Countdown for Shuttle Blastoff Gets Green Light

NASA managers Tuesday cleared the repaired space shuttle Columbia for the overnight start of its countdown for a Saturday blastoff, setting the stage for the first shuttle flight in four months.

The countdown was scheduled to begin early today for a pre-dawn liftoff on Saturday. Columbia’s seven-member crew was scheduled to fly to Florida from Houston tonight for final preparations.

Space agency managers discussed the possibility of delaying the flight at least a day in order to first move the shuttle Discovery to a nearby launching pad for work to ready it for an Oct. 5 flight to carry the Ulysses solar probe into space.

But, late Tuesday, engineers reported that Discovery would not be ready for the move until Saturday night at the earliest, and officials decided to press ahead with plans to launch Columbia on time.

Columbia originally was scheduled to be launched on May 30, but the flight was delayed because of a hydrogen fuel leak in the ship’s 17-inch-wide “disconnect” fitting, which allows the external tank to be jettisoned in space.