Tag: Space News

NASA Selects Mission to Study Churning Chaos in our Milky Way and Beyond

NASA has selected a science mission that will measure emissions from the interstellar medium, which is the cosmic material found between stars. This data will help scientists determine the life cycle of interstellar gas in our Milky Way galaxy, witness the formation and destruction of star-forming clouds, and understand the dynamics and gas flow in the vicinity of the center of our galaxy.

The Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory (GUSTO) mission, led by the principal investigator of the University of Arizona, Christopher Walker, will fly an Ultralong-Duration Balloon (ULDB) carrying a telescope with carbon, oxygen, and nitrogen emission line detectors. This unique combination of data will provide the spectral and spatial resolution information needed for Walker and his team to untangle the complexities of the interstellar medium, and map out large sections of the plane of our Milky Way galaxy and the nearby galaxy known as the Large Magellanic Cloud.

“GUSTO will provide the first complete study of all phases of the stellar life cycle, from the formation of molecular clouds, through star birth and evolution, to the formation of gas clouds and the re-initiation of the cycle,” said Paul Hertz, astrophysics division director in the Science Mission Directorate in Washington. “NASA has a great history of launching observatories in the Astrophysics Explorers Program with new and unique observational capabilities. GUSTO continues that tradition.”

The mission is targeted for launch in 2021 from McMurdo, Antarctica, and is expected to stay in the air between 100 to 170 days, depending on weather conditions. It will cost approximately $40 million, including the balloon launch funding and the cost of post-launch operations and data analysis.

The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, is providing the mission operations, and the balloon platform where the instruments are mounted, known as the gondola. The University of Arizona in Tucson will provide the GUSTO telescope and instrument, which will incorporate detector technologies from NASA’s Jet Propulsion Laboratory in Pasadena, California, the Massachusetts Institute of Technology in Cambridge, Arizona State University in Tempe, and SRON Netherlands Institute for Space Research.

NASA’s Astrophysics Explorers Program requested proposals for mission of opportunity investigations in September 2014. A panel of NASA and other scientists and engineers reviewed two mission of opportunity concept studies selected from the eight proposals submitted at that time, and NASA has determined that GUSTO has the best potential for excellent science return with a feasible development plan.

NASA’s Explorers Program is the agency’s oldest continuous program and is designed to provide frequent, low-cost access to space using principal investigator-led space science investigations relevant to the astrophysics and heliophysics programs in agency’s Science Mission Directorate. The program has launched more than 90 missions. It began in 1958 with the Explorer 1, which discovered the Earth’s radiation belts, now called the Van Allen belt, named after the principal investigator. Another Explorer mission, the Cosmic Background Explorer, led to a Nobel Prize. NASA’s Goddard Space Flight Center in Greenbelt, Maryland manages the program for the Science Mission Directorate in Washington.

For more information on the Explorers Program, visit:

https://explorers.gsfc.nasa.gov

For more information on scientific balloons, visit:

https://www.nasa.gov/scientificballoons

-end-

Felicia Chou
Headquarters, Washington
202-358-0257
felicia.chou@nasa.gov

Last Updated: March 24, 2017
Editor: Katherine Brown

Photo Credit: NASA

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NASA’s Juno Spacecraft Set for Fifth Jupiter Flyby

NASA’s Juno spacecraft will make its fifth flyby over Jupiter’s mysterious cloud tops on Monday, March 27, at 1:52 a.m. PDT (4:52 a.m. EDT, 8:52 UTC).

At the time of closest approach (called perijove), Juno will be about 2,700 miles (4,400 kilometers) above the planet’s cloud tops, traveling at a speed of about 129,000 miles per hour (57.8 kilometers per second) relative to the gas-giant planet. All of Juno’s eight science instruments will be on and collecting data during the flyby.

“This will be our fourth science pass — the fifth close flyby of Jupiter of the mission — and we are excited to see what new discoveries Juno will reveal,” said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio. “Every time we get near Jupiter’s cloud tops, we learn new insights that help us understand this amazing giant planet.”

The Juno science team continues to analyze returns from previous flybys. Scientists have discovered that Jupiter’s magnetic fields are more complicated than originally thought and that the belts and zones that give the planet’s cloud tops their distinctive look extend deep into its interior. Observations of the energetic particles that create the incandescent auroras suggest a complicated current system involving charged material lofted from volcanoes on Jupiter’s moon Io.

