At last, Nasa's Odyssey is orbiting the red planet

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The Independent Online

American space officials at Nasa were celebrating after the successful orbit of the Odyssey spacecraft around Mars, long considered the "Bermuda triangle" of the Solar System because of the many missions that have been lost there.

Engineers at Nasa's jet propulsion laboratory in Pasadena, California successfully fired the engine of the Odyssey early yesterday to put the space probe into a wide, elliptical orbit.

Failure could have sent the spacecraft hurtling past the red planet, but a change in the probe's transmitting signal indicated it had successfully reappeared from behind Mars as was hoped and expected.

Odyssey has taken six months to travel the 286 million-mile route to rendezvous with Mars. Over the next 80 days, it will reach the circular orbit needed for its experiments to map Mars and search for water.

Less than 10 of the 30 missions to Mars during the past 40 years have been successful. In 1993, the Mars Observer disappeared as it approached the planet, probably due to a fuel tank explosion. In 1999, a mix-up over metric and imperial units caused the Climate Orbiter to come too close to Mars and it burned up in the atmosphere. Three months later, Nasa's Polar Lander disappeared, probably due to a software error causing it to crash into the planet.

Nasa desperately needed a successful orbit with Odyssey and has now been rewarded with the completion of the first, most difficult stage when the probe is "captured" by the planet. "This embodies the American spirit," said Dr Daniel Goldin, Nasa's administrator who last week announced his retirement. "We showed we could win after being slammed a few times.

"We were successful only because we had a failure last time. They checked and rechecked and the failure caused them to pay attention to things they had ignored before."

Ed Weiler, Nasa's associate adminstrator of space science, said it was not just the space agency that needed Odyssey to succeed. "These guys really redeemed themselves. America needs good news, especially now. Not many countries do this and we showed we could."

Mars Odyssey will now begin a complicated series of manoeuvres in which it will use the planet's thin atmosphere as an "aerobrake", bringing the craft's egg-shaped orbit into a more circular trajectory.

The method has been tried only twice, in 1992 when the Magellen spacecraft came close to Venus, and in 1997 when the Mars Global Surveyor dipped its twin solar panels into the Martian atmosphere.

Aerobraking, caused by Odyssey using its single solar panel to slow and lose height as it makes its closest approach to the Martian surface, is considered essential for conserving rocket fuel.

Space engineers will have to take careful note of the dust storms on Mars which can dramatically affect the height and density of the Martian atmosphere, both crucial to aerobraking.

After the main phase of aerobraking is complete, the Odyssey's egg-shaped orbit will come within 60 miles of the Martian surface. A final boost of the probe's engine should send it into the desired circular orbit which is essential for efficient use of its instruments.

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