HOUSTON (AP) – Space shuttle Endeavour provided an orbital lift to the attached international space station on Friday as the astronauts encountered more problems with a new water recycling system.

The machine for turning urine into drinking water wasn’t working right Thursday, and flight controllers turned it back on Friday morning. It shut down after running about two hours.

Endeavour’s extra push, meanwhile, elevated the docked space shuttle and space station complex about a mile. That puts the space station at the right altitude to receive a Russian Progress spaceship scheduled to deliver cargo to the orbiting outpost three days after Endeavour starts heading back to Earth on Thanksgiving.

Endeavour’s astronauts delivered the recycling system to the space station last weekend and have been trying to get it up and running.

NASA wants samples from the recycling system returned to Earth for analysis before giving the go-ahead for the space station astronauts to drink it. Once running, the system will help the space station support six residents instead of the current three inhabitants.

Just as the alarm on the urine recycling system went off inside the space station Thursday evening, two spacewalkers wrapped up a nearly seven-hour spacewalk outside.

To everyone’s relief, Heidemarie Stefanyshyn-Piper and Shane Kimbrough deftly stepped through their work without any mishaps. During Tuesday’s spacewalk, Stefanyshyn-Piper’s tool bag slipped away while she was trying to clean grease leaked from a gun used to lubricate a jammed solar wing joint outside the space station.

There were two small hitches at the very end of Thursday’s spacewalk: Kimbrough had trouble communicating with Mission Control and also had elevated levels of carbon dioxide in his spacesuit. Neither problem put the astronaut in danger. The communication problem was likely caused by a bump to his headset’s volume control.