Astronauts are spacewalking outside the International Space Station for the first time in half a year.

Monday's spacewalk got started late because of a leaky valve on the Russian side of the orbiting outpost.

The crew had to reopen the air lock and check the seals to ensure a tight fit, before Russians Gennady Padalka and Yuri Malenchenko could go out. Padalka assured Moscow flight controllers they were in no rush. But he admitted it was boring to wait an extra hour.

The two spacewalking pros will attach shields to protect against space junk. The panels were supposed to go up during a spacewalk in February, but got put on hold. The men also will move a crane and release a small satellite, all Russian-based work.