Washington U. professor, student to aid Mars mission landing

ST. LOUIS (AP) -- A Washington University professor and some of his students are again playing a key role in helping a space vehicle land safely on the rocky soil of Mars.

The Phoenix Mars Mission is expected to touch down Sunday afternoon on the northern Mars terrain. Just as they did in a Mars landing last year, Washington University professor Raymond Arvidson and recent graduate Tabatha Heet are again playing a key role in the landing.

Arvidson is chairman of the earth and planetary sciences department at the university in St. Louis and has guided many planetary landings. He participated in the two Viking Lander missions in 1976, helped select the landing site for the 2004 Mars Exploration Rover (MER) mission, and guided the activities of the rovers Spirit and Opportunity.

"We'll know within two hours of landing if Phoenix landed nominally," Arvidson said. "It will land, deploy its solar panels, take a picture and then go to bed."

Arvidson is NASA's Phoenix landing site working group chair. He also is the co-investigator for the Phoenix robotic arm, an instrument that will collect soil and ice samples; the lead for archiving mission data; and a key science lead for the first week of surface operations.

Phoenix will dig to an ice-rich layer near the surface. It will analyze the water and soil for evidence about climate cycles and investigate whether the environment has been favorable for microbial life. It also carries a weather station to monitor changes in the atmosphere.

The University of Arizona's Peter Smith is principal investigator for the 90-day mission.

Phoenix will touch down with the aid of a parachute, retro rockets and three legs with shock absorbing footpads to slow it down.

Heet will be joined by undergraduates Rebecca Greenberger and Kirsten Siebach, and doctoral candidate Selby Cull. They will be responsible for recording all that is done on the mission and for informally naming geological sites in the landing area.

Heet also has been involved in rock measurement and counting on Mars missions since 2006, a role that helps ensure a safe landing.