Shuttle astronauts complete another spacewalk

Spacewalking astronauts completed almost all of the greasy repairs on a gummed-up joint at the international space station, leaving just a few chores behind for another day.

As spacewalk number three was getting under way 225 miles up, a new recycling system for converting urine into drinking water broke down again.

It was the third day in a row that the urine processor inexplicably shut down, and it appeared to be the same kind of sluggish motor trouble seen before.

Engineers on the ground scrambled to figure out what might be wrong. The problem could jeopardise Nasa’s plan to return recycled water to Earth aboard space shuttle Endeavour next weekend.

The $154m (€123m) water recycling system, delivered a week ago by the space shuttle, is essential for allowing more astronauts to live on the space station next year.

Mission Control wanted to keep the spacewalk close to the seven-hour mark and, six hours in, told the astronauts to wrap up what they were doing and start heading back in.

The remaining chores – cleaning and greasing one final section of the joint and installing the one more bearing – will be squeezed into the fourth and final spacewalk of the mission tomorrow. That’s when astronauts will grease up the good rotary joint on the left side of the orbiting complex.

“We really appreciate how hard you’re all working,” Mission Control radioed. “I know it’s painful to call it quits like that, but we think it’s the right thing to do.”

Their spacewalk lasted just three minutes shy of seven hours, enough to make it the longest of the mission – barely.

“Welcome back aboard our beautiful space station,” said skipper Mike Fincke.