CAPE CANAVERAL, Fla.—Two astronauts are safely back inside the international space station after finishing a spacewalk to clean and lube a jammed solar-wing rotatry joint.

Spacewalkers Stephen Bowen and Shane Kimbrough ended their six-hour, seven-minute spacewalk by climbing back inside a space station airlock.

It was the fourth and final spacewalk during space shuttle Endeavour’s nearly two-week visit to the space station.

Just before Monday’s spacewalk began, NASA added a 16th day to space shuttle Endeavour’s mission. Managers wanted to give the astronauts more time to fix a machine that’s supposed to turn urine into drinking water.

Additional repairs were performed Monday for the fifth day in a row.