[meteorite-list] New Images Reveal Threatening Conditions That Two Rovers Face in Giant Martian Dust Storm

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 29 Aug 2007 13:32:40 -0700 (PDT)
Message-ID: <200708292032.NAA11704_at_zagami.jpl.nasa.gov>

http://www.news.cornell.edu/stories/Aug07/Mars.images.html

New images reveal threatening conditions that two rovers face in
giant Martian dust storm

Cornell University
Aug. 29, 2007

The mighty Mars rovers Spirit and Opportunity continue to persevere
in brutal conditions, as revealed in images of the sun they are
sending home. The images show how opaque the Martian atmosphere has
been in the face of a raging, two-month dust storm.

To understand the gravity of the storm, engineers and astronomers
monitor the situation by examining the images of the sun and
measuring the amount of dust or the opacity of the atmosphere.

Emily Lakdawalla of the Planetary Society assembled the mosaic of
images, which were taken daily by the panoramic cameras (Pancams) on
both rovers, Spirit and Opportunity. The images were calibrated by
students in Cornell's MarsLab image-processing facility and made
available through collaboration with Jim Bell, Cornell professor of
astronomy and the principal investigator on the rovers' Pancam
imaging team.

"Emily's mosaics are quite remarkable. They show a rover's-eye view
of the storm getting worse, and this little light bulb we call the
sun getting dimmer and dimmer and dimmer as the dust clouds built
up," said Bell.

Since June, a massive dust storm has engulfed much of the Martian
surface. The storm has put the rovers in danger, as they depend upon
solar power to run during the day and to survive the harsh, cold
Martian nights. As dust clouds block the sunlight and dust settles on
the solar panels, the rovers' energy is depleted. Only wind can
remove the dust, Bell said.

For the rover Spirit, the Jet Propulsion Laboratory (JPL) in
Pasadena, Calif., reports that even though the Martian sky above
Gusev Crater is clearing, solar power levels remained fairly low and
constant dust now appears to be accumulating on the solar panels.
Between sol -- a Martian day -- 1283 (Aug. 12) and sol 1286 (Aug.
16), the atmosphere cleared by about 35 percent, leading to daily
energy levels of about 300 watt-hours (the amount of energy needed to
light a 100-watt bulb for three hours). Typical levels before the
dust storms were around 700 to 900 watt-hours for the rovers.

On the other side of Mars, Opportunity, now waiting to enter Victoria
Crater from the rim, is currently experiencing its lowest power
levels to date. The sky was so dark in mid-July that less than 200
watt-hours of daily energy was available, according to JPL. But skies
are slowly clearing, offering hope that the rover will be ready for a
descent into the crater soon. Opportunity benefited from wind blowing
some dust off solar panels on Aug. 22. Under gradually clearing
skies, Opportunity's solar panels were producing about 300 watt hours
daily by Aug. 24.

The Jet Propulsion Laboratory, a division of the California Institute
of Technology, Pasadena, manages the Mars Exploration Rover Project
for the NASA Science Mission Directorate, Washington, D.C.
Received on Wed 29 Aug 2007 04:32:40 PM PDT