Roscosmos Identifies Cause of Soyuz Failure

Horizontal assembly of a Soyuz core booster with third stage (Credits: Roscosmos).

Russian space agency Roscosmos released a press statement on the failure of the third stage of a Soyuz rocket, which was carrying Progress M12-M to the ISS on August 24.

Interministerial Commission for the launch of the transport of cargo spacecraft “Progress M-12M” under the supervision of the Director of the State Scientific Center, Federal State Unitary Enterprise “Research Center named after MV Keldysh,” Academician AS Koroteev completed its work, which revealed the reasons for the emergency starter booster (LV), “Soyuz-U” 24 August 2011.

   As a result of organizational and technical measures, the Commission found that the preparation of assemblies, