When a tiny hole was discovered inside a spacecraft attached to the International Space Station (ISS) last Wednesday, U.S. and Russian authorities initially suspected a micrometeoroid strike. More than 170 million pieces of space debris circle in Earth orbit, and collisions are inevitable.

Authorities said last week that the leak in the Russian-made Soyuz capsule had led to a small drop in cabin pressure, but the six ISS crew members were at no point in real danger. A sealant was applied Thursday, and cabin pressure returned to normal.

But the incident's fallout continued this week, after Russian officials who were subsequently tasked with examining the hole concluded that it had been drilled — potentially deliberately. Even the possibility of human interference could prove to be explosive, given that the ISS is one of the last remaining joint projects between Moscow and Washington.

The station’s crew is currently composed of three Americans, two Russians and one German. Crew members arrive and depart using the Russian capsules; the leaking one had arrived in June. The hole was discovered in a section of the ship not used to transport the crew members, but with the next departure to Earth scheduled for December, any interference could have ripple effects on the space station’s operations.

Investigators did not specify whether they believed the hole was drilled on Earth or in space, but Russia's Roscosmos space agency did not exclude the possibility of sabotage.

“There were several attempts at drilling,” Roscosmos head Dmitry Rogozin was quoted as saying by Russian media outlets.

“We are checking the Earth version. But there is another version that we do not rule out: deliberate interference in space,” Rogozin said.

It's not the first time that Russia is speculating about possible sabotage of its space operations.

Six years ago, Rogozin’s predecessor in the job, Vladimir Popovkin, suggested that foreign powers were responsible for spacecraft launch failures at the time.

And this week, Russian cosmonaut-turned-lawmaker Maxim Surayev raised the possibility that the hole may have been drilled by a station crew member who “might want to go home,” even though he acknowledged that a Russian production mistake could also not be ruled out. “I wish to God that this is a production defect, although that’s very sad, too — there’s been nothing like this in the history of Soyuz ships.” Russia said it was checking its spacecraft units in construction for similar defects.

In an emailed statement, NASA said on Wednesday that it “will support the commission's work as appropriate,” referring to Roscosmos' investigatory committee.

"Our Russian partners have demonstrated their human and technological resilience many times throughout the history of their efforts in human spaceflight. We are confident they will identify the cause of the leak,” NASA said.

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