Two Russian cosmonauts took a spacewalk on Tuesday seeking to resolve the mystery of a small hole found in the side of a craft docked at the International Space Station.
Russia's space agency Roscosmos has ruled out a manufacturing defect causing the 2 mm-wide hole found in August on the Russian Soyuz capsule, but NASA has sought to dampen speculation of sabotage.
Oleg Kononenko and Sergey Prokopyev's six-hour-long spacewalk began at 9 p.m. a live broadcast by Roscosmos showed.
"Sergey, how are we doing with the time schedule?" a voice from the control center asked them after an hour.
"We are working, working leisurely," Prokopyev answered.
They will take samples from the exterior wall of the Soyuz to look into the hole in the capsule's internal covering.
The puncture has been sealed since August, halting the oxygen leak. Officials said the crew — three U.S. astronauts, two Russian cosmonauts and one German — were never in danger.