The cause of the accident was off-nominal mechanical separation of the launch vehicle’s third stage and the cargo spacecraft. The members of the emergency committee established the following:
- The most likely cause of the contigency was the third stage liquid oxygen tank opening as a result of exposure of 11D55 engine destruction elements that occurred in result of fire and further destruction of the oxidizer compound pump.
- The cause of the oxidizer compound pump’s fire could be possible in case of foreign particles entry into the pump cavity or possible violation 11D55 engine assembly technology.
The plan of priority actions to ensure the next Progress MS-05 secure launch will be submitted in the near future.