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Mars Odyssey shifts orbit to follow NASA's latest lander

Paul Sutherland, Feature writer
Jul 26, 2012, 7:00 UTC

Sen—Fears that contact with NASA's newest visitor to Mars will be lost when it lands in less than two weeks have been allayed following the successful shift of another probe in orbit.

Curiosity, the heaviest rover ever sent to the Red Planet, will descend to its surface on August 6 using a novel technique never tried by a mission before. At the climax of a descent through the martian atmosphere that has been dubbed "seven minutes of terror", the rover will be lowered on a tether from a hovering Skycrane.

Space scientists back at mission control at NASA's Jet Propulsion Laboratory in Pasadena, California, are bound to be biting their nails as the critical manoeuvre is carried out. But earlier this month it looked like their anxious wait would be prolonged because of a problem with orbiting probe Mars Odyssey, which was due to provide a vital communications link.

After entering a safe mode on July 11, it seemed Odyssey would be too far around the planet to hear from Curiosity - also known as Mars Science Laboratory - at the moment of landing in Gale Crater and would not arrive over the landing area until two minutes later.

The absence of Odyssey, which has been circling Mars since October 2001, would not have affected the success or otherwise of Curiosity's landing. But it was clearly not an ideal situation. Yesterday NASA announced the problem had been resolved after Odyssey fired a thruster for six seconds to adjust its orbit and put it six minutes ahead in its orbit.

Information about Curiosity's landing, at the start of its search for clues to life on Mars, is now due to arrive back at Earth at 05.31 UT on August 6 (22.31pm Pacific time back at JPL) just as was previously planned.

Mars Odyssey Project Manager Gaylon McSmith, of JPL, said: "Information we are receiving indicates the manoeuvre has completed as planned. Odyssey has been working at Mars longer than any other spacecraft, so it is appropriate that it has a special role in supporting the newest arrival."

NASA has another probe, Mars Reconnaissance Orbiter, that can relay signals. And the European Space Agency has promised to assist with its own Mars Express orbiter. However, both are only capable of recording the data for sending home later, which would still have left a delay.

Mars Express Spacecraft Operations Manager Michel Denis said: "We began optimising our orbit several months ago, so that Mars Express will have an orbit that is properly 'phased' and provides good visibility of MSL's planned trajectory."

Mars Express will turn to start listening for Curiosity at 05:10 UT on August 6. It will record data until 05:38 under present plans before turning to beam the information to ESA's listening station at New Norcia, Australia.