ASU instrument plays key role in NASA mission

An instrument designed at Arizona State University to identify and map the minerals on the surface of an asteroid is a key element in a new NASA mission-concept. Philip Christensen, in the School of Earth and Space Exploration on ASU's Tempe campus, is the instrument's designer and principal investigator.

The proposed mission under study is called OSIRIS-Rex (for Origins Spectral Interpretation Resource Identification Security — Regolith Explorer). The flight plan calls for OSIRIS to rendezvous with a primitive asteroid between the orbits of Mars and Jupiter, go into orbit around the asteroid, survey it extensively, and finally bring back to Earth a small sample of its surface. The proposed mission is led by Michael Drake of the University of Arizona in Tucson.

OSIRIS-Rex is one of three missions selected by NASA as finalists for its New Frontiers Program. The others are a mission to return a sample from the South Pole-Aitken Basin on the Moon and a probe to study the atmosphere and surface of Venus.

NASA is giving each of the three missions $3.3 million to conduct a 12-month concept study focusing on feasibility, cost, management and technical plans. The studies also will include plans for educational outreach and small business opportunities. NASA will make its final selection in mid-2011. The selected mission's costs will be capped at $650 million (excluding the launch vehicle) and it must be ready for launch no later than the end of 2018. 

Successful heritage

The ASU instrument that forms an essential part of the OSIRIS mission is the OSIRIS Thermal Emission Spectrometer, or OTES. Operating in the infrared part of the spectrum, it will determine the mineral composition and thermal inertia of the asteroid's surface rocks and soils.

"The infrared is great for identifying minerals," said Christensen, a Regents' Professor of geological science and the director of the Mars Space Flight Facility in ASU's College of Liberal Arts and Sciences. "The role of our OTES instrument will be to map the composition of the asteroid to identify the best region to sample. The OTES is a direct descendant of two highly successful infrared instruments we've sent to Mars that have mapped the rocks and minerals on that planet."

One of these instruments is the Thermal Emission Spectrometer on NASA's Mars Global Surveyor mission; it discovered the landing site for one of NASA's two Mars Exploration Rovers (Opportunity). The other instrument is the Miniature Thermal Emission Spectrometer, or Mini-TES, one of which is on each Mars rover as a scouting camera, much the same role that OTES will provide for OSIRIS.

"If NASA gives the OSIRIS mission the go-ahead, then OTES will be developed by ASU's School of Earth and Space Exploration," Christensen said.  Overall, the OSIRIS project would be a boost for Arizona's economy, bringing about $100 million to the state.