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  • richardmitnick 12:37 pm on May 24, 2018 Permalink | Reply
    Tags: Blazar 3C 279, Gamma-ray emission regions, , NASA Goddard, USA based VLBA   

    From NASA Goddard and NASA/Fermi via phys.org: “Multiple gamma-ray emission regions detected in the blazar 3C 279” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    NASA Fermi Banner

    NASA/Fermi Telescope
    NASA Fermi

    phys.org

    May 23, 2018
    Tomasz Nowakowski

    1
    An example composite image of 3C 279 convolved with a beam size of 0.1 mas (circle in the bottom left corner). The contours represent the total intensity while the color scale is for polarized intensity image of 3C 279. The line segments (length of the segments is proportional to fractional polarization) marks the EVPA direction. Credit: Rani et al., 2018.

    Using very long baseline interferometry (VLBI), astronomers have investigated the magnetic field topology of the blazar 3C 279, uncovering the presence of multiple gamma-ray emission regions in this source. The discovery was presented May 11 in a paper published in The Astrophysical Journal.

    Blazars, classified as members of a larger group of active galaxies that host active galactic nuclei (AGN), are the most numerous extragalactic gamma-ray sources. Their characteristic features are relativistic jets pointed almost exactly toward the Earth. In general, blazars are perceived by astronomers as high-energy engines serving as natural laboratories to study particle acceleration, relativistic plasma processes, magnetic field dynamics and black hole physics.

    NASA’s Fermi Gamma-ray Space Telescope is an essential instrument for blazar studies. The spacecraft is equipped with in the Large Area Telescope (LAT), which allows it to detect photons with energy from about 20 million to about 300 billion electronvolts. So far, Fermi has discovered more than 1,600 blazars.

    NASA/Fermi LAT

    A team of astronomers led by Bindu Rani of NASA’s Goddard Space Flight Center has analyzed the data provided by LAT and by the U.S.-based Very Long Baseline Array (VLBA) to investigate the blazar 3C 279.

    NRAO VLBA

    The studied object, located in the constellation Virgo. It is one of the brightest and most variable sources in the gamma-ray sky monitored by Fermi. The data allowed Rani’s team to uncover more insight into the nature of gamma-ray emission from this blazar.

    “Using high-frequency radio interferometry (VLBI) polarization imaging, we could probe the magnetic field topology of the compact high-energy emission regions in blazars. A case study for the blazar 3C 279 reveals the presence of multiple gamma-ray emission regions,” the researchers wrote in the paper.

    Six gamma-ray flares were observed in 3C 279 between November 2013 and August 2014. The researchers also investigated the morphological changes in the blazar’s jet.

    The team found that ejection of a new component (designated NC2) during the first three gamma-ray flares suggests the VLBI core as the possible site of the high-energy emission. Furthermore, a delay between the last three flares and the ejection of a new component (NC3) indicates that high-energy emission in this case is located upstream of the 43 GHz core (closer to the blazar’s black hole).

    The astronomers concluded that their results are indicative of multiple sites of high-energy dissipation in 3C 279. Moreover, according to the authors of the paper, their study proves that VLBI is the most promising technique to probe the high-energy dissipation regions. However, they added that still more observations are needed to fully understand these features and mechanisms behind them.

    “The Fermi mission will continue observing the GeV sky at least for next couple of years. The TeV missions are on their way to probe the most energetic part of the electromagnetic spectrum. High-energy polarization observations (AMEGO, IXPE, etc.) will be of extreme importance in understanding the high-energy dissipation mechanisms,” the researchers concluded.

    See the full article here.


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    The Fermi Gamma-ray Space Telescope , formerly referred to as the Gamma-ray Large Area Space Telescope (GLAST), is a space observatory being used to perform gamma-ray astronomy observations from low Earth orbit. Its main instrument is the Large Area Telescope (LAT), with which astronomers mostly intend to perform an all-sky survey studying astrophysical and cosmological phenomena such as active galactic nuclei, pulsars, other high-energy sources and dark matter. Another instrument aboard Fermi, the Gamma-ray Burst Monitor (GBM; formerly GLAST Burst Monitor), is being used to study gamma-ray bursts. The mission is a joint venture of NASA, the United States Department of Energy, and government agencies in France, Germany, Italy, Japan, and Sweden.

    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

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  • richardmitnick 12:22 pm on May 11, 2018 Permalink | Reply
    Tags: Astronomers Have Found a Record-Breaking Pair of Stars Orbiting With a Dizzying Speed, , , , , NASA Goddard, ,   

    From Goddard via Science Alert: “Astronomers Have Found a Record-Breaking Pair of Stars Orbiting With a Dizzying Speed” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    Science Alert

    11 MAY 2018
    MICHELLE STARR

    1
    Artist’s impression of a rotating neutron star. (Pitris/iStock)

    Astronomers have discovered a record-breaking star system. It’s called IGR J17062-6143, and it’s a very compact binary, where one of the stars is a rapidly spinning, superdense neutron star called an X-ray pulsar.

    The two stars take just 38 minutes to orbit each other. That’s the fastest orbital period of any X-ray pulsar binary ever observed.

    IGR J17062-6143 (or J17062 for short) was only discovered in 2006; it’s very low mass, and very faint, and around 7.3 kiloparsecs, or 23,809 light-years, away.

    It’s been studied fairly extensively, but finding out more about it required some pretty up-to-date technology – NASA’s Neutron star Interior Composition Explorer (NICER), an X-ray detection instrument installed on the International Space Station in June 2017.

    NASA NICER on the ISS

    NASA/NICER

    Previous research had revealed an accretion disc associated with the binary, and that one of the stars was a pulsar, but a 20-minute 2008 observation using NASA’s Rossi X-Ray Timing Explorer could only set a lower limit for the binary’s orbital period.

    NASA/ROSSI

    Neutron stars are also extremely hot, and shine extremely brightly. However, because they’re so small, they’re difficult for us to see – except in X-ray. They can also spin incredibly fast, which creates an electric field that accelerates electrons away from the poles, creating relativistic radiation jets. If this beam passes between us and the pulsar, we can see it flash, or “pulse”, like a cosmic lighthouse.

    In the case of binary X-ray pulsars, these jets are fed by the matter stolen from the donor star. This material falls to the surface of the pulsar, where it travels along its strong magnetic field lines to the poles.

    It was by observing these X-ray jets that the 2008 observation led to the discovery – the J17062 pulsar was rotating 163 times per second, nearly 9,800 revolutions per minute.

    NICER has been able to observe the system for a lot longer – over 7 hours of observing time taken over 5.3 days in August 2017. This has allowed researchers to obtain a lot more detailed information.

