Four Years on Mars...

About four years ago, NASA landed two robotic explorers on the surface of Mars: Spirit and Opportunity. Preceding those missions was a string of high-profile failures, some mysterious, some turning out to be simple human error. All were very embarrassing for NASA.

The hope was that with two entirely separate explorers, the chances were good that at least one would be successful – but both of them made it to Mars in one piece, and were competely functional. NASA's goal was for these explorers to survive 90 days on the surface, driving around and sending back scientific data. When both of them were still working after 90 days, the team got more funding and they kept on going. That's been repeated several times now, and four years later – more than 16 times the design life expectancy – both explorers are still going. It's been an amazing technological success, and a far richer source of solid science than anyone dared dream at the mission's inception.

At upper right is a recent panorama taken by Spirt, showing the scene from the Columbia Hills. It's parked for the Martian winter right now, conserving power until the sun shines brightly again. Spirit's in reasonably good shape; it's major problem is one dragging wheel – but it's got five more that let it keep right on truckin'. At lower right is a recent panorama taken by Opportunity – nearly on the opposite side of Mars from Spirit, near Victoria Crater (visible near the horizon). Opportunity has no major problems at all, and plans are for it to aggressively explore the inside of Victoria Crater, taking risks now that mission planners wouldn't even have considered earlier in the mission.

These two intrepid explorers (and their Earth-bound controllers) get very little attention in the media these days. I guess they're boring to most people. They have returned far more science with their sustained explorations than any manned mission would, for a tiny fraction of the cost of a manned mission. Frankly, I'm surprised (but delighted!) that NASA has funded this unexpectedly long mission – they're so focused on manned space exploration that any such robotic mission is always at risk of being de-funded (and missions that have yet to fly are always at risk of being canceled, as so many already have been).

More like this, please, NASA...