Rover on Mars Hits Big Rock, But 'Driver' Keeps License
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By JOHN NOBLE WILFORD
Published: July 11, 1997
The roving vehicle Sojourner has had its first mishap on Mars. While trying to park snugly against a large rock, the rover pulled in a little too aggressively and wound up with the Martian equivalent of jumping the curb, leaving it tilted with one of its six metal wheels resting a few inches up the face of the rock.
As a result, Sojourner failed in its first effort to analyze the chemistry of the rock, dubbed Yogi. Another try is to begin late tonight.
Richard Cook, the mission manager at the Jet Propulsion Laboratory here, said today that Sojourner was undamaged and that such an accident was not unexpected. The delay in getting scientific data on the rock should not be a problem, he added, because the rover was showing every indication that it should be able to function far beyond the minimum seven days estimated by some conservative engineers.
''We are all at this point expecting it to live for a long time,'' Mr. Cook said at a news conference. ''We are confident that we can spend several days at Yogi and still have time to go to other rocks.''
So far, the 23-pound Sojourner, about the size of a microwave oven, has been on the Martian surface since late Saturday. Its principal scientific instrument, called an alpha proton X-ray spectrometer, has conducted an analysis of the chemical composition of soil at the landing site and one other rock, known as Barnacle Bill. Geologists said the data indicated that Barnacle Bill was a volcanic rock resembling andesite, a fine-grained rock that has the characteristics of granite.
One of the next destinations for Sojourner, after Yogi, may be a whitish rock nicknamed Scooby Doo.
After its accident, Sojourner could with justification fall back on the familiar excuse that it was someone else's fault. No, the rock did not jump out in front of the rover. Instead, the driver in the control center, Jack Morrison, apparently miscalculated Sojourner's distance to the rock and radioed commands that sent the vehicle bumping into and trying to climb Yogi.
''The driver here sent rover too far,'' Mr. Cook said, referring to Mr. Morrison. ''It was a fairly tricky traverse, so his driver's license is still valid.''
Indeed, mission officials were pleased with Sojourner's response to the mishap. When it found itself against an unexpected and insurmountable object, it stopped automatically to await further instructions from Earth. At any rate, it would have been difficult for the rover to injure itself, going at a speed of less than two feet a minute at the time.
Sojourner had been having difficulty with the dark Yogi rock, which is more than 15 feet from the Mars Pathfinder landing craft. The rock, about three feet long, somewhat resembles a sleeping bear. But close-up pictures show a low overhang on its side and other obstacles in the way of the rover's getting close enough for its spectrometer to take measurements. Before the mishap, Sojourner had to make several turns and try several places for the tests.
Project scientists today also showed new pictures of the landing site processed in the laboratory to look at the terrain at Ares Vallis from different perspectives: the rocks as seen from the lander, the rover, from high above and from different angles.
Dr. Carol Stoker, a scientist from the Ames Research Center in Mountain View, Calif., said these perspective images were being used in deciding which rocks to study next and in planning future rover traverses. In flashing different views of Yogi on the screen, she added, ''you can imagine we're having a lot of fun with these, too.''
Dr. Jens Martin Knudsen of the Niels Bohr Institute at the University of Copenhagen announced the first preliminary findings of tests with magnets embedded on top of Pathfinder. Their purpose is to collect windblown dust with magnetic properties as part of studies of the evolution of soil on the surface of Mars.
Although extremely small amounts of dust have adhered to the magnets so far, Dr. Knudsen said the early indication is that the particles contain significant amounts of the mineral maghemite, a weathering byproduct of iron.
Dr. Julio Magalhaes, a physicist at the Ames Research Center, reported on temperature measurements in the atmosphere that Pathfinder took as it descended toward its landing on the Fourth of July. He found that the upper atmosphere was considerably colder than when the two Viking spacecraft landed in 1976, but the temperatures in the lower atmosphere were about the same.
writePost();
By JOHN NOBLE WILFORD
Published: July 11, 1997
The roving vehicle Sojourner has had its first mishap on Mars. While trying to park snugly against a large rock, the rover pulled in a little too aggressively and wound up with the Martian equivalent of jumping the curb, leaving it tilted with one of its six metal wheels resting a few inches up the face of the rock.
As a result, Sojourner failed in its first effort to analyze the chemistry of the rock, dubbed Yogi. Another try is to begin late tonight.
Richard Cook, the mission manager at the Jet Propulsion Laboratory here, said today that Sojourner was undamaged and that such an accident was not unexpected. The delay in getting scientific data on the rock should not be a problem, he added, because the rover was showing every indication that it should be able to function far beyond the minimum seven days estimated by some conservative engineers.
''We are all at this point expecting it to live for a long time,'' Mr. Cook said at a news conference. ''We are confident that we can spend several days at Yogi and still have time to go to other rocks.''
So far, the 23-pound Sojourner, about the size of a microwave oven, has been on the Martian surface since late Saturday. Its principal scientific instrument, called an alpha proton X-ray spectrometer, has conducted an analysis of the chemical composition of soil at the landing site and one other rock, known as Barnacle Bill. Geologists said the data indicated that Barnacle Bill was a volcanic rock resembling andesite, a fine-grained rock that has the characteristics of granite.
One of the next destinations for Sojourner, after Yogi, may be a whitish rock nicknamed Scooby Doo.
After its accident, Sojourner could with justification fall back on the familiar excuse that it was someone else's fault. No, the rock did not jump out in front of the rover. Instead, the driver in the control center, Jack Morrison, apparently miscalculated Sojourner's distance to the rock and radioed commands that sent the vehicle bumping into and trying to climb Yogi.
''The driver here sent rover too far,'' Mr. Cook said, referring to Mr. Morrison. ''It was a fairly tricky traverse, so his driver's license is still valid.''
Indeed, mission officials were pleased with Sojourner's response to the mishap. When it found itself against an unexpected and insurmountable object, it stopped automatically to await further instructions from Earth. At any rate, it would have been difficult for the rover to injure itself, going at a speed of less than two feet a minute at the time.
Sojourner had been having difficulty with the dark Yogi rock, which is more than 15 feet from the Mars Pathfinder landing craft. The rock, about three feet long, somewhat resembles a sleeping bear. But close-up pictures show a low overhang on its side and other obstacles in the way of the rover's getting close enough for its spectrometer to take measurements. Before the mishap, Sojourner had to make several turns and try several places for the tests.
Project scientists today also showed new pictures of the landing site processed in the laboratory to look at the terrain at Ares Vallis from different perspectives: the rocks as seen from the lander, the rover, from high above and from different angles.
Dr. Carol Stoker, a scientist from the Ames Research Center in Mountain View, Calif., said these perspective images were being used in deciding which rocks to study next and in planning future rover traverses. In flashing different views of Yogi on the screen, she added, ''you can imagine we're having a lot of fun with these, too.''
Dr. Jens Martin Knudsen of the Niels Bohr Institute at the University of Copenhagen announced the first preliminary findings of tests with magnets embedded on top of Pathfinder. Their purpose is to collect windblown dust with magnetic properties as part of studies of the evolution of soil on the surface of Mars.
Although extremely small amounts of dust have adhered to the magnets so far, Dr. Knudsen said the early indication is that the particles contain significant amounts of the mineral maghemite, a weathering byproduct of iron.
Dr. Julio Magalhaes, a physicist at the Ames Research Center, reported on temperature measurements in the atmosphere that Pathfinder took as it descended toward its landing on the Fourth of July. He found that the upper atmosphere was considerably colder than when the two Viking spacecraft landed in 1976, but the temperatures in the lower atmosphere were about the same.
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