ASU, UA work together on asteroid mission

Editor's Note: Arizona State will take on the University of Arizona in a rivalry matchup at 7:30 p.m. Nov. 19, in Sun Devil Stadium in Tempe.

A NASA mission to collect a sample of an asteroid and return it to Earth will include an instrument built at Arizona State University's School of Earth and Space Exploration (SESE). The mission is managed by NASA's Goddard Space Flight Center and the University of Arizona.

The ASU instrument will analyze long-wavelength infrared light emitted from the asteroid to map the minerals on its surface. The device is a modified version of the highly successful miniature infrared spectrometers carried on Spirit and Opportunity, NASA's twin Mars Exploration Rovers.

The new asteroid sample-return mission is called OSIRIS-REx. The mission's goals are to return a sample of rocks, soil and dust from a pristine carbonaceous asteroid, map the asteroid's global properties, characterize this class of asteroid for comparison with meteorites and measure a subtle effect of sunlight that can alter the orbits of asteroids.

The instrument to be built at ASU is the OSIRIS-REx Thermal Emission Spectrometer, or OTES for short. It will be the first complex electro-optical instrument for spaceflight to be built at ASU.

"In the past, each of the five instruments we’ve built for NASA were built at an aerospace company in California," says Philip Christensen, instrument scientist for OTES. He is Regents' Professor of Geological Sciences in SESE, in the College of Liberal Arts and Sciences. "For the first time, a piece of complicated space hardware will be built on the ASU campus."

OTES will be built in cleanroom facilities in the new Interdisciplinary Science and Technology Building (ISTB) 4, currently being constructed on the Tempe campus. "ISTB-4 is a remarkable building that will not only support advanced research by SESE and other academic and research units, but will also serve as a public showcase for scientific exploration," notes Kip Hodges, director of SESE. "The OTES fabrication facility will be on the first floor of ISTB-4, in space designed for public viewing through high-bay windows. It will be fantastic to be able to use this state-of-the-art laboratory as a teaching tool."

If all goes as planned, OSIRIS-REx will launch in September 2016 and rendezvous with asteroid 1999 RQ36 in November 2019. It will spend up to 15 months surveying the asteroid's mineralogy with OTES and another spectrometer working at shorter visible and infrared wavelengths. A suite of three visible-light cameras and a laser altimeter will complete the picture of the asteroid.

Mission scientists will then select a target area. The spacecraft will approach the asteroid, touch it very briefly, and collect at least 60 grams (2 ounces) of dust, soil, and rubble from its surface. With sample collection completed, OSIRIS-REx will cruise back to Earth and use a separable return capsule to deliver the sample to a landing site in Utah in September 2023. After flying past Earth, the spacecraft should be available to survey other asteroids, although it will not be able to collect samples from them.

For his part, Christensen is enjoying the change in scientific targets. "After spending most of my career studying Mars, it's going to be exciting and challenging for me and my research group to focus our attention to the origin and history of asteroids."

OSIRIS-REx is the third mission chosen in NASA's New Frontiers program for unmanned planetary missions. Its budget (not counting launch vehicle) is approximately $800 million, of which the OTES budget is about $17 million.

The University of Arizona is responsible for coordinating the science team, science operations, data archiving, education and public outreach, and building the visible-light camera suite.

Written by Robert Burnham