Viking 1 & 2 USA: Orbiter/lander missions surveyed planet several years. Mars 6 & 7 USSR: Both landed, but got little data.(x)(x) Mariner 9 USA: Orbited for 348 days returned 7,329 photos.(x) Kosmos 419 USSR: Lander achieved Earth orbit only.(y) Mariner 8 USA: Orbiter lost during launch.(y) Mariner 4 USA: First Mars flyby returned 21 photos.(x) Zond 2 USSR: Passed Mars but radio failed.(y) Unnamed USSR: Two missions reached Earth orbit only.(y)(y) Unnamed USSR: Two missions did not reach Earth orbit.(y)(y) Mission leaders plan a three- day stand-down for Spirit until that hazardous landing effort is over. Pacific time, on a flat plain called Meridiani Planum, halfway around the planet from the Spirit site in Gusev Crater. Spirit's twin rover, Opportunity, is due to land on Mars on Saturday at 9: 05 p.m. Even if Spirit's problem is diagnosed and fixed, the work may be delayed even longer. The scientists had also planned to use Spirit's Rock Abrasion Tool - the RAT - to grind away a bit of Adirondack's surface so the Microscopic Imager can take pictures and the Alpha Particle X-Ray Spectrometer can determine the varied elements that make up the rock. When Spirit's problems cropped up Wednesday, the rover's long tool- carrying arm had already deployed its German-made Mossbauer Spectrometer to scan the surface of the rock Adirondack for iron-bearing minerals that might have formed in hot, watery environments. "It can do a lot to protect itself, or even to fix itself." "But Spirit has a lot of intelligence built into it," Naderi said. Among the problems they will consider, Naderi said, is that the spacecraft may have experienced an unexpected voltage drop, a "corrupted" piece of software, a "memory corruption" or even a period of unanticipated overheating. Mission engineers knocked off for a few hours of sleep during the day Thursday and planned to work through Thursday night. That's what we hope we can do overnight tonight." "A good doctor can put the symptoms together and make a diagnosis. "It may be a bug in the software, it may be a temperature problem - just like a patient who first reports a cough and then a ringing in the ears," Naderi said. Naderi likened the mission engineers to doctors and said their job now was to diagnose Spirit's symptoms, one at a time.
But what it sent us was only an envelope - an envelope with nothing in it." "It was good news because it told us Spirit had power and a communication link. "That's when he heard a tone come back from Spirit's low-gain antenna," said Firouz Naderi, the Mars Exploration program manager, in an interview. However, when it is standing inactive on Mars and in what engineers call a "safe mode," Spirit is automatically programmed to listen for signals on a second channel at an extremely slow rate of only 7 bits per second.
plea from Spirit on that first channel but heard nothing. Thursday, the engineers listened for a response to their 7:24 a.m. Spirit's highly sophisticated communication system is automatically programmed to listen for signals from Earth on one of two channels at a rate of 32 bits per second.Īt about 9:15 a.m. Then at 7:30 Thursday night, the Surveyor's orbit carried it over the Spirit site once again, but it was unable to receive any signal at all, mission controllers said.
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The Surveyor orbiter heard faint tones as if Spirit were responding to pleas from Mission Control, but the radio tones carried no real information at all, only a random series of zeroes and ones, said Richard Cook, the mission's deputy project manager. Mars Global Surveyor and Mars Odyssey, the two orbiting spacecraft flying over Spirit and relaying its signals to Earth, had both passed over the site Wednesday night. Initially, engineers attributed the communication problem to the bad weather and declared the rover healthy, but by early Thursday, none of the mission specialists were so sanguine. "Not a lot of science was done," said mission manager Jennifer Trosper in Pasadena. It is only 8 inches high, with a flat, pyramid-shaped cliff face just right for chemical and geological study.īut a thunderstorm on Wednesday whipping up rain at the huge radio antenna of the National Aeronautics and Space Administration's Deep Space Network in Canberra, Australia, distorted the image data that Canberra received and prevented scientists from interpreting it. The first sign of trouble came early Wednesday when Spirit was preparing its array of tools to study an intriguing rock that engineers have named Adirondack. Another craft, Opportunity, is expected to land on the other side of Mars on Saturday evening to join its twin in a search for evidence that water, and perhaps life, ever existed on the Red Planet. Spirit is the first act of a two-act, $820 million mission.