The Phoenix has landed.

After a nine-month, 422-million-mile voyage, followed by a delicate series of manuevers that slowed the Phoenix Mars Lander from about 13,000 mph to just 5 mph at touchdown seven minutes later, NASA tonight has placed a spacecraft on the Martian surface.

"A signal has been detected from Phoenix indicating that the lander is on the surface of Mars," NASA reported on its Web site just after the 7:53 p.m. EDT landing.

For NASA, the successful landing was a long time coming. More than eight years ago, in December 1999, NASA's Mars Polar Lander project came to a disastrous end when the craft's descent engines shut down early as it prepared to land on the Martian surface. That lander went out of control from a high altitude, crashed and was destroyed.

That mission was followed by the successes of the two 2004 Mars rover missions, which have been traversing the planet in a series of experiments and exploratory missions. The rovers, however, were delivered to the Mars surface in large, cushy "air bags" that bounced onto the surface. Later the air bags deflated and the rovers drove out of them and began their work.

Lander descents are much trickier, because they use large parachutes and thruster engines to bring the craft into a controlled approach to the surface.

The last time NASA had successfully landed a spacecraft this way on Mars was in 1976, when the Viking I and Viking II landers touched down safely for a series of science and photography missions.

At NASA's Jet Propulsion Laboratory in Pasdena, California, where the mission is being monitored, the safe touchdown of the Phoenix brought cheers and smiles, said Randii Wessen, a NASA project system engineer. "We were all cheering and hugging. These things are like your children. You want them to succeed. We're all excited."

As the lander approached the planet's surface, "it gently touched the ground," he said. "At about five mph, it just parked [itself]. It's got about a one-degree tilt. It's just parked very neatly and flat. It's just great."

Once the dust raised by the descent thrusters settled after a few minutes, Phoenix was set to deploy its solar panel array so it can begin quickly generating electricity for its experiments and other on-board systems, Wessen said.

Once the panels are deployed, the lander was expected to begin sending data back to Earth via three orbiting spacecraft that will relay the information to project scientists. The first live photographs from Phoenix were expected to begin arriving about 10 p.m. US EDT, he said. The lander will have to raise its camera mast and antenna mast before it could begin sending photos, he said.

The likely subject of those first photos will probably be the craft's solar panels to be sure that they properly deployed, according to Wessen.

The Phoenix now begins a three-month-long science mission made up of a series of soil analysis projects that involve digging lightly into the Mars surface to study the history of water, ice and life potential in the planet's soil.

"We think it's way cool," Wessen said of the successful landing.