UA Mars Scientists Hold Open House As Mars Odyssey Arrives At

Press Release From: Arizona State University
Posted: Tuesday, October 16, 2001

TUCSON, Ariz. -- University of Arizona space scientists are inviting the public to join them on campus at a special open house at the Lunar and Planetary Laboratory (LPL) 6 p.m. - 9 p.m. next Tuesday, Oct. 23, as the 2001 Mars Odyssey spacecraft arrives at Mars.

The State of Arizona has a lot riding on the mission -- namely two of the three primary science instruments, said LPL director Michael Drake.

Drake chairs NASA's Solar System Exploration Subcommittee, the chief U.S. advisory committee for planetary exploration. Tuesday will be an important moment in the history of Mars exploration, Drake told UA students last Friday. Not only will scientists see the planet as never before, Odyssey will help target where future rovers and landers should go in missions leading to a 2013 Mars sample-return mission, he said.

UA planetary sciences Professor William V. Boynton heads the Gamma Ray Spectrometer (GRS) on the Odyssey spacecraft. The GRS will for the first time map the amount and distribution of chemical elements that make up the martian surface.

Scientists led by Arizona State University's Philip R. Christensen and NASA Johnson Space Center scientists, respectively, have a thermal emission imaging experiment and a radiation environment experiment on the Mars Odyssey spacecraft.

Boynton and his team will be at the Tuesday evening open house in LPL's 3rd-floor atrium to answer questions as events unfold.

Odyssey will begin the difficult and risky orbit-entry maneuver at 7:30 p.m. Tucson time, when the spacecraft fires its main engine to slow its velocity so it can be captured by the planet's gravity. Then the spacecraft will disappear behind Mars, unable to communicate with Earth for the next 20 minutes. When Odyssey re-emerges, it will transmit a radio signal back to the NASA Deep Space Network on Earth. The network will relay that very welcome signal to the LPL in Tucson at around 7:50 p.m.

David A. Kring, director of the NASA/UA Space Imagery Center and organizer of the open house, said exhibits will highlight recent Mars mission discoveries and research by several UA professors involved, including Victor Baker, Boynton, Kring, Alfred McEwen, Robert Strom and Peter Smith. Kring also has arranged tours of the Space Imagery Center and the "Mars Garden," where UA teams test their Mars mission instruments.

LPL is in the Kuiper Space Sciences Building, located east of the Flandrau Science Center on the mall. Parking is available in lots across the mall next to the Optical Sciences Center, and at the Second Street garage north of the Administration Building.

The GRS during its 917 Earth-day-long geological mission will map the amounts of the chemical elements over the entire surface of Mars -- including hydrogen, most likely in the form of water ice, buried up to a meter (more than 3 feet) beneath the martian dust.

It is research that Boynton was ready to begin with his GRS experiment on Mars Observer in 1993, when the spacecraft vanished as it arrived at the Red Planet.

Gamma rays are induced by cosmic rays from space and occur along with natural radioactivity in rocks and soil. Different chemical elements emit gamma rays at specific "signature" energies. The GRS will measure the energies of gamma rays emitted from Mars' surface, mapping the amount and distribution of chemical elements over the planet.

The GRS is actually a suite of three instruments that include a gamma sensor head and two neutron detectors.

Boynton and his team designed and built the GRS at their university laboratories in Tucson. William Feldman of the Los Alamos National Laboratory and Igor Mitrofanov of Russia's Space Institute designed and built the neutron detectors.

The GRS neutron spectrometers were turned on soon after the Odyssey spacecraft was launched from Cape Canaveral on April 7, 2001. Scientists opened the gamma sensor head door at the end of June and collected data to calibrate the instrument, then closed the door at the end of August to prepare for next week's Mars Orbital Insertion.

All three parts of the GRS are performing well, "up to our expectations," team members say.

After Odyssey is safely in Mars' orbit, mission managers will begin "aerobraking," a technique that uses friction of Mars' upper atmosphere to slow the spacecraft still further, smoothing its initially elliptical orbit into the circular orbit required to do science. Aerobraking is a 76-day process, and transition to science orbit takes another approximately 14 days, UA team members say.

If everything goes as planned, the GRS neutron spectrometers will begin mapping hydrogen in the planet's surface and carbon dioxide at the poles around mid-January 2002, they add.

The GRS is scheduled to begin mapping other elements in the martian surface 200 days after Mars orbit insertion. This operation is contingent on sun angle, temperature and detector performance. Team members say they are hoping to start this data collection earlier, perhaps as early as March 2002.

Boynton and his team of scientists, engineers, graduate students and undergraduate students will run GRS science operations from the UA campus. Scientists from other research institutions across the United States and from several other nations are involved. The 2001 Mars Odyssey project overall is managed for NASA by the Jet Propulsion Laboratory in Pasadena, Calif.

Boynton's team has more details on the mission at their website, (EDITORS: The NASA/UA Space Imagery Center will also hold open house from 1 p.m. - 4 p.m. next Saturday, October 20. In addition to the exhibits and tours described above, UA Regents' Professor Victor Baker will talk at 1 p.m. on "Water on Mars," and UA Professor Alfred McEwen will talk at 1:30 p.m. on "Ongoing Mars Global Surveyor Mission." Kids, their parents and teachers are especially invited to Saturday's event.

(VIDEO: NASA-generated Beta-footage on the 2001 Mars Odyssey Mission will be available Friday afternoon, Oct. 19, from Vern Lamplot in UA News Services, 621-1877. For photo opportunities as exhibits are installed later this week, contact David Kring at 621-2024.)

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