emission are the solar wind, the sea of solar material that fills the solar system, and the Local Hot Bubble, a theorized area of hot interstellar material that surrounds our solar system.

    “We show that the X-ray contribution from the solar wind charge exchange is about forty percent in the galactic plane, and even less elsewhere,” said Massimiliano Galeazzi, an astrophysicist at the University of Miami and an author on the study. “So the rest of the X-rays must come from the Local Hot Bubble, proving that it exists.”

    However, DXL also measured some high-energy X-rays that couldn’t possibly come from the solar wind or the Local Hot Bubble.

    “At higher energies, these sources contribute less than a quarter of the X-ray emission,” said Youaraj Uprety, lead author on the study and an astrophysicist at University of Miami at the time the research was conducted. “So there’s an unknown source of X-rays in this energy range.”

    In the decades since we first discovered the X-ray emission that permeates space, three main theories have been bandied about to explain its origins. First, and quickly ruled out, was the idea that these X-rays are a kind of background noise, coming from the distant reaches of the universe. Our galaxy has lots of neutral gas that would absorb X-rays coming from distant sources – meaning that these X-rays must originate somewhere near our solar system.

    3
    The Diffuse X-ray emission from the Local galaxy, or DXL, sounding rocket launched from White Sands Missile Range in New Mexico on Dec. 13, 2012, to study the source of certain X-rays observed near Earth. Credits: White Sands Missile Range, Visual Information Branch

    So what could produce this kind of X-ray so close to our solar system? Scientists theorized that there was a huge bubble of hot ionized gas enveloping our solar system, with electrons energetic enough that they could release X-rays like this. They called this structure the Local Hot Bubble.

    “We think that around 10 million years ago, a supernova exploded and ionized the gas of the Local Hot Bubble,” said Galeazzi. “But one supernova wouldn’t be enough to create such a large cavity and reach these temperatures – so it was probably two or three supernova over time, one inside the other.”

    The Local Hot Bubble was the prevailing theory for many years. Then, in the late 1990s, scientists discovered another source of X-rays – a process called solar wind charge exchange.

    Our sun is constantly releasing solar material in all directions, a flow of charged particles called the solar wind. Like the sun, the solar wind is made up of ionized gas, where electrons and ions have separated. This means that the solar wind can carry electric and magnetic fields.

    When the charged solar wind interacts with pockets of neutral gas, where the electrons and ions are still tightly bound together, it can pick up electrons from these neutral particles, exciting them. As these electrons settle back into a stable state, they lose energy in the form of X-rays – the same type of X-rays that had been thought to come from the Local Hot Bubble.

    The discovery of this solar wind X-ray source posed a problem for the Local Hot Bubble theory, since the only indication that it existed were these X-ray observations. But if the hot bubble did exist, it could tell us a lot about how our corner of the galaxy formed.

    “Identifying the X-ray contribution of the Local Hot Bubble is important for understanding the structure surrounding our solar system,” said Uprety, who is now an astrophysicist at Middle Tennessee State University. “It helps us build better models of the interstellar material in our solar neighborhood.”

    Distinguishing between X-rays from the solar wind and X-rays from the Local Hot Bubble was a challenge – that’s where DXL comes in. DXL flew on what’s called a sounding rocket, which flies for some 15 minutes. These few minutes of observing time above Earth’s atmosphere are valuable, since Earth’s blocks most of these X-rays, making observations like this impossible from the ground. Such short-duration sounding rockets provide a relatively inexpensive way to gather robust space observations.

    DXL is the second spacecraft to measure the X-rays in question, but unlike the previous mission – a satellite called ROSAT – DXL flew at a time when Earth was passing through something called the helium-focusing cone. The helium-focusing cone is a region of space where neutral helium is several times denser than in the rest of the inner solar system.

    “The solar system is moving through interstellar space at about 15 miles per second,” said Uprety. “This space is filled with hydrogen and helium. The helium is a little heavier, so it carves around the sun to form a tail.”

    Because solar wind charge exchange is dependent on having lots of neutral material to interact with, measuring X-rays in the helium-focusing cone could help scientists definitively determine how much of the X-ray emission comes from the solar wind, and how much – if any – comes from the Local Hot Bubble.

    DXL’s data revealed that about forty percent of most observed X-rays come from the solar wind. But in higher energy ranges, some X-rays are still unexplained. DXL’s observations show that less than a quarter of the X-ray emission at higher energy levels comes from the solar wind, and the Local Hot Bubble isn’t a good explanation either.