    As well as the 38-minute orbital period, researchers were able to ascertain that the two stars are separated by a distance of just 300,000 kilometres (186,000 miles) – less than the distance that separates Earth and the Moon.

    These two factors, and analysis of the spectra produced by the binary, has led the research team on the new paper to the conclusion that the pulsar’s companion star is a very low-mass, low-hydrogen white dwarf, only around 1.5 percent the mass of the Sun. “It’s not possible for a hydrogen-rich star, like our Sun, to be the pulsar’s companion,” said lead researcher Tod Strohmayer, an astrophysicist at NASA Goddard.

    “You can’t fit a star like that into an orbit so small.”

    The pulsar, by comparison, is around 1.4 times the mass of the Sun, but much, much smaller. Neutron stars – of which pulsars are a subset – are the collapsed cores of stars below around three times the mass of the Sun, in the final stage of their life cycle. They’re usually only around 10-20 kilometres in diameter.

    Because they’re so massive, though, neutron stars have a pretty strong gravitational pull – hence the accretion disc, as the J17062 pulsar pulls material from the white dwarf, the binary’s ‘donor star’. That high mass imbalance also means that the central point of the orbit – circular, as the team discovered – is much closer to the pulsar, just 3,000 kilometres (1,900 miles) from it. It’s so close that the white dwarf almost seems to be orbiting a stationary star; but, although faint, it does exert a gravitational pull on the pulsar.

    “The distance between us and the pulsar is not constant,” Strohmayer said. “It’s varying by this orbital motion. When the pulsar is closer, the X-ray emission takes a little less time to reach us than when it’s further away.” “This time delay is small, only about 8 milliseconds for J17062’s orbit, but it’s well within the capabilities of a sensitive pulsar machine like NICER.”

    The team’s research has been published in The Astrophysical Journal Letters.

    See the full article here.

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    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.


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  • richardmitnick 8:23 am on May 10, 2018 Permalink | Reply
    Tags: , , , , , NASA Goddard, , NASA Spacecraft Discovers New Magnetic Process in Turbulent Space   

    From NASA Goddard Space Flight Center: “NASA Spacecraft Discovers New Magnetic Process in Turbulent Space” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    May 9, 2018

    Mara Johnson-Groh
    mara.johnson-groh@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    1
    In a turbulent magnetic environment, magnetic field lines become scrambled. As the field lines cross, intense electric currents (shown here as bright regions) form and eventually trigger magnetic reconnection (indicated by a flash), which is an explosive event that releases magnetic energy accumulated in the current layers and ejects high-speed bi-directional jets of electrons. Credit: NASA Goddard’s Conceptual Image Lab/Lisa Poje; Simulations by: University of Chicago/Colby Haggerty; University of Delaware/Tulasi Parashar

    Though close to home, the space immediately around Earth is full of hidden secrets and invisible processes. In a new discovery reported in the journal Nature, scientists working with NASA’s Magnetospheric Multiscale spacecraft — MMS — have uncovered a new type of magnetic event in our near-Earth environment by using an innovative technique to squeeze extra information out of the data.

    Magnetic reconnection is one of the most important processes in the space — filled with charged particles known as plasma — around Earth. This fundamental process dissipates magnetic energy and propels charged particles, both of which contribute to a dynamic space weather system that scientists want to better understand, and even someday predict, as we do terrestrial weather. Reconnection occurs when crossed magnetic field lines snap, explosively flinging away nearby particles at high speeds. The new discovery found reconnection where it has never been seen before — in turbulent plasma.


    In a new discovery reported in the journal Nature, scientists working with NASA’s Magnetospheric Multiscale spacecraft — MMS — uncovered a new type of magnetic event in our near-Earth environment. Credits: NASA’s Goddard Space Flight Center/Joy Ng

    NASA MMS prior to launch Credit: NASA/ Ben Smegelsky

    NASA MMS satellites in space. Credit: NASA

    “In the plasma universe, there are two important phenomena: magnetic reconnection and turbulence,” said Tai Phan, a senior fellow at the University of California, Berkeley, and lead author on the paper. “This discovery bridges these two processes.”

    Magnetic reconnection has been observed innumerable times in the magnetosphere — the magnetic environment around Earth — but usually under calm conditions. The new event occurred in a region called the magnetosheath, just outside the outer boundary of the magnetosphere, where the solar wind is extremely turbulent. Previously, scientists didn’t know if reconnection even could occur there, as the plasma is highly chaotic in that region. MMS found it does, but on scales much smaller than previous spacecraft could probe.


    In a turbulent magnetic environment, magnetic field lines become scrambled. As the field lines cross, intense electric currents (shown here as bright regions) form and eventually trigger magnetic reconnection (indicated by a flash), which is an explosive event that releases magnetic energy accumulated in the current layers and ejects high-speed bi-directional jets of electrons. NASA’s Magnetospheric Multiscale mission witnessed this process in action as it flew through the electron jets the turbulent boundary just at the edge of Earth’s magnetic environment. Credits: NASA’s Goddard Space Flight Center’s Conceptual Image Lab/Lisa Poje; Simulations by: Colby Haggerty (University of Chicago), Tulasi Parashar (University of Delaware)

    MMS uses four identical spacecraft flying in a pyramid formation to study magnetic reconnection around Earth in three dimensions. Because the spacecraft fly incredibly close together — at an average separation of just four-and-a-half miles, they hold the record for closest separation of any multi-spacecraft formation — they are able to observe phenomena no one has seen before. Furthermore, MMS’s instruments are designed to capture data at speeds a hundred times faster than previous missions.

    Even though the instruments aboard MMS are incredibly fast, they are still too slow to capture turbulent reconnection in action, which requires observing narrow layers of fast moving particles hurled by the recoiling field lines. Compared to standard reconnection, in which broad jets of ions stream out from the site of reconnection, turbulent reconnection ejects narrow jets of electrons only a couple miles wide.

    “The smoking gun evidence is to measure oppositely directed electron jets at the same time, and the four MMS spacecraft were lucky to corner the reconnection site and detect both jets”, said Jonathan Eastwood, a lecturer at Imperial College, London, and a co-author of the paper.

    Crucially, MMS scientists were able to leverage the design of one instrument, the Fast Plasma Investigation, to create a technique to interpolate the data — essentially allowing them to read between the lines and gather extra data points — in order to resolve the jets.

    “The key event of the paper happens in only 45 milliseconds. This would be one data point with the basic data,” said Amy Rager, a graduate student at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the scientist who developed the technique. “But instead we can get six to seven data points in that region with this method, allowing us to understand what is happening.”


