We're getting close to the fifth anniversary of the landings of Spirit and Opportunity, but was we approach that milestone, we're passing another. I've been told that as of yesterday, Spirit and Opportunity have operated on Mars for a combined length of time that is longer than the combined number of sols that the twin Viking landers operated.
I am greatly relieved to report that Spirit did talk to Earth as ordered today, indicating that the rover's power situation did not get so bad that a "low power fault" was triggered. The rover's still following instructions, and is still with us, though the power situation is still critical.
There was a worrying update posted on the JPL website for Spirit today: an early-season dust storm has darkened its skies enough that its solar panels produced only 89 watt-hours of power yesterday, sol 1,725. Neither rover has ever, ever seen power production levels that low, not even during last year's massive dust storm.
Another day, another drive: on sols 1,693 and 1,695 the Opportunity rover conducted two more lengthy drives to the south, totaling almost 200 meters. On the other side of the planet, Spirit is FINALLY in motion again.
I was delighted to receive an email from Morten Bo Madsen, who I knew from the Mars Exploration Rover mission as "that Danish magnet guy," the fellow responsible for the magnet experiments on nearly every American Mars mission. The magnets were originally designed to study the properties of airborne Martian dust, which would help determine its composition.
A majority of the people who work in planetary geology are usually associated with one or maybe two missions, doing all their research on the results from one instrument on one mission. But there are a few people whose expertise cuts across many space missions, and an even smaller number of people who seem to work on almost everything. Randy Kirk is one of those people.