Discovery Ready to Fly, NASA Says

With the scheduled launch of the space shuttle Discovery weeks away, NASA managers declared Tuesday that they were ready to fly, while acknowledging that it was impossible to eliminate the risk of another catastrophic accident like the one that claimed Columbia two years ago.

“I believe this is the safest vehicle we’ve ever flown,” Bill Parsons, manager of the space shuttle program, told reporters at the Johnson Space Center in Houston. “You can never eliminate all risk in human spaceflight, but I believe we’re ready to roll out and go launch.”

Discovery and its crew of seven are scheduled to launch from Kennedy Space Center in Florida as early as May 15.

The 13-day mission will take 600 pounds of food and 185 gallons of water to the International Space Station. It also will deliver a gyroscope to replace one that failed, and pick up months of garbage.

Several potential stumbling blocks to the May 15 launch date remain, however. An outside review committee canceled its meeting here last week because NASA failed to deliver key test data showing it had found a way to prevent insulating foam on the external fuel tank from striking the shuttle.

Columbia was damaged during liftoff in January 2003 by a 1.6-pound piece of foam. When the orbiter tried to land two weeks later, the 3,000 degree heat of reentry burned through the damaged left wing and destroyed the craft, killing all seven astronauts.

The Columbia Accident Investigation Board issued 15 recommendations for improving the shuttle and NASA’s hierarchical decision-making process.

Solving the debris problem was considered among the most important.

NASA said Tuesday it was virtually impossible to protect the shuttle from all foam debris that came off the external tank. Foam is used as insulation to keep ice from forming on the surface of the tank, which contains super-cooled liquid hydrogen and oxygen. Without the foam, ice could be a more deadly projectile than foam.

“It is my opinion it will still be possible for a golden BB to hit us,” said N. Wayne Hale Jr., deputy manager of the space shuttle program. “There will be some residual risk. If that’s not acceptable, it’s not acceptable.”

Hale said, “We have tried our damnedest for the past two years to do everything we could to comply” with the accident board recommendations.

To address the foam problem, engineers redesigned the bipod fitting that attached the orbiter to its fuel tank, the place where the piece of foam came off on Columbia. Other changes include installing a boom to allow the crew to inspect the skin of the orbiter after reaching space. Windows have been hardened and the mechanism that keeps the two solid rocket boosters attached to the external tank has been upgraded.

More than 100 cameras will monitor the shuttle, allowing observers from the ground, air and space to spot damage.

“We’re expecting to see more debris than ever before,” said John F. Muratore, manager of shuttle systems engineering and integration.

Improvements to the external tank and solid rocket boosters aim to keep the size of debris to less than a tenth of a pound, which is smaller than engineers think could do serious damage.

If the orbiter is damaged on launch, shuttle managers are keeping open the possibility of using the space station as a haven until the shuttle Atlantis could be launched to rescue them.