    “The temperature of the Local Hot Bubble is not high enough to produce X-rays in this energy range,” said Uprety. “So we’re left with an open question on the source of these X-rays.”

    DXL launched from White Sands Missile Range in New Mexico on Dec. 13, 2012. DXL is supported through NASA’s Sounding Rocket Program at the agency’s Wallops Flight Facility at Wallops Island, Virginia, which is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland. NASA’s Heliophysics Division manages the sounding-rocket program for the agency.

    Related Links

    Article in the Astrophysical Journal
    NASA-Funded X-ray Instrument Settles Interstellar Debate

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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
    NASA/Goddard Campus
    NASA

     
  • richardmitnick 10:08 pm on September 20, 2016 Permalink | Reply
    Tags: , , NASA Goddard, , NASA Scientists Find ‘Impossible’ Cloud on Titan – Again   

    From Goddard and JPL-Caltech: “NASA Scientists Find ‘Impossible’ Cloud on Titan – Again” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    NASA JPL Banner

    JPL-Caltech

    Sept. 20, 2016
    Preston Dyches
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-7013
    preston.dyches@jpl.nasa.gov

    1
    Scientists from NASA’s Cassini mission think the appearance of a cloud of dicyanoacetylene (C4N2) ice in Titan’s stratosphere is explained by “solid-state” chemistry taking place inside ice particles. The particles have an inner layer of cyanoacetylene (HC3N) ice coated with an outer layer of hydrogen cyanide (HCN) ice. (Left) When a photon of light penetrates the outer shell, it can interact with the HC3N, producing C3N and H. (Center) The C3N then reacts with HCN to yield (right) C4N2 and H. Another reaction that also yields C4N2 ice and H also is possible, but less likely. Credits: NASA’s Goddard Space Flight Center

    NASA/ESA/ASI Cassini Spacecraft
    NASA/ESA/ASI Cassini Spacecraft

    The puzzling appearance of an ice cloud seemingly out of thin air has prompted NASA scientists to suggest that a different process than previously thought — possibly similar to one seen over Earth’s poles — could be forming clouds on Saturn’s moon Titan.

    Located in Titan’s stratosphere, the cloud is made of a compound of carbon and nitrogen known as dicyanoacetylene (C4N2), an ingredient in the chemical cocktail that colors the giant moon’s hazy, brownish-orange atmosphere.

    Decades ago, the infrared instrument on NASA’s Voyager 1 spacecraft spotted an ice cloud just like this one on Titan. What has puzzled scientists ever since is this: they detected less than 1 percent of the dicyanoacetylene gas needed for the cloud to condense.

    Recent observations from NASA’s Cassini mission yielded a similar result. Using Cassini’s composite infrared spectrometer — or CIRS, which can identify the spectral fingerprints of individual chemicals in the atmospheric brew — researchers found a large high-altitude cloud made of the same frozen chemical. Yet, just as Voyager found, when it comes to the vapor form of this chemical, CIRS reported that Titan’s stratosphere is as dry as a desert.

    “The appearance of this ice cloud goes against everything we know about the way clouds form on Titan,” said Carrie Anderson, a CIRS co-investigator at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the study.

    The typical process for forming clouds involves condensation. On Earth, we’re familiar with the cycle of evaporation and condensation of water. The same kind of cycle takes place in Titan’s troposphere — the weather-forming layer of Titan’s atmosphere — but with methane instead of water.

    A different condensation process takes place in the stratosphere — the region above the troposphere — at Titan’s north and south winter poles. In this case, layers of clouds condense as the global circulation pattern forces warm gases downward at the pole. The gases then condense as they sink through cooler and cooler layers of the polar stratosphere.

    Either way, a cloud forms when the air temperature and pressure are favorable for the vapor to condense into ice. The vapor and the ice reach a balance point — an equilibrium — that is determined by the air temperature and pressure. Because of this equilibrium, scientists can calculate the amount of vapor where ice is present.

    “For clouds that condense, this equilibrium is mandatory, like the law of gravity,” said Robert Samuelson, an emeritus scientist at Goddard and a co-author of the paper.

    But the numbers don’t compute for the cloud made from dicyanoacetylene. The scientists determined that they would need at least 100 times more vapor to form an ice cloud where the cloud top was observed by Cassini’s CIRS.

