The robot spacecraft rover named Spirit landed safely on Mars yesterday, Taiwan time, after a perfectly programmed descent by parachute and a final programmed adjustment of its position to place it precisely on its target near the center of a Martian crater that may once have been a brimming lake billions of years ago.
It was America's fourth successful landing on the Red Planet and marked the beginning of a new mission to learn whether Mars was once a habitable place where water flowed abundantly in lakes, rivers, creeks and canyons -- and life, perhaps, may once have flourished.
As applause and cheers erupted and tension eased among Mission Controllers here at NASA's Jet Propulsion Laboratory, scientists began sending computer commands across 160 million kilometers of space to prepare the spacecraft for its travels across the Martian terrain and its search for evidence of ancient sediments in Martian rocks that will start within the next nine days.
Spirit, the size of a golf cart and weighing a ton, landed in the Gusev crater on Mars almost precisely at its programmed time of 8:35pm, California time, bouncing again and again for more than 10 minutes inside its protective cluster of Kevlar until it finally rolled to a stop hundreds of yards from where it first hit the Martian surface.
The computers at Mission Control timed the landing at precisely 8:35pm, Ed Theisinger, the project director, said. "Within a second or two at most," said Rob Manning, the engineer who directed the spacecraft's entry into the Martian atmosphere, its descent by parachute and retro-rocket, and its final landing.
And the position of the landing was precisely as it was designed, said the engineers -- with the base of the spacecraft safely down rather than canted -- a sign that before many days Spirit will be ready to roll off the three petal-shaped runways that had enfolded the spacecraft all the way from Earth and begin to work.
Engineers and scientists had been biting their nails throughout the day, but the spacecraft's course was set on Friday without chance of change by Spirit's mission controllers here at the Jet Propulsion Laboratory.
The giant antennae of NASA's Deep Space Network in Australia and California's Owens Valley picked up the faintest signals from Spirit's final arrival, and Mission Control strained to decipher faint humming tones from the lander itself, but minute after minute passed before the engineers were satisfied that the landing had indeed been successful.
Aside from the incredible technical challenges posed by this unprecedented effort to land a vehicle the size of a golf cart on a precise spot in the precise center of a giant Martian crater, mission controllers had warned of fresh dangers as the landing moment neared.
A sandstorm on the surface many kilometers away was changing the density of the atmosphere over the landing site, according to Rob Manning, who runs the team overseeing the entry and parachute landing of the Spirit. Winds up to 32kph may have been blowing at the site as the landing moment approached, Manning said.
That would make things tougher than ever, although a camera on the base of the spacecraft can detect any dangerous swaying of its parachute above, and tiny rockets are programmed to detect the swaying and correct Spirit's downward course only seconds from the surface.
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