The abort of a crewed Soyuz launch to the International Space Station last month was caused by a damaged sensor pin in a mechanism designed to separate one of the rocket’s four strap-on boosters from the core stage, Roscosmos has announced.
“The abnormal separation was caused by the non-opening of the lid of the nozzle intended to separate a side Block D oxidizer tank due to the deformation of the separation sensor pin,” the space corporation said in a press release. “It was damaged during the assembling of the strap-on boosters with the core stage (the Packet) at the Baikonur Cosmodrome. The LV [launch vehicle] failure cause is of the operational nature and spreads to the stock of already assembled packets of the Soyuz rocket.”
Oleg Skorobogatov, who headed up the investigation, said at a press conference that the nose of the strap-on booster hit the core stage in the area of the fuel tank, resulting in a decompression that triggered the abort. Skorobogatov is deputy director general of TsNIImash.
Russian cosmonaut Alexey Ovchinin and NASA astronaut Nick Hague landed safely under parachute in their MS-10 Soyuz spacecraft. Neither one was injured.
“The Emergency Crew Rescue System of Soyuz MS-10 spaceship functioned properly,” Roscosmos said in its press statement. “The crew was acting as required by the on-board instructions and those given by the Mission Control Center.”
Roscosmos has taken steps to prevent a recurrence of the incident and approved a plan to resume launches to the space station.
“The State Committee has approved the launch dates under the International Space Station Program as follows: the launch of Soyuz-FG rocket with Progress MS −10 cargo spaceship to go on November 16, 2018, and the launch of Soyuz MS-11 manned spaceship to go on December 3, 2018. The crew of Soyuz MS-09 — Alexander Gerst (ESA), Sergey Prokopiev (Roscosmos) and Serina Auñón-Chensellor (NASA) — will return to the Earth on December 20, 2018,” the corporation said.