Engineers restarted the shuttle Endeavour's countdown overnight on the assumption the ship's damaged robot arm will be cleared for launch Friday night "as is." While an analysis of the arm's structural integrity continues, engineers have wrapped protective tape around an area of torn outer insulation and plan to close Endeavour's cargo bay doors later today.

Endeavour's seven-man crew - commander James Wetherbee, pilot Paul Lockhart, John Herrington, Michael Lopez-Alegria and the international space station's next crew, Expedition 6 commander Kenneth Bowersox, Nikolai Budarin and science officer Donald Pettit - presumably will fly to the Kennedy Space Center later today. But under NASA's post Sept. 11 security plan, the agency will not discuss crew movements or even announce when the countdown began.

Likewise, Endeavour's exact launch time will not be released until 24 hours before liftoff. As of this writing, NASA will only say launch is targeted for sometime during a four-hour window that opens at 7 p.m. Friday. The forecast calls for an 80 percent chance of good weather, with more of the same on tap Saturday should launch be delayed another day. But the weather at two emergency landing sites in Spain is currently forecast "no go" and one of them must be available for Endeavour to be cleared for launch.

NASA originally hoped to launch the shuttle Nov. 11, but the flight was delayed the night before by a leak in a line that feeds oxygen to the crew cabin. During work to insert a work platform into the shuttle's cargo bay to repair the leak, workers inadvertently rammed Endeavour's robot arm, tearing its outer insulation and causing a small area of carbon composite in the arm itself, near the shoulder joint, to delaminate, or separate.

The oxygen leak was repaired and, to be on the safe side, an associated nitrogen line was replaced as well. An examination of other flex hoses in the fleet turned up no signs of a generic problem. This issue has not been officially "put to bed" yet, but it appears to be well on the road to resolution. The arm issue, however, has proved more troublesome.

The arm is needed to pull a 14.5-ton solar array truss segment from Endeavour's cargo bay so the international space station's robot arm can attach it to the lab complex. Engineers have been carrying out tests and analysis to determine whether the damaged arm can safely handle the vibrations and forces it will experience during launch and when handling the P1 solar array truss. That analysis continues today.

Shuttle program manager Ronald Dittemore will chair a mission management team meeting starting at 6 p.m. this evening to review the arm analysis and to make a decision, one way or the other, on whether to press ahead for launch Friday. Only three options are under study: 1) Launch as is; 2) remove the arm at the pad and carry out the mission without it; 3) attempt to repair the damage at the pad.

The latter two options would delay launch until the first week of December, probably between Dec. 4 and 6. The shuttle must be off the ground by around Dec. 9 or the flight will be delayed to early January because of solar power issues on the space station.

This status report will be updated this evening, after Dittemore holds a teleconference with reporters to discuss the results of the engineering review.