    Earth is surrounded by a protective magnetic environment — the magnetosphere — shown here in blue, which deflects a supersonic stream of charged particles from the Sun, known as the solar wind. As the particles flow around Earth’s magnetosphere, it forms a highly turbulent boundary layer called the magnetosheath, shown in yellow. Scientists, like those involved with NASA’s Magnetospheric Multiscale mission, are studying this turbulent region to help us learn more about our dynamic space environment.
    Credits: NASA’s Goddard Space Flight Center/Mary Pat Hrybyk-Keith; NASA Goddard’s Conceptual Image Lab/Josh Masters

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

    As the particles flow around Earth’s magnetosphere, it forms a highly turbulent boundary layer called the magnetosheath, shown in yellow [in video]. Scientists, like those involved with NASA’s Magnetospheric Multiscale mission, are studying this turbulent region to help us learn more about our dynamic space environment.
    Credits: NASA’s Goddard Space Flight Center/Mary Pat Hrybyk-Keith; NASA Goddard’s Conceptual Image Lab/Josh Masters

    With the new method, the MMS scientists are hopeful they can comb back through existing datasets to find more of these events, and potentially other unexpected discoveries as well.

    Magnetic reconnection occurs throughout the universe, so that when we learn about it around our planet — where it’s easiest for Earthlings to examine it — we can apply that information to other processes farther away. The finding of reconnection in turbulence has implications, for example, for studies on the Sun. It may help scientists understand the role magnetic reconnection plays in heating the inexplicably hot solar corona — the Sun’s outer atmosphere — and accelerating the supersonic solar wind. NASA’s upcoming Parker Solar Probe mission launches directly to the Sun in the summer of 2018 to investigate exactly those questions — and that research is all the better armed the more we understand about magnetic reconnection near home.

    Related Links

    Learn more about the Magnetospheric Multiscale Mission
    Learn more about NASA’s research on the Sun-Earth environment

    See the full article here.

    See also here.

    See also here .

    Please help promote STEM in your local schools.

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    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 9:38 am on May 7, 2018 Permalink | Reply
    Tags: Ganymede, , , NASA Goddard   

    From NASA Goddard Space Flight Center: “Old Data, New Tricks: Fresh Results from NASA’s Galileo Spacecraft 20 Years On” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    April 30, 2018
    Mara Johnson-Groh
    mara.johnson-groh@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    6
    Banner image: NASA’s Hubble Space Telescope has caught Jupiter’s moon Ganymede playing a game of “peek-a-boo.” In this crisp Hubble image, Ganymede is shown just before it ducks behind the giant planet. This color image was made from three images taken on April 9, 2007, with the Wide Field Planetary Camera 2 in red, green, and blue filters. The image shows Jupiter and Ganymede in close to natural colors. Credit: NASA, ESA and E. Karkoschka (University of Arizona)

    1
    This image of Ganymede, one of Jupiter’s moons and the largest moon in our solar system, was taken by NASA’s Galileo spacecraft. Credits: NASA

    Far across the solar system, from where Earth appears merely as a pale blue dot, NASA’s Galileo spacecraft spent eight years orbiting Jupiter.

    NASA/Galileo 1989-2003

    During that time, the hearty spacecraft — slightly larger than a full-grown giraffe — sent back spates of discoveries on the gas giant’s moons, including the observation of a magnetic environment around Ganymede that was distinct from Jupiter’s own magnetic field. The mission ended in 2003, but newly resurrected data from Galileo’s first flyby of Ganymede is yielding new insights about the moon’s environment — which is unlike any other in the solar system.

    “We are now coming back over 20 years later to take a new look at some of the data that was never published and finish the story,” said Glyn Collinson, lead author of a recent paper about Ganymede’s magnetosphere at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We found there’s a whole piece no one knew about.”

    The new results showed a stormy scene: particles blasted off the moon’s icy surface as a result of incoming plasma rain, and strong flows of plasma pushed between Jupiter and Ganymede due to an explosive magnetic event occurring between the two bodies’ magnetic environments. Scientists think these observations could be key to unlocking the secrets of the moon, such as why Ganymede’s auroras are so bright.

    In 1996, shortly after arriving at Jupiter, Galileo made a surprising discovery: Ganymede had its own magnetic field.

    2
    Magnetosphere of Ganymede based on model of Xianzhe Jia (JGR, 113, 6212, 2008), with location of auroral emissions (in blue).

    While most planets in our solar system, including Earth, have magnetic environments — known as magnetospheres — no one expected a moon to have one.

    Between 1996 and 2000, Galileo made six targeted flybys of Ganymede, with multiple instruments collecting data on the moon’s magnetosphere. These included the spacecraft’s Plasma Subsystem, or PLS, which measured the density, temperature and direction of the plasma — excited, electrically charged gas — flowing through the environment around Galileo. New results, recently published in the journal Geophysical Research Letters, reveal interesting details about the magnetosphere’s unique structure.

    We know that Earth’s magnetosphere — in addition to helping make compasses work and causing auroras — is key to in sustaining life on our planet, because it helps protect our planet from radiation coming from space.

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

    Some scientists think Earth’s magnetosphere was also essential for the initial development of life, as this harmful radiation can erode our atmosphere. Studying magnetospheres throughout the solar system not only helps scientists learn about the physical processes affecting this magnetic environment around Earth, it helps us understand the atmospheres around other potentially habitable worlds, both in our own solar system and beyond.

    3
    This infographic describes Ganymede’s magnetosphere.
    Credits: NASA’s Goddard Space Flight Center/Mary Pat Hrybyk-Keith

    Ganymede’s magnetosphere offers the chance to explore a unique magnetic environment located within the much larger magnetosphere of Jupiter. Nestled there, it’s protected from the solar wind, making its shape different from other magnetospheres in the solar system. Typically, magnetospheres are shaped by the pressure of supersonic solar wind particles flowing past them. But at Ganymede, the relatively slower-moving plasma around Jupiter sculpts the moon’s magnetosphere into a long horn-like shape that stretches ahead of the moon in the direction of its orbit.

    Flying past Ganymede, Galileo was continually pummeled by high-energy particles — a battering the moon is also familiar with. Plasma particles accelerated by the Jovian magnetosphere, continually rain down on Ganymede’s poles, where the magnetic field channels them toward the surface. The new analysis of Galileo PLS data showed plasma being blasted off the moon’s icy surface due to the incoming plasma rain.

    “There are these particles flying out from the polar regions, and they can tell us something about Ganymede’s atmosphere, which is very thin,” said Bill Paterson, a co-author of the study at NASA Goddard, who served on the Galileo PLS team during the mission. “It can also tell us about how Ganymede’s auroras form.”


