Mars lander completes first day on Red Planet

[May 27, 2008]  TUCSON, Ariz. (AP) -- Fresh images sent back by NASA's Phoenix Mars Lander during its first full day operating in the Martian northern polar region showed most of its science instruments in good health, mission scientists said.

The one snag on the lander occurred when the protective sheath around the trench-digging robotic arm failed to unwrap all the way after touchdown and now covers the arm's elbow joint.

Deputy project scientist Deborah Bass of NASA's Jet Propulsion Laboratory said scientists still planned to start the process of unstowing the arm Tuesday, but it could take an extra day to fully stretch the arm.

"I would say this is an inconvenience," Bass said.

Since landing on Mars on Sunday, Phoenix has delighted scientists with the first-ever peek of the planet's unexplored northern latitudes. The terrain where Phoenix set its three legs is relatively flat with polygon-shaped patterns in the ground likely caused by the expansion and contraction of underground ice.

Phoenix is on a three-month mission to excavate the soil using its 8-foot-long robotic arm to reach the ice believed to be buried inches to a foot deep.

The lander will study whether the landing site could have supported primitive life. Among the things it will look for is whether the ice melted in Mars' history and whether the soil samples contain traces of organic compounds, one of the building blocks of life.

On Monday, NASA released a black-and-white image captured during Phoenix's descent by the Mars Reconnaissance Orbiter, which had a bird's-eye view of the lander coming down on its parachute. It's the first time a spacecraft had taken an image of another craft during landing.

Alfred McEwen of the University of Arizona's Lunar and Planetary Laboratory said the camera aboard Reconnaissance Orbiter has taken many unique pictures of Mars, but "this one's really unique."

"It's the first time any camera has imaged an actual descent through an atmosphere of another planet," said McEwen, who operates the orbiter's camera. "This will be on my Top Ten list."

The $420 million Phoenix mission is led by University of Arizona, Tucson and managed by JPL.

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On the Net:

Phoenix Mars: http://phoenix.lpl.arizona.edu/

[Associated Press; By ARTHUR H. ROTSTEIN]

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