With Hurricane Dennis churning in the Caribbean, NASA managers this evening decided to begin preparing the shuttle Discovery for a possible roll back to the protection of the Vehicle Assembly Building should the storm take a turn to the east and threaten the Space Coast.

If the storm stays on its projected course and winds remain below NASA safety limits, the launch team will simply continue readying Discovery for blastoff Wednesday on the first post-Columbia mission. The ship's seven-member crew is scheduled to arrive Sunday for the start of a three-day countdown. But the storm could force the astronauts to change their travel plans even if it doesn't delay launch.

Engineers plan to meet at midnight and again at 7 a.m. Friday to assess the storm's path and their readiness to respond, with a noon meeting on tap to make a final decision. As of Thursday afternoon, the storm's projected track stayed well clear of the Kennedy Space Center, but NASA managers opted to play it safe just in case.

"We are beginning the rollback preparations," said NASA spokeswoman Jessica Rye. "They will not make a decision about rollback until tomorrow, probably about midday. The storm is continuing to take little trends to the right (east) and because of that they want to protect againt possible rollback by getting some preps done this evening."

If the storm does, in fact, take a turn toward Kennedy, Rye said the shuttle would be ready to roll by 8 p.m. Friday and back in the VAB by around 5 a.m. Saturday.

Discovery's launch period extends to July 31 and it's not clear as of this writing how many launch opportunities would remain if the ship had to be hauled off the pad. Rye said that from the point the shuttle returned to the pad, it would take engineers nine days or so to prepare the craft for flight and to run a countdown.

Under that scenario, it would appear Discovery's crew would still have a week or so to get off the ground before the July launch window expired. The next available window opens Sept. 9.

A shuttle is not allowed to remain at the pad if sustained 60-knot winds are expected. The limit for the move back to the VAB, when the shuttle is exposed to the elements, is 40 knots. NASA has moved shuttles off the launch pad 15 times in program history, four of them due to tropical storms or hurricanes.

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