As 2008 fades to the pages of history, Spirit and Opportunity are closing in on the end of their fifth year of exploration on the Red Planet and moving the Mars Exploration Rover mission forward into a new year of bold scientific objectives.
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.
The period of Mars solar conjunction has just begun, which means that a host of scientists and engineers whose day jobs entail interaction with the five active Mars spacecraft are getting a five-week break from the daily grind of operations.
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.
After taking a "direct hit" from one of Mars' notorious dust storms last weekend, Spirit phoned home today at 11 a.m. Pacific Standard Time, exactly like its ground team had asked it to do and members of the rover team at the Jet Propulsion Laboratory (JPL) cheered. "She's talking!"
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.
Spring is still off a ways on the horizon in the Red Planet's southern hemisphere, but the solar-powered Mars Exploration Rovers seemed to shake off their third Martian winter this month, as they roved into new phases and looked to new destinations on their overland expeditions of Gusev Crater and Meridiani Planum. In the process, Spirit and Opportunity both chalked up notable achievements in October, adding to their already long list of accomplishments accrued as the world's first long-lived roving robot field geologists.
Victoria crater, the site of a Mars year's worth of study, is now far over the horizon, as Opportunity has lately completed a series of very long drives. Opportunity is once again sailing the sand seas of Meridiani Planum.