After nine years, a student-designed-and-built satellite is being readied for launch into orbit, where it will be a test bed for a new type of space telescope that assembles itself in flight from multiple components.
With telescopes, bigger is better: the larger their primary mirror, the more light they can capture and the better the images they can create. Currently, however, space telescopes are limited in size and must be folded up to fit inside the rockets that launch them into space. Hubble is 2.4 meters in diameter, for instance, and the James Webb Space Telescope will be 6.5 meters in diameter when it launches in 2021. To build a telescope that exceeds 10 meters, scientists and engineers will need to develop new, modular designs that can be sent to space in multiple pieces—even on multiple rockets.
In 2008, a series of workshops at the Keck Institute of Space Studies (KISS) at Caltech inspired a low-cost mission to demonstrate the feasibility of sending a telescope to space in pieces and having it assemble itself once in orbit.
That telescope, which came to be known as AAReST (Autonomous Assembly of a Reconfigurable Space Telescope), was designed and built in large part by students in Caltech's Ae 105 Aerospace Engineering class, working in collaboration with the Surrey Space Centre in England and the Indian Institute of Space Science and Technology. Over the years, these students planned the mission and designed the telescope. With the spacecraft nearly complete, 2018 marks the conclusion of the AAReST project for the Ae 105 students. The AAReST satellite is scheduled to be launched on an Indian Space Research Organization (ISRO) rocket in 2019.
Ae 105 is a yearlong class taught by JPL instructors Oscar Alvarez-Salazar, Andy Klesh, Scott Ploen, and Dan Scharf. At Caltech, aerospace engineer Sergio Pellegrino is AAReST's campus coordinator and JPL's John Baker is its project manager. Over the past near decade, the Ae 105 students have dealt with countless design and technical issues regarding the project. But by far the biggest challenge the class faced, Pellegrino says, was an informational one: how to pass on information from one generation of students to the next.
"Continuity is a challenge in every project. You always have to cope with the fact that people leave because they retire or get different jobs. But in our case, the entire workforce was replaced every year," says Pellegrino, the Joyce and Kent Kresa Professor of Aerospace and Civil Engineering and a JPL senior research scientist. "In a normal project, outgoing team members produce detailed write-ups. For us, that just wasn't enough."
To cope with the turnover, Pellegrino invited many former students to stay on as mentors to the incoming Ae 105 classes. This ultimately spawned a second class, Ae 205, Advanced Space Project, to formalize the student-mentorship role. That student mentorship, coupled with the fact that the mission was actually going to space, translated into a uniquely valuable experience according to those who went through the program.
"Having a form of practical experience to point to is very useful after university when looking for a job," says Lee Wilson (PhD '17), who now works on spacecraft design at Deep Space Industries in San Jose. "This project helped expose me to vibration testing and spacecraft design, assembly, and integration, and actually let me get my hands dirty."
Thibaud Talon, who took Ae 105 during the 2013–14 school year and remains involved in the project to this day as a graduate student, echoes Wilson's sentiments.
"Since the class is taught by JPL engineers, I started to make a network at JPL. I still meet, talk, and sometimes work with the professors who taught me Ae 105," says Talon. "Also, working on an actual space mission is a great addition to my resume. As many people working in the space industry told me, such an experience is very valuable and looked at when applying for a job. Participating in such a project teaches you many concepts of designing a space mission that are hard to learn otherwise."
The final design that the students came up with for the AAReST spacecraft features a central core unit that contains the attitude and control system, the radio and the antennas, and two rigid mirrors. Surrounding that central unit are two smaller spacecraft containing deformable mirrors that will be co-focused with the rigid mirrors on the main spacecraft. The whole package is small, measuring just 46 x 34 x 30 centimeters. Once in orbit, the two smaller spacecraft will detach from the main one via splitting bolts and then float about 30 centimeters away from the spacecraft before reconnecting to the main body in a wider configuration via electromagnets.
The final project for this year's Ae 105 class was focused on testing the main spacecraft, with particular attention paid to ensuring that the recoil from the splitting bolts will not throw the side segments too far away from the main spacecraft.
Ae 105 will no longer focus on AAReST, but there are still several details to be worked out before the spacecraft is launched, so Pellegrino will be taking a sabbatical during the 2018–19 academic year to work with the senior students on the project. Soon-Jo Chung, associate professor of aerospace and Bren Scholar and JPL research scientist, will take over Ae 105 and pick a new project for its students to tackle.
