I DIDN'T KNOW WE HAD A URINE MACHINE?

HOUSTON (Nov. 23) - Astronauts tinkered Sunday on a troublesome piece of equipment which can convert urine and sweat into drinkable water once it's functioning and allow the international space station to grow to six crew members.

Station commander Michael Fincke and Endeavour astronaut Donald Pettit changed how a centrifuge is mounted in the $154 million water recycling system. The centrifuge is on mounts and Mission Control asked Fincke to remove them and bolt it down without them.

The astronauts have been working for the past three days to get the system running so it can generate samples for testing back on Earth, but the urine processor only operates for two hours at a time before shutting down.

The water recycling system, delivered a week ago by the space shuttle Endeavour, is essential for allowing more astronauts to live on the space station next year.

Lead flight director Ginger Kerrick said engineers hope the problem is fixed, but they were studying whether six crew members would still be able live at the space station with the urine processor only working for two hours at a time. The space station crew is scheduled to grow from three to six residents next year.

"If this is as good as it's going to get, we do need to be able to answer that question," Kerrick said.

Flight controllers had hoped the water samples brought back for testing had a mixture in which 70 percent came from condensation and 30 percent came from urine. Given the problems with the urine processor, that ratio stands at 90 percent condensation and 10 percent urine. Crew members won't be able to use the contraption until several rounds of tests show it is safe.