Posted: Fri, Mar 7, 2008, 5:26 AM ET (1026 GMT)
NASA's Mars Reconnaissance Orbiter (MRO) spacecraft has taken images of what scientists believe is an ancient lakebed that could have once supported life. Images of Holden Crater show old conglomerations of rocks, called megabreccia, topped by a layer of clay sediment. Planetary scientists believe that the clay was deposited over a period of thousands of years when the crater was a lake; that clay could preserve any evidence of a past habitable environment there. The crater wall was later breached in a flood, exposing those lower layers as well as boulder-strewn upper layers. The crater is one of six candidate landing sites for NASA's Mars Science Laboratory rover, scheduled for launch in 2009, and could be considered for future sample return missions.

Related Links:

•  SPACE.com article
•  Univ. of Arizona press release