With Atlantis back on the ground after a surprise Florida landing, NASA is gearing up to launch the shuttle Columbia in less than two weeks, around Dec. 2, to kick off a long-delayed astronomy flight.

Atlantis and its five-man crew, diverted from a California landing because of dangerous crosswinds, glided to a flawless day-late touchdown at the Florida shuttleport at 4:43 p.m. EST Tuesday to close out a five-day mission, the last top-secret flight currently planned by NASA.It was the first Florida shuttle landing in 5 1/2 years - only the sixth in the 37-flight history of the program - and NASA officials said the $2 billion orbiter appeared to sail through its 2 million-mile 79-orbit flight in excellent condition.

"I was very pleased to see the successful completion of the mission here," said Forrest McCartney, director of the Kennedy Space Center. "We have had in place . . . contingency plans such that if we needed to land the orbiter here, we could. We implemented the plan and it turned out extremely well."

But William Lenoir, NASA's associate administrator for spaceflight, said more landing tests are needed on the broad lakebed runways at Edwards Air Force Base, Calif., the normal shuttle landing site, before shuttles will be cleared for routine touchdowns in the Sunshine State.

Atlantis' picture-perfect touchdown closed out a presumably successful mission to launch a top-secret military satellite. But with a Pentagon-imposed news blackout in effect, it was not immediately possible to determine if all the flight's goals were met.

Landing originally was scheduled for Monday at Edwards in California's Mojave Desert, but dangerous crosswinds forced NASA managers to delay re-entry one day. After more of the same was observed Tuesday, Atlantis was diverted to the Kennedy Space Center.

The shuttle's all-military crew - commander Richard Covey, 44, co-pilot Frank Culbertson, 41, Charles Gemar, 35, Carl Meade, 40, and Robert Springer, 48 - flew back to their homes in Houston about 41/2 hours after landing.

On board Columbia will be commander Vance Brand, 59, co-pilot Guy Gardner, 42, John "Mike" Lounge, 44, Robert Parker, 53, Jeffrey Hoffman, 46, and civilian astronomers Ronald Parise, 39, and Samuel Durrance, 47.

Brand and company originally were scheduled for takeoff May 30, but the ship was grounded the night before liftoff by a dangerous hydrogen fuel leak. A second leak grounded the ship twice more in September.

An official launch date will be set next week after a one-day flight readiness review at the Kennedy Space Center.