NASA probe sends never-seen pictures of Mars' north pole

After a nine-month journey from Earth, the Phoenix probe touched down in a relatively flat target area, according to Barry Goldstein, Phoenix project manager at the mission's control center at the Jet Propulsion Laboratory (JPL) in Pasadena, California.

Radio signals received at 7:53 pm Eastern Time (2353 GMT) Sunday confirmed the Phoenix Mars Lander had survived its difficult final descent and touchdown, officials said.

"For the first time in 32 years, and only the third time in history, a JPL team has carried out a soft landing on Mars ," National Aeronautics and Space Administration head Michael Griffin said in a statement. "I couldn't be happier to be here to witness this incredible achievement."

As planned, Phoenix stopped transmitting signals one minute after landing and focused its limited battery power on opening its solar arrays, and other critical activities.

But a key task still ahead was the first use of the lander's robotic arm, which was planned for Tuesday.

The backhoe-like arm, 2.35 meters (7.7 feet) long, is designed to dig trenches up to one meter (three feet) deep for samples of soil and water ice.

The arm will deliver the samples to instruments aboard the lander for detailed chemical and geological analysis.

The robotic arm also carries a box-shaped camera with a double Gauss lens system like that in 35mm cameras, and two lighting assemblies. This will take images of the surrounding area and of samples the arm picks up.

Another camera device is the surface stereo imager, what NASA calls Phoenix's "eyes." Sitting two meters (6.6 feet) above the ground, the SSI will produce high-definition and panoramic images of the surrounding landscape. Its stereo capability will help give scientists on Earth three-dimensional views of the work the robotic arm does. It can also be turned vertically to take images that will provide information on atmospheric particles.

Working in the flat circumpolar region known as Vastitas Borealis -- akin to northern Canada in Earth's latitude -- Phoenix, with a panoply of high-tech equipment, will over three months dig below the surface to probe the icy ground for signs of liquid water and organic, life-supporting minerals.

Given that Mars' polar region is subject to Earth-like seasonal changes, the scientists think that, like on Earth, the Martian arctic might have a geological record of a warmer, habitable climate.

Pictures from the Phoenix probe provided the first glimpse of the planet's Arctic plains -- a desolate landscape of stony, frozen ground.

The dramatic images showed the spacecraft's footpad planted on the dusty surface as well polygonal patterns on the ground that looked similar to icy arctic regions on Earth.

The flat Martian valley floor is expected to have water-rich permafrost within reach of the lander's robotic arm.