Dust Storm Passing Over Spirit
Jet Propulsion Laboratory
August 25, 2009

The amount of electricity generated by the solar panels on Spirit has
been declining for the past several Martian days, or sols, as a regional
dust storm moved southward and blocked some of the sunshine at Spirit's
location. The team operating the rover has responsively trimmed Spirit's
daily activities and is keeping an eye on weather reports from
observations by NASA's Mars Reconnaissance Orbiter.

Spirit's solar panels generated 392 watt-hours during the mission's Sol
2006 (Aug. 24, 2009), down from 744 watt-hours five sols earlier, but
still generous compared with the 240 watt-hours per sol that was typical
before a series of panel-cleaning events about four months ago.

"We expect that power will improve again as this storm passes, but we
will continue to watch this vigilantly," said JPL's John Callas, project
manager for Spirit and its twin, Opportunity. "Spirit remains power
positive with healthy energy margins and charged batteries. The weather
prediction from the Mars Color Imager team is that the storm is abating,
but skies will remain dusty over Spirit for the next few sols."

Recent images from the Mars Color Imager camera on Mars Reconnaissance
Orbiter showed this regional storm becoming less extensive Monday even
as it shifted southward so that its southern edge covered the Gusev
Crater area where Spirit is working. Malin Space Science Systems in San
Diego, which operates that camera, provides frequent weather updates to
the rover team. Weekly reports are posted at http://www.msss.com/msss_images/latest_weather.html .

Meanwhile, in JPL's In-Situ Instrument Laboratory, the rover team is
continuing testing of strategies for getting Spirit out of a patch of
soft soil where it is embedded on Mars. On Sol 2005 (Aug. 23, 2009)
Spirit used its panoramic camera to examine the nature of how soil at
the site has stuck to the rover's middle wheels. The team has also used
Spirit's rock abrasion tool as a penetrometer to measure physical
properties of the soil around Spirit by pressing into the soil with
three different levels of force. The team is aiming to start sending
drive commands to Spirit in September.