Spacewalking astronauts improved the safety of their orbiting home by installing shields to protect against zooming pieces of junk.
Gennady Padalka and Yuri Malenchenko hung the panels on the Russian side of the International Space Station, after moving a bulky crane and tossing overboard a small spherical satellite.
The Russian spacewalkers - the two have 14 spacewalks between them - kept going even after Mission Control in Moscow advised them to take a break three and a half hours into their six-hour excursion.
They surged ahead despite a late start to the spacewalk, the first at the space station in six months.
A leaky valve somewhere on the Russian side forced the crew to reopen the air lock and check the seals to ensure a tight fit, before Mr Padalka and Mr Malenchenko could go out.
Mr Padalka assured flight controllers they were in no rush, but admitted it was "kind of boring" to wait an extra hour.