NASA on Friday scheduled space shuttle Discovery for a Sept. 29 midmorning launch on the first mission since the Challenger accident.

The launch was set for 9:59 a.m. EDT but could come any time in the following three hours, the National Aeronautics and Space Administration said.The announcement was made after a meeting at NASA headquarters between administrator James C. Fletcher and Richard Truly, the head of the shuttle program. Truly briefed Fletcher on the flight readiness review held earlier in the week at Kennedy Space Center in Florida.

"I'm delighted to have reached this point," Truly said. "My hat is off to all members of the shuttle team whose tireless efforts have brought us here to the brink of America's return to manned space."

That two-day meeting in Florida evaluated all of Discovery's systems and cleared the shuttle for flight.

A launch date had been expected following completion of the review Wednesday. But Truly delayed any announcement because of the possibility Hurricane Gilbert could disrupt operations at the Johnson Space Center in Houston where shuttle flights are controlled once they are launched.

Truly said late predictions were that the Houston area would be hit only by moderate winds and "no threat to Johnson Space Center facilities is projected if Gilbert continues on its current path."

The inaugural flight will be a four-day mission to deploy a $100 million Tracking and Data Relay Satellite, a twin of one lost in the Challenger explosion Jan. 28, 1986.

Five veteran astronauts will be on the flight.

They are Navy Capt. Frederick Hauck, the commander; Air Force Col. Richard O. Covey, the pilot; and mission specialists George D. Nelson, John M. Lounge and Marine Lt. Col. David C. Hilmers.

In addition to launching the satellite, they will conduct 11 science and technology experiments and check out hundreds of design changes made to the shuttle.

NASA had hoped to return to manned space flight sooner with the 26th shuttle mission. But five announced launch dates had to be scrubbed because of technical problems involved in the $1.2 billion redesign. There were 56 major changes and more than 400 lesser ones; the orbiter alone received 210 fixes.

The most extensive changes were made to solid fuel rockets that provide more than 70 percent of the power to propel the shuttle into orbit. But there also was a complete reworking of the shuttle's three main engines.

The Challenger explosion, which claimed the lives of seven astronauts including schoolteacher Christa McAuliffe, was caused by a leak in one booster that allowed a plume of flame to reach the fuel tank.

NASA grounded the shuttles following the explosion.

One major change implemented is an escape system designed for use if the shuttle has to ditch in the ocean.