A decision then will be made on what type of inspections should be performed on the nosecap, and where those inspections should be done.

NASA ultimately could decide to send the nosecap back to its Texas manufacturer. It's not clear yet whether that work could be finished in time to launch in mid-July.

"It's premature to discuss that until you determine whether removing and inspecting the nosecap is the right thing to do from a safety standpoint," said James Hartsfield, a spokesman for NASA's Johnson Space Center in Houston. "But I can tell you that decision will be made on what is appropriate to ensure that Atlantis is safe to fly and nothing else."

But officials already are saying any launch date at this point is just a target -- one set primarily for work scheduling purposes.

What's more, they say further delays can be anticipated as the agency puts in place new safety enhancements ordered by Columbia accident investigators.

"A lot of that development work is still in the early stages, and until it reaches a certain level of maturity, you can probably expect change," Hartsfield said.

"A target launch date is a target launch date, and we have said they can move."

Atlantis is to be launched to the International Space Station on a mission aimed at testing new orbital inspection and repair techniques as well as other safety enhancements.

Among other major challenges facing the agency: manufacturing a boom that will be used to inspect shuttle thermal tiles and wing panels in orbit - an effort that could push the Atlantis flight back to next September or later.

Laden with cameras and laser sensors, the boom will play a key role in detecting any damage that might endanger a shuttle crew during atmospheric re-entry.

The Columbia accident was traced to a wing panel hole that enabled hot gases to tear the ship apart during re-entry.

Investigators recommended that NASA develop a way to perform orbital inspections and repairs on wing panels and thermal tiles before shuttles fly again.

NASA is progressing with tile-repair techniques. High-tech caulk guns will be used to fill gouges with a material that cures to a consistency like a pencil eraser and can withstand intense temperatures.

Development work on wing panel patches is going more slowly. NASA has engineered a way to patch holes up to four-inches in diameter with an umbrella-like fastener similar to toggle bolts used to attach hardware to drywall.

Also under consideration: Balloon-like bladders containing heat-resistant material, adhesive patches, and metal overlays that can be bolted to wing panels.

But none of the methods appear adequate enough to fix the type of 6- to 10-inch hole that investigators think doomed Columbia.

The return-to-flight development efforts are complicated by new restrictions that limit the shuttle to daylight launches. Liftoffs also must be timed so the shuttle's external tank is jettisoned on the sunlit side of Earth.

The idea is capture sharp images of any damage done during flight.

Acceptable windows include a six-week period beginning around July 15 and a month-long period that begins in mid-October. Two, three-day launch opportunities exist in November 2004 and January 2005. But NASA would be unable to launch in late October 2004 or much of November 2004 and January 2005.

No launch opportunities exist in February 2005 and March 2005.

An effort, however, is under way to determine whether photographic capabilities can be enhanced enough to expand the number of launch opportunities available.

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