    One explanation suggested early on was that the vapor might be present, but Voyager’s instrument wasn’t sensitive enough in the critical wavelength range needed to detect it. But when CIRS also didn’t find the vapor, Anderson and her Goddard and Caltech colleagues proposed an altogether different explanation. Instead of the cloud forming by condensation, they think the C4N2 ice forms because of reactions taking place on other kinds of ice particles. The researchers call this “solid-state chemistry,” because the reactions involve the ice, or solid, form of the chemical.

    The first step in the proposed process is the formation of ice particles made from the related chemical cyanoacetylene (HC3N). As these tiny bits of ice move downward through Titan’s stratosphere, they get coated by hydrogen cyanide (HCN). At this stage, the ice particle has a core and a shell comprised of two different chemicals. Occasionally, a photon of ultraviolet light tunnels into the frozen shell and triggers a series of chemical reactions in the ice. These reactions could begin either in the core or within the shell. Both pathways can yield dicyanoacteylene ice and hydrogen as products.

    The researchers got the idea of solid-state chemistry from the formation of clouds involved in ozone depletion high above Earth’s poles. Although Earth’s stratosphere has scant moisture, wispy nacreous clouds (also called polar stratospheric clouds) can form under the right conditions. In these clouds, chlorine-bearing chemicals that have entered the atmosphere as pollution stick to crystals of water ice, resulting in chemical reactions that release ozone-destroying chlorine molecules.

    “It’s very exciting to think that we may have found examples of similar solid-state chemical processes on both Titan and Earth,” said Anderson.

    The researchers suggest that, on Titan, the reactions occur inside the ice particles, sequestered from the atmosphere. In that case, dicyanoacetylene ice wouldn’t make direct contact with the atmosphere, which would explain why the ice and the vapor forms are not in the expected equilibrium.

    “The compositions of the polar stratospheres of Titan and Earth could not differ more,” said Michael Flasar, CIRS principal investigator at Goddard. “It is amazing to see how well the underlying physics of both atmospheres has led to analogous cloud chemistry.”

    The findings are published in the journal Geophysical Research Letters.

    The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington. JPL designed, developed and assembled the Cassini orbiter. The CIRS instrument was built by Goddard.

    For more information about Cassini, visit:

    http://www.nasa.gov/cassini

    http://saturn.jpl.nasa.gov

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    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
    NASA/Goddard Campus
    NASA image

     
  • richardmitnick 7:49 am on August 24, 2016 Permalink | Reply
    Tags: , NASA Goddard,   

    From Goddard: “NASA Establishes Contact With STEREO Mission” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    Aug. 22, 2016
    Karen C. Fox
    karen.c.fox@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    NASA/STEREO spacecraft
    NASA/STEREO spacecraft

    2
    On Aug. 21, 2016, NASA reestablished contact with the sun-watching STEREO-B spacecraft, after communications were lost in October 2014. STEREO-B is one of two spacecraft of the Solar Terrestrial Relations Observatory mission, which over the course of their lifetime have viewed the sun from vantage points such as the ones shown here, on the other side of the sun from Earth. This graphic shows the positions of the two STEREO spacecraft and their orbits in relation to Earth, Venus, Mercury and the sun. Credits: NASA

    On Aug. 21, 2016, contact was reestablished with one of NASA’s Solar Terrestrial Relations Observatories, known as the STEREO-B spacecraft, after communications were lost on Oct. 1, 2014. Over 22 months, the STEREO team has worked to attempt contact with the spacecraft. Most recently, they have attempted a monthly recovery operation using NASA’s Deep Space Network, or DSN, which tracks and communicates with missions throughout space.

    The DSN established a lock on the STEREO-B downlink carrier at 6:27 p.m. EDT. The downlink signal was monitored by the Mission Operations team over several hours to characterize the attitude of the spacecraft and then transmitter high voltage was powered down to save battery power. The STEREO Missions Operations team plans further recovery processes to assess observatory health, re-establish attitude control, and evaluate all subsystems and instruments.

    Communications with STEREO-B were lost during a test of the spacecraft’s command loss timer, a hard reset that is triggered after the spacecraft goes without communications from Earth for 72 hours. The STEREO team was testing this function in preparation for something known as solar conjunction, when STEREO-B’s line of sight to Earth – and therefore all communication – was blocked by the sun.

