MOSCOW -- Two Russian cosmonauts stepped out into space for more than three hours Friday, collecting science experiments and successfully troubleshooting a leaky hatch on the Mir space station.
Cosmonauts Anatoly Solovyov and Pavel Vinogradov discovered that one of the 10 main locks on the hatch door was broken, causing a partial loss pressure, said Mission Control Chief Viktor Blagov.
Blagov said he was relieved by the news, since the repair is comparably simple and can be done without another spacewalk, he said.
During the spacewalk, the two veteran cosmonauts also crawled along the hull to a neighboring module to retrieve a box containing American tests of various materials designed for use in the vacuum of space.
NASA astronaut David Wolf filmed his crewmates' movements from inside the station and stood by to help out in case of an emergency.
The hatch on the Mir's Kvant-2 module had failed to close properly after a spacewalk last November. However, the situation was not considered serious because the resulting loss of pressure affected only Kvant's docking chamber, which is sealed off from the rest of the station.
Still, it has been inconvenient, forcing the crew to don their bulky spacesuits in a smaller compartment nearby.
During their examination of the hatch, Solovyov and Vinogradov discovered that the spoke that inserts into the lock had become frozen and would need to be replaced, Blagov said.
But he said a tight seal was possible in the interim because the hatch has an additional 10 auxiliary locks. But only five of the auxiliary locks were latched after the previous spacewalk, which is why they did not prevent the leakage, Blagov said.
Blagov said the hatch repair will be scheduled sometime after Wednesday, when the crew's next spacewalk is scheduled.
"If we disassemble the hatch, we may not have enough time to reassemble it before the next spacewalk," he explained.
During the upcoming mission, Solovyov and Wolf will gather another set of U.S. scientific experiments attached to the outside of the orbiter. It will be the American's first walk in space.
Solovyov is the most experienced space walker in history, logging more than 70 hours in open space on his previous 14 spacewalks, five of which he made during his current Mir mission, starting last August.
He and Vinogradov, who has accompanied him on a total of five spacewalks, have managed to restore most of the power lost in last June's collision with a cargo ship.
Mir, the world's longest-flying space outpost, will mark its 12th anniversary in orbit next month, although it only had been expected to last for five years.
Despite continuing computer breakdowns, the latest of which occurred last week, Mir has been relatively quiet in recent months after a steady string of accidents earlier last year.