Testifying before the House Science Committee Thursday on the agencys new space exploration agenda, OKeefe told lawmakers that the prospects for making the early fall launch window are very low owing to slower than expected progress clearing the shuttles external fuel tank for flight and developing an instrumented boom for inspecting the underside of a shuttle for damage.

A chunk of foam shed from the Space Shuttle Columbias giant orange external tank on liftoff damaged the orbiters left wing, setting the stage for the vehicles disastrous Feb.1, 2003 re-entry and landing attempt. NASA has been taking steps to better understand foam shedding and, where possible, prevent it. In recent weeks, NASAs efforts to characterize and mitigate foam shedding have been expanded to cover more of the tank. As a result, NASA needs more time for added testing and any design changes that might be warranted.

NASA is also not making as much progress as expected developing an instrumented boom that would be deployed at the end of the shuttles giant robot arm to inspect the vehicle for damage.

OKeefe said that because of these two technical issues, prospects for an early fall launch are growing dim.

I have my doubts and do not believe the September-October timeframe will be met, OKeefe said.

After the hearing, OKeefe would not predict the odds the shuttle would be ready to launch by the end of the year.  But shuttle officials have said that the comparatively short launch windows available in November and December are less than ideal opportunities for conducting NASAs first launch since losing Columbia.  These officials have said they would prefer to wait until at least January -- when launch opportunities start to become more numerous again -- if they miss the September-October launch window.