Pellegrino says that the Caltech students working on AAReST have learned how to collaborate across continents and gained skills that will continue to serve them for years to come. In addition, he says, he's proud to have given several generations of aerospace students the opportunity to work on a real space mission. When the mission launches in 2019, dozens of past and present Caltech students—along with their collaborators nearby and abroad—will be watching and holding their breath to see whether their hard work pays off.
Manan Arya (PhD '16), an Ae 105 student from 2011 who now works on large deployable spacecraft structures at JPL, says he's looking forward to watching the launch. "Overall it's a feeling of excitement and great joy that something that I've worked on will end up in space, mixed with the nervousness that all engineers must experience when they press the 'on' button and hope, wish, and pray that it actually turns on."
The AAReST mission is a collaborative effort between Caltech, the University of Surrey in England, and the Indian Institute of Space Science and Technology. The AAReST project has received funding from KISS; Caltech's Division of Engineering and Applied Science; and the Innovation in Education Fund, which was made possible in part by the Caltech Associates.
BJ Fulton, a staff scientist at NASA's Exoplanet Science Institute (NExScI) at Caltech, is being honored with the 2018 Robert J. Trumpler Award—an honor bestowed by the Astronomical Society for the Pacific (ASP) to the recipient of a "PhD degree in North America whose research is considered unusually important to astronomy."
Fulton received his doctorate from the University of Hawaii in 2017. Part of his graduate research took place at Caltech in the research group of Professor of Astronomy Andrew Howard, who himself moved from the University of Hawaii to Caltech in 2016.
Fulton's thesis revealed that the majority of exoplanets found to date fall into two distinct size groups: rocky Earth-like planets and larger mini-Neptunes. In a 2017 news release, Fulton and his team compared the finding—made using data from NASA's Kepler mission and the W. M. Keck Observatory—to discovering a new branch in the family tree of exoplanets.
"BJ's discovery gets to the heart of exoplanetary science by categorizing planets into their fundamental types," says Howard. "This categorization, in turn, sparked other astronomers to propose physical processes that sculpted the planet population into the types we see today."
Fulton is now a staff scientist at NExScI, which is based at IPAC, a science and data center for astronomy at Caltech. He is the deputy project scientist for the NASA-National Science Foundation Exoplanet Observational Research (NN-EXPLORE) program, which funds and operates the NEID spectrograph.
For more information about the ASP, visit https://www.astrosociety.org.
Using an unprecedented number of satellite radar images, geophysicists at Caltech have tracked how the ground in Southern California rises and falls as groundwater is pumped in and out of aquifers beneath the surface.
Their findings are presented in a study that tracks deformation of the earth's surface over an 18-year period. The work can be used by water management districts to assess the precise shape and size of aquifers and the impact of the region's water use on those aquifers. The work also reveals what could be a previously unmapped fault running across northeast Orange County.
"What we see through the rising and falling of the ground surface is the elastic response of the land to regular changes in groundwater level," says lead author Bryan Riel (MS '14, PhD '17), who was a graduate student in the lab of Caltech's Mark Simons at the time of the research, and is now a signal analysis engineer at JPL, which is managed by Caltech for NASA. "Because we have data over a long period of time, we were also able to isolate long-term surface deformation signals, including subsidence of the land that seems to be caused by compaction of clay layers in response to background variations in groundwater withdrawal." Riel and Simons were also able to see sharp features where water was not flowing, which can indicate boundaries of aquifers as well as faults.
The study, which was published online on April 30 by the journal Water Resources Research, uses publicly available radar data captured between 1992 and 2011 by European Space Agency satellites. The satellite data was compiled into 881 radar interferograms—images created by bouncing radar signals off of the earth's surface—to track nearly vertical ground motion down to the millimeter with a horizontal resolution of tens of meters, over an area that stretches from San Fernando, northwest of downtown Los Angeles, down to Irvine, in Orange County.
When all of the images are stitched together, they show the ground beneath Southern California rising and falling annually, like a giant breathing in and out. The results were checked against GPS measurements taken by the Orange County Water District (OCWD) and the Water Replenishment District of Southern California, which corroborated the findings. The periodic rising and falling of the ground tells the story of the management of Southern California's aquifers and how that management has changed over time, says Simons, the John W. and Herberta M. Miles Professor of Geophysics at Caltech and JPL chief scientist.
