Carrying the largest crew in space flight history, the shuttle Challenger today returned to the Kennedy Space Center where the five men and two women were launched into earth orbit eight days ago.

The 100-ton Challenger glided out of clear Florida skies and touched down on runway 33 at 12:27 p.m. EDT after crossing over the heartland of North America from Alaska, western and central Canada down to Cape Canaveral.

The landing here of the 13th space shuttle flight means that the government can move ahead with a stepped-up schedule of shuttle flights.

It was the second time in four attempts that a shuttle crew landed in Florida instead of at California's Edwards Air Force Base and the first time in three missions that Challenger Commander Robert L. Crippen was not waved off a Florida landing by bad weather.

"You outfoxed us again, Crip," astronaut Dick Richards said from Mission Control Center at Houston's Johnson Space Center. "You landed at KSC Kennedy Space Center but the beer's been sent to Edwards."

Before leaving on a NASA plane for Houston, Crippen said, "Well, I've tried to land here three times and, like some people say, the third time is a charm."

Landing as often as possible in Florida where the shuttle is launched is a crucial goal of NASA planners. It saves time and money by eliminating the spaceliner's ferry trip from California and by having it available to maintain a speeded-up schedule of one shuttle flight a month for the next year and a half.

"We're delighted that Challenger was able to make it back to KSC today," Jesse W. Moore, NASA associate administrator for space flight, said at a news conference after today's landing. "We are now reaching the flight schedule we'd set out for ourselves."

The 14th shuttle flight, the second for the spaceliner Discovery, is due Nov. 7 and the 15th flight, the first mission turned over completely to the Defense Department for classified work, is set for Dec. 8.

The November and December flights are scheduled to land in Florida as are the three flights early next year.

"Our last landing was 36 days ago, the shortest time between landings on our first 13 flights. Ahead of us we have one flight a month right through next May and approximately one flight a month for the next year and a half. We believe the system efficiency is increasing and we believe the teams are capable of meeting this new schedule," Moore said.

The eight-day mission that ended today was successful, Dr. Shelby Tilford, NASA director of space science said, even though fewer than half the planned observations were made in the most important experiment on the shuttle.

"There is some disappointment that the shuttle's imaging radar has achieved about 40 percent of what we set out to do," Tilford said. "In spite of that, we got most of our high-priority targets."

Problems with a radio antenna that links the imaging radar to Earth prevented transmission of data to Earth during the first few days of the mission.

The imaging radar involves sending thousands of radar pulses to the ground each second, allowing scientists receiving the echoes to construct photograph-like images of the terrain. Not only does the radar penetrate cloud cover and vegetation, it does so with such speed that it may someday replace airborne radar mapping. In four seconds, the shuttle's imaging radar is able to "photograph" a strip of land 25 miles wide and 100 miles long.

Tilford said all the other Challenger experiments worked perfectly. The space-borne mapping camera, carried on a shuttle flight for the first time, took 2,300 frames of film in mapping parts of every continent on Earth. The goal was 18 million square miles but, as expected, about half of the target sites were covered by clouds.

Challenger apparently returned to Earth in tip-top condition, except for minor damage to the two rear engine parts suffered during ascent eight days ago. "We think we saw a couple of other dings but the bird looks in reasonably good shape," Moore said.

The crew, including Kathryn D. Sullivan, Sally K. Ride and Canadian Marc Garneau, stepped down from the shuttle onto a red carpet that said: "Welcome Back."

They were then taken by van to a dispensary where another sign hung from the door saying: "The Grass Is Always Greener at KSC."