    This visualization shows a simplified model of Jupiter’s magnetosphere, designed to illustrate the scale, and basic features of the structure and impacts of the magnetic axis (cyan arrow) offset from the planetary rotation axis (blue arrow). The semi-transparent gray mesh in the distance represents the boundary of the magnetosphere.
    Credits: NASA’s Scientific Visualization Studio/JPL NAIF

    4
    In this illustration, the moon Ganymede orbits the giant planet Jupiter. Ganymede is depicted with auroras, which were observed by NASA’s Hubble Space Telescope.
    Credits: NASA/ESA

    NASA/ESA Hubble Telescope

    Ganymede has auroras, or northern and southern lights, just like Earth does. However, unlike our planet, the particles causing Ganymede’s auroras come from the plasma surrounding Jupiter, not the solar wind. When analyzing the data, the scientists noticed that during its first Ganymede flyby, Galileo fortuitously crossed right over Ganymede’s auroral regions, as evidenced by the ions it observed raining down onto the surface of the moon’s polar cap. By comparing the location where the falling ions were observed with data from Hubble, the scientists were able to pin down the precise location of the auroral zone, which will help them solve mysteries, such as what causes the auroras.

    As it cruised around Jupiter, Galileo also happened to fly right through an explosive event caused by the tangling and snapping of magnetic field lines. This event, called magnetic reconnection, occurs in magnetospheres across our solar system. For the first time, Galileo observed strong flows of plasma pushed between Jupiter and Ganymede due to a magnetic reconnection event occurring between the two magnetospheres. It’s thought that this plasma pump is responsible for making Ganymede’s auroras unusually bright.

    Future study of the PLS data from that encounter may yet provide new insights related to subsurface oceans previously determined to exist within the moon using data from both Galileo and the Hubble Space Telescope.

    The research was funded by NASA’s Solar System Workings program and the Galileo mission managed by NASA’s Jet Propulsion Laboratory in Pasadena, California, for the agency’s Science Mission Directorate in Washington.

    Related Links

    Learn more about NASA’s Galileo mission
    “NASA’s Hubble Observations Suggest Underground Ocean on Jupiter’s Largest Moon” (March 12, 2015)

    See the full article here.

    Please help promote STEM in your local schools.

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    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 2:14 pm on February 23, 2018 Permalink | Reply
    Tags: NASA Goddard, NASA’s SDO Reveals How Magnetic Cage on the Sun Stopped Solar Eruption,   

    From Goddard: “NASA’s SDO Reveals How Magnetic Cage on the Sun Stopped Solar Eruption” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    Feb. 23, 2018
    Lina Tran
    lina.tran@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    A dramatic magnetic power struggle at the Sun’s surface lies at the heart of solar eruptions, new research using NASA data shows. The work highlights the role of the Sun’s magnetic landscape, or topology, in the development of solar eruptions that can trigger space weather events around Earth.

    The scientists, led by Tahar Amari, an astrophysicist at the Center for Theoretical Physics at the École Polytechnique in Palaiseau Cedex, France, considered solar flares, which are intense bursts of radiation and light. Many strong solar flares are followed by a coronal mass ejection, or CME, a massive, bubble-shaped eruption of solar material and magnetic field, but some are not — what differentiates the two situations is not clearly understood.

    Using data from NASA’s Solar Dynamics Observatory, or SDO, the scientists examined an October 2014 Jupiter-sized sunspot group, an area of complex magnetic fields, often the site of solar activity.

    NASA/SDO

    This was the biggest group in the past two solar cycles and a highly active region. Though conditions seemed ripe for an eruption, the region never produced a major CME on its journey across the Sun. It did, however, emit a powerful X-class flare, the most intense class of flares. What determines, the scientists wondered, whether a flare is associated with a CME?

    1
    On Oct. 24, 2014, NASA’s SDO observed an X-class solar flare erupt from a Jupiter-sized sunspot group. Credits: Tahar Amari et al./Center for Theoretical Physics/École Polytechnique/NASA Goddard/Joy Ng.

    The team of scientists included SDO’s observations of magnetic fields at the Sun’s surface in powerful models that calculate the magnetic field of the Sun’s corona, or upper atmosphere, and examined how it evolved in the time just before the flare. The model reveals a battle between two key magnetic structures: a twisted magnetic rope — known to be associated with the onset of CMEs — and a dense cage of magnetic fields overlying the rope.

    The scientists found that this magnetic cage physically prevented a CME from erupting that day. Just hours before the flare, the sunspot’s natural rotation contorted the magnetic rope and it grew increasingly twisted and unstable, like a tightly coiled rubber band. But the rope never erupted from the surface: Their model demonstrates it didn’t have enough energy to break through the cage. It was, however, volatile enough that it lashed through part of the cage, triggering the strong solar flare.

    By changing the conditions of the cage in their model, the scientists found that if the cage were weaker that day, a major CME would have erupted on Oct. 24, 2014. The group is interested in further developing their model to study how the conflict between the magnetic cage and rope plays out in other eruptions. Their findings are summarized in a paper published in Nature on Feb. 8, 2018.

    “We were able to follow the evolution of an active region, predict how likely it was to erupt, and calculate the maximum amount of energy the eruption can release,” Amari said. “This is a practical method that could become important in space weather forecasting as computational capabilities increase.”

    3
    In this series of images, the magnetic rope, in blue, grows increasingly twisted and unstable. But it never erupts from the Sun’s surface: The model demonstrates the rope didn’t have enough energy to break through the magnetic cage, in yellow. Credits: Tahar Amari et al./Center for Theoretical Physics/École Polytechnique/NASA Goddard/Joy Ng.

    Related:

    NASA Watches the Sun Put a Stop to Its Own Eruption
    Two Weeks in the Life of a Sunspot

    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

     
  • richardmitnick 11:21 am on February 21, 2018 Permalink | Reply
    Tags: , , , , JAXA ERG-Exploration of energization and Radiation in Geospace satellite, NASA Goddard, Pulsating Aurora Mysteries Uncovered with Help from NASA’s THEMIS Mission   

    From Goddard: “Pulsating Aurora Mysteries Uncovered with Help from NASA’s THEMIS Mission” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    Feb. 20, 2018
    Mara Johnson-Groh
    mara.johnson-groh@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    Sometimes on a dark night near the poles, the sky pulses a diffuse glow of green, purple and red. Unlike the long, shimmering veils of typical auroral displays, these pulsating auroras are much dimmer and less common. While scientists have long known auroras to be associated with solar activity, the precise mechanism of pulsating auroras was unknown. Now, new research, using data from NASA’s Time History of Events and Macroscale Interactions during Substorms — or THEMIS — mission and Japan’s Exploration of energization and Radiation in Geospace — shortened to ERG, or also known as Arase — satellite, has finally captured the missing link thought responsible for these auroras. The answer lies in chirping waves that rhythmically pulse the particles that create the auroras.

