Ready for liftoff
Discovery's mission is to restore confidence in shuttle program
By Michael Coren
Discovery's launch window is from July 13 to July 31. After that, it moves to September.
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(CNN) -- The space shuttle Discovery returned America to space two years after the Challenger explosion in 1986.
This year, Discovery will attempt the feat again.
Discovery was scheduled to launch from Florida's Kennedy Space Center on Wednesday, but was scrubbed after a faulty fuel tank sensor.
NASA hopes a successful shuttle launch will restore confidence in the United States' embattled shuttle program after the loss of Columbia in 2003. Following a wrenching overhaul of the shuttle program, and much of the agency, NASA officials say they can safely mount another space shuttle mission.
"There are folks that have the impression that NASA needs to fly this flight so that we can demonstrate that we really understand how to fly in space again," said Paul Hill, flight director for the Discovery mission. "Well, that's not technically true. If we don't know that this is all going to work, we're not ready to fly ... You know you can do it again, but you got to do it again."
The space agency plans to return to the international space station, the moon and eventually press on to Mars under President Bush's Vision for Space Exploration.
NASA is currently refining its shuttle and space station building options. In June, NASA administrator Michael Griffin told the House Science Committee the shuttle could not fly the 28 missions needed to finish building the space station before retiring the shuttle fleet in 2010.
Griffin told lawmakers he would have a refined mission plan by later this summer.
"(Discovery) is a competency test for us," said Wayne Hale, deputy manager of the shuttle program at Johnson Space Center in Houston. "If we fail in that effort, then we have probably failed to demonstrate the competency to carry out that vision at all."
The space agency has operated under enormous scrutiny since Columbia burned up during reentry in 2003. Foam struck Columbia's left wing during launch, a problem observed and virtually ignored by mission managers. Once the shuttle entered the atmosphere, superheated gasses destroyed the vehicle.
The disaster prompted the appointment of an independent panel, the Columbia Accident Investigation Board, to investigate the tragedy. The 13-member panel found NASA had systematically ignored signs the shuttle was operating unsafely and repeated the mistakes that led to the destruction of Challenger 17 years earlier.
NASA acknowledges its complacency about the space shuttle, which had completed 112 missions before the loss of Columbia. Managers dismissed, or were never informed, of concerns from lower level engineers. Waivers were regularly issued for shuttle components that did not perform as intended.
"We were playing the odds," said Hale. "The hardware was talking to us, and we were not paying attention."
But after Columbia, some say, the agency may have finally started listening.
"Maybe the point wasn't driven completely home with Challenger, but it certainly was with Columbia," said Keith Cowing, a former NASA scientist who now runs the independent watchdog publication nasawatch.com. "It certainly seems that the senior management gets it. Whether it has filtered down to everyone involved ... it's a bureaucracy, and it probably never will, but there are some changes."
NASA says even before CAIB issued its report, it began cataloging potential threats to the shuttle and seeking to eliminate them. NASA said shuttle engineers crawled through each orbiter and found unsuspected problems. Rudder gears were installed backwards in the tail assembly. Corrosion had eaten away at critical components in the wing flaps. NASA also retested tolerances for shuttle materials so that mission controllers could decide whether a damaged shuttle, like Columbia, could be repaired.
"We've looked end to end at the shuttle to make improvements and make it safer than it has ever been," said Hale.
By June, NASA said it had fulfilled 12 of CAIB's 15 Return to Flight recommendations. Despite the critical report which also praised NASA's efforts to improve the vehicle's safety, NASA administrator Griffin felt confident that Discovery was safe enough to launch during its July 13-31 window.
"Based on a very thorough and very successful flight readiness review, we're currently go for launch of Discovery on July 13," Griffin said.
"The past two and half years have resulted in significant improvements that have greatly reduced the risk of flying the shuttle. But we should never lose sight of the fact that space flight is risky."
Cutting-edge and obsolete technology
It has been a formidable task. The shuttle stands among the most complex vehicles ever constructed, says NASA. Each orbiter weighs about 4.5 million pounds, containing 230 miles of wires and 2.5 million working parts. The three main engines, the most efficient rocket engines ever built, burn enough fuel to drain a swimming pool in 20 seconds and create 375,000 pounds of thrust.
All of this machinery accomplishes one lofty goal: to safely send humans into space and return them home.
"People want a space program that goes somewhere and does something," says NASA administrator Michael Griffin.
Achieving that with the "inherently flawed design of the Space Shuttle" has proved problematic, according to CAIB. Unreasonable demands and compromises during shuttle construction means the vehicle has never been "operational" in terms of access to space. Each flight entails significant risks.
Despite regular additions and upgrades, the vehicles are a mix of cutting-edge and obsolete technology.
"It's kind of like getting an old car and redoing and redoing it again. Some of it is 40 years old and some of it is last week's technology," said Cowing. "It's a strange hybrid."
The shuttles, which first arrived at Kennedy Space Center in 1981, will have to fly much longer if the Vision for Space Exploration is fulfilled. Bush has set 2010 as the year to finish the space station and retire the shuttle fleet. That goal has been affirmed by Griffin.
"People want a space program that goes somewhere and does something," he said to employees on April 14, referring to the plan for the moon and Mars. He said he had "great confidence in the team that will carry out our nation's exciting, outward-focused, destination-oriented program."
For now, that means accepting the risk of the shuttle in the coming years. NASA must convince Congress and the public that putting humans in space is worth the enormous resources devoted to it, and can be done safely enough. Realistically, the risks will not be eliminated until the last shuttle takes off from Kennedy Space Center, says NASA.
"Are there parts of the shuttle that we haven't identified that we need to worry about? I hope not," Hale said. "But realistically there is something that we will uncover in the days to come that we need to work on."
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