Tuesday, 31 July 2012

'Mission of the decade’ nears Mars



WASHINGTON: The last time the United States landed a mission on Mars to look for extraterrestrial life or its building blocks, Gerald Ford was president and the nation had just finished celebrating its 1976 bicentennial.

Next week, the long-delayed second attempt will try to deposit a rover on the planet’s surface.

The descent and landing in the early hours of Aug. 6 will be the most complex and hair-raising in planetary history. The destination is a deep crater with a three-mile-tall mountain that NASA could only dream about using as a landing site until very recently.

It’s the most ambitious, the most costly ($2.5 billion) and the most high-stakes mission ever to another planet. It was also described last week by the agency’s top scientist, former astronaut John M. Grunsfeld, as “the most important NASA mission of the decade.”

“There is no doubt that this is a risky mission, and that is coming from a human-spacecraft guy,” Grunsfeld said. “It’s hard to get something this big and complex to the surface of Mars, and then to get it to start roving. Thousands of people around the world working on it will be feeling their lives are riding on the mission landing successfully. We’ll all know soon if the risk was worth it.”

What the Mars Science Laboratory mission and its rover named Curiosity bring to Mars is a capacity to analyze the planet with much more sophistication than before, and to do it over a sizable and scientifically rich expanse.

The goal is not to find Martian life per se but rather to ferret out carbon-based organic compounds that are building blocks of life, and then to determine whether the Gale Crater landing site was ever suitable for creatures. Both are integral parts of the science of astrobiology — the search for life beyond Earth.

At 10 feet long and seven feet high at the top of its camera mast, Curiosity is the size of an SUV and weighs almost a ton, about three times more than the Spirit and Opportunity rovers sent to Mars in 2003 on a primarily geological mission. Its robotic arm for digging soil and drilling rock is seven feet long, almost three times longer than previous rover arms. This tool will provide more and better samples for the lab’s instruments, which will do their analysis on Mars and send back the results to scientists here.

Curiosity will have numerous ovens to bake soil and rocks up to 1,800 degrees and analyze what comes out; it will have a laser zapper to free up potentially important targets in rocks; it will have cameras with unprecedented capabilities, including one that will take video of the last several minutes of the high-drama landing, now dubbed “seven minutes of terror” by NASA.

Getting to Mars, and especially landing on it, is difficult. Forty-four missions — flybys, orbits and landings — have been sent to the planet by NASA, the former Soviet Union, Russia, the European Space Agency, Japan and China, and about one-third have made it. All six successful landings were flown by NASA. (A Soviet capsule made a soft landing in 1971 but then sent back only 14 seconds of data, so it is not considered to have succeeded.)

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