    NASA THEMIS satellite

    JAXA ERG-Exploration of energization and Radiation in Geospace satellite

    Earth’s magnetic bubble — the magnetosphere — protects the planet from high-energy radiation coming from the Sun and interstellar space, but during particularly strong solar events, particles can slip through. Once inside, the particles and the energy they carry are stored on the nightside of the magnetosphere, until an event, known as a substorm, releases the energy. The electrons are then sent speeding down into Earth’s upper atmosphere where they collide with the other particles and produce the characteristic glow.

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

    Pulsating auroras, however, have a slightly different cause. The magnetosphere is home to a type of plasma wave known as whistler mode chorus. These waves have characteristic rising tones — reminiscent of the sounds of chirping birds — and are able to efficiently disturb the electrons. When these waves make their appearance within the magnetosphere, some of the electrons scattered by the wave careen down into Earth’s atmosphere, causing the pulsating auroras.

    While scientists have long believed this mechanism to be responsible for pulsating auroras, they had no definitive proof until now. The multipoint observations from the ERG satellite and ground-based all-sky cameras from the THEMIS mission allowed scientists to pinpoint the cause and effect, seeing the event from start to end. The results were published in the journal Nature.

    Research done with NASA’s ground-based camera and Japan’s spacecraft in the near-Earth laboratory has applications further afield. Chorus waves have been observed around other planets in the solar system, including Jupiter and Saturn. Likely, the processes observed around Earth can help explain auroral features on these gas giants as well as on planets around other stars. The results also help scientists better understand how plasma waves can influence electrons — something that occurs in processes across the universe.

    2
    Illustration of the ERG satellite in orbit.
    Credits: ISAS/JAXA

    See the full article here.

    Please help promote STEM in your local schools.

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    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 10:18 pm on February 15, 2018 Permalink | Reply
    Tags: , , , , NASA Goddard, NASA Space Network, NASA TDRS   

    From Goddard: “Last NASA Communications Satellite of its Kind Joins Fleet” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    Feb. 15, 2018
    Ashley Hume
    ashley.hume@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    NASA TDRS Tracking and Data Relay Satellite

    NASA has begun operating the last satellite of its kind in the network that provides communications and tracking services to more than 40 NASA missions, including critical, real-time communication with the International Space Station. Following its August launch and a five-month period of in-orbit testing, the third-generation Tracking and Data Relay Satellite (TDRS), referred to as TDRS-M until this important milestone, was renamed TDRS-13, becoming the tenth operational satellite in the geosynchronous, space-based fleet.

    “With TDRS-13’s successful acceptance into the network, the fleet is fully replenished and set to continue carrying out its important mission through the mid-2020s,” said Badri Younes, NASA’s deputy associate administrator for Space Communications and Navigation at NASA Headquarters in Washington. “Now, we have begun focusing on the next generation of near-Earth communications relay capabilities.”

    The 10 TDRS spacecraft comprise the space-based portion of the Space Network, relaying signals from low-Earth-orbiting missions with nearly 100 percent coverage.

    “The acceptance of this final third-generation TDRS into the Space Network is the result of many years of dedication and hard work by the TDRS team,” said Dave Littmann, the TDRS project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “As a result, critical space communication and tracking services that enable NASA human spaceflight and scientific discovery will continue well into the next decade.”

    ​TDRS-13 launched on Aug. 18, 2017, aboard a United Launch Alliance Atlas V rocket from Cape Canaveral Air Force Station in Florida. Built by Boeing in El Segundo, California, TDRS-13 and its nearly identical third-generation sister spacecraft are performing well. TDRS-K and -L launched in 2013 and 2014, respectively.

    NASA established the TDRS project in 1973, and the first satellite launched 10 years later, providing NASA an exponential increase in data rates and contact time communicating with the space shuttle and other orbiting spacecraft, such as the Hubble Space Telescope. Since then, NASA has continued to expand the TDRS constellation and advance the spacecraft capabilities.

    “NASA looks forward to the future, developing even better ways to meet missions’ communications needs,” said Younes. “We will leverage NASA’s success in optical communications and other innovative technologies, as well as significantly increase our partnership with industry, as we envision a shift to increased reliance on commercial networks for most, if not all, of our communications needs in the near-Earth environment.”

    Goddard is home to the TDRS project, which is responsible for the development and launch of these communication satellites. Boeing, headquartered in Chicago, Illinois, is the private contractor for the third-generation TDRS spacecraft. TDRS is the space element of NASA’s Space Network, providing the critical communication and navigation lifeline for NASA missions. NASA’s Space Communications and Navigation (SCaN) program, part of the Human Exploration and Operations Mission Directorate at the agency’s Headquarters in Washington, is responsible for NASA’s Space Network.
    For more information about NASA’s TDRS satellites, visit:
    https://www.nasa.gov/tdrs

    For more information about SCaN, visit:
    https://www.nasa.gov/SCaN

    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

     
  • richardmitnick 3:52 pm on February 9, 2018 Permalink | Reply
    Tags: A Detailed Timeline of The IMAGE Mission Recovery, , , , , NASA Goddard   

    From Goddard: “A Detailed Timeline of The IMAGE Mission Recovery” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    Feb. 8, 2018
    By Miles Hatfield
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    The Imager for Magnetopause-to-Aurora Global Exploration, or IMAGE, spacecraft was re-discovered in January 2018 after more than twelve years of silence. A powerhouse of magnetosphere and aurora research, the IMAGE mission was a key driver of studies of the Sun-Earth connection from its launch on March 25, 2000, until its last contact on Dec. 18, 2005.

    Now a watchful citizen scientist, NASA, and a team of IMAGE scientists and engineers detected and received data from the spacecraft. Here’s how it happened.

    Saturday, Jan. 20

    1:39 AM EST: Amateur astronomer Scott Tilley in Roberts Creek, British Columbia, using his home satellite detection rig, begins his nightly sky scan then goes to bed.

    Sometime in the afternoon – Reviewing the previous night’s data manually – 4 MHz at a time – Tilley detects an unexpected radio frequency signal. Analyzing the specifics of its Doppler Curve – the way the frequency modulates as it crosses the sky, like the siren of a passing ambulance – and comparing it to the orbital elements logged in the space-track catalog, it came back as NASA spacecraft 26113, corresponding to the IMAGE mission.

    Unaware of any details of the mission, Tilley shrugged, logged the finding into his database, and continued looking through his data.

    A few minutes later. Reconsidering his findings — why hadn’t he ever detected the satellite in any previous scans? — Tilley took a closer look. Suddenly a portion of the spectrum just below the data he’d read jumped out. The (relatively weak) signal he’d originally detected had only been a harmonic of the spacecraft’s fundamental frequency, which was much stronger – one of the strongest he’d seen.

