U.S. astronaut William McArthur and Russian cosmonaut Valery Tokarev took part in a Monday spacewalk at the International Space Station.

The spacewalk was delayed about an hour past its scheduled time when Tokarev, who was making a spacewalk for the first time, forgot to open a pressure equalizer valve in the air lock. He had to re-open the hatch, return to the station and repeat the procedure, ITAR-Tass, Russia's official news agency, reported.

"This is the 12th expedition's first space walk. It comes as part of the American flight program. The main task is to replace video cameras at the truss construction installed on the station's surface," Sergei Puzanov, NASA's representative at Russia's Mission Control Center in Kovalyov, near Moscow, said.

Copyright 2005 by United Press International