Nav: Home

NASA instrument to use X-rays to map an asteroid

July 12, 2016

NASA's OSIRIS-REx spacecraft will launch September 2016 and travel to the near-Earth asteroid Bennu to harvest a sample of surface material and return it to Earth for study. But before the science team selects a sample site, they can find out a bit about Bennu's elemental make-up.

To determine the composition of Bennu's surface, the Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) team equipped the spacecraft with an instrument that will identify which elements are present on the asteroid and measure their abundance.

The Regolith X-ray Imaging Spectrometer, or REXIS can image X-ray emission from Bennu in order to provide an elemental abundance map of the asteroid's surface.

"REXIS is different from the other imaging instruments on OSIRIS-REx because we're going to determine what Bennu is made of at the level of individual atomic elements," said Richard Binzel, REXIS principal investigator and instrument scientist at the Massachusetts Institute of Technology (MIT), Cambridge. "We're sniffing the atoms on the surface of Bennu."

To do that, REXIS gets a little help from the sun. Atoms on Bennu's surface absorb incoming solar X-rays that are emitted along with the solar wind. This causes electrons in the atom to move to a higher energy level. However, because these excited electrons are unstable, they quickly de-excite and drop back down to their original energy level and emit their own X-ray in turn. This process is known as fluorescence.

"You have all this energy coming in, and it kicks electrons up to the next energy level, but the electrons quickly decay back down and emit X-rays of precisely that same energy," said Josh Grindlay, REXIS co-principal investigator and deputy instrument scientist at Harvard University, Cambridge, Massachusetts. "The net result is a glowing surface on Bennu."

The energies of the re-emitted X-rays are characteristic of the elements from which they came. Elements absorb and re-emit X-rays at different, specific energies. The energies that the science team will see glowing at Bennu's surface will tell the researchers which elements are present.

In order to map these emitted X-rays, REXIS is fitted with what's known as a coded aperture mask. The mask consists of a pattern of pinholes that, when X-rays shine through, creates a shadow pattern on REXIS' detector.

Imagine sitting in your bedroom at night and a car drives by. The headlights cast a pattern of light and shadow on the walls. As the car moves, so do the shadows. In REXIS' case, it's the spacecraft that moves over the asteroid surface. The changing shadow patterns allow the team to identify any particular bright spots on Bennu that might be especially abundant in a certain element.

REXIS was selected as a Student Collaboration Experiment for the OSIRIS-REx mission. Built by a team from MIT and Harvard, students will perform data analysis of REXIS as part of their coursework.

"This has been an amazing experience for the students," said Rebecca Masterson, REXIS co-principal investigator and instrument manager at MIT. "They get to see how a mission evolves and what it takes to get to the point of launch. They're getting to see how an idea goes from conception to completion and actually play a role in its success."

More than 100 students will have been involved in REXIS upon the completion of the OSIRIS-REx mission.

"Even though OSIRIS-REx hasn't left the ground, I think REXIS is already a success," said David Miller, NASA's chief technologist and a former REXIS team lead at MIT. "We've inspired so many students. They are our next generation of space scientists and engineers, and they've already had a profound impact on our abilities to go further and explore deep space."
-end-
Goddard provides overall mission management, systems engineering and safety and mission assurance for OSIRIS-REx. Dante Lauretta is the mission's principal investigator at the University of Arizona. Lockheed Martin Space Systems in Denver built the spacecraft. OSIRIS-REx is the third mission in NASA's New Frontiers Program. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages New Frontiers for the agency's Science Mission Directorate in Washington.

For more information about OSIRIS-REx, visit:

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

http://www.asteroidmission.org

NASA/Goddard Space Flight Center

Related Asteroid Articles:

Designing better asteroid explorers
Recent NASA missions to asteroids have used robotic explorers to gather data about the early evolution of our Solar System, planet formation, and how life may have originated on Earth.
Protecting Earth from asteroid impact with a tethered diversion
A new paper published in EPJ Special Topics, co-authored by Flaviane Venditti, Planetary Radar Department, Arecibo Observatory, University of Central Florida, Arecibo, suggests the use of a tether assisted system to prevent PHA impact.
ATLAS telescope discovers first-of-its-kind asteroid
University of Hawai'i telescope discovers extraordinary asteroid with comet-like features that has researchers puzzled.
An iron-clad asteroid
Mineralogists from Jena and Japan discover a previously unknown phenomenon in soil samples from the asteroid 'Itokawa': the surface of the celestial body is covered with tiny hair-shaped iron crystals.
Asteroid impact enriches certain elements in seawater
University of Tsukuba researchers found two processes immediately after the end-Cretaceous asteroid impact that likely supplied chalcophile elements to the ocean, i.e., impact heating and acid rain.
Turbulent times revealed on Asteroid 4 Vesta
Planetary scientists at Curtin University have shed some light on the tumultuous early days of the largely preserved protoplanet Asteroid 4 Vesta, the second largest asteroid in our solar system.
In death of dinosaurs, it was all about the asteroid -- not volcanoes
Volcanic activity did not play a direct role in the mass extinction event that killed the dinosaurs, according to an international, Yale-led team of researchers.
Active asteroid unveils fireball identity
At around 1 a.m. local standard time on April 29, 2017, a fireball flew over Kyoto, Japan.
It really was the asteroid
Fossil remains of tiny calcareous algae not only provide information about the end of the dinosaurs, but also show how the oceans recovered after the fatal asteroid impact.
Uncovering the hidden history of a giant asteroid
A massive 'hit-and-run' collision profoundly impacted the evolutionary history of Vesta, the brightest asteroid visible from Earth.
More Asteroid News and Asteroid Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.