ASU scientists selected for NASA observatory Science Investigation Team

December 23, 2015

NASA has announced the selection of Science Investigation Teams for its Wide Field Infrared Survey Telescope (WFIRST). ASU will be the lead institution for one of these teams, which includes School of Earth and Space Exploration scientists James Rhoads, Sangeeta Malhotra, Rogier Windhorst, Rolf Jansen, and Vithal Tilvi, along with scientists from the University of Texas, Texas A&M, University of Arizona, Stockholm University and Uppsala University in Sweden.

WFIRST will be a NASA observatory designed to settle essential questions in the areas of dark energy, exoplanets, and infrared astrophysics. The telescope has a primary mirror 2.4 meters in diameter (7.9 feet), the same size as the Hubble Space Telescope's primary mirror. WFIRST will have two instruments, the Wide Field Instrument, and the Coronagraph Instrument. Artistic view of NASA’s Wide Field Infrared Survey Telescope (WFIRST) space observatory. Photo by NASA/Goddard Space Flight Center Download Full Image

The Wide Field Instrument will have a field of view 100 times greater than the Hubble wide field instrument, capturing more of the sky with less observing time. As the primary instrument, the Wide Field Instrument will measure light from 380 million galaxies over the course of the mission lifetime. WFIRST is expected to discover about 2,600 exoplanets over the course of the mission.

The ASU team will develop a detailed plan for how to use WFIRST to study cosmic dawn, the period when the first stars formed in the earliest galaxies, and when the light produced by those earliest objects flooded the universe and ionized most of the ordinary matter. 

“We made the case to NASA that WFIRST can and should explore this exciting time in cosmic history, in tandem with its primary science goals of studying dark energy and finding extrasolar planets,” says Rhoads.  “And we put together a team with the scientific and technical expertise to help plan for that.” 

Adds Malhotra, “A six-month survey with WFIRST will be equivalent to about a hundred years of Hubble Space Telescope infrared observations. We will show how this can be used to chronicle both the early history of galaxy and quasar formation, and the effect those objects had on the universe around them.” 

With this announcement, ASU’s School of Earth and Space Exploration, an academic unit of the College of Liberal Arts and Sciences, is now playing a significant role in three of NASA’s flagship observatories: The Hubble Space Telescope, the James Webb Space Telescope, and now the Wide Field Infrared Survey Telescope.

WFIRST is designed for a six-year mission, and will launch on an Evolved Expendable Launch Vehicle (EELV) out of Cape Canaveral in 2024.

Karin Valentine

Media Relations & Marketing manager, School of Earth and Space Exploration


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Shooting for the moon: ASU lunar camera chief shares what's ahead

Did you know the moon is shrinking? ASU professor shares the lunar latest.
Dramatic new NASA image of Earth from ASU cameras was a complicated maneuver.
December 24, 2015

Professor Mark Robinson shares what it took to take dramatic new Earth photo, new discoveries and what is to come

On the eve of both Christmas and a full moon, ASU Now spoke with Mark Robinson, a professor in ASU’s School of Earth and Space ExplorationThe School of Earth and Space Exploration is a unit of ASU's College of Liberal Arts and Sciences., who is principal investigator for the ASU-operated cameras aboard NASA’s Lunar Reconnaissance Orbiter (LRO).

Last week, NASA released dramatic photos of Earth taken by the cameras (shown below). Robinson shared some of the challenges of the shot seen ‘round the moon, the little-known news that the moon is shrinking and what lies ahead for the lunar cameras. 

NASA image of the Earth from the Lunar Reconnaissance Orbiter

A full Earth straddles the edge of the moon, as seen from lunar orbit above Compton crater in the foreground. On Earth, Africa is visible at center right, and South America can be glimpsed through clouds at left. Photo by NASA/GSFC/Arizona State University

Question: This was no selfie. It was complicated. What are some of the pieces that had to come together to make this photo?

Answer: Just a few of the steps: You have to roll the spacecraft, in this case about 70 degrees, but the spacecraft is traveling at over 1,600 meters per second. We’re restricted in the length of one exposure time to something close to 0.4 milliseconds. You also move the spacecraft in the direction of flight so that you can get a wide enough field of view. When a spacecraft is in an elliptical orbit, the timing changes from image-to-image in an orbit. We have to compute all of that beforehand to get it exactly right. … That timing has to be precisely carried out. … We have to predict the temperature of the CCD (electronic equivalent of film). The Wide Angle Camera (WAC) is imaging an area multiple times while the Narrow Angle Cameras (NAC) takes just one picture. We blow up the WAC images and combine them to produce higher resolution, and then overlay this sharper image on the NAC image. We wanted the Earth to be on the horizon, and that only happens from certain areas of the moon. It’s only when the spacecraft is above the boundary between the nearside and farside that you can see the Earth behind the limb (edge of the moon).

Q: How did you know this image would be possible?

A: We’ve taken pictures of the Earth more than 10 times in the past. We wanted to get a limb shot (showing the edge of the moon). What makes it really hard is getting the moon in the foreground. … That was not by accident. We have software tools that allow us to visualize observations. We know where the spacecraft is going to be in the future. … We determined from which orbits the Earth will be visible near the limb. Once we know the ground track where the Earth will be visible, we then find a view with a dramatic foreground.

Q: LRO has been in orbit for more than six years. If you picked the best shots to show your friends, what are they? 

A: We’ve taken more than a million images. My answer changes every three days. The Apollo landing sites are fantastic. You can see the tracks the astronauts left on the surface of the moon. To me, as a scientist, it’s really great because it helps me visualize the photographs they took on the surface. The significance of the geologic context. ‘All right, now I know they got that soil sample there, and I can see what it looks like.’  

See a sampling of images (and explanations) from the LROC website below; Q&A continues below the gallery.

Q: What are the most interesting maneuvers and shots you plan with the cameras for the coming year?

A: We’re writing a proposal to get funding to extend the mission — right now we are scheduled to be turned off on Sept. 15. One of the fantastic things we’re doing with the cameras now … we would like to get temporal coverage (photos of the same area months or years apart). We compare the before image and the after image. In 70 percent of them, we find small changes to the surface; almost all are due to impacts. We have discovered 222 new craters that have formed since we’ve been in orbit (2009). The pace of discovery is going to accelerate. One thing we want to nail down is the current impact rate.

Q: What is the most important thing you, and scientists generally, have learned from the LRO?

A: That the moon is a dynamic place. There is this paradigm that grew up with the moon as this dead place, kind of shut off, nothing happening on it anymore except impacts.  We’ve discovered there are very young volcanic deposits, maybe even eruptions in the future. Conventional wisdom was that all lunar volcanism shut off between 1 billion and 2 billion years ago. That’s a big change in how we think about the moon. … There’s a lot more heat in the moon than we thought. … We have discovered thousands of small fault scarps — some even deform very small craters (10 meters).  Small craters erode away quickly due to other small impacts. Since the faults deform these craters, the faults must have formed recently. Since there are thousands of these faults randomly distributed around the moon, that’s proof that the lunar core is still cooling and transitioning from liquid to solid. The moon is shrinking.

An exhibit that includes images from the ASU cameras, 3-D models of the lunar surface and an interactive kiosk is scheduled to open in February at the National Air & Space Museum in Washington, D.C.