    Saturday Evening

    A review of public frequency lists – where other amateur astronomers post their findings – came up empty. No one else had detected this satellite in recent years. After some research, Tilley turned up an article on EO PORTAL about the IMAGE mission. “But they were referring to IMAGE in the past-tense,” Tilley said.

    Tilley eventually found IMAGE’s detailed Failure Report which stated that the spacecraft’s power source had likely been tripped, and that NASA had watched to see if it might be rebooted by an extended eclipse. But a 2007 eclipse came and went while IMAGE remained silent, and the mission was declared over.

    “The realization came over me . . . that what I was observing was the fact that the spacecraft had rebooted,” Tilley remarked. “But who’s going to listen to some guy in his basement with a coil of copper wire on his roof?”

    Sunday, Jan. 21

    01:48 am EST – Tilley publishes his findings in a blog post, then spends the next two days at work.

    Tuesday, Jan. 23

    01:38 am EST – Ruminating on his findings with his wife over dinner (who, according to Tilley, admonished him that “someone who’s smart enough to find a lost satellite surely can find the guy who built the thing”), Tilley gets up from the table to do some more research. He discovers the contact information for Dr. James Burch, the IMAGE principal investigator at the Southwest Research Institute in San Antonio, Texas, and emails him about his findings.

    4:41 am EST – Burch responds. “This is very exciting. I really appreciate your doing this and letting me know about it.”

    Burch shares the news with Richard J. Burley, former ground system manager and mission director for IMAGE at Goddard Space Flight Center in Greenbelt, Maryland. Burley (after reportedly having to “clean all the coffee off of my laptop that I spit on it when I saw Jim Burch’s email…”) jumps to action, contacting NASA’s Space Science Mission Operations Office (SSMO) and Deep Space Network (DSN) to alert them.

    11:44 am EST – With the news of the discovery spreading amongst the hobbyist community, amateur observer Paul Marsh reports to Tilley the first independent observation of a similar satellite signal:

    1
    Credits: Twitter: @uhf_satcom

    :12 pm EST – Burley begins communicating with a team of IMAGE scientists and engineers. His plan is to first determine if the object sending the signal is indeed IMAGE, and if so, whether the Deep Space Network can communicate with it.

    3:31 pm EST – Lisa Rhoads, system engineer and former IMAGE DSN Scheduler at NASA Goddard, recovers the last known Nominal Sequence of Events (NSOE) codes used by IMAGE – essential files used to control the Deep Space Network systems during the execution of pre-pass, pass, and post-pass actions that tell the antennae how to communicate with the spacecraft.

    She also updates Burley on the ways that the Deep Space Network had changed since 2005. Major changes include the decommissioning of several ground stations and antennae that were used to track IMAGE in the past, as well as several significant functionality changes in how the communications work.

    11:02 pm EST – Rhoads begins setting up the software required to communicate with IMAGE, including the NSOE codes.

    Thursday, Jan. 25

    To verify Tilley’s radio frequency observations as well as attempt to directly contact the satellite, NASA team members across the US begin coordinating to verify the downlink signal with a spectrum analyzer and capture a digital spectrum recording.

    Steve Waldher (NASA’s Jet Propulsion Laboratory in Pasadena, California), Jack Lippincott (JPL) and Lisa Rhoads (Goddard) coordinate to recover and read the old NSOE files.

    Leslie Ambrose (Goddard) and the Telecom Networks & Technology Branch at Goddard attempt to use a local Near Earth Network antenna to track the spacecraft. Unable to detect a signal on its first attempt, a review of pointing data and center frequency and adjustments are made and another attempt is planned for the following day.

    Rebecca Besser (Goddard) and Dale Fink (Goddard) create orbit models for IMAGE to determine when recent long-duration eclipses occurred and understand when IMAGE could have been rebooted. They identify an eclipse in mid 2012, which was as long as that of 2007, and another in early 2017, though it was not as long.

    Friday, Jan. 26

    11:54 am EST – Engineers at Goddard acquire the downlink signal and analyze its characteristics. Initial readings are consistent with those expected from the IMAGE spacecraft. Further analysis reveals that the signal strength is oscillating, indicating that the target object may be spinning, as would be expected if the object was, in fact, IMAGE.

    Throughout the day, five antennae located throughout the US—in Greenbelt, Maryland; Laurel, Maryland; Berkeley, California; White Sands, New Mexico; and Wallops Island, Virginia—come online to monitor and track the object. With all five sites producing consistent readings, there is much optimism that it is, in fact, IMAGE.

    Saturday, Jan. 27

    2:59 am EST – Tilley completes a review of his data archive and sends results to Burley, suggesting based on analysis of the Doppler Curve that the spacecraft has been transmitting since at least May 4, 2017.

    3
    Doppler curves matching those of IMAGE are detected on May 4, 2017. Credits: Scott Tilley, AScT

    9:28 am EST – Notifying the team that the five antennae have agreed on basic radio frequency characteristics of the object, Burley sets the next goal: to read data from the spacecraft.

    “Once we successfully capture data, we need the tools to examine the data in order to verify with certainty that it is IMAGE,” Burley writes in an email. “The definitive proof of identity requires reading the data, which will contain IMAGE’s unique [NASA-internal] spacecraft ID number: 166. Until this is done, although the evidence may be strong, we cannot be certain that the spacecraft is in fact IMAGE.”

    The challenge for doing so is primarily technical. “The hardware and operating systems that we used back in the day no longer exist,” Burley explains. “The FEDS/ASIST systems still exist and are in use on other missions, but they have been re-hosted, moved from AIX to Linux, and are about a dozen versions ahead of what we used on IMAGE. I’m certain that we’ll run into some compatibility issues.”

    Burley adds a closing question: “Does anyone happen to have a 4 mm tape cartridge reader that will work on a modern Linux workstation and a 16-year-old data tape and not disintegrate it?”

    3:06 pm EST – Meanwhile, Dr. Cees Bassa, an astronomer at the Netherlands Institute for Radio Astronomy and collaborator with Tilley, reviews his own data and detects the purported IMAGE signal as early as October 2016:

    4
    Timeline of IMAGE’s operational periods and eclipses that could have rebooted it. Credits: Dr. Cees Bassa (ASTRON, the Netherlands)

    Monday, Jan. 29

    Word continues to spread of IMAGE’s potential recovery. Burley and the team continue to re-work the software and locate documentation in preparation for retrieving data from the spacecraft.

    Having overcome the first challenges of knowing the signal signature and where to point the antenna to find it, the hard work begins at the Johns Hopkins University Applied Physics Lab, or APL, in Laurel, Maryland, to track and read data from the spacecraft.