"At the beginning of the study period, we see big sinusoids—higher highs and lower lows. Toward the later half of the study, that flattens out a bit, indicating that water control districts were more actively managing aquifers, and making sure to put water back into them instead of just taking it out," Simons says.
Roy Herndon, chief hydrogeologist for the OCWD, says that his team works to make sure that the ground never sinks too far—a development from which it might never recover.
"We suspect that the geology of our basin might allow subsidence to occur if we allowed too much groundwater to be pumped out but never refilled it. We have clays and silts that can compress and compact with time," Herndon says.
That strategy is codified in the Sustainable Groundwater Management Act (SGMA), signed into law by California Governor Jerry Brown in 2014, which dictates that groundwater managers need to avoid permanent lowering of the ground level. The phenomenon has plagued the San Joaquin Valley of Central California for generations. Soil compaction driven by a shrinking water table has caused the ground in the area to subside by as much as 28 feet, according to the United States Geological Survey (USGS). Herndon says that the study by Riel, Simons, and co-authors—and other surveys like it—will help water districts make sure that their water management strategies are effective at avoiding such soil compaction in California.
While the rising and falling of the ground was to be expected, the radar data also showed some unexpected features, Simons says, including a sharp boundary at the edge of an aquifer, which could indicate a buried fault along the eastern edge of a basin where the Santa Ana River passes through the Santa Ana/Garden Grove area. In addition, the map revealed a small area with anomalously large ground level uplift that turned out to be caused by petroleum operations pumping oil out and water in.
Riel, Simons, and co-authors relied upon data from ESA satellites. Meanwhile, JPL, NASA, and the Indian Space Research Organisation (ISRO) are planning to launch a new radar satellite called NISAR in early 2022 that will provide observations from two directions every 12 days—providing higher-quality, higher-resolution data than have previously been available.
"With that kind of data, we'll be able to paint an even clearer picture that could reveal even more about the ground beneath our feet," Simons says.
The study is titled "Quantifying Ground Deformation in the Los Angeles and Santa Ana Coastal Basins Due to Groundwater Withdrawal." Other co-authors include Daniel Ponti of the USGS; JPL's Piyush Agram, who is a visiting associate at Caltech; and Romain Jolivet of the
Researchers with the Advanced Rapid Imaging and Analysis (ARIA) project, a NASA mission led by Caltech scientists, used new satellite data to produce a map of ground deformation on the resort island of Lombok, Indonesia, following a deadly 6.9-magnitude earthquake on August 5.
The false-color map shows the amount of permanent surface movement that occurred, almost entirely due to the quake, over a six-day period between satellite images taken on July 30 and August 5.
From the pattern of deformation in the map, scientists have determined that the earthquake fault slip was on a fault beneath the northwestern part of Lombok Island, and it caused as much as 10 inches (25 centimeters) of uplift of the ground surface. White areas in the image are places where the radar measurement was not possible, largely due to dense forests in the middle of the islands.
Through these maps, NASA and its partners are contributing important observations and expertise that can assist with response to earthquakes and other natural or human-produced hazards.
A new NASA mission, set to launch on August 11, will whip through the sun's sizzling outer atmosphere, or corona, flying closer to the sun than any spacecraft before it. Observations by the mission, called the Parker Solar Probe, will lead to better predictions of space weather and address fundamental mysteries about the sun's dynamic corona.
One of these mysteries has to do with high-speed solar particles that zip toward Earth at close to the speed of light. Scientists know the particles originate in the corona but they don't understand how they are being accelerated. To address the question, a team led by Mark Wiedenbeck of the Jet Propulsion Laboratory and including members from Caltech and NASA's Goddard Space Flight Center, developed one of several instruments onboard the Parker Solar Probe, called the Energetic Particle Instrument-Hi, or EPI-Hi. (The instrument has a partner, EPI-Lo, and both are overseen by the dual instrument's principal investigator, David McComas of Princeton University.)
"We will be exploring a region of space that has never before been visited," says Wiedenbeck (PhD '78), a Caltech alumnus who studied under Ed Stone—an investigator on the EPI-Hi instrument and the David Morrisroe Professor of Physics at Caltech."We have ideas about what will be found, but the most important results may well come from observations that are completely unexpected," says Wiedenbeck.
The namesake of the mission is another Caltech alumnus, 91-year-old Eugene Parker (PhD '51), who predicted, in 1958, the existence of a supersonic solar wind—a flow of charged particles that stream off the sun, accelerating at speeds faster than that of sound.
