New spacecraft images show a lake that may have filled a crater for a long time on early Mars might once have been habitable.
NASA's Mars Reconnaissance Orbiter captured the images that suggest the debris-strewn Holden Crater once held a calm body of water that could have harbored life. There is so far no convincing evidence life does or ever did exist on Mars, however.
The crater debris includes a mix of broken boulders and smaller particles called megabreccia.
"Holden Crater has some of the best-exposed lake deposits and ancient megabreccia known on Mars," said Alfred McEwen, principal scientist for MRO's HiRISE camera. "Both contain minerals that formed in the presence of water and mark potentially habitable environments. This would be an excellent place to send a rover or sample-return mission to make major advances in understanding if Mars supported life."
That mission could be NASA's Mars Science Laboratory, set for launch next year. The Holden Crater is one of six landing sites under consideration.
The Holden impact crater formed inside a larger impact basin that was crisscrossed by large, natural channels. Blocks as large as 164 feet (50 meters) were blasted from the basin by the impact, before falling back to the surface to form the megabreccia layer.
Water later settled a layer of fine-grained sediment on top of the megabreccia, including clay that could preserve any signs of life that might have existed.
"If we were looking on Earth for an environment that preserves signatures related to habitability, this is one of the kinds of environments we would look at," said John Grant, Hi-RISE scientist.
Source:Xinhua/Agencies
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