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Mars Lander course correction goes 'smoothly'

Mars Polar Lander
Kennedy Space Center technicians lower the Mars Polar Lander onto a workstand in this 1998 file photo.  

November 30, 1999
Web posted at: 7:59 p.m. EST (0359 GMT)

PASADENA, California (CNN) -- A spacecraft approaching Mars underwent a smooth course correction three days before its scheduled landing, according to Jet Propulsion Laboratory engineers.

The Mars Polar Lander, tasked with studying the planet's climate and searching for water, had an adjustment of slightly more than 1 mph (1.6 km/h) -- a tiny correction, considering it is approaching the red planet at 12,000 times that speed.

"The changes this morning went well," Dr. Sam Thurman, the MPL flight operations manager, told reporters Tuesday at the JPL center in Pasadena. "The spacecraft is in excellent health." Earlier in the day, the lander was 780,000 miles (1.3 million km) from Mars, he said.

Some six hours before a Friday touchdown, JPL scientists will decide whether to do a final course correction. "Things will get real exciting then," said Richard Cook, the MPL project manager for operations. "We'll be waiting with baited breath. That's for sure."

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The lander's sister ship, the Mars Climate Orbiter, was lost as it entered Mars orbit in September, primarily because of a math mixup. JPL scientists were calculating thrust firings in metric units, but the prime mission contractor, Lockheed-Martin Aeronautics, used English measurements.

In guiding the lander, NASA engineers have said they have corrected the problems that doomed the orbiter. "We've been through a lot in the last ten weeks," Cook said. "Because of the extra scrutiny, I'm sure it's a robust mission."

The lander is expected to touchdown on the edge of the southern polar cap shortly after 3 p.m. EST on Friday. The $165 million spacecraft is equipped with a robotic arm, microphone, oven and cameras. Two soil probes will separate from the main craft and crash to the surface about 60 miles (97 km) from the main landing site.

NASA expects the lander to operate 60 to 90 martian days, or Sols. A Sol lasts about 24 hours, 37 minutes. If the lander continues to operate well, the mission may be extended.

  • Mars Polar Lander: 4 days till touchdown
November 29, 1999
  • NASA: Human error caused loss of Mars orbiter
November 10, 1999
  • Lander to listen for the sounds of Mars
November 1, 1999
  • Course of Mars Lander corrected for December landing
October 30, 1999

Mars Polar Lander: Official Web site
Deep Space 2
Jet Propulsion Laboratory
Mars Pathfinder
Mars Meteorite home page
Planetary Society
Mars Society
The Nine Planets: Mars
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