    STEREO-A continues to work normally.

    For more on STEREO: http://www.nasa.gov/stereo

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    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
    NASA/Goddard Campus
    NASA image

     
  • richardmitnick 3:57 pm on August 15, 2016 Permalink | Reply
    Tags: NASA Goddard, ,   

    From Goddard: “NASA’s Van Allen Probes Catch Rare Glimpse of Supercharged Radiation Belt” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    Aug. 15, 2016
    Lina Tran
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    Our planet is nestled in the center of two immense, concentric doughnuts of powerful radiation: the Van Allen radiation belts, which harbor swarms of charged particles that are trapped by Earth’s magnetic field. On March 17, 2015, an interplanetary shock – a shockwave created by the driving force of a coronal mass ejection, or CME, from the sun – struck Earth’s magnetic field, called the magnetosphere, triggering the greatest geomagnetic storm of the preceding decade.

    Magnetosphere of Earth, original bitmap from NASA. SVG rendering by Aaron Kaase
    Magnetosphere of Earth, original bitmap from NASA. SVG rendering by Aaron Kaase

    And NASA’s Van Allen Probes were there to watch the effects on the radiation belts.

    1
    Artist concept of accelerated electrons circulating in Earth’s Van Allen radiation belts. Credits: NASA’s Goddard Space Flight Center; Tom Bridgman, animator

    NASA Van Allen Probes


    On March 17, 2015, an interplanetary shock – a shockwave created by the driving force of a coronal mass ejection, or CME, from the sun – struck the outermost radiation belt, triggering the greatest geomagnetic storm of the preceding decade. NASA’s Van Allen Probes were there to watch it. Credits: NASA’s Goddard Space Flight Center; Genna Duberstein, producer

    One of the most common forms of space weather, a geomagnetic storm describes any event in which the magnetosphere is suddenly, temporarily disturbed. Such an event can also lead to change in the radiation belts surrounding Earth, but researchers have seldom been able to observe what happens. But on the day of the March 2015 geomagnetic storm, one of the Van Allen Probes was orbiting right through the belts, providing unprecedentedly high-resolution data from a rarely witnessed phenomenon. A paper on these observations was published in the Journal of Geophysical Research on Aug. 15, 2016.

    Researchers want to study the complex space environment around Earth because the radiation and energy there can impact our satellites in a wide variety of ways – from interrupting onboard electronics to increasing frictional drag to disrupting communications and navigation signals.

    “We study radiation belts because they pose a hazard to spacecraft and astronauts,” said David Sibeck, the Van Allen Probes mission scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who was not involved with the paper. “If you knew how bad the radiation could get, you would build a better spacecraft to accommodate that.”

    Studying the radiation belts is one part of our efforts to monitor, study and understand space weather. NASA launched the twin Van Allen Probes in 2012 to understand the fundamental physical processes that create this harsh environment so that scientists can develop better models of the radiation belts. These spacecraft were specifically designed to withstand the constant bombardment of radiation in this area and to continue to collect data even under the most intense conditions. A set of observations on how the radiation belts respond to a significant space weather storm, from this harsh space environment, is a goldmine.

    The recent research describes what happened: The March 2015 storm was initiated by an interplanetary shock hurtling toward Earth – a giant shockwave in space set off by a CME, much like a tsunami is triggered by an earthquake.

    Swelling and shrinking in response to such events and solar radiation, the Van Allen belts are highly dynamic structures within our planet’s magnetosphere. Sometimes, changing conditions in near-Earth space can energize electrons in these ever-changing regions. Scientists don’t yet know whether energization events driven by interplanetary shocks are common. Regardless, the effects of interplanetary shocks are highly localized events – meaning if a spacecraft is not precisely in the right place when a shock hits, it won’t register the event at all. In this case, only one of the Van Allen Probes was in the proper position, deep within the magnetosphere – but it was able to send back key information.

    The spacecraft measured a sudden pulse of electrons energized to extreme speeds – nearly as fast as the speed of light – as the shock slammed the outer radiation belt. This population of electrons was short-lived, and their energy dissipated within minutes. But five days later, long after other processes from the storm had died down, the Van Allen Probes detected an increased number of even higher energy electrons. Such an increase so much later is a testament to the unique energization processes following the storm.

