Mission specialist Shane Kimbrough cleans and lubricates the end of the International Space Station's robotic arm during a spacewalk on Thursday. (NASA TV/Associated Press)

Spacewalking astronauts performed more repair work on a jammed joint at the international space station on Thursday, keeping a tight grip on all their tools so nothing would get away this time.

A $100,000 US tool bag was lost during the first spacewalk of the mission two days ago.

To everyone's relief, Heidemarie Stefanyshyn-Piper and Shane Kimbrough deftly stepped through their work without any mishaps. They had double- and triple-checked their equipment before venturing out to make certain everything was tied down.

As they packed up their tools to go back inside, Stefanyshyn-Piper said, "Hopefully, I won't lose anything on the way."

She didn't. Mission Control and astronauts inside the space station complimented the astronauts on the spacewalk, which lasted 6 hours, 45 minutes.

"Welcome back," said Endeavour commander Christopher Ferguson. "Outstanding job."

Stefanyshyn-Piper's tool bag slipped away Tuesday after one of the grease guns inside exploded and got bits of the dark gray stuff everywhere. She later owned up to making a mistake by not checking to make sure the bag was secured.

With two grease guns lost in space, only two remained for all the repair work, each with a different type of nozzle to reach specific parts of the clogged solar wing-rotating joint. That meant Stefanyshyn-Piper and Kimbrough had to share the remaining grease guns and other tools.

To save time, Stefanyshyn-Piper tested an alternative method for applying grease: wiping it on with a terry mitt. That seemed to work well.

10th anniversary of space station

Thursday's spacewalk — the second of four planned for shuttle Endeavour's visit — fell on the 10th anniversary of the space station.

Before the action got under way outside, wishes of "Happy Birthday!" and "Happy Anniversary!" flew back and forth between flight controllers around the world and the space station's skipper, Mike Fincke.

The spacewalkers' primary job 350 kilometres up was to clean and lubricate the massive joint that controls the solar wings on the right side of the space station, and to replace its bearings.

It's been used sparingly since September 2007, hampering energy production at the space station. A lack of lubrication caused parts inside the joint to grind together, producing metal shavings that gummed up everything.

Other chores that the spacewalkers polished off — moving a pair of rail carts to clear a path for construction work planned on the next shuttle flight in February and lubricating the bearings for the snares on the end of the space station's robot arm.

Meanwhile, much cleaner and less grueling home improvements continued inside the space station. Over the weekend, Endeavour delivered an extra bathroom and kitchen, two more bedrooms and a recycling system for turning urine and sweat into drinking water.

The first sip won't happen until next spring; NASA wants to return samples aboard Endeavour and the next visiting shuttle to make sure the recycled water is safe.

The additions will allow NASA to double the size of the space station crew from three to six by June, it hopes.