A patch of Martian soil analyzed by NASA's rover Spirit is so rich in silica that it may provide some of the strongest evidence yet that ancient Mars was much wetter than it is now. The processes that could have produced such a concentrated deposit of silica require the presence of water.
Members of the rover science team heard from a colleague during a recent teleconference that the alpha particle X-ray spectrometer, a chemical analyzer at the end of Spirit's arm, had measured a composition of about 90 percent pure silica for this soil.
"You could hear people gasp in astonishment," said Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the Mars rovers' science instruments. "This is a remarkable discovery. And the fact that we found something this new and different after nearly 1,200 days on Mars makes it even more remarkable. It makes you wonder what else is still out there."
This whole rover project is probably the grandest story to come out of NASA in years, maybe decades. Whenever something goes wrong, it's on the front page for days. But here we have a couple of rovers whose initial mission was supposed to last 3 months, and here it is over three years later and they're still cranking out data -- and you rarely hear about it. This is mostly due to good design, but they have also had some incredible luck. Ferinstance, the solar panels were expected to get a coating of dust and eventually become inoperable, but for whatever reason, dust buildup has turned out not to be a problem.
If you find the book Rovin Mars by Squyers, it's an excellent read. And you'll be amazed at how big and complex these rovers really are.