    9:40 am EST – IMAGE track begins and the APL Satellite Communications Facility, or SCF, team starts the process of trying to achieve “frame sync lock” – locking onto the spacecraft’s telemetry signal to allow data to be retrieved. The SCF team, working with an incomplete set of IMAGE spacecraft RF and telemetry parameters, try different combinations for over seven hours without success.

    Tuesday, Jan. 30

    Burley successfully locates a 4 mm tape reader – borrowing a backup from the 1995 Solar and Heliospheric Observatory , or SOHO, mission – and begins attempting to read the 16-year-old tapes. Meanwhile, work continues at APL.

    1:40 pm EST – IMAGE track begins again at the APL Satellite Communications Facility.

    2:15 pm EST (approximate) – After slowly fine-tuning the parameters for APL’s 18-meter antenna (APL-18) to find the right combination, lead station engineer Tony Garcia achieves frame sync lock from the spacecraft.

    2:16 pm EST – Bill Dove, SCF manager and engineer at APL, verifies telemetry data frames are being received and files stored correctly. A quick look at the raw telemetry files show they contain actual spacecraft data.

    3:01 pm EST – Bill Dove sends first telemetry file to NASA personnel.

    3:21 pm EST – Tom Bialas (Goddard) downloads the first data file, and at last reads its ID number: 166, matching the IMAGE spacecraft. Emails quickly circulate amongst the team that there has been definitive confirmation that the spacecraft is IMAGE.

    6:20 pm EST – Engineers at APL start an unattended IMAGE track and continue to capture IMAGE data for a continued 8 ½ hours.

    Wednesday, Jan. 31

    The first data is downloaded and its ID read, but actually accessing and decoding the data it contains requires several more steps – and Burley and the team at Goddard are hard at work deciphering them.

    Thursday, Feb. 1

    12:40 pm EST – The first data files, indicating the state of the spacecraft, are successfully decoded. The team learns that the battery is fully charged at 100%, and its temperature is in line with those in 2005 and historic values.

    3:19 pm EST – Engineers at APL continue to capture IMAGE data. Scientists determine that they are now running on Side A of the Power Distribution Unit (PDU) – a surprise given that it had been thought that the side A was dead after a presumed power failure on Thanksgiving Day in 2004.

    The ultimate cause of the current reboot is still not known, but these findings suggest that a reboot in some form has in fact, occurred.

    But the data indicate an overall healthy spacecraft. Next steps for the IMAGE team are to see if they can do more than just listen to the spacecraft, and talk back to it. As of Feb. 7, efforts are still underway.

    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

     
  • richardmitnick 2:51 pm on February 6, 2018 Permalink | Reply
    Tags: , , , BurstCube, , , , , , NASA Goddard   

    From Goddard: “NASA Technology to Help Locate Electromagnetic Counterparts of Gravitational Waves” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    Feb. 6, 2018
    By Lori Keesey
    NASA’s Goddard Space Flight Center

    1
    Principal Investigator Jeremy Perkins and his co-investigator, Georgia de Nolfo, recently won funding to build a new CubeSat mission, called BurstCube. Respectively, Perkins and de Nolfo hold a crystal, or scintillator, and silicon photomultiplier array technology that will be used to detect and localize gamma-ray bursts for gravitational-wave science. The photomultiplier array shown here specifically was developed for another CubeSat mission called TRYAD, which will investigate gamma-ray bursts in high-altitude lightning clouds.
    Credits: NASA/W. Hrybyk

    A compact detector technology applicable to all types of cross-disciplinary scientific investigations has found a home on a new CubeSat mission designed to find the electromagnetic counterparts of events that generate gravitational waves.

    NASA scientist Georgia de Nolfo and her collaborator, astrophysicist Jeremy Perkins, recently received funding from the agency’s Astrophysics Research and Analysis Program to develop a CubeSat mission called BurstCube. This mission, which will carry the compact sensor technology that de Nolfo developed, will detect and localize gamma-ray bursts caused by the collapse of massive stars and mergers of orbiting neutron stars. It also will detect solar flares and other high-energy transients once it’s deployed into low-Earth orbit in the early 2020s.

    The cataclysmic deaths of massive stars and mergers of neutron stars are of special interest to scientists because they produce gravitational waves — literally, ripples in the fabric of space-time that radiate out in all directions, much like what happens when a stone is thrown into a pond.

    Since the Laser Interferometer Gravitational Wave Observatory, or LIGO, confirmed their existence a couple years ago, LIGO and the European Virgo detectors have detected other events, including the first-ever detection of gravitational waves from the merger of two neutron stars announced in October 2017.

    Less than two seconds after LIGO detected the waves washing over Earth’s space-time, NASA’s Fermi Gamma-ray Space Telescope detected a weak burst of high-energy light — the first burst to be unambiguously connected to a gravitational-wave source.

    These detections have opened a new window on the universe, giving scientists a more complete view of these events that complements knowledge obtained through traditional observational techniques, which rely on detecting electromagnetic radiation — light — in all its forms.

    Complementary Capability

    Perkins and de Nolfo, both scientists at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, see BurstCube as a companion to Fermi in this search for gravitational-wave sources. Though not as capable as the much larger Gamma-ray Burst Monitor, or GBM, on Fermi, BurstCube will increase coverage of the sky. Fermi-GBM observes the entire sky not blocked by the Earth. “But what happens if an event occurs and Fermi is on the other side of Earth, which is blocking its view,” Perkins said. “Fermi won’t see the burst.”

    BurstCube, which is expected to launch around the time additional ground-based LIGO-type observatories begin operations, will assist in detecting these fleeting, hard-to-capture high-energy photons and help determine where they originated. In addition to quickly reporting their locations to the ground so that other telescopes can find the event in other wavelengths and home in on its host galaxy, BurstCube’s other job is to study the sources themselves.

    Miniaturized Technology

    BurstCube will use the same detector technology as Fermi’s GBM; however, with important differences.

    Under the concept de Nolfo has advanced through Goddard’s Internal Research and Development program funding, the team will position four blocks of cesium-iodide crystals, operating as scintillators, in different orientations within the spacecraft. When an incoming gamma ray strikes one of the crystals, it will absorb the energy and luminesce, converting that energy into optical light.

    Four arrays of silicon photomultipliers and their associated read-out devices each sit behind the four crystals. The photomultipliers convert the light into an electrical pulse and then amplify this signal by creating an avalanche of electrons. This multiplying effect makes the detector far more sensitive to this faint and fleeting gamma rays.

    Unlike the photomultipliers on Fermi’s GBM, which are bulky and resemble old-fashioned television tubes, de Nolfo’s devices are made of silicon, a semiconductor material. “Compared with more conventional photomultiplier tubes, silicon photomultipliers significantly reduce mass, volume, power and cost,” Perkins said. “The combination of the crystals and new readout devices makes it possible to consider a compact, low-power instrument that is readily deployable on a CubeSat platform.”