Peer-reviewed papers with more in-depth science results from Juno’s first flybys are expected to be published within the next few months.

Juno launched on Aug. 5, 2011, from Cape Canaveral, Florida, and arrived in orbit around Jupiter on July 4, 2016. During its mission of exploration, Juno soars low over the planet’s cloud tops — as close as about 2,600 miles (4,100 kilometers). During these flybys, Juno is probing beneath the obscuring cloud cover of Jupiter and studying its auroras to learn more about the planet’s origins, structure, atmosphere, and magnetosphere.

NASA’s Jet Propulsion Laboratory, Pasadena, California, manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the Science Mission Directorate. Lockheed Martin Space Systems, Denver, built the spacecraft. JPL is a division of Caltech in Pasadena, California.

More information on the Juno mission is available at:

http://www.nasa.gov/juno

http://missionjuno.org

The public can follow the mission on Facebook and Twitter at:

http://www.facebook.com/NASAJuno

http://www.twitter.com/NASAJuno

DC Agle
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011
agle@jpl.nasa.gov

Dwayne Brown / Laurie Cantillo
NASA Headquarters, Washington
202-358-1726 / 202-358-1077
dwayne.c.brown@nasa.gov / laura.l.cantillo@nasa.gov

 

Editor: Martin Perez

Photo Credit: NASA

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Andromeda’s Bright X-Ray Mystery Solved by NuSTAR

The Milky Way’s close neighbor, Andromeda, features a dominant source of high-energy X-ray emission, but its identity was mysterious until now. As reported in a new study, NASA’s NuSTAR (Nuclear Spectroscopic Telescope Array) mission has pinpointed an object responsible for this high-energy radiation.

The object, called Swift J0042.6+4112, is a possible pulsar, the dense remnant of a dead star that is highly magnetized and spinning, researchers say. This interpretation is based on its emission in high-energy X-rays, which NuSTAR is uniquely capable of measuring. The object’s spectrum is very similar to known pulsars in the Milky Way.

It is likely in a binary system, in which material from a stellar companion gets pulled onto the pulsar, spewing high-energy radiation as the material heats up.

“We didn’t know what it was until we looked at it with NuSTAR,” said Mihoko Yukita, lead author of a study about the object, based at Johns Hopkins University in Baltimore. The study is published in The Astrophysical Journal.

This candidate pulsar is shown as a blue dot in a NuSTAR X-ray image of Andromeda (also called M31), where the color blue is chosen to represent the highest-energy X-rays. It appears brighter in high-energy X-rays than anything else in the galaxy.

The study brings together many different observations of the object from various spacecraft. In 2013, NASA’s Swift satellite reported it as a high-energy source, but its classification was unknown, as there are many objects emitting low energy X-rays in the region. The lower-energy X-ray emission from the object turns out to be a source first identified in the 1970s by NASA’s Einstein Observatory. Other spacecraft, such as NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton had also detected it. However, it wasn’t until the new study by NuSTAR, aided by supporting Swift satellite data, that researchers realized it was the same object as this likely pulsar that dominates the high energy X-ray light of Andromeda.

Traditionally, astronomers have thought that actively feeding black holes, which are more massive than pulsars, usually dominate the high-energy X-ray light in galaxies. As gas spirals closer and closer to the black hole in a structure called an accretion disk, this material gets heated to extremely high temperatures and gives off high-energy radiation. This pulsar, which has a lower mass than any of Andromeda’s black holes, is brighter at high energies than the galaxy’s entire black hole population.

Even the supermassive black hole in the center of Andromeda does not have significant high-energy X-ray emission associated with it. It is unexpected that a single pulsar would instead be dominating the galaxy in high-energy X-ray light.

“NuSTAR has made us realize the general importance of pulsar systems as X-ray-emitting components of galaxies, and the possibility that the high energy X-ray light of Andromeda is dominated by a single pulsar system only adds to this emerging picture,” said Ann Hornschemeier, co-author of the study and based at NASA’s Goddard Space Flight Center, Greenbelt, Maryland.

Andromeda is a spiral galaxy slightly larger than the Milky Way. It resides 2.5 million light-years from our own galaxy, which is considered very close, given the broader scale of the universe. Stargazers can see Andromeda without a telescope on dark, clear nights.

“Since we can’t get outside our galaxy and study it in an unbiased way, Andromeda is the closest thing we have to looking in a mirror,” Hornschemeier said.

