Senior space agency officials decided Friday to aim for a launch in September 2004 for Atlantis. That date could slip even further into next year or even into 2005, depending on the progress of the shuttle repair work.
NASA had been using next March as a planning date for the first shuttle flight following the Columbia disaster.
"We're going to be very much driven by milestones and by the content that we have to accomplish here," said Bill Readdy, the head of NASA's human spaceflight program.
Readdy said the work involves coming up with astronaut repair kits for potential damage to the shuttle's outer thermal layer, redesigning the fuel tank so insulating foam does not break off and building an extension boom for the shuttle robot arm to conduct in-orbit surveys of the entire ship.
"I can't tell you whether or not we're going to have more (repairs) creep in over time, whether we're going to come up on some technical hurdles," Readdy said. "I can almost guarantee that this is going to be a long, uphill climb back to return to flight. But I'll guarantee you that we're getting an awful lot smarter about this."
Columbia and its seven astronauts were doomed by a flyaway piece of foam that tore a hole in the leading edge of the left wing during liftoff. The ship broke apart over Texas in February after the searing gases of re-entry penetrated the gash and melted the wing from the inside out.
Shuttle program manager Bill Parsons said the launch window that extends from about Sept. 12 through Oct. 10, 2004, represents "the best planning date for the information that we know today" and gives NASA a reasonable amount of time in which to accomplish everything.
The next mission, a trip to the international space station, will be essentially a test flight to assess all the repairs that might be needed to find and fix a hole caused by launch debris. An extra flight will be added to the shuttle lineup, as early as November 2004.
NASA has not yet decided how to check Atlantis' nose cap for possible corrosion, which could mean even more work before the ship's return to flight.
The last time the shuttle was fully inspected for corrosion to the cap's underlying metal framework was in 1991. A partial inspection was conducted in 1997, but because of a paperwork error it was listed as a complete check, Parsons said.
Because of a new safety requirement for daylight launches in order to photograph any debris strikes and check the fuel tank for missing foam insulation, NASA is extremely limited in the number of days it can send a shuttle to the space station. Half the days in any given year are blacked out.
If Atlantis is not off the ground by mid-October, Parsons told CBS News Space Consultant William Harwood there may be one other launch window in 2004.
"I think we have some opportunities, some small opportunities in November and possibly January and some other places," he said.