    In another success for Goddard technology, the BurstCube team also has baselined the Dellingr 6U CubeSat bus that a small team of center scientists and engineers developed to show that CubeSat platforms could be more reliable and capable of gathering highly robust scientific data.

    “This is high-demand technology,” de Nolfo said. “There are applications everywhere.”

    For other Goddard technology news, go to https://www.nasa.gov/sites/default/files/atoms/files/winter_2018_final_lowrez.pdf

    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

     
  • richardmitnick 11:30 am on January 31, 2018 Permalink | Reply
    Tags: , , , , , IceCube cubesat, NASA Goddard   

    From Goddard: “NASA’s Small Spacecraft Produces First 883-Gigahertz Global Ice-Cloud Map” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    Jan. 30, 2018
    Lori Keesey
    NASA’s Goddard Space Flight Center

    1
    The bread loaf-sized IceCube was deployed from the International Space Station in May. One month later, it began science operations gathering global data about atmospheric ice clouds in the submillimeter wavelengths. Credits: NASA.

    2
    IceCube Principal Investigator Dong Wu set out to demonstrate a commercial 883-Gigahertz radiometer in space, but ended up getting much more: the world’s first ice-cloud map in that frequency. Here he is pictured holding the instrument. Credits: NASA.

    3
    Relatively small teams from both Goddard and the Wallops Flight Facility built the IceCube mission. The Goddard team included (left photo, back row, from left to right): Dong Wu, Michael Solly, Jared Lucey, Jeffrey Piepmeier, Paul Racette, Derek Hudson; (front row, left to right): Melyane Ortiz-Acosta, Armi Pellerano, Carlos Duran-Aviles, Kevin Horgan, Negar Ehsan, and Mark Wong. Credits: NASA

    A bread loaf-sized satellite has produced the world’s first map of the global distribution of atmospheric ice in the 883-Gigahertz band, an important frequency in the submillimeter wavelength for studying cloud ice and its effect on Earth’s climate.

    IceCube — the diminutive spacecraft that deployed from the International Space Station in May 2017— has demonstrated-in-space a commercial 883-Gigahertz radiometer developed by Virginia Diodes Inc., or VDI, of Charlottesville, Virginia, under a NASA Small Business Innovative Research contract. It is capable of measuring critical atmospheric cloud ice properties at altitudes between 3-9 miles (5 Km-15 Km).

    NASA scientists pioneered the use of submillimeter wavelength bands, which fall between the microwave and infrared on the electromagnetic spectrum, to sense ice clouds. However, until IceCube, these instruments had flown only aboard high-altitude research aircraft. This meant scientists could gather data only in areas over which the aircraft flew.

    “With IceCube, scientists now have a working submillimeter radiometer system in space at a commercial price,” said Dong Wu, a scientist and IceCube principal investigator at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “More importantly, it provides a global view on Earth’s cloud-ice distribution.”

    Sensing atmospheric cloud ice requires scientists deploy instruments tuned to a broad range of frequency bands. However, it’s particularly important to fly submillimeter sensors. This wavelength fills a significant data gap in the middle and upper troposphere where ice clouds are often too opaque for infrared and visible sensors to penetrate. It also reveals data about the tiniest ice particles that can’t be detected clearly in other microwave bands.

    The Technical Challenge

    IceCube’s map is a first of its kind and bodes well for future space-based observations of global ice clouds using submillimeter-wave technology, said Wu, whose team built the spacecraft using funding from NASA’s Earth Science Technology Office’s (ESTO) In-Space Validation of Earth Science Technologies (InVEST) program and NASA’s Science Mission Directorate CubeSat Initiative. The team’s challenge was making sure the commercial receiver was sensitive enough to detect and measure atmospheric cloud ice using as little power as possible.

    Ultimately, the agency wants to infuse this type of receiver into an ice-cloud imaging radiometer for NASA’s proposed Aerosol-Cloud-Ecosystems, or ACE, mission. Recommended by the National Research Council, ACE would assess on a daily basis the global distribution of ice clouds, which affect the Earth’s emission of infrared energy into space and its reflection and absorption of the Sun’s energy over broad areas. Before IceCube, this value was highly uncertain.

    “It speaks volumes that our scientists are doing science with a mission that primarily was supposed to demonstrate technology,” said Jared Lucey, one of IceCube’s instrument engineers. He was one of only a handful of scientists and engineers at Goddard and NASA’s Wallops Flight Facility in Virginia who developed IceCube in just two years. “We met our mission goals and now everything else is bonus,” he said.

    Multiple Lessons Learned

    In addition to demonstrating submillimeter-wave observations from space, the team gained important insights into how to efficiently develop a CubeSat mission, determining which systems to make redundant and which tests to forgo because of limited funds and a short schedule, said Jaime Esper, IceCube’s mission systems designer and technical project manager at Goddard.

    “It wasn’t an easy task,” said Negar Ehsan, IceCube’s instrument system lead. “It was a low-budget project” that required the team to develop both an engineering test unit and a flight model in a relatively short period of time. In spite of the challenges, the team delivered the VDI-provided instrument on time and budget. “We demonstrated for the first time 883-Gigahertz observations in space and proved that the VDI-provided system works appropriately,” she said. “It was rewarding.”

    The team used commercial off-the-shelf components, including VDI’s radiometer. The components came from multiple commercial providers and didn’t always work together harmoniously, requiring engineering. The team not only integrated the radiometer to the spacecraft, but also built spacecraft ground-support systems and conducted thermal-vacuum, vibration, and antenna testing at Goddard and Wallops.

    “IceCube isn’t perfect,” Wu conceded, referring to noise or slight errors in the radiometer’s data. “However, we can make a scientifically useful measurement. We came away with a lot of lessons learned from this CubeSat project, and next time engineers can build it much more quickly.”

    “This is a different mission model for NASA,” Wu continued. “Our principal goal was to show this small mission could be done. The question was, could we can get useful science and advance space technology with a low-cost CubeSat developed under an effective government-commercial partnership. I believe the answer is yes.”

    Small satellites, including CubeSats, are playing an increasingly larger role in exploration, technology demonstration, scientific research and educational investigations at NASA, including: planetary space exploration; Earth observations; fundamental Earth and space science; and developing precursor science instruments like cutting-edge laser communications, satellite-to-satellite communications and autonomous movement capabilities.

    NASA ESTO supports InVEST missions like IceCube and technologies at NASA centers, industry and academia to develop, refine and demonstrate new methods for observing Earth from space, from information systems to new components and instruments.

    For more Goddard technology news, go to https://www.nasa.gov/sites/default/files/atoms/files/winter_2018_final_lowrez.pdf

    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

     
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