NuSTAR is a Small Explorer mission led by Caltech and managed by JPL for NASA’s Science Mission Directorate in Washington. NuSTAR was developed in partnership with the Danish Technical University and the Italian Space Agency (ASI). The spacecraft was built by Orbital Sciences Corp., Dulles, Virginia. NuSTAR’s mission operations center is at UC Berkeley, and the official data archive is at NASA’s High Energy Astrophysics Science Archive Research Center. ASI provides the mission’s ground station and a mirror archive. JPL is managed by Caltech for NASA.

For more information on NuSTAR, visit:

http://www.nasa.gov/nustar

http://www.nustar.caltech.edu

Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
elizabeth.landau@jpl.nasa.gov

Photo Credit: NASA

 

Editor: Tony Greicius

 

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NASA Participates in the NOAA GOES-16 Field Campaign

NOAA’s GOES-16 satellite is ready to embark on another major milestone— The GOES-16 Field Campaign. During a three month long event, a combination of NOAA and NASA planes, sensors and satellites will fine-tune GOES-16’s brand new instruments.

artists concept of satellite
Artist’s concept of GOES-16 (GOES-R) in orbit.
Credits: NOAA/NASA

NASA successfully launched NOAA’s GOES-R satellite at 6:42 p.m. EST on November 19, 2016 from Cape Canaveral Air Force Station in Florida and it was renamed GOES-16 when it achieved orbit. GOES-16 is now observing the planet from an equatorial view approximately 22,300 miles above the surface of the Earth.

Since launch the GOES-R team, which consists of scientists and engineers from both NOAA and NASA has been working around the clock to power on the satellite’s advanced instruments and to get their data back to Earth.

During this campaign, a team of instrument scientists, meteorologists, GOES-16 engineers, and specialized pilots will use an outfit of high-altitude planes, ground-based sensors, unmanned aircraft systems, the International Space Station, and the NOAA/NASA Suomi NPP polar-orbiting satellite to collect measurements across the United States.

Ranging from arid deserts and areas of dense vegetation, to open oceans and storms exhibiting lightning activity, these measurements will cover nearly everything NOAA’s GOES satellites see.

airplane lifts into a blue sky
NASA’s ER-2 takes off from its base of operations at NASA’s Armstrong Flight Research Center Building 703 in Palmdale, California to test instruments that will support upcoming science flights for the Geostationary Operational Environmental Satellite-R-series.
Credits: NASA

 

While these measurements are being taken on Earth, GOES-16’s operators will be obtaining similar measurements of the same locations using two of the satellite’s most revolutionary instruments—the Advanced Baseline Imager and the Geostationary Lightning Mapper. The two data sets will be analyzed and compared by meteorologists to validate and calibrate the sensors on the satellite.

Making Data Accurate

Data from NOAA’s GOES satellites are used 24 hours a day, seven days a week for everything from flight plan forecasting and air quality alerts to potentially life-saving severe storm and tornado warnings. They provide vital information to support storm tracking, seasonal predictions, drought outlooks, and space weather predictions.

It’s NOAA’s mission to ensure that these data are as precise, accurate, and readily available as possible. Because of this, GOES-16’s data are going through an exhaustive testing phase, being checked and re-checked using measurements from a vast range of verified sources before it is put into operational use.

All of the GOES-16 Field Campaign information will be permanently stored as reference data at NOAA’s National Centers for Environmental Information.

Running a Field Campaign

This is the first NOAA satellite-focused field campaign since GOES-8 launched in April 1994. In many cases, the satellite’s predecessor is used to ensure that the new satellite is taking accurate measurements. When NOAA launched the Jason-3 ocean altimetry satellite, it orbited directly behind Jason-2 for several weeks in order to verify and fine-tune its instruments.

The instruments aboard GOES-16, however, are brand new and more advanced than any GOES satellite before it. So, scientists will use instruments mounted on NASA’s ER-2 high-altitude aircraft, as well as various other instruments closer to Earth and one on the International Space Station, to validate what the GOES-16 satellite is seeing and fine-tune its instruments.

You Can Follow Along

The GOES-16 Field Campaign officially begins on March 22, 2017 and concludes on May 19, 2017. Throughout the campaign, progress updates, news stories, interviews, and more will be available at www.nesdis.noaa.gov and on NOAA’s Twitter, Facebook, and Instagram accounts.

