On May 25, 2008, approaching 5 p.m. PDT, NASA scientists will be wondering: Just how green is their valley?
That's because at that time the Phoenix Mars Mission space vehicle will be touching down on its three legs to make a soft landing onto the northern Mars terrain called Green Valley.
Of course, no valley is actually green on the Red Planet. The place got its name after analysis of images from Mars Reconnaissance Orbiter's HiRISE instrument. HiRISE can image rocks on Mars as small as roughly a yard and a half across. Green is the color that that landing site selection team used to represent the fewest number of rocks in an area, corresponding to a desirable place to land. Thus, "green valley," a relatively rock-less region, is a "sweet spot" where the Phoenix spacecraft will land.
Also playing a key role in the Phoenix Mars mission is Raymond E. Arvidson, Ph.D., the James S. McDonnell Distinguished University Professor and chair of the earth and planetary sciences department in Arts & Sciences at Washington University in St. Louis.
Arvidson has extensive experience in planetary landing operations. He participated in the two Viking Lander missions in 1976 and has spent the past four years, first helping select the landing site for the 2004 Mars Exploration Rover (MER) mission, then guiding the activities of the rovers Spirit and Opportunity as the mission's deputy principal investigator.
Accordingly, Arvidson is NASA's Phoenix landing site working group chair. He also is the co-investigator for the Phoenix robotic arm, a crucial 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 touch down in Green Valley with the aid of a parachute, retro rockets and three strong legs with shock absorbing footpads to slow it down.
That's sol (a Martian day) zero.
"We'll know within two hou
|Contact: Gerry Everding|
Washington University in St. Louis