Shuttle to race home out of Navy's field of fire

ByTraci Watson, USA TODAY

— -- Space shuttle Atlantis departs the International Space Station Monday to return to Earth as quickly as possible, to maximize the amount of time the Pentagon has to shoot down a dying spy satellite.

The shuttle must be safely on the ground before a Navy ship fires a missile at the satellite, which is slowly falling out of the sky with its load of toxic fuel. The shootdown is intended to shatter the satellite's fuel tank into fragments, allowing the fuel to dissipate.

If the fuel tank isn't blown up, it will plunge to Earth and spew a cloud of fumes that could injure or kill anyone nearby, said Gen. James Cartwright, vice chairman of the Joint Chiefs of Staff.

Cartwright and other officials estimated they have a seven- to eight-day window to bring down the satellite before it would make a final, uncontrolled dive to the Earth's surface in early March. To give the military more flexibility, NASA will take the rare step of opening two runways Wednesday, the day Atlantis is scheduled to come home: the shuttle's normal runway in Florida and a backup landing strip in California.

The shuttle usually doesn't touch down in California unless Florida has bad weather for two consecutive landing days. Landing in California costs an extra $1 million, in part to ferry the shuttle back to its Florida hangar.

In preparation for their homecoming, the Atlantis crew closed the door between the shuttle and the station Sunday. The shuttle launched Feb. 7 on a mission to expand the station by adding a European laboratory.

Among the astronauts aboard Atlantis was Daniel Tani, who has lived for the past four months on the orbiting lab. During Tani's stay in space, his 90-year-old mother was killed when a train hit her car in December, making Tani the first astronaut in orbit to lose a close relative. Tani's mother raised him after his father died when he was a young boy.

During a farewell ceremony Sunday, Tani said he had been thinking about "my mother, my inspiration." Another subject on his mind, he said as he choked up, was his wife, "the love of my life," prompting station commander Peggy Whitson to wipe away tears.

Whitson will be aboard the station when the military takes aim at the errant satellite, but both she and shuttle commander Stephen Frick dismissed concerns about the safety of their spacecraft. The shuttle will have landed by the time the missile has been fired, Frick said, so "on the shuttle, we're not worried about it."

"I think NASA and the (Department of Defense) love the station crew as much as they love" the Atlantis crew, Whitson said, to the loud laughter of the two crews. "So we're not worried about it either."

Destruction of the 5,000-pound satellite will add to the amount of debris in space, at least temporarily. Such debris is a serious problem for the station, as was shown Monday when Atlantis astronaut Stan Love discovered a dimple in the station's surface during a spacewalk.

Love attributed the dimple to a collision with a bit of space rock. Spacewalker Rex Walheim determined Friday that the dent had jagged edges and might be the culprit behind rips in the spacesuits of several spacewalkers in the past 18 months. A deeply torn suit could allow an astronaut's air to leak out.

The station has had to move out of the way of oncoming space objects six times in its 10-year lifetime, NASA's Bob Dempsey said Sunday. After China used a missile to blow up a dead satellite in 2007, the risk that orbital debris posed to the station doubled, he said.

The Pentagon plans to blast the satellite to pieces when it's just above the Earth's atmosphere. As a result, most of the debris that would be created would fall out of orbit in a few days, rather than hanging around in space to threaten the station.

Even so, some fraction of the debris would be blasted higher into space, where it would circle the Earth on a path that could lead it close to the space station, said ex-NASA scientist Donald Kennedy, who studied orbital debris. There's so much debris already in orbit that the satellite's remains would have a "negligible" impact, Kennedy said.

Some of the station has strong shielding against orbital collisions. Other parts are so vulnerable that a safety panel said in 2007 that there is a "high risk" of the destruction of the station and the loss of its crew because of space debris.

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