'Phoenix' spacecraft lands intact on Mars

5/26/2008

PASADENA, Calif. - The first spacecraft designed to taste the water of an alien planet landed safely on Mars' northern pole yesterday, beginning a three-month mission to determine whether the Red Planet ever did, or still might, support rudimentary forms of life.

The Phoenix spacecraft parachuted to the planet's surface at 7:53 p.m., successfully ending a 422-million mile journey through space.

Cheers and applause echoed through the halls of the Jet Propulsion Laboratory, which is managing the mission.

"Touchdown signal detected," said Richard Kornfeld, a communications specialist. "Welcome to the northern plains of Mars."

The landing was an elegant feat of engineering and artistry.

"We have the best team in the world," said project manager Barry Goldstein, who has de-voted the past five years of his life to this mission.

"In my dreams it couldn't have gone as perfectly as it went," he said. "It went right down the middle."

Among Phoenix's first tasks were to check its power supply and the health of its science instruments, then unfurl its solar panels after the dust settled.

Mission managers said there would be a two-hour blackout period as Phoenix conducted the checks while out of view from Earth.

The entry-descent-landing period, when the lander separates from the spacecraft, enters the atmosphere, and brakes from 12,000 mph to 5 mph, has been described as "seven minutes of terror."

The landing appeared to be almost picture perfect.

After the lander deploys the solar arrays that will supply power for the three-month mission, Phoenix will begin assessing its environment, from temperature and humidity to wind conditions.

Then it will deploy its 7.7-foot-long robotic arm, which will be used to dig into the soil.

Lying just beneath the lander is an ice layer that Phoenix will dig into, searching for evidence of organic molecules that could provide a habitat for life.

The 7-foot-tall, 904-pound Phoenix lander touched down after a 296-day trek across space.

It's the first successful soft landing on Mars since the twin Viking landers touched down in 1976.

NASA's twin rovers, which successfully landed on Mars four years ago, used a combination of parachutes and cushioned air bags to bounce to the surface.

Phoenix's landing is a relief for NASA, because Mars has a reputation of swallowing spacecraft. More than half of all nations' attempts to land on Mars have failed.

Phoenix's science instruments will look for molecules such as carbon and hydrogen, which are the basic building blocks of life as we know it on Earth.

Phoenix also will check for other ingredients of life. It will examine the acidity of the soil at different layers, and will look for sulfates, which could be an energy source for microbes.

Scientists speculate that if some of the ice in the soil melts during warm periods, some form of microbial life could persist, potentially for millions of years.

Next year, the Mars Science Laboratory, a lander as large as an automobile and equipped with a ray-gun type laser to zap rocks at a distance of 30 feet, is scheduled to follow up on Phoenix's discoveries.

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 program.

Phoenix was created out of spare parts from the failed Polar Lander mission and the mothballed probe.

Like the 1970s-era Viking probes, Phoenix used 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."

Built by Lockheed Martin Corp., Phoenix is the first mission from NASA's Scout program, a lower-cost complement to the space agency's pricier Mars missions.