http://www.panspermia.org/whatsnew.htm

There's an unexplained brown stain in the Genesis science canister. It is clearly visible on the interior anodized aluminum components, but not significantly on the collector. The stain is 160 angstrons thick in places, containing 70% carbon, 1.8-3.5% nitrogen, 17-20% oxygen, and about 4% each of flourine and silicon. The canisters were very carefully prepared to prevent contamination before launch, but contamination is now being reconsidered as the source of the stain. Could it be organic material encountered in space?

NASA launched Genesis on 8 August 2001, to collect solar wind particles for 884 days. The capsule containing the collectors was damaged when its parachute failed to deploy over the Utah desert on 8 September 2004. In spite of the damage, much is being learned from the mission.

D.S. Burnett et al., "Molecular Contamination on Anodized Aluminum Components of the Genesis Science Canister" [PDF #2045], Lunar and Planetary Science XXXVI (Proceedings of the LPS Conference), 14-18 Mar 2005.
Picking Up Where the Genesis Mission Left Off, by Leonard David, Space.com, 30 Mar 2005.
Genesis Mission Homepage at JPL, NASA.
Comets ... is a related CA webpage.