For more information about GOES-16, visit: www.goes-r.gov/  or www.nasa.gov/goes

Kyle Herring – NOAA

Photo Credit: NASA

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NASA’s Swift Mission Maps a Star’s ‘Death Spiral’ into a Black Hole

Some 290 million years ago, a star much like the sun wandered too close to the central black hole of its galaxy. Intense tides tore the star apart, which produced an eruption of optical, ultraviolet and X-ray light that first reached Earth in 2014. Now, a team of scientists using observations from NASA’s Swift satellite have mapped out how and where these different wavelengths were produced in the event, named ASASSN-14li, as the shattered star’s debris circled the black hole.

“We discovered brightness changes in X-rays that occurred about a month after similar changes were observed in visible and UV light,” said Dheeraj Pasham, an astrophysicist at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts, and the lead researcher of the study. “We think this means the optical and UV emission arose far from the black hole, where elliptical streams of orbiting matter crashed into each other.”

This animation illustrates how debris from a tidally disrupted star collides with itself, creating shock waves that emit ultraviolet and optical light far from the black hole. According to Swift observations of ASASSN-14li, these clumps took about a month to fall back to the black hole, where they produced changes in the X-ray emission that correlated with the earlier UV and optical changes.
Credits: NASA’s Goddard Space Flight Center

Astronomers think ASASSN-14li was produced when a sun-like star wandered too close to a 3-million-solar-mass black hole similar to the one at the center of our own galaxy. For comparison, the event horizon of a black hole like this is about 13 times bigger than the sun, and the accretion disk formed by the disrupted star could extend to more than twice Earth’s distance from the sun.

When a star passes too close to a black hole with 10,000 or more times the sun’s mass, tidal forces outstrip the star’s own gravity, converting the star into a stream of debris. Astronomers call this a tidal disruption event. Matter falling toward a black hole collects into a spinning accretion disk, where it becomes compressed and heated before eventually spilling over the black hole’s event horizon, the point beyond which nothing can escape and astronomers cannot observe. Tidal disruption flares carry important information about how this debris initially settles into an accretion disk.

Astronomers know the X-ray emission in these flares arises very close to the black hole. But the location of optical and UV light was unclear, even puzzling. In some of the best-studied events, this emission seems to be located much farther than where the black hole’s tides could shatter the star. Additionally, the gas emitting the light seemed to remain at steady temperatures for much longer than expected.

ASASSN-14li was discovered Nov. 22, 2014, in images obtained by the All Sky Automated Survey for SuperNovae (ASASSN), which includes robotic telescopes in Hawaii and Chile. Follow-up observations with Swift’s X-ray and Ultraviolet/Optical telescopes began eight days later and continued every few days for the next nine months. The researchers supplemented later Swift observations with optical data from the Las Cumbres Observatory headquartered in Goleta, California.

In a paper describing the results published March 15 in The Astrophysical Journal Letters, Pasham, Cenko and their colleagues show how interactions among the infalling debris could create the observed optical and UV emission.

Tidal debris initially falls toward the black hole but overshoots, arcing back out along elliptical orbits and eventually colliding with the incoming stream.

“Returning clumps of debris strike the incoming stream, which results in shock waves that emit visible and ultraviolet light,” said Goddard’s Bradley Cenko, the acting Swift principal investigator and a member of the science team. “As these clumps fall down to the black hole, they also modulate the X-ray emission there.”

Future observations of other tidal disruption events will be needed to further clarify the origin of optical and ultraviolet light.

Goddard manages the Swift mission in collaboration with Pennsylvania State University in University Park, the Los Alamos National Laboratory in New Mexico and Orbital Sciences Corp. in Dulles, Virginia. Other partners include the University of Leicester and Mullard Space Science Laboratory in the United Kingdom, Brera Observatory and the Italian Space Agency in Italy, with additional collaborators in Germany and Japan.

Related:

Scientists Identify a Black Hole Choking on Stardust (MIT)

ASASSN-14li: Destroyed Star Rains onto Black Hole, Winds Blow it Back

‘Cry’ of a Shredded Star Heralds a New Era for Testing Relativity

Researchers Detail How a Distant Black Hole Devoured a Star


Banner image:

This artist’s rendering shows the tidal disruption event named ASASSN-14li, where a star wandering too close to a 3-million-solar-mass black hole was torn apart. The debris gathered into an accretion disk around the black hole. New data from NASA’s Swift satellite show that the initial formation of the disk was shaped by interactions among incoming and outgoing streams of tidal debris.

