This article is more than 1 year old

This article is more than 1 year old

Spacewalking astronauts have ripped through thick insulation on a capsule docked to the International Space Station looking for clues about a mysterious drilled hole that caused a leak four months ago.

Russians cosmonauts Sergei Prokopyev and Oleg Kononenko located the tiny hole in the external hull of the Soyuz capsule, more than five hours into their gruelling spacewalk.

“That is exactly the hole we’ve been looking for, guys,” radioed Russian Mission Control outside Moscow.

Facebook Twitter Pinterest The hole found in the International Space Station. Photograph: Nasa/EPA

In August the station crew plugged the hole from the inside with epoxy and gauze. Russian space officials wanted it surveyed from the outside before the Soyuz module detaches next week to return Prokopyev and two others to Earth. The holed section is not used for re-entry, so poses no risk for descent.

Prokopyev and Kononenko had to use a pair of telescoping booms to reach the Soyuz. It took nearly four hours to cross the approximately 30 metres to the capsule and the insulation proved harder to remove than expected, taking another one to two hours of effort.

Bits of shredded silver insulation floated away as the two removed it with a knife and long cutters so they could collect a 2mm sample of the black epoxy sealant protruding from the hole. Mission control repeatedly urged them to take a few minutes’ rest.

The capsule leak caused tension between the US and Russian space agencies. The Russian space chief Dmitry Rogozin observed that it could have been drilled during manufacturing or in orbit. The space station’s commander at the time flatly denied any wrongdoing by himself or his crew.

Rogozin has since backpedalled and accused the media of twisting his words.

The spacewalkers reported seeing none of the drill marks around the hole that were visible on the inside.

A Russian investigation is ongoing, according to Rogozin, and samples collected during the spacewalk will be returned to Earth on the Soyuz.