Shuttle astronauts installed part of cooling system on International Space Station.  The U.S. space agency NASA says two astronauts from the shuttle Atlantis have completed a spacewalk to install part of a cooling system on the International Space Station.

Astronauts Rex Walheim and Hans Schlegel installed a nitrogen tank on the orbital outpost.  The outing Wednesday lasted just over six-and-a-half hours.

Schlegel, a German, missed a previous spacewalk due to an undisclosed illness.

On Monday, two astronauts installed a European science laboratory with help from crewmates inside the space station.

Crewmembers set up electrical and data lines linking the Columbus laboratory to the space station before European astronaut Leopold Eyharts of France briefly floated inside the module for the first time. 

Atlantis will remain at the space station until at least Sunday.