Credit: NASA’s Goddard Space Flight Center

Editor: Karl Hille

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Hubble Discovery of Runaway Star Yields Clues to Breakup of Multiple-Star System

As British royal families fought the War of the Roses in the 1400s for control of England’s throne, a grouping of stars was waging its own contentious skirmish — a star war far away in the Orion Nebula.

The stars were battling each other in a gravitational tussle, which ended with the system breaking apart and at least three stars being ejected in different directions. The speedy, wayward stars went unnoticed for hundreds of years until, over the past few decades, two of them were spotted in infrared and radio observations, which could penetrate the thick dust in the Orion Nebula.

Three-panel hubble image shows star motion

This three-frame illustration shows how a grouping of stars can break apart, flinging the members into space. Panel 1: members of a multiple-star system orbiting each other. Panel 2: two of the stars move closer together in their orbits. Panel 3: the closely orbiting stars eventually either merge or form a tight binary. This event releases enough gravitational energy to propel all of the stars in the system outward, as shown in the third panel.

Credits: NASA, ESA, and Z. Levy (STScI)

Now NASA’s Hubble Space Telescope has helped astronomers find the final piece of the puzzle by nabbing a third runaway star. The astronomers followed the path of the newly found star back to the same location where the two previously known stars were located 540 years ago. The trio reside in a small region of young stars called the Kleinmann-Low Nebula, near the center of the vast Orion Nebula complex, located 1,300 light-years away.

“The new Hubble observations provide very strong evidence that the three stars were ejected from a multiple-star system,” said lead researcher Kevin Luhman of Penn State University in University Park, Pennsylvania. “Astronomers had previously found a few other examples of fast-moving stars that trace back to multiple-star systems, and therefore were likely ejected. But these three stars are the youngest examples of such ejected stars. They’re probably only a few hundred thousand years old. In fact, based on infrared images, the stars are still young enough to have disks of material leftover from their formation.”

All three stars are moving extremely fast on their way out of the Kleinmann-Low Nebula, up to almost 30 times the speed of most of the nebula’s stellar inhabitants. Based on computer simulations, astronomers predicted that these gravitational tugs-of-war should occur in young clusters, where newborn stars are crowded together. “But we haven’t observed many examples, especially in very young clusters,” Luhman said. “The Orion Nebula could be surrounded by additional fledging stars that were ejected from it in the past and are now streaming away into space.”

The team’s results will appear in the March 20, 2017 issue of The Astrophysical Journal Letters.

Luhman stumbled across the third speedy star, called “source x,” while he was hunting for free-floating planets in the Orion Nebula as a member of an international team led by Massimo Robberto of the Space Telescope Science Institute in Baltimore, Maryland. The team used the near-infrared vision of Hubble’s Wide Field Camera 3 to conduct the survey. During the analysis, Luhman was comparing the new infrared images taken in 2015 with infrared observations taken in 1998 by the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). He noticed that source x had changed its position considerably, relative to nearby stars over the 17 years between Hubble images, indicating the star was moving fast, about 130,000 miles per hour.

hubble nebula image with annotations and insets

The image by NASA’s Hubble Space Telescope shows a grouping of young stars, called the Trapezium Cluster (center). The box just above the Trapezium Cluster outlines the location of the three stars. A close-up of the stars is top right. The birthplace of the multi-star system is marked “initial position.” Two of the stars — labeled BN, and “I,” for source I — were discovered decades ago. Source I is embedded in thick dust and cannot be seen. The third star, “x,” for source x, was recently discovered to have moved noticeably between 1998 and 2015, as shown in the inset image at bottom right.

Credits: NASA, ESA, K. Luhman (Penn State University), and M. Robberto (STScI)

BN was discovered in infrared images in 1967, but its rapid motion wasn’t detected until 1995, when radio observations measured the star’s speed at 60,000 miles per hour. Source I is traveling roughly 22,000 miles per hour. The star had only been detected in radio observations; because it is so heavily enshrouded in dust, its visible and infrared light is largely blocked.

The three stars were most likely kicked out of their home when they engaged in a game of gravitational billiards, Luhman said. What often happens when a multiple system falls apart is that two of the member stars move close enough to each other that they merge or form a very tight binary. In either case, the event releases enough gravitational energy to propel all of the stars in the system outward. The energetic episode also produces a massive outflow of material, which is seen in the NICMOS images as fingers of matter streaming away from the location of the embedded source I star.