"Many of his colleagues thought he must be wrong, but when Mariner 2 was on the trip to Venus in 1962, it revealed that a supersonic wind was always present," says Stone, who is also the longtime project scientist for NASA's Voyager mission, which includes Voyager 1 and 2—both launched in 1977 on tours of the solar system. The Voyager spacecraft each have instruments similar to EPI-Hi that are designed to detect charged particles from the sun, planetary radiation belts, and beyond our solar system.
Stone, who worked across the hall from Parker in the early 1960s at the University of Chicago, says that Parker also correctly predicted that the solar wind would create a large bubble around the sun, now called the heliosphere. "In 2012, Voyager 1 finally left the bubble first predicted by Parker, entering interstellar space," he says.
The Parker Solar Probe will study the source of the solar wind: the sun's blistering corona, with temperatures of several million degrees Celsius. When the solar wind slams into Earth's atmosphere, it sometimes creates beautiful, glowing aurorae, but can also lead to harmful "space weather" that disrupts satellite communications and navigation systems.
Of particular interest to the EPI-Hi team is the unsolved riddle of how a small fraction of the solar-wind charged particles reach near-light speeds.
"When the sun is active, it can suddenly eject a billion tons of material that creates a shock wave traveling at speeds up to 10 million kilometers per hour. These shocks accelerate protons, electrons, and heavier ions that can reach Earth in less than an hour, creating space weather hazards to humans and hardware in space," says EPI-Hi team member Richard Mewaldt, a research professor of physics at Caltech who has been studying high-energy particles in space for 47 years.
"We believe that these solar-wind charged particles, the nuclei of atoms, get bounced around by shock waves like ping pong balls, gaining more and more speed," says Stone. (A similar phenomenon is thought to happen outside our solar system, except there the particles are known as cosmic rays.) "We have been observing from a distance the effects of what is happening near the sun. Now we will fly through the region where it is happening. This should provide us with new clues about the process," he says.
The EPI-Hi instrument consists of stacks of silicon detectors designed to snag high-speed particles and measure their energies. Graduate student Jamie Rankin, who works with the EPI-Hi team, helped test the detectors at Caltech. "Some of the detectors are very thin, with the thinnest being about one-eighth the thickness of a standard sheet of paper. For the detectors to make the required measurements, we had to verify that their thickness only varied by no more than one-hundredth the thickness of a sheet of paper," she says.
The team says that figuring out how the sun accelerates particles to high energy will also rely on complementary measurements from other instruments onboard the Parker Solar Probe—instruments that will measure the solar wind, turbulent magnetic fields, radio bursts, and other phenomena.
After launch, the Parker Solar Probe will swing by Venus for a gravitational boost toward the sun. The spacecraft, protected by a thermal shield, will ultimately circle the sun two dozen times over seven years. At closest approach, it will skim about 6 million kilometers above the sun's surface; at that point, it will be the fastest spacecraft of all time, traveling fast enough to get from Los Angeles to New York in less than 20 seconds. The mission's first batch of data is expected to arrive on Earth in December.
The joint EPI-Hi and EPI-Lo investigation, called the Integrated Science Investigation of the Sun, is led by Princeton University. EPI-Hi was built largely at Caltech, with significant contributions from the Southwest Research Institute and NASA's Goddard Space Flight Center. EPI-Lo was built by Johns Hopkins University Applied Physics Laboratory. The Integrated Science Investigation of the Sun Operations Center is located at the University of New Hampshire in Durham.
Working in a Caltech chemical engineering lab this summer, Maggie Higginbotham spends a lot of her time coaxing bacteria to make extremely small bags of gas that can be used to improve the diagnostic abilities of ultrasound equipment.
While that task may be fairly routine for the faculty, postdocs, graduate students, and undergraduates in the lab, it's a brand-new experience for Higginbotham: she's still in high school.
Higginbotham, a 10th-grade student at Blair High School in Pasadena, is one of 22 local high school students—and three teachers—participating in Caltech's Summer Research Connection (SRC). The six-week program brings high school students and teachers to campus to conduct research in a dozen labs in fields ranging from chemistry, physics, and materials science to chemical engineering, astronomy, and planetary science.
After several weeks in the program, Higginbotham says working as a member of the research team "has been a fantastic experience that's allowed me to see what doing research is really like. I've learned how to use the tools and how to handle myself in a lab."
