Faulty sensor identified as cause of aborted Soyuz launch
Roscosmos announced today that manned Soyuz flights to the International Space Station (ISS) will resume on December 3, 2018 after an investigation into the aborted October 11 launch of the Soyuz-FG LV/ Soyuz MS-10 spacecraft found a faulty sensor in the first stage of the rocket was to blame. The announcement means both the present crew aboard the ISS and the 15 partner nations that operate the space laboratory can breathe a sigh of relief.
When the Soyuz MS-10 spacecraft was destroyed in October only two and half minutes into the flight, it did more than place the lives of American astronaut Nick Hague and Russian cosmonaut Alexey Ovchinin into peril. Hague and Ovchinin where rescued by response teams in Kazakhstan after their capsule ejected from the booster in what is called a ballistic landing, but the subsequent grounding of the Soyuz booster placed the very future of the ISS in jeopardy.
Without the means to replace the present crew, which is due to depart in December, the station would have had to have been abandoned and operated by remote control for the first time in 18 years.
However, Roscosmos says that the cause of the October abort has been determined as a problem with a separation sensor pin in the first stage that was bent almost seven degrees out of alignment.
The Soyuz first stage consists of a core booster surrounded by a cluster of four strap-on chemical boosters. These outside rockets are supposed to break away from the core during ascent, with the core then shutting down and separating from the second stage. According to the investigation committee, what happened instead was that the faulty sensor caused one of the strap-on boosters to improperly separate and collide with the main rocket, resulting in decompression of one of the fuel tanks and triggering the automatic abort.
Roscosmos says that the sensor pin was damaged during assembly of the rocket and that new preventative measures have been implemented to prevent a similar occurrence in the future.
The Roscosmos video below shows the ill-fated Soyuz flight.