SPACE CENTER, Houston - NASA said yesterday that when shuttle launches resume next year, the first mission will essentially be a test flight, with astronauts inspecting their ship and practicing repair techniques to guard against another Columbia-type disaster.
The National Aeronautics and Space Administration considered flying the minimum number of astronauts and keeping the mission short. But NASA decided to go with a full set of six or seven astronauts on a normal-length mission of about a week and a half to perform overdue repair work at the international space station.
"If we're going to go through all this risk to get there and do that, we ought to go ahead and make sure that we do some of those things that are important to the international space station because if we don't do those things, it raises the risk of the station," said Bill Parsons, new shuttle program manager.
No firm launch date has been set for the next shuttle, Atlantis. But in all likelihood, it will not deliver a fresh crew to the space station as originally intended. Instead, the focus will be on inspecting the shuttle for exterior damage, using cameras on both the shuttle and space station and practicing repair techniques.
Other objectives, such as delivering supplies to the space station, will take a back seat, said William Readdy, a former shuttle commander who is now NASA's top spaceflight official.
Readdy said the next flight might not represent as much of a shakedown as the first shuttle trip in 1981, a two-day mission by Columbia and two pilots.
But he noted, "This is really and truly a developmental test flight getting back to building and assembling the space station" and implementing all 15 of the Columbia accident board's recommendations required for return to flight.
NASA has yet to settle on all the details of an emergency rescue plan.
But in a 156-page return-to-flight report issued yesterday, the space agency said it is looking at using the space station as an emergency shelter for stranded shuttle astronauts and considering having another spacecraft ready to blast off on a rescue mission.
"Our first line of defense is: Don't have any debris come off and strike the shuttle," Parsons said. "The second line is to have inspection techniques and repair capabilities so we can come home safely."
The release of NASA's initial return-to-flight plan comes two weeks after the Columbia Accident Investigation Board concluded that a stray piece of insulating foam and a broken safety culture were responsible for the shuttle's destruction on Feb. 1. All seven astronauts were killed.
Readdy stressed that the plan is "a living document" that will evolve in the coming weeks and months.
Some NASA officials have talked about resuming shuttle flights as early as March, but most have said privately that next summer would be a more realistic estimate.
"Whether that turns out to be March or April or May or June or July, so be it," Readdy said. "We will be safety-driven and not schedule-driven."
The biggest challenge, officials said, will be to come up with a repair for the vulnerable carbon panels that protect the leading edges of the shuttle wings. The leading edge of Columbia's left wing suffered a 6- to 10-inch hole from being hit with the foam.
NASA is looking for outside help in coming up with a leading-edge patch capable of withstanding the thousands of degrees of re-entry heat.
Atlantis will be launched in daylight to ensure good camera views of the foam insulation on the external fuel tank and any debris hitting the spaceship. Readdy said shuttles will be restricted to daylight liftoffs for the foreseeable future.
As for the newly ordered inspections, the astronauts will connect an extension boom to the end of the shuttle's 50-foot robot arm and check the underside of the wings and the ship's belly for damage. Cameras and lasers will be mounted on the end of the boom; the lasers will measure the depth of any gashes.
Readdy and other officials said they do not know how much all the improvements will cost.
As for the steps necessary to fix NASA's broken culture, those will take longer and require help from outside experts, Readdy said.
Readdy said it will be a balancing act to retain the space agency's can-do attitude while eliminating the bureaucratic problems that prevented lower-level employees from speaking up during Columbia's mission.