Mars lander's robotic arm touches soil

TUCSON, Arizona (AP) -- NASA's new robot on Mars has reached out and touched the soil for the first time, leaving behind a striking footprint-like impression.

The Phoenix Mars Lander's robotic arm was making a test run, just one week after the craft's landing. The spacecraft, which is also its own laboratory, will soon start scooping up soil and ice and running tests on them.

David Spencer, Phoenix's surface mission manager at the Jet Propulsion Laboratory in Pasadena, California, said Sunday the first touch "allows us to utilize the robotic arm accurately."

NASA on Saturday showed sharp images of what appeared to be ice exposed under the lander. The mission's main goal is to test ice for evidence of organic compounds that are the chemical building blocks of life.

Team members said Friday that photos showing the ground beneath the lander suggested that the vehicle was resting on splotches of ice. Washington University scientist Ray Arvidson said the spacecraft's thrusters may have blown away dirt covering the ice when the robot landed one week ago.

On Saturday, scientists said that a more detailed image taken under the lander shows one of the craft's three legs sitting on coarse dirt and a large patch of what appears to be ice -- possibly 3 feet in diameter -- that apparently had been covered by a thin layer of dirt.

"We were worried that it may be 30, 40, 50 centimeters deep, which would be a lot of work. Now we are fairly certain that we can easily get down to the ice table," said Peter Smith, a University of Arizona scientist who is the chief project investigator.

The spacecraft is equipped with a backhoe-like robotic arm that will dig into the ground and retrieve samples for testing in the lander's small laboratories. The lander was sent to a spot on Mars' northern regions in hopes of finding frozen water, but just how deep underground it would be found was unknown.

The robot arm is expected to begin its first digging operations after several more days of testing.

The final proof that the material is ice could take weeks, but close-up color images that were taken Saturday could improve the researchers' confidence level, said Horst Uwe Keller, the scientist in charge of the camera on the robotic arm. The initial image released Saturday was in black and white.

Once the arm starts digging, the dirt and ice it scoops up will be deposited in several small ovens to be heated. Measuring devices will test the resulting gases. Watch a report on the lander's mission »

The University of Arizona in Tucson is leading and NASA's Jet Propulsion Laboratory is managing the three-month scientific mission.

Copyright 2008 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.

All About Mars Exploration