Future telescopes, such as the James Webb Space Telescope, will be able to observe a large swath of the Orion Nebula. By comparing images of the nebula taken by the Webb telescope with those made by Hubble years earlier, astronomers hope to identify more runaway stars from other multiple-star systems that broke apart.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

By The Space Telescope Science Institute (STScI) in Baltimore, Md.

Editor: Karl Hille

Photo Credit: NASA


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Relativistic Electrons Uncovered with NASA’s Van Allen Probes

Earth’s radiation belts, two doughnut-shaped regions of charged particles encircling our planet, were discovered more than 50 years ago, but their behavior is still not completely understood. Now, new observations from NASA’s Van Allen Probes mission show that the fastest, most energetic electrons in the inner radiation belt are not present as much of the time as previously thought. The results are presented in a paper in the Journal of Geophysical Research and show that there typically isn’t as much radiation in the inner belt as previously assumed — good news for spacecraft flying in the region.

Since their discovery at the dawn of the Space Age, Earth’s radiation belts continue to reveal new complex structures and behaviors. This visualization shows how the radiation belts change in response to the injection of electrons from a storm in late June 2015. Red colors indicate higher numbers of electrons.
Credits: NASA’s Goddard Space Flight Center/Tom Bridgman

Past space missions have not been able to distinguish electrons from high-energy protons in the inner radiation belt. But by using a special instrument, the Magnetic Electron and Ion Spectrometer — MagEIS — on the Van Allen Probes, the scientists could look at the particles separately for the first time. What they found was surprising —there are usually none of these super-fast electrons, known as relativistic electrons, in the inner belt, contrary to what scientists expected.

“We’ve known for a long time that there are these really energetic protons in there, which can contaminate the measurements, but we’ve never had a good way to remove them from the measurements until now,” said Seth Claudepierre, lead author and Van Allen Probes scientist at the Aerospace Corporation in El Segundo, California.

Of the two radiation belts, scientists have long understood the outer belt to be the rowdy one. During intense geomagnetic storms, when charged particles from the sun hurtle across the solar system, the outer radiation belt pulsates dramatically, growing and shrinking in response to the pressure of the solar particles and magnetic field.  Meanwhile, the inner belt maintains a steady position above Earth’s surface. The new results, however, show the composition of the inner belt isn’t as constant as scientists had assumed.

Ordinarily, the inner belt is composed of high-energy protons and low-energy electrons. However, after a very strong geomagnetic storm in June 2015, relativistic electrons were pushed deep into the inner belt.

The findings were visible because of the way MagEIS was designed. The instrument creates its own internal magnetic field, which allows it to sort particles based on their charge and energy. By separating the electrons from the protons, the scientists could understand which particles were contributing to the population of particles in the inner belt.

“When we carefully process the data and remove the contamination, we can see things that we’ve never been able to see before,” said Claudepierre. “These results are totally changing the way we think about the radiation belt at these energies.”

triptych of Van Allen Belt depictions, pre-, during and post-solar storm
During a strong geomagnetic storm, electrons at relativistic energies, which are usually only found in the outer radiation belt, are pushed in close to Earth and populate the inner belt. While the electrons in the slot region quickly decay, the inner belt electrons can remain for many months.
Credits: NASA’s Goddard Space Flight Center/Mary Pat Hrybyk-Keith

Given the rarity of the storms, which can inject relativistic electrons into the inner belt, the scientists now understand there to typically be lower levels of radiation there — a result that has implications for spacecraft flying in the region. Knowing exactly how much radiation is present may enable scientists and engineers to design lighter and cheaper satellites tailored to withstand the less intense radiation levels they’ll encounter.

In addition to providing a new outlook on spacecraft design, the findings open a new realm for scientists to study next.

“This opens up the possibility of doing science that previously was not possible,” said Shri Kanekal, Van Allen Probes deputy mission scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, not involved with the study. “For example, we can now investigate under what circumstances these electrons penetrate the inner region and see if more intense geomagnetic storms give electrons that are more intense or more energetic.”

The Van Allen Probes is the second mission in NASA’s Living with a Star Program and one of many NASA heliophysics missions studying our near-Earth environment. The spacecraft plunge through the radiation belts five to six times a day on a highly elliptical orbit, in order to understand the physical processes that add and remove electrons from the region.

Related

Editor: Rob Garner

 

Photo Credit: NASA

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