Discovery's astronauts generally toed the line on a new NASA edict to cut the comedy, at least for public viewing, but they showed some flashes of fun in space, mainly in the battle of wakeup songs.

When Discovery made the first post-Challenger flight last September, the five astronauts awoke to Beach Boys music parodies and clowned for television cameras in bright Hawaiian shirts.And even though the December flight of Atlantis was a classified military mission, word leaked of special wakeup music not particularly flattering to the Pentagon.

And both crews videotaped themselves playing in the weightlessness of orbit, turning somersaults, throwing a football and feeding each other candy. The tapes were shown at public gatherings.

The astronauts' wacky wakeup calls and zany acrobatics got attention, which upset NASA because it felt the reports made the flights look like all play and no work.

"We've learned that if you crack a joke or show somebody doing something funny, that's the 10 seconds that gets on the evening news, and not the two hours worth of work you just showed," Discovery commander Michael Coats said in a prelaunch interview.

So space agency officials told Discovery's crew to cool it when the cameras or microphones were on.

"NASA has no official sense of humor anymore," said Bob Springer, one of Coats' crewmates. "So we're somewhat restricted now on what we can do."

Discovery's flight started out strictly following the policy, with wake-up calls played by Mission Control limited to presentations like the Marine hymn, for the two crewmen who are Marines.

But on Day 3, things loosened up.

The astronauts pre-empted Mission Control by playing their own wake-up music first - the theme music from "Star Trek."

They followed that with a tape recorded for them by actor William Shatner, who gave a brief performance in his character of Capt. James T. Kirk in the "Star Trek" movies and television series.

"Discovery, tell Scotty to beam me up," replied capsule communicator David Low in Houston.

Mission Control then responded with its planned wakeup - a medley of school songs from the alma maters of the crew members.

The next day, the astronauts again were first in the wakeup battle - broadcasting a recording of "Hi Ho, Hi Ho, It's Off to Work We Go," the work song of the seven dwarfs in the animated movie classic "Snow White."

Mission Control regained the upper hand on the final day, Saturday, hitting the airwaves first with a raucous recording of the astronauts' children shouting such things as, "Get up, Dad, get out of bed and get to work," and "Hi, Daddy, this is your darling daughter telling you to wake up."