Astronaut Randy Bresnik salutes his crewmates while positioned near the European Space Agency's Columbus module on International Space Station during his first-ever space walk Saturday ((NASA/The Associated Press))

Two NASA astronauts left the International Space Station on Monday for the third and final spacewalk of their mission.

Robert Satcher Jr. and Randolph Bresnik exited the station an hour behind schedule because of a problem with Satcher's spacesuit. A valve on the suit's drink valve came off as Satcher was putting on the suit.

If the valve to the water pouch doesn't have a tight seal, there would be a risk of weightless blobs of water floating up into the astronaut's face.

The astronauts' main job on their spacewalk is to install a 550-kilogram high-pressure oxygen tank to the station's airlock. They will also hang some science experiments outside the station.

Bresnik is the father of a new baby girl, Abigail Mae, born just after his first spacewalk on Saturday. His wife, Rebecca, delivered the six-pound, 13-ounce baby back in Houston. Both baby and mother were said to be doing well.

The space shuttle Atlantis will leave the space station on Wednesday carrying one more crew member than it had when it arrived. Astronaut Nicole Stott has lived on the station for 2½ months, and Atlantis is her ride home.

Atlantis is schedule to land on Friday at Kennedy Space Center in Florida.

With files from The Associated Press