A U.S. spacecraft has landed on Mars to begin a three-month mission to search for traces of ancient water. The vehicle will eventually roam for dozens of kilometers to examine rocks for this evidence.

After a seven month journey, the Spirit spacecraft endured a fiery plunge through 130 kilometers of Martian atmosphere to land on target in a crater near the red planet's equator.

Spirit deployed a parachute and fired braking rockets to slow its 19 thousand kilometer per hour entry. After bouncing along the ground on cushioning airbags for several minutes, the lander emitted strong tones confirming a safe landing, creating jubilation in the mission control room.

Navigation team chief Louis D'Amario equated the precision landing to threading a needle from 25 kilometers away. "This is essentially perfect navigation," he said. "This is hitting the bullseye."

Three hours after landing, Spirit began transmitting the first detailed pictures of the surrounding Martian terrain.

The celebration over these remote feats was the second in two days for engineers and scientists at the Jet Propulsion Laboratory near Los Angeles, California. On Friday, another U.S. spacecraft successfully plowed its way through a dusty halo around a comet. It became the first craft to capture pristine matter from the birth of the solar system that, when returned to Earth, scientists hope will inform them about conditions back then.

A cheerful chief of the U.S. space agency NASA, Sean O'Keefe, poured champagne at Spirit mission control. His mood was very different from that when the space shuttle Columbia disintegrated nearly one year ago, killing seven astronauts and shutting down the U.S. human spaceflight program for the time being. "This is a big night for NASA," he noted. "We're back! I'm very, very proud of this team, and we're on Mars!"

Before this, two out of three efforts to reach Mars have failed in the last four decades, including NASA's previous attempt in 1999. The latest apparent failure is the British lander Beagle, which supposedly touched down on Christmas Day, but has not been heard from since.

The Spirit spacecraft is to deploy a six-wheeled rover in about nine days. Mission controllers will then begin maneuvering it to rocks in the vicinity after studying pictures of the terrain sent back this week by a high resolution panoramic camera.

Mission scientist Steve Squyres of Cornell University says the rover is equipped with a scraper and other instruments to look inside and analyze the rocks for evidence of past water, an indication the planet might have been once habitable by past microbial life.

"We see dried up river beds on Mars. We see dried-up lake beds," he said. "We see these intriguing hints that Mars may have been a very different world in the past. Now, if you want to find out whether or not those hints are really telling us that Mars was once a place that would have been suitable for life, then what you really need to do is go there and read the story in the rocks."

An identical U.S. lander named Opportunity is trailing Spirit by three weeks and is to perform the same water search on the opposite side of Mars.