High tension in NASA before Sunday’s Mars landing

May 21st, 2008 - 2:31 pm ICT by admin  

DPA
Washington, May 21 (DPA) For nearly 10 months, the US space probe Phoenix has been travelling the 195 million km from Earth to Mars. On Sunday comes the tense moment of truth. That’s when NASA’s planetary probe is to land on the north pole of Mars. Phoenix’s mission is to look for signs of life in a region of the red planet where earlier missions showed evidence of ice.

But before it gets that far, it must land successfully, and nerves were strained in the run-up to touch down.

“This is not a trip to grandma’s house. Putting a spacecraft safely on Mars is hard and risky,” said Ed Weiler, associate administrator for NASA’s Science Mission Directorate at NASA Headquarters in Washington.

Mars’ terrain is rough, and only five of a total 15 international attempts to land on Mars have made it. All five successes were NASA’s.

In the control centre on Earth, instinct and sensitivity will be needed to get through the descent to land. The probe will enter Mars’ atmosphere moving at 20,000 km per hour.

In a series of complicated manoeuvres, including deployment of a heat shield and a parachute, Phoenix will be slowed down to about 215 km per hour. In the last bit of the descent, special rocket thrusters will reduce speed to less than 10 km per hour to ensure it alights gently on Mars’ surface.

The next hurdle comes immediately afterward with the extension of the solar panels - vital to run the probe’s power generators. Experts fear the probe could have difficultly because of rugged terrain. As a precaution, the landing zone was photographed carefully from space.

In the three months that follow - spring and summer on Mars - the probe will use a 2.4 metre robotic arm to dig up ice on Mars’ permafrost plains and use instruments to analyse the samples to determine whether the surface regularly melts.

That would mean it could support microorganisms. It’s still not known whether the icy ground at the landing zone is only a few centimetres or more than a half metre thick.

Phoenix is a follow-up to NASA’s “follow the water” approach initiated after the NASA Mars Odyssey, while orbiting in 2002, discovered water ice just beneath the surface of the upper half of the planet.

“Phoenix will land farther north on Mars than any previous mission,” said Phoenix Project Manager Barry Goldstein of NASA’s Jet Propulsion Laboratory, Pasadena, California. The total cost of the project is $420 million.

The equipment on the probe will allow for onsite testing for organic material. Phoenix has its own mini-oven to heat samples from the ground and analyse them for chemical composition.

However, the probe is not only searching for signs of life. Scientists hope to gain further knowledge of climate change. They would like an explanation as to why the once damp and warm Mars became a cold planet with iced-over polar caps.

“The Phoenix mission not only studies the northern permafrost region, but takes the next step in Mars exploration by determining whether this region, which may encompass as much as 25 percent of the Martian surface, is habitable,” said Peter Smith, Phoenix’ principal investigator at the University of Arizona, Tucson.

The probe originally was to be launched in 2001 as part of the Mars Surveyor Programme. Its trip was cancelled after the Mars Polar Lander was lost in 1999 near the south pole of Mars.

Phoenix has been stored since then at defence contractor and technology company Lockheed Martin, where it has been stocked up with further technical equipment.

The name of the probe is taken from the mythical bird that rose from the ashes and became immortal - just like the eternal question of whether there is life on Mars.
DPA

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