A Russian cosmonaut who explored a mysterious hole in a capsule anchored on the International Space Station said the opening was made inside the spacecraft.
Sergei Prokopyev said investigators are looking at samples he and his crew colleague, Oleg Kononenko, collected during a space walk on Dec. 12, while Russian officials are examining what caused it.
Prokopyev and two other astronauts returned to Earth last week from a 197-day space station mission.
The hole in the Russian Soyuz spacecraft attached to the station was sighted Aug. 30.
The team discovered a leak that created a slight loss of pressure and plugged the hole with epoxy and gauze.
Prokopyev told a news conference that the cavity started inside the capsule and "it's up to the investigative bodies to judge when the hole was made."
The astronauts' quick identification and repair of the hole demonstrated that "the crew was ready for any evolution," he said.
The hole posed no danger to Prokopyev and his crewmates, Serena Aunon-Chancellor of NASA, and Alexander Gerst of the European Space Agency, during his return because the section of the capsule he was in was discarded before reentry into Earth's atmosphere . .
Roscosmos chief Dmitry Rogozin said in September that the hole could have been drilled when the capsule was manufactured or in orbit.
Rogozin did not come to blame the crew members, but the statement caused some friction between Roscosmos and NASA.
Since then, he has returned behind the statement, blaming the media for twisting his words.
Prokopyev mocked the idea that the hole could have been pierced by an astronaut, saying, "You should not think so badly about our crew."