Cherita Chen writes, "Yesterday NASA, Cornell University, and the USGS celebrated the Mars Exploration Rovers' 1000th Sol on the Red Planet. The first rover to land, Spirit, reached the 1000 Sol mark a few weeks ago while the planet was in Solar conjunction. 'Opportunity,' Spirit's twin, and the second lander to make the bounce to Mars, celebrated the milestone yesterday while sitting atop Victoria Crater on the other side of Mars. Both Rovers are still operational (though Spirit is limping) and are sending back valuable data. Not bad for what was slated to be a '90 Sol' mission."