Ever since a 2mm-wide hole appeared in Russia's Soyuz MS-09 spacecraft docked with the International Space Station (ISS), several theories have been put up to describe how such a damage could occur on the lab orbiting more than 400 km above the ground.

Some thought it occurred due to micrometeoroid impact or production marriage, while others indicated a deliberate effort to compromise the ship. The effort to establish the cause still continues, but a new report from Russian news agency Kommersant revealed another version of the case — one involving American astronauts.

Soyuz MS-09 US astronauts were suspected of drilling hole on Soyuz MS-09 spacecraft docked with ISS. Pictured, Russia's two docked spacecraft, the Soyuz MS-09 (left) crew ship and the Progress 70 resupply ship. Photo: NASA

According to a source from the special Roscosmos commission established to study the plausible causes of damage, the experts think American astronauts could have drilled the hole, first detected on Aug. 30, in a bid to help one of their ailing crewmember return to Earth sooner than scheduled.

The theory, which was being considered analyzed as a priority aspect of the case, comes from the photographic evidence and documents forwarded by the Russian astronauts. The evidence, as the source described, indicated the hole wasn’t made on the first attempt as there were signs of another touch of the drill.

This indicates a lack of pressure from the person using it — a trait that is relatively common in airless environments such as that of the space station. On the basis of this and the fact that the Russian module, where the hole was discovered, was relatively close to the American segment, the investigators were considering the possibility of a breach by the Americans.

As the source described, American astronauts are not allowed to enter the Russian segment of the ISS without the permission of their commander, but the possibility of illegal access cannot be ignored. The astronauts might have entered the Russian segment to drill the hole and trigger an emergency evacuation of the station so that the sick colleague in question could return home and seek treatment.

In the routine procedure for medical emergency-related return, the Americans would have had to pay for a new spacecraft to bring back the sick astronaut.

Though the theory has not been proven, Roscosmos has asked NASA to provide DVR copies of American astronauts’ activity on the station as well as their medical information to examine their current health status as part of the investigation. The report doesn’t mention if the same was being sought for European Space Agency astronaut Alexander Gerst, who was also a part of the current investigation.

That said, it was also worth noting this was just one aspect of the case. According to several reports, the damage, which was originally thought to be a micrometeoroid impact, could also have occurred on Earth due to a worker-based error or a deliberate effort by an individual to drill a hole during the assembly process. These two scenarios were also being explored and the final results of the investigation are expected to be revealed by mid-September.