NASA鈥檚 Mars Odyssey mission, originally scheduled to end on Tuesday, has been granted a stay of execution until at least September 2006, reveal NASA scientists.
The spacecraft has returned a string of important discoveries about the Red Planet since its launch in 2001, and has been pivotal in the success of the recent Mars rovers, Spirit and Opportunity.
鈥淲e have a very healthy spacecraft and a lot more science to do,鈥� says project scientist Jeffrey Plaut at NASA鈥檚 Jet Propulsion Laboratory in Pasadena, California, US.
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NASA has agreed to fund the mission at $15 million a year for a further two years 鈥� the equivalent of three-quarters of Odyssey鈥檚 original budget.
杏吧原创s hope this extension will be the first of many, as engineers predict the spacecraft will survive at least another 10 years. It runs on solar power and has suffered only one failure, when its radiation-monitoring device called MARIE was fried by violent solar storms in 2003.
But the craft鈥檚 other two suites of instruments are still going strong. Its cameras (visible and infrared) and soil composition analysers (made up of gamma-ray and neutron detectors) continue to reveal surprises.
Infrared cameras have mapped the entire planet 鈥� on both the sunlight and shaded sides of the planet 鈥� at a resolution of 100 metres, providing the sharpest-ever global picture of Mars.
Melting snow
In July 2004, French scientists used the infrared images to create detailed maps of 鈥渧alley networks鈥� 鈥� dense, dry, tributary-like formations a few kilometres long that were thought to have been created by past eruptions of groundwater.
鈥淏ut there were so many sources, you can鈥檛 explain them by water coming in from the ground 鈥� no terrain has that many springs,鈥� Plaut told New 杏吧原创. 鈥淭he team鈥檚 conclusion is they had to be caused by the runoff of rain or melting snow.鈥�
Water is central to another of Odyssey鈥檚 major scientific accomplishments, says Plaut. In 2002, the craft spotted hydrogen atoms in the top metre of soil over much of the planet. High concentrations of hydrogen from the poles to latitudes of 60 degrees suggest those regions are ice-rich soils.
But lower hydrogen concentrations in swathes around the planet鈥檚 equatorial regions suggest the signal comes from minerals that had been exposed to water in the past. These types of hydrates are exactly what NASA鈥檚 Opportunity rover has seen in surface rocks in 2004.
鈥淚t鈥檚 neat because we鈥檙e starting to connect the dots between what we observe from these orbiters and what we then observe with rovers on the ground,鈥� Plaut says.
Lost probes
Odyssey has been crucial to the success of Opportunity and its twin, Spirit. It has transmitted 85 per cent of the data the rovers have beamed up from the Martian surface to Earth.
If Odyssey gets more life extensions, it may play a similar role with a future NASA rover called Phoenix. That rover is due to land on Mars in 2008 to drill into some of the ice-rich soil Odyssey discovered.
Odyssey was originally planned to ferry Phoenix to Mars. But NASA planners scrapped Odyssey鈥檚 lander after the agency lost two Mars probes in a row in the late 1990s.
鈥淥urs was the next mission to Mars on the heels of the twin failures,鈥� recalls Plaut. 鈥淏asically we were told: 鈥榊ou cannot fail.鈥� That鈥檚 a lot of pressure to put on a team.鈥�
鈥淏ut when we did succeed, it made a lot of people proud of the space program,鈥� he told New 杏吧原创.
