Friday, August 10, 2007

The record-holder (without steroids)

Today, Spirit reaches Sol 1281, which matches the lifetime of the Viking II Lander (late 70s-early 80s) on the surface of Mars. Tomorrow it will be the all-time champion! And all on solar power! Go Spirit!

Both rovers have survived the worst part (we hope) of the current dust storms. The opacity of the air is no longer climbing, there are no new storms forming, and the solar power is holding steady. In the coming weeks and months we expect the dust to settle (though hopefuly not all on our solar panels) and activities will resume. It is a good thing the first storm gusts cleaned both rovers' solar panels! Opportunity is holding tight, keeping warm enough and keeping her batteries mostly charged. We've been able to do some atmospheric monitoring, but not much else. Spiritspide it's been more interesting.

Around sol 1257 the winds were howling at their worst. Here's an animation (from Larry Crumpler) of two microscopic images the rock Spirit has been parked over for the storm. It is a bit of silica-rich rock we've been trying to characterize, so it's light-toned and rough. The darker part is the dark basaltic soil and sand in the area. These two images were taken 7 minutes apart. If you look carefully, you can actually see sand grains moving around all over the place. Estimates of the wind velocity are between 60 and 70 miles per hour to get that type of motion on particles that large. (The images are 31 mm across, for scale).

We've also been monitoring the motion of sand on the ground. Here's an image in front of Spirit showing ripples crawling along and one behind Spirit showing her tracks get obliterated by the wind.