PASADENA, Calif. -- The Spirit rover successfully rolled onto Mars early Thursday, placing its six wheels on solid martian ground for the first time since the robot bounced down on the Red Planet nearly two weeks ago.
Engineers and scientists at NASA's Jet Propulsion Laboratory cheered loudly after receiving confirmation at 5 a.m. EST that the maneuver was a success.
"Mars now is our sandbox, and we are ready to play and learn," said JPL director Charles Elachi.
Black-and-white pictures beamed from Spirit showed its two rear wheels on the martian soil, with its lander 32 inches behind it. Two parallel tracks led away from the lander through the cakey dust.
"This is a big relief. We are on Mars. Spirit has landed," said Rob Manning, manager of the entry, descent and landing portion of the mission. "Our wheels are finally dirty."
Jennifer Trosper, mission manager for surface operations, opened a celebratory bottle of champagne at a news conference.
"Now we are the mission that we all envisioned 3 1/2 years ago," she said.
Elachi noted President Bush's call on Wednesday for moon missions and long-term robotic and human journeys to Mars.
"We at NASA, we move awfully fast," Elachi joked. "In less than 15 hours, we are doing our first step."
Spirit took 78 seconds to travel the 10 feet from the unfolded petals of its lander onto Mars. Engineers said the move likely would be the riskiest of Spirit's entire three-month mission.
Engineers delayed the move for three days to give Spirit time to reposition itself atop its lander, where it had sat since arriving. Spirit had to turn in place 115 degrees to line up with one of the exit ramps that ring the lander.
Originally, Spirit was to roll straight off the lander on its ninth day on Mars. But the now-deflated air bags that cushioned the rover's Jan. 3 landing blocked that way, forcing Spirit to perform a slow pirouette, turning clockwise in three separate moves.
Mission plans call for Spirit to spend three to four days parked beside its lander after rolling off, giving it time to find its bearings and perform some preliminary analysis of the soil and pebbles around it.
On Friday, Spirit should deploy its robotic arm and take its first photographs with its microscopic imager, said Steven Squyres of Cornell University, the mission's main scientist.
NASA then planned for Spirit to begin a meandering trip in the direction of an impact crater about 825 feet away. Spirit was designed to travel dozens of yards a day.
On its way, scientists said Spirit would prospect for geologic evidence that the now dry Red Planet was once wetter and hospitable to life. Spirit landed in the middle of Gusev Crater, a 95-mile-wide depression scientists believe contained a lake during the ancient past.
One of two rocks, dubbed "Adirondack" and "Sashimi," both about five yards from the rover, is expected to be Spirit's first target. The rover then might visit a shallow depression if there is enough time before its twin, Opportunity, lands Jan. 24 on the opposite side of the planet.
NASA wants to park Spirit for the three days immediately following Opportunity's arrival so scientists in the $820 million double mission can focus on Opportunity.
Even while parked 16 inches above Mars atop its lander, Spirit remained busy. It used its nine cameras to take at least 3,900 pictures of its surroundings. Mission scientists used those images, including sweeping panoramas, to chart the rover's planned movements.
Sojourner, the far smaller rover that NASA landed on Mars in 1997, spent a single day atop the Pathfinder lander before shoving off to roam its surroundings. It rolled about 300 feet and provided 500 pictures of Mars' surface before losing contact. Spirit is far more complex and took 12 days to unfold and ready itself.
A few hours before the rover's big move, Vice President Dick Cheney toured the Mars mission control center and praised the staff as "America's most dedicated and successful scientists and researchers."
His visit Wednesday coincided with President Bush's announcement in Washington of a renewed push for space research. Bush unveiled a plan to send astronauts back to the moon as early as 2015 and to land someone on Mars.
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