NASA has selected a proposal for a mission that would collect samples of martian atmospheric dust as one of four finalists for the first Mars Scout mission. The proposal, directed by Arizona State University geologist and cosmochemist Laurie Leshin, and in major partnership with the Jet Propulsion Laboratory and Lockheed Martin, will receive a $500,000 grant to complete its refinement prior to the agency’s final selection process, which will take place next summer. The Mars Scout Program plans to mount at least one (and perhaps several) Scout missions to Mars beginning in 2007, with budgets of up to $325 million per mission.
Leshin’s proposal is called "Sample Collection for Investigation of Mars” (SCIM), and involves a mission that would do a ”swoop and scoop” into the dusty Martian atmosphere. The proposed mission would perform the first return of a Martian sample at less cost, lower risk and in a shorter time frame than the more complicated missions that will eventually be launched to collect samples from the planet's surface. For full details on the mission proposal, including images and animations, see http://scim.asu.edu.
In brief, the proposal calls for a spacecraft to make a "high pass" of Mars, to an altitude ~23 miles above the surface, to collect dust and gas samples from the Martian atmosphere for about one minute at about 14,000miles per hour, before swinging back and beginning the return to earth. On the spacecraft, a light-weight and porous high-tech substance called "aerogel" would cushion, trap and preserve dust particles. The aerogel collection device is similar that currently flying on NASA’s Stardust mission to collect dust streaming off of a comet.
Leshin projects that the aerogel would capture about 1000 fine dust particles measuring 10 microns (1/100 of a millimeter) or larger. "Martian dust is an interesting thing because there is dust all over the Martian surface," said Leshin. "It's the ubiquitous layer - it's everywhere, yet we really know very little about it. It samples virtually the whole planet, yet it is so fine-grained that it is very hard to study when you're sitting there on the surface. You really need to bring it back to Earth to characterize it grain by grain. And each grain is like a little rock from Mars."