And that is precisely the point of the program, according to Mitch Aiken, associate director for educational outreach for the Center for Teaching, Learning, and Outreach, which runs the program each summer.
Aiken says the goal of the program is threefold: to provide graduate students and postdocs with the opportunity to practice mentoring, teaching, and polishing their scientific communications skills; to offer K–12 teachers opportunities to learn techniques that they can take back to their classrooms; and to give local high school students firsthand exposure to how research is conducted at the university level. "SRC also provides an avenue for many researchers on campus to engage in community outreach and meet a key component of the Broader Impacts fulfillment requirement of National Science Foundation grants," Aiken says.
Working for 20 hours a week in the lab of Mikhail G. Shapiro, assistant professor of chemical engineering, Higginbotham joined Marshall High School student Thomas Scott as well as Garrett Gibson, a teacher from Environmental Charter Middle School in Gardena. The team's work focuses on growing flasks of bacteria and archaea that produce gas vesicles—air-filled protein structures that the cells normally use as flotation devices. The Shapiro lab is developing the vesicles as imaging agents for ultrasound, making it possible for this imaging technology to visualize specific cells and molecules in the body.
In the lab, Higginbotham and Gibson work under the mentorship of research technician Dina Malounda, who has been teaching them proper lab techniques such as purifying gas vesicles from bacteria that will be used by other scientists in the lab for their experiments.
Malounda says SRC provides "a rare opportunity for high school students and K–12 teachers to witness and experience the atmosphere in an actual scientific research laboratory … and to interact with scientists."
Higginbotham and Gibson say they are learning a great deal about the process of conducting research by participating in regular lab discussions where all of the group's members pitch ideas, talk about their projects and goals, and ask questions about each other's work.
"I love asking questions," Higginbotham says. "It's always great when you can ask questions and learn."
Gibson praised SRC as intellectually rigorous and rewarding for teachers like himself and added that it greatly helps to "demystify research for students. Going from being an undergraduate to a PhD student is a big leap, but it's not impossible. Having an experience like this can make it much less scary for them."
The program culminates with a seminar day on August 10, when student-teacher-mentor teams from the various campus labs will explain their work to their peers and invited guests during formal 10-minute presentations followed by question-and-answer periods.
After being involved in her lab's weekly meetings, Higginbotham says she feels well prepared for her presentation: "I've seen how to present ideas at meetings and now know how to set up our information and explain it."
Shapiro says the program also serves a crucial function as a channel for "investing in future PhD students. Research relies on young, ambitious people, and this can help us encourage them to become scientists."
SRC is one of several programs for youth running on campus this summer, including iD Tech Camps, Alexa Caf
Storm chasing takes luck and patience on Earth—and even more so on Mars.
For scientists watching the Red Planet from data gathered by NASA's orbiters, the past month has been a windfall. "Global" dust storms, where a runaway series of storms creates a dust cloud so large it envelops the planet, only appear every six to eight years (that's three to four Mars years). Scientists still don't understand why or how exactly these storms form and evolve.
In June, one of these dust events rapidly engulfed the planet. Scientists first observed a smaller-scale dust storm on May 30. By June 20, it had gone global.
For the Opportunity rover, that meant a sudden drop in visibility from a clear, sunny day to that of an overcast one. Because Opportunity runs on solar energy, scientists had to suspend science activities to preserve the rover's batteries. As of July 18th, no response has been received from the rover.
Luckily, all that dust acts as an atmospheric insulator, keeping nighttime temperatures from dropping down to lower than what Opportunity can handle. But the nearly 15-year-old rover isn't out of the woods yet: it could take weeks, or even months, for the dust to start settling. Based on the longevity of a 2001 global storm, NASA scientists estimate it may be early September before the haze has cleared enough for Opportunity to power up and call home.
From July 14 to 22, the world's leading experts in space science will gather in Pasadena, informally known as the City of Astronomy, for the 42nd assembly of the Committee on Space Research, or COSPAR. Caltech is hosting the meeting, with the support of the Jet Propulsion Laboratory, which is managed by Caltech for NASA.
"We call Pasadena the City of Astronomy because it's home to many astronomy institutions, such as Caltech and JPL, the Carnegie Observatories and Mount Wilson and more," says Thomas (Tom) Prince, the Ira S. Bowen Professor of Physics at Caltech and chair of the scientific organizing committee for the COSPAR 2018 meeting. "It made sense that Pasadena would host the entire international community involved in space science and exploration."
