Russian spacewalkers have cut samples of material around a mysterious hole in a spacecraft docked on the International Space Station (ISS) that’s been at the center of sinister rumors and conspiracy theories.

Roscosmos space agency said the aim was to discover whether the “small but dangerous” hole had been made on Earth or in space.

The 2-millimeter cavity on the Russian Soyuz spaceship docked at the ISS was discovered on Aug. 30, when an air leak was detected two months after the craft’s last voyage.

Rumors the hole could be the work of a saboteur began after Roscosmos chief, Dmitry Rogozin, ruled out a manufacturing error and failed to exclude the possibility of “deliberate interference in space.”

One theory reported in Russian media is that U.S. astronauts deliberately drilled the hole to get a sick colleague sent back home.

Until Tuesday, astronauts had only been able to examine the hole from inside the spacecraft.

During a seven hour, 45 minute spacewalk, veteran cosmonauts Oleg Kononenko and Sergei Prokopyev struggled, but eventually succeeded, in cutting away the insulation covering the hole and taking out a sample to analyze.

What made it especially hard is that the Soyuz spacecraft, unlike the ISS, was not designed to be repaired in spacewalks and has no outside railings for astronauts to hold onto.

“There’s nothing, that’s the problem,” Kononenko said ahead of the outing.

Rogozin said in October that an investigation had ruled out a manufacturing error. He had said earlier that Russia did not exclude “deliberate interference in space.”

Russian media reported the investigation was probing the possibility U.S. astronauts deliberately drilled the hole to get a sick colleague sent back home.

Russian officials later denied those reports.

The discovery of the hole was followed in October by the failure of a manned Soyuz launch, although the Russian and U.S. astronauts returned safely to Earth.

The samples will be sent to Earth to “get at the truth” of the cavity’s origins, the space agency said.

The cosmonauts also took photographs and filmed video before putting new insulation over the area.

The spacewalk was the fourth for Kononenko and the second for Prokopyev.

Rogozin called the mission “unprecedented in its complexity” on Twitter and Roscosmos said it would “enter the history of space exploration.”

The Soyuz spacecraft is used to ferry astronauts to and from the ISS. The hole is in a section that will not be used for the return journey to Earth on Dec. 20.

The ISS is one of the few areas of Russia-U.S. cooperation that remains unaffected by the slump in relations and Washington’s sanctions.

This story originally appeared in news.com.au.