NASA Clears Space Shuttle for Dec. 7 Launch

Wednesday, November 29, 2006; 9:00 PM

CAPE CANAVERAL, Fla. - NASA Wednesday cleared the space shuttle Discovery for launch from Florida Dec. 7 on a mission to continue building the International Space Station, a space agency official said.

The flight from the Kennedy Space Center will be the third and final shuttle mission of the year. NASA needs to fly 14 shuttle flights by 2010 to complete assembly of the half-built $100 billion space station.

Discovery is expected to lift off about 9:36 p.m. on the first nighttime launch since the 2003 Columbia accident. The first three missions after the accident were launched during daylight hours so cameras would have clear views of the spacecraft's fuel tank to spot any falling debris.

A piece of insulating foam that fell off the tank during launch hit and critically damaged Columbia's wing. The damage went undetected and Columbia broke apart as it attempted to return to Earth. All seven astronauts aboard were killed.

NASA has since redesigned the fuel tank twice to stem foam shedding, with additional safety improvements planned.

"I think we're all ready to resume night launches," NASA shuttle program manager Wayne Hale told a news briefing at the Kennedy Space Center.

NASA needs to launch at night so it can maintain the busy flight schedule to complete the space station by 2010, when the shuttle fleet is scheduled to be retired.

A test last week showed the shuttle's solid rocket boosters would provide good illumination for shuttle-mounted cameras to watch the tank during the critical moments of flight, Hale said.

"The light is spectacular for the first two minutes. We'll be able to get data for a number of cameras -- maybe not all of them," he said.

Shuttle astronauts will rewire the space station to prepare for the arrival of additional laboratory modules. The station has been on a temporary power system since the U.S. laboratory module arrived in orbit six years ago.

The rewiring is a delicate task that requires the station to be partly powered down while the connections are made. Flight controllers will keep a close eye on the clock because some components have strict limits on how long they can be left without heaters.


If the shuttle does not fly by Dec. 17, NASA will wait until January to launch in order to avoid flying the shuttle during the transition to the new year. The shuttle's computers were not designed to handle a year-end rollover.

NASA has developed software to alleviate the problem, but would prefer to wait so the crew can focus on the mission instead of the shuttle's systems, said NASA's associate administrator for space operations, Bill Gerstenmaier.

"I don't expect everything to go perfectly well," he said. "You don't want to have the year-end rollover in the midst of all that."

NASA's problems may already be starting. On Tuesday, a device to rotate the station's new solar arrays malfunctioned, setting off an around-the-clock effort to determine if software is behind the glitch, or if a more serious issue looms that could force a postponement.

An overnight test at the Johnson Space Center in Houston should give engineers a better idea of what happened.

The seven-member shuttle crew, which is due to arrive at the Kennedy Space Center Sunday for launch preparations, includes Sweden's first astronaut, Christer Fuglesang.

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