[meteorite-list] NASA Mars Rovers Braving Severe Dust Storms

[Ron Baalke]

July 20, 2007

Dwayne Brown/Tabatha Thompson 
Headquarters, Washington 
202-358-1726/3895 
dwayne.c.brown at nasa.gov, tabatha.thompson-1 at nasa.gov

Guy Webster/Gay Yee Hill
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6278/5011
guy.w.webster at nasa.gov, gay.y.hill at nasa.gov 

RELEASE: 07-162

NASA MARS ROVERS BRAVING SEVERE DUST STORMS

PASADENA, Calif. - Having explored Mars for three-and-a-half years in 
what were missions originally designed for three months, NASA's Mars 
rovers are facing perhaps their biggest challenge.

For nearly a month, a series of severe Martian summer dust storms has 
affected the rover Opportunity and, to a lesser extent, its 
companion, Spirit. The dust in the Martian atmosphere over 
Opportunity has blocked 99 percent of direct sunlight to the rover, 
leaving only the limited diffuse sky light to power it. Scientists 
fear the storms might continue for several days, if not weeks. "We're 
rooting for our rovers to survive these storms, but they were never 
designed for conditions this intense," said Alan Stern, associate 
administrator of NASA's Science Mission Directorate, Washington.

If the sunlight is further cut back for an extended period, the rovers 
will not be able to generate enough power to keep themselves warm and 
operate at all, even in a near-dormant state. The rovers use electric 
heaters to keep some of their vital core electronics from becoming 
too cold.

Before the dust storms began blocking sunlight last month, 
Opportunity's solar panels had been producing about 700 watt hours of 
electricity per day, enough to light a 100-watt bulb for seven hours. 
When dust in the air reduced the panels' daily output to less than 
400 watt hours, the rover team suspended driving and most 
observations, including use of the robotic arm, cameras and 
spectrometers to study the site where Opportunity is located.

On Tuesday, July 17, the output from Opportunity's solar panels 
dropped to 148 watt hours, the lowest point for either rover. On 
Wednesday, Opportunity's solar-panel output dropped even lower, to 
128 watt hours.

NASA engineers are taking proactive measures to protect the rovers, 
especially Opportunity, which is experiencing the brunt of the dust 
storm. The rovers are showing robust survival characteristics. 
Spirit, in a location where the storm is currently less severe, has 
been instructed to conserve battery power by limiting its activities.

"We are taking more aggressive action with both rovers than we needed 
before," said John Callas, project manager for the twin rovers at the 
Jet Propulsion Laboratory, Pasadena, Calif.

By Opportunity's 1,236th Martian day, which ended Tuesday, driving and 
all science observations had already been suspended. The rover still 
used more energy than its solar panels could generate on that day, 
drawing down its battery. "The only thing left to cut were some of 
the communication sessions," Callas said.

To minimize further the amount of energy Opportunity is using, mission 
controllers sent commands on Wednesday, July 18, instructing the 
rover to refrain from communicating with Earth on Thursday and 
Friday. This is the first time either of the rovers has been told to 
skip communications for a day or more in order to conserve energy. 
Engineers calculate that skipping communications sessions should 
lower daily energy use to less than 130 watt hours.

A possible outcome of this storm is that one or both rovers could be 
damaged permanently or even disabled. Engineers will assess the 
capability of each rover after the storm clears. 

NASA will provide mission updates as events warrant. The Jet 
Propulsion Laboratory manages the rover project for the Science 
Mission Directorate.

For more information about the rovers, visit: 

http://marsrovers.jpl.nasa.gov

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