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SPIRIT GETS INSTRUCTIONS



Submitted by Arthur  - N1ORC

Donald Savage 
Headquarters, Washington            January 13, 2004
(Phone: 202/358-1547)

Guy Webster 
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-5011)

RELEASE: 04-021

GO TO THAT CRATER AND TURN RIGHT: SPIRIT GETS A TRAVEL 
ITINERARY 

     NASA's Spirit has begun pivoting atop its lander 
platform on Mars, and the robot's human partners have 
announced plans to send it toward a crater, then toward some 
hills, during the mission.

Determining exactly where the spacecraft landed, in the 
context of images taken from orbit, has given planners a 
useful map of the vicinity. After Spirit drives off its 
lander and examines nearby soil and rocks, the scientists and 
engineers managing it from NASA's Jet Propulsion Laboratory, 
Pasadena, Calif., intend to tell it to head for a crater that 
is about 250 meters (about 270 yards) northeast of the 
lander.

"We'll be careful as we approach. No one has ever driven up 
to a martian crater before," said Dr. Steve Squyres of 
Cornell University, Ithaca, N.Y., principal investigator for 
the science instruments on Spirit and on its twin Mars 
Exploration Rover, Opportunity.

The impact that dug the crater about 200 meters (about 220 
yards) wide probably flung rocks from as deep as 20 to 30 
meters (22 to 33 yards) onto the surrounding surface, where 
Spirit may find them and examine them. "It will provide a 
window into the subsurface of Mars," Squyres said.

Craters come in all sizes. The main scientific goal for 
Spirit is to determine whether the Connecticut-sized Gusev 
Crater ever contained a lake. Taking advantage of the nearby 
unnamed crater for access to buried deposits will add to what 
Spirit can learn from surface materials near the lander. 
After that, if all goes well, the rover will head toward a 
range of hills about 3 kilometers (2 miles) away for a look 
at rocks that sit higher than the landing neighborhood's 
surface. That distance is about five times as far as NASA's 
mission-success criteria for how far either rover would 
drive. The highest hills in the group rise about 100 meters 
(110 yards) above the plain.

"I cannot tell you we're going to reach those hills," Squyres 
said. "We're going to go toward them.'' Getting closer would 
improve the detail resolved by Spirit's panoramic camera and 
by the infrared instrument used for identifying minerals from 
a distance. 

First, though, comes drive-off. Overnight Monday to Tuesday, 
Spirit began rolling. It backed up 25 centimeters (10 
inches), turned its wheels and pivoted 45 degrees.

"The engineering team is just elated that we're driving," 
said JPL's Chris Lewicki, flight director. "We've cut loose 
our ties and we're ready to rove."  After two more pivots, 
for a total clockwise turn of 115 degrees, Spirit will be 
ready for driving onto the martian surface very early 
Thursday morning, according to latest plans.

Engineers and scientists have determined where on the martian 
surface the lander came to rest. NASA's Mars Odyssey orbiter 
was used in a technique similar to satellite-based global 
positioning systems on Earth to estimate the location of the 
landing site, said JPL's Joe Guinn of the rover mission's 
navigation team. Other researchers correlated features seen 
on the horizon in Spirit's panoramic views with hills and 
craters identifiable in images taken by Mars Global Surveyor 
and Odyssey. "We've got a tremendous vista here with all 
kinds of features on the horizon," said JPL's Dr. Tim Parker, 
landing site-mapping geologist.

The spacecraft came to rest only about 250 to 300 meters (270 
to 330 yards) southeast of its first impact. Transverse 
rockets successful slowed horizontal motion seconds before 
impact, said JPL's Rob Manning, who headed development of the 
entry, descent and landing system. The spacecraft, encased in 
airbags, was just 8.5 meters (27.9 feet) off the ground when 
its bridle was cut for the final freefall to the surface. It 
first bounced about 8.4 meters (27.6 feet) high, then bounced 
27 more times before stopping.

Analysis of Spirit's landing may aid in minor adjustments for 
Opportunity, on track for landing on the opposite side of 
Mars on Jan. 25 EST. 
JPL, a division of the California Institute of Technology in 
Pasadena, manages the Mars Exploration Rover project for 
NASA's Office of Space Science, Washington. For more 
information about NASA and the Mars mission on the Internet, 
visit:
http://www.nasa.gov
Additional information about the project is available from 
NASA's JPL at:
http://marsrovers.jpl.nasa.gov 
For information from Cornell University, visit:
http://athena.cornell.edu
-end-

                           



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