NASA Mars Exploration Rover Status by Steve Squyres 11 June 2005

We’ve had a good weekend so far at Meridiani. Our objective at the moment is to turn Opportunity around so that we can safely approach Purgatory Dune and investigate it with both the instrument arm and our Mini-TES instrument. Rather than do a 180 turn in place — which is possible but a little funky with a stuck left front steering actuator — we’re doing a three-point turn instead. We’re partway through it now, and it’s going really well… there has been very little slip, and much of the fine-grained debris that had been adhering loosely to the wheels has now fallen off. So we’re very pleased with the progress.

So wait a minute, you may be thinking… Mini-TES? Wasn’t the Mini-TES instrument on Opportunity malfunctioning? You may recall that the Mini-TES on Opportunity seemed to have failed, presumably due to the dangerously cold temperatures it sees each time we use Deep Sleep. But we’ve been keeping an eye on Mini-TES, and the last few times we have used it, it has worked just fine. Whatever was wrong inside the instrument, the problem is intermittent. And right now the instrument seems to be okay. Whatever was wrong, we’re convinced that using Mini-TES won’t make matters worse, and in a situation like that the thing to do is use it… aggressively. So for now the Opportunity Mini-TES is back in business. We’ll see what happens.

And in the “it’s always something” department… we are now facing a new threat to both vehicles. It is dust storm season on Mars. Dust storm season happens once per martian year, during the southern summer when the input of solar energy into the martian atmosphere is highest. And southern summer is now upon us. The dust levels at both of our landing sites are high and climbing, and in fact the dust level at the Opportunity site is the highest we’ve ever encountered. It’s not a serious threat yet, but it’s a worry, and we’re watching the dust levels in the atmosphere closely.

The thing to realize about dust storms is that the threat is not high winds, and the threat is not dust buildup on the solar arrays. Instead, the threat is simply the attenuation of sunlight by the dust in the air, and the resultant loss of power from our solar arrays. RIght now we’ve got power to spare on both vehicles, and there is no imminent danger. But martian dust storms are notoriously hard to predict. In some years things are pretty quiet, and in other years what starts out as a small regional storm can blow up quickly into a monster that covers the whole planet. We don’t know what’s going to happen this year.

With both vehicles in such good shape, and with the solar arrays as clean as they are at the moment, we can handle a lot of atmospheric dust and come through it okay. And even if things do get very bad, there are a number of tricks we can use to save power and ride it out until the atmosphere clears. But exploring Mars, it seems, involves nearly constant peril, and the dust storm season is starting to loom as the next significant one we’re going to have to face. We’ll see what happens.