    “The shock injected – meaning it pushed – electrons from outer regions of the magnetosphere deep inside the belt, and in that process, the electrons gained energy,” said Shri Kanekal, the deputy mission scientist for the Van Allen Probes at Goddard and the leading author of a paper on these results.

    Researchers can now incorporate this example into what they already know about how electrons behave in the belts, in order to try to understand what happened in this case – and better map out the space weather processes there. There are multiple ways electrons in the radiation belts can be energized or accelerated: radially, locally or by way of a shock. In radial acceleration, electrons are carried by low-frequency waves towards Earth. Local acceleration describes the process of electrons gaining energy from relatively higher frequency waves as the electrons orbit Earth. And finally, during shock acceleration, a strong interplanetary shock compresses the magnetosphere suddenly, creating large electric fields that rapidly energize electrons.

    Scientists study the different processes to understand what role each process plays in energizing particles in the magnetosphere. Perhaps these mechanisms occur in combination, or maybe just one at a time. Answering this question remains a major goal in the study of radiation belts – a difficult task considering the serendipitous nature of the data collection, particularly in regard to shock acceleration.

    Additionally, the degree of electron energization depends on the process that energizes them. One can liken the process of shock acceleration, as observed by the Van Allen Probe, to pushing a swing.

    “Think of ‘pushing’ as the phenomenon that’s increasing the energy,” Kanekal said. “The more you push a swing, the higher it goes.” And the faster electrons will move after a shock.

    In this case, those extra pushes likely led to the second peak in high-energy electrons. While electromagnetic waves from the shock lingered in the magnetosphere, they continued to raise the electrons’ energy. The stronger the storm, the longer such waves persist. Following the March 2015 storm, resulting electromagnetic waves lasted several days. The result: a peak in electron energy measured by the Van Allen Probe five days later.

    This March 2015 geomagnetic storm was one of the strongest yet of the decade, but it pales in comparison to some earlier storms. A storm during March 1991 was so strong that it produced long-lived, energized electrons that remained within the radiation belts for multiple years. With luck, the Van Allen Probes may be in the right position in their orbit to observe the radiation belt response to more geomagnetic storms in the future. As scientists gather data from different events, they can compare and contrast them, ultimately helping to create robust models of the little-understood processes occurring in these giant belts.

    The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, built and operates the Van Allen Probes for NASA’s Heliophysics Division in the Science Mission Directorate. The Van Allen Probes are the second mission in NASA’s Living With a Star program, an initiative managed by Goddard and focused on aspects of the sun-Earth system that directly affect human lives and society.

    Related Links

    Van Allen Probes Mission Overview
    NASA’s Van Allen Probes Spot an Impenetrable Barrier in Space
    NASA’s Van Allen Probes Revolutionize View of Radiation Belts

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    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
    NASA/Goddard Campus
    NASA

     
  • richardmitnick 12:26 pm on August 12, 2016 Permalink | Reply
    Tags: , , , NASA Goddard, , OSIRIS-REx Laser Altimeter (OLA)   

    From Goddard: “NASA to Map Asteroid Bennu from the Ground Up” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    Aug. 11, 2016
    Sarah Schlieder
    sarah.schlieder@nasa.gov
    NASA’s Goddard Space Flight Center in Greenbelt, Maryland

    1
    The OSIRIS-REx Laser Altimeter (OLA), contributed by the Canadian Space Agency (CSA), will create 3-D maps of asteroid Bennu to help the mission team select a sample collection site. NASA’s OSIRIS-REx spacecraft will travel to the near-Earth asteroid Bennu and bring at least a 60-gram (2.1-ounce) sample back to Earth for study. Credit: NASA/Goddard/Debbie McCallum. phys.org

    How do you study the topography of an asteroid millions of miles away? Map it with a robotic cartographer!

    NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, or OSIRIS-REx, will launch in September 2016 and travel to a near-Earth asteroid known as Bennu to harvest a sample of surface material and return it to Earth for study.

    NASA OSIRIS-REx Spacecraft
    NASA OSIRIS-REx Spacecraft

    But before the science team can select a sample site, it needs to know a little something about the asteroid’s topography.

    The OSIRIS-REx Laser Altimeter, or OLA, is provided by the Canadian Space Agency and will be used to create three-dimensional global topographic maps of Bennu and local maps of candidate sample sites.

