With a leaky air purifier repaired and working well, the astronauts aboard space shuttle Columbia have returned to a normal routine and even received some well-deserved time off.

Crew members completed a half-day's worth of experiments Sunday before taking the rest of the day to relax and enjoy the view."The experience of looking out the window at the beautiful planet below us is just awe-inspiring," shuttle Commander Richard Sear-foss said.

Searfoss reported no problems with the carbon dioxide removal unit that shut down late Friday because of a leaky valve. He patched up the unit Saturday by removing one end of a small hose, blocking it with tape to bypass the faulty valve, and reinstalling it.

He said it was like fixing the water hose on his car.

"Everything's working great," Searfoss said Sunday.

Before taking some time off, crew members took a spin in a centrifuge chair that allows scientists to see how the brain interprets motion in weightlessness. Some crew members also repeated an experiment that studies the effect of weightlessness on eye-hand coordination.

In all, 26 experiments are being conducted on the Neurolab mission - the most in-depth study ever of the brain and nervous system in weightlessness. Eleven tests involve Columbia's human crew, and the rest focus on the shuttle's other passengers - thousands of crickets, snails, fish, rats and mice.

The two-week mission is scheduled to end early next week.