Up to 2,500 participants are expected at the meeting, taking place at the Pasadena Convention Center and the Hilton Pasadena.
The meeting will feature talks, roundtable discussions, and exhibits on a wide range of space science subjects, including icy worlds in our solar system, such as Jupiter's moon Europa; the search for life beyond Earth; upcoming space telescopes; Earth climate science; exoplanets; and more. Prince says that the European Space Agency's Gaia mission, which recently released a three-dimensional map containing more than one billion stars in our Milky Way galaxy, will be a hot topic.
"Even though the topic is space science, the atmosphere is very much down to Earth," says Prince. "It's a place for people to get together and collaborate."
"COSPAR was created by the United Nations Committee on Peaceful Uses of Outer Space, at the dawn of the space age and height of the Cold War, specifically to facilitate exchanges between scientists in the U.S. and former USSR," says Gregg Vane, a senior strategist for solar system exploration at JPL and chair of the local organizing committee for COSPAR 2018. "Today, COSPAR is the primary means for facilitating communications between space scientists across the globe."
A public lecture—scheduled for Wednesday, July 18 at 8 p.m. at the Pasadena Civic Auditorium—will feature Sara Seager, a planetary scientist and astrophysicist at MIT. A panel discussion about searching for life in the solar system will follow, moderated by Bill Nye "The Science Guy" and including Bethany Ehlmann, a professor of planetary science at Caltech and a JPL research scientist, and Kevin Hand, a planetary scientist and astrobiologist at JPL.
At the same time as the COSPAR meeting, Pasadena will host AstroFest 2018—a week-long series of space-themed events and activities for the public. AstroFest 2018 kicks off July 14 at the Pasadena Convention Center with exhibits, planetarium shows, and evening stargazing. Activities later in the week include Astronomy on Tap, an informal evening at a local pub, where astronomers and the public discuss everything from black holes to bratwurst. A full list of events is online at cityofastronomy.org.
"We all share the same sky and its cosmic treasures, and the occasion of COSPAR provides an opportunity for the City of Astronomy partnership to share those wonders with the public during AstroFest," says Janice Lee, an astronomer at IPAC, Caltech's science and data center for astronomy, and chair of AstroFest 2018.
COSPAR is celebrating its 60th anniversary this year. It was founded in 1958—the same year the U.S. launched the Explorer 1 spacecraft, a research satellite built and operated by JPL. The goal of COSPAR is to exchange results, information, and opinions in space research, primarily through its biennial meetings. The last meeting, scheduled to take place in Istanbul in 2016, did not occur due to political unrest and an attempted coup. The upcoming Pasadena meeting is therefore the first to happen in four years. JPL senior research scientist Rosaly Lopes is deputy chair of the scientific program committee for 2018 and David Imel, manager of Caltech's IPAC astronomy center, is co-chair of the local organizing committee.
More information about COSPAR can be found online at cospar2018.org.
A new study using data from the NuSTAR space telescope suggests that Eta Carinae, the most luminous and massive stellar system within 10,000 light-years of Earth, is accelerating particles to high energies—some of which may reach our planet as cosmic rays.
"We know the blast waves of exploded stars can accelerate cosmic ray particles to speeds comparable to that of light, an incredible energy boost," says Kenji Hamaguchi, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and the lead author of the study. "Similar processes must occur in other extreme environments. Our analysis indicates Eta Carinae is one of them."
Eta Carinae, located about 7,500 light-years away in the southern constellation of Carina, is famous for a 19th century outburst that briefly made it the second-brightest star in the sky. This event also ejected a massive hourglass-shaped nebula, but the cause of the eruption remains poorly understood.
The system contains a pair of massive stars whose eccentric orbits bring them unusually close every 5.5 years. The stars contain 90 and 30 times the mass of our sun and pass 140 million miles (225 million kilometers) apart at their closest approach—about the average distance separating Mars and the sun.
"We've known for some time that the region around Eta Carinae is the source of energetic emission in high-energy X-rays and gamma rays," says Fiona Harrison, the principal investigator of NuSTAR; the Benjamin M. Rosen Professor of Physics; and the Kent and Joyce Kresa Leadership Chair of the division of physics, mathematics and astronomy at Caltech. "But until NuSTAR was able to pinpoint the radiation, show it comes from the binary and study its properties in detail, the origin was mysterious."
Read the full story at JPL News.
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. Caltech manages JPL for NASA.
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