Columbia landed today after an unprecedented third weather "wave-off" from Florida and NASA said it had a "good shot" at meeting the space shuttle's next launch date despite this mission's problems from start to finish.

"It sure took us a number of tries to get up in the air, and it sure took us a number of tries to get back down, but it was all completely worth it," said Robert (Hoot) Gibson, commander of the hard-luck crew.

Columbia and its crew of seven were 25 days late in getting off and two days late returning to Earth. They had covered 2.5 million miles during six days in orbit and successfully launched a $50 million RCA television satellite.

The space agency's timetable calls for Columbia to be launched again on March 6 for a Halley's comet observation mission. Today's landing diversion set back the schedule for preparing the shuttle for that mission by at least five days because it will take that long to get the ship back to Cape Canaveral.

But engineers flown to the Mojave Desert air base overnight from Florida worked around the clock so the shuttle could be readied, and perhaps meet the deadline, for the Halley's mission.

"I'm optimistic we're going to come very close to the 6th," said Jesse Moore, associate NASA administrator in charge of the shuttle program. "We've got a shot at the 6th, a very good shot at the 6th."

Today's landing appeared flawless. The 105-ton spaceship glided out of the predawn desert darkness like a ghost ship and touched down at 8:59 EST on a concrete runway lined with floodlights.

Unlike the red-carpet greeting that awaited them in Florida, only a few technicians and astronauts were on hand at Edwards to welcome Gibson, Charles Bolden, George Nelson, Steven Hawley, Franklin Chang-Diaz, RCA engineer Robert Cenker and Rep. Bill Nelson (D-Fla.).

The congressman, chairman of a House subcommittee that oversees NASA's budget, said NASA wanted him to learn a lot about the space program, and he did.

"I didn't realize that I was going to have all the experience that I've had," Nelson said.

Moore said the ship appeared to have lost about a dozen white insulation tiles but damage appeared minimal.

The shuttle Challenger is up next, and Kennedy Space Center launch chief Robert Sieck said it should be able to meet its liftoff appointment next Saturday with a high school teacher on board. It will be the first time shuttle missions have scheduled so closely together.

Challenger is scheduled for a six-day mission during which social sciences teacher Christa McAuliffe of Concord, N.H., is to give two lessons that will be beamed to classrooms in the United States and aired on televison by Public Broadcasting Service.

McAuliffe, one of seven crew members, also will be filmed in flight demonstrating how magnetism works, how plants grow and how other items function in weightlessness. This film will be edited for distribution to schools.

The 37-year-old teacher was chosen for NASA's citizen-in-space program from more than 11,000 teachers who applied.