    “OLA will measure the asteroid’s topography and shape in a detail that is unprecedented compared to other asteroid missions,” said Michael Daly, OLA instrument scientist at York University in Toronto, Canada. ” This 3-D shape will be the foundational dataset for the other instruments.”

    Think of your favorite computer animated movie. The characters and environment are colored and shaded in such a way that they look almost lifelike. But all of those details need a 3-D shape in order to take form. The same is true for the detailed data gathered by OSIRIS-REx’s instruments.

    To create these 3-D models, OLA uses LIDAR, which stands for light detection and ranging. LIDAR is similar to radar, but uses light instead of radio waves to measure distance. OLA will emit infrared laser pulses toward the surface of Bennu as the spacecraft moves around the asteroid. The laser pulses reflect back from the surface to a detector. The team will measure the time difference between outgoing and incoming pulses to calculate the distance between the spacecraft and Bennu.

    LIDAR has been used on prior spacecraft, including the Mars Global Surveyor and the Lunar Reconnaissance Orbiter. Those laser altimeters are fixed to the spacecraft, meaning that the laser pulse will only travel in the direction that the spacecraft is pointing. This can limit the coverage and spatial resolution of their topographic maps. So, while they have generated a vast amount of data, fixed LIDAR are not ideal for missions where the data must be gathered quickly.

    “OLA is the first scanning LIDAR to fly on a planetary mission,” said Beau Bierhaus, an OLA team member at Lockheed Martin. “Because the LIDAR can articulate independently of the spacecraft, the LIDAR provides improved operational flexibility, and more importantly, much greater spatial coverage and resolution.”


    The OSIRIS-REx Laser Altimeter (OLA) will provide a three-dimenional map of asteroid Bennu’s shape, which will allow scientists to understand the context of the asteroid’s geography and the sample location. OLA is provided by the Canadian Space Agency in exchange for Canadian ownership of a portion of the returned asteroid sample.
    Credits: Credit: NASA’s Goddard Space flight Center/Katrina Jackson
    This video is public domain and can be downloaded from the Scientific Visualization Studio.

    OLA is expected to thoroughly map Bennu with about 6 billion measurements of the asteroid’s surface, which measures about one-third of a mile (one-half kilometer) in diameter. In comparison, the laser altimeter on the Lunar Reconnaissance Orbiter has received more than 6.8 billion measurements of the surface of the moon, which has a diameter of about 2,159 miles (3,500 kilometers).

    The fundamental data of the asteroid’s shape and topography that OLA will provide are essential for several key phases during the mission.

    The science team will use the high-resolution topographic data, in conjunction with camera images and on-board navigation algorithms, to navigate around the asteroid and guide the spacecraft to the selected sample site.

    “We’re measuring topography down to one centimeter,” said Olivier Barnouin, the Altimetry Working Group lead at Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. “We’re looking at an asteroid at a scale that no other mission has before. We don’t want to be off in some unknown area during sample acquisition.”

    The three-dimensional maps will also give geologic context to the returned asteroid sample. Just as geologists on Earth document where they collect their samples in the field on topographic maps, OLA will allow the science team to take their measurements and observations of the collected sample and apply them to their broader understanding of Bennu.

    OLA will also allow the science team to study how regolith, or loose surface material, behaves in a microgravity environment. Scientists have done similar studies on the moon and Mars, but unlike Bennu, these bodies have relatively high gravity.

    “What happens on asteroids is that you take that gravity dial and turn it way down,” Bierhaus said. “The dynamics of how regolith moves on the surface of the asteroid are foreign to us. OLA data will give us a greater understanding of how granular material behaves in space.”

    This understanding is especially important for future asteroid missions. Scientists will need to know how regolith behaves in micro-gravity environments if we want to send astronauts to an asteroid someday to collect samples.

    “Collaborating on this project reminds us of the unique relationship between Canada and the United States,” said Daly. “It provides both countries access to additional technological expertise and people that they would not otherwise have.”

    Goddard will provide overall mission management, systems engineering and safety and mission assurance for OSIRIS-REx. Dante Lauretta is the mission’s principal investigator at the University of Arizona. Lockheed Martin Space Systems in Denver built the spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages New Frontiers for the agency’s Science Mission Directorate in Washington.

    For more information about OSIRIS-REx, visit:

    http://www.nasa.gov/osiris-rex

    http://www.asteroidmission.org

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    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
    NASA/Goddard Campus
    NASA

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: