The spacecraft, known as Phoenix, landed at 12:53 a.m. British time Monday after a do-or-die plunge through the planet's thin atmosphere. It marked the first time that a spacecraft had successfully landed at one of the planet's polar regions.
Pulled by Mars' gravity, Phoenix was tearing along at 20,400 kph before it entered the atmosphere, which slowed the craft so it could pop out a parachute and fire thruster rockets to gently float to the ground.
"It's down, baby, it's down!," yelled a NASA flight controller, looking at signals from Mars showing that Phoenix had landed.
Scientists found in 2002 that Mars' polar regions have vast reservoirs of water frozen beneath a shallow layer of soil. Phoenix was launched August 4, 2007, to sample the water and determine if the right ingredients for life are present.
NASA attempted a landing on Mars' south pole in 1999, but a problem during the final minutes of descent ended the mission.
The U.S. space agency cancelled its next Mars lander but successfully dispatched two rovers, Spirit and Opportunity, to the planet's equatorial region to search for signs of past surface water.
Phoenix was created out of spare parts from the failed Polar Lander mission and the mothballed probe. Unlike the rovers, Phoenix will not be bouncing to the planet's surface in airbags, which are not suitable for larger spacecraft.
Instead, like the 1970s-era Viking probes and the failed Polar Lander mission, it uses a jet pack to lower itself to the ground and fold-out legs to land on.
"We haven't landed successfully on legs and propulsive rockets in 32 years," said NASA's space sciences chief Ed Weiler. "When we send humans there, women and men, they're going to be landing on rockets and legs, so it's important to show that we still know how to do this."
