Theory one – it was caused by a small meteorite
A tiny hole appeared in a Russian space capsule locked to the ISS on 30th August.
The ‘micro fracture’ believed to be around 2mm wide in the $150 billion (£115 billion) space station was discovered after astronauts noticed a drop in pressure.
European Space Agency astronaut Alexander Gerst reportedly put his finger over the hole before crew patched it with tape.
The hole was confirmed repaired by Friday (31 August) after cabin pressure returned to normal.
It was initially believed to have been caused by a small meteorite and astronauts used tape to seal the leak after it caused a minor loss of pressure.
Theory two – it was made deliberately while in orbit
However, as the investigation went on it began to look like the hole was made from someone inside as opposed to outside, either back on Earth or in space, the Russian space agency claimed.
Roscosmos chief Dmitry Rogozin said in September that the hole could have been drilled during manufacturing or while in orbit with a ‘wavering hand’.
He didn’t say if he suspected any of the US crew, but the statement has caused some bewilderment.
Sources suggest the question of how to fix the hole may have strained relations between Moscow and Houston.
Rogozin has since reneged on his statement blaming the media for twisting his words and said that he ‘never pointed the finger at U.S. astronauts’.
Theory three – it was caused by a worker at Energia
A leading theory from an unnamed source at Energia said the hole was made on the ground – potentially caused by ‘deliberate interference’ – with suggestions the person responsible may have already been identified.
Another anonymous source said the hole was drilled by a worker who hid their mistake with a seal instead of reporting it.
An unnamed source at Energia told the Russian news agency RIA Novosti that ‘[t]he hole was made on the ground’.
According to the source, ‘[t]he person responsible for the act of negligence has been identified’.
Another anonymous source said the hole was not made intentionally but by a worker who hid their mistake with a seal instead of reporting it.
The patchwork repair lasted the trip up to the ISS but after three weeks in orbit gradually peeled away.