Spacecraft lands on Mars
2008-05-26 07:20
Pasadena - A Nasa spacecraft plunged into the atmosphere of Mars and landed in the Red Planet's northern polar region on Sunday to begin 90 days of digging in the permafrost to look for evidence of the building blocks of life.
Less than two hours later, the Phoenix Mars Lander beamed back four dozen black-and-white images including one of its foot sitting on Martian soil amid tiny rocks. Others included the horizon of the arctic plain and ground with polygon patterns similar to what can be found in Earth's permafrost regions.
"Absolutely beautiful," said Dan McCleese, a chief scientist at Nasa's Jet Propulsion Laboratory. "It looks like a good place to start digging."
Cheers swept through mission control when the touchdown signal from the Phoenix Mars Lander was detected after a nailbiting descent. Engineers and scientists hugged and high-fived one another.
"In my dreams it couldn't have gone as perfectly as it went," project manager Barry Goldstein said. "It went right down the middle."
The initial pictures were primarily to give engineers information on the condition of the lander, including its power supply and the health of its science instruments. An image showed the lander unfurled its solar panels as planned after the dust settled.
Initial results show Phoenix landed almost level, tilted at a quarter of a degree.
"The hardest part is over. There's still a lot of drama left," said Goldstein, who kept up a JPL tradition by passing out bowls of lucky peanuts during the landing.
Phoenix plunged into the Martian atmosphere at more than 19 311km/h after a 10-month, 711m-kilometre voyage through space. The lander kept in contact with Earth through the orbiting Mars Odyssey during the entire "seven minutes of terror".
'Touchdown detected!!'
It performed a choreographed dance that included unfurling its parachute, shedding its heat shield and backshell, and firing thrusters to slow to an eight kilometres per hour touchdown.
"Touchdown detected!! We're on the surface of Mars and there is celebration in Mission Control!!" JPL engineer Brent Shockley blogged from inside mission control.
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.
Mission chief scientist Peter Smith of the University of Arizona, Tucson, had two words to describe the landing: "Picture perfect."
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-kilometre-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 two Mars orbiters, which will relay data and images.
Phoenix is equipped with an 2.4 metre-long arm capable of digging trenches in the soil to get to ice that is believed to be buried up to 0.3m deep. Then it will analyse 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's history when the planet had a warmer environment than the current harsh, cold one it currently has.
Phoenix avoided the doom of its sister spacecraft
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.
Phoenix, named after the mythical bird that is reborn from its ashes, inherited hardware from a lander mission that was scrapped after the back-to-back Mars losses, and carries similar instruments that flew on Polar Lander.
Built by Lockheed Martin Corp, Phoenix is the first mission from Nasa's Scout programme, a lower-cost complement to the space agency's pricier Mars missions. It cost $420m to develop and launch Phoenix compared to the $820m originally invested in the twin rovers.
The rovers have dazzled scientists with their Energiser Bunny-like ability to keep going and their geologic findings that ancient Mars once had water that flowed at or near the surface.
Mission managers do not expect Phoenix to be as hardy as the rovers since winter will set in later this year at the landing site with fewer hours of sunlight available each day to power the lander's solar panels.
- AP