[meteorite-list] Mars Rovers Survive Severe Dust Storms, Ready for Next Objectives

[Ron Baalke]

Sept. 7, 2007

Dwayne Brown
Headquarters, Washington 
202-358-1726
dwayne.c.brown at nasa.gov

Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6278
guy.w.webster at jpl.nasa.gov

RELEASE: 07-187

MARS ROVERS SURVIVE SEVERE DUST STORMS, READY FOR NEXT OBJECTIVES

PASADENA, Calif. -- Two months after sky-darkening dust from severe 
storms nearly killed NASA's Mars exploration rovers, the 
solar-powered robots are awake and ready to continue their mission. 
Opportunity's planned descent into the giant Victoria Crater was 
delayed, but now the rover is preparing to drive into the half-mile 
diameter crater as early as Sept. 11.

Spirit, Opportunity's rover twin, also survived the global dust storm. 
The rovers are 43 months into missions originally planned to last 
three months. On Sept. 5, Spirit climbed onto its long-term 
destination called Home Plate, a plateau of layered bedrock bearing 
clues to an explosive mixture of lava and water. 

"These rovers are tough. They faced dusty winds, power starvation and 
other challenges -- and survived. Now they are back to doing 
groundbreaking field work on Mars. These spacecraft are amazing," 
said Alan Stern, associate administrator of NASA's Science Mission 
Directorate, Washington.

Victoria Crater contains an exposed layer of bright rocks that may 
preserve evidence of interaction between the Martian atmosphere and 
surface from millions of years ago, when the atmosphere might have 
been different from today's. Victoria is the biggest crater 
Opportunity has visited.

Martian dust storms in July blocked so much sunlight that researchers 
grew concerned the rovers' daily energy supplies could plunge too low 
for survival. Engineers at NASA's Jet Propulsion Laboratory, 
Pasadena, Calif., put Opportunity onto a very low-energy regimen of 
no movement, few observations and reduced communication with Earth. 
Skies above both rovers remain dusty but have been clearing gradually 
since early August.

Dust from the sky has been falling onto both rovers' solar panels, 
impeding their ability to collect energy from the sun. However, 
beneficial wind gusts removed some of the new buildup from 
Opportunity almost as soon as it accumulated. 

Opportunity drove to the lip of Victoria Crater in late August and 
examined possible entry routes. This week, Opportunity has been 
driving about 130 feet toward its planned entry point. The route will 
provide better access to a top priority target inside the crater: a 
bright band of rocks about 40 feet from the rim. "We chose a point 
that gives us a straight path down, instead of driving cross-slope 
from our current location," said Paolo Bellutta, a JPL rover driver 
plotting the route. "The rock surface on which Opportunity will be 
driving will provide good traction and control of its path into the 
crater."

For its first foray into the crater, Opportunity will drive just far 
enough to get all six wheels in; it will then back out and assess 
slippage on the inner slope. "Opportunity might be ready for that 
first 'toe dip' into the crater as early as next week," said JPL's 
John Callas, rover project manager. "In addition to the drives to get 
to the entry point, we still need to conduct checkouts of two of 
Opportunity's instruments before sending the rover into the crater."

The rover team plans to assess if dust has impaired use of the 
microscopic imager. If that tool is working, the team will use it to 
observe whether a scanning mirror for the miniature thermal emission 
spectrometer (Mini-TES) can function accurately. This mirror is high 
on the rover's camera mast. It reflects infrared light from the 
landscape to the spectrometer at the base of the mast, and it also 
can be positioned to close the hole in the mast as protection from 
dust. The last time the spectrometer was used, some aspects of the 
data suggested the instrument may have been viewing the inside of the 
mast instead of the Martian landscape.

"If the dust cover or mirror is no longer moving properly, we may have 
lost the ability to use that instrument on Opportunity," said Steve 
Squyres of Cornell University, Ithaca, N.Y., principal investigator 
for the rovers' science instruments. "It would be the first permanent 
loss of an instrument on either rover. But we'll see."

The instrument already has provided extensive valuable information 
about rocks and soils in the Meridiani region where Opportunity 
works. "Mini-TES has told us a lot about the rocks and soils at 
Meridiani, but we've learned that the differences among Meridiani 
rocks are often too subtle for it to distinguish," Squyres said. "The 
same instrument on Spirit, at Gusev Crater, has a much more crucial 
role for us at this point in the mission because there is such 
diversity at Gusev." Researchers will rely heavily on a different 
type of instrument, Opportunity's alpha particle X-ray spectrometer, 
for analysis of rocks at the bright-band target layer in the crater.

For images and information about the rovers, visit:

http://www.nasa.gov/rovers

	
-end-