The US Mars Phoenix spacecraft landed in the frigid north pole region of Mars late on Sunday night after a risk-laden descent, NASA said.
"Phoenix has landed," a NASA official said as the safe touchdown was confirmed.
Phoenix was the first spacecraft ever to land on the Martian arctic, where it will dig into the icy soil in search of signs of the conditions that might have made the area once habitable for forms of life.
After the landing, the $420-million spacecraft's radio was expected to go silent for 20 minutes to save its batteries, during which it would deploy its two solar antennas to generate power.
Phoenix's landing is a relief for NASA since Mars has a reputation of swallowing spacecraft. More than half of all nations' attempts to land on Mars have failed.
Phoenix's target landing site was 48-kilometer-wide shallow valley in the high northern latitudes similar in location to Earth's Greenland or northern Alaska. The site was chosen because images from space spied evidence of a reservoir of frozen water close to the surface.
Like a tourist in a foreign country, the lander initially will take in the sights during its first week on the Red Planet. It will talk with ground controllers through three Mars orbiters, which will relay data and images.
{{/usCountry}}Like a tourist in a foreign country, the lander initially will take in the sights during its first week on the Red Planet. It will talk with ground controllers through three Mars orbiters, which will relay data and images.
{{/usCountry}}Phoenix is equipped with an 8-foot-long arm capable of digging trenches in the soil to get to ice that is believed to be buried up to a foot deep. Then it will analyze the dirt and ice samples for traces of organic compounds, the chemical building blocks of life.
The lander also will study whether the ice ever melted at some point in Mars' history when the planet had a warmer environment than the current harsh, cold one it currently has.
Scientists do not expect to find water in its liquid form at the Phoenix landing site because it's too frigid. But they say that if raw ingredients of life exist anywhere on the planet, they likely would be preserved in the ice.
Phoenix, however, cannot detect signs of alien life that may exist now or once existed.
The only other time NASA searched for chemical signs of life was during the Viking missions. Neither lander found conclusive evidence of life.
Phoenix avoided the doom of its sister spacecraft, the Mars Polar Lander, which in 1999 crashed into the south pole after prematurely cutting off its engines. The Polar Lander loss, along with the earlier loss of an orbiter the same year, forced NASA to overhaul its Mars exploration programme.