If Gusev Crater near Mars’ equator has a wet history, it will be tough to prove.
Scientists picked the site for the Mars Exploration Rover mission because photos from space show what appear to be riverbeds flowing into the basin.
Ever since Viking missions in 1975 failed to detect biological life on the Red Planet, NASA has focused on finding water as a first step toward finding life.
Now, the Spirit rover is standing on its lander in the crater, poised to move onto Martian soil this week.
But the flat desert where the Spirit rover sits is dotted with rocks that seem to be volcanic basalts – not the layered sedimentary rocks that are typically found after a lake dried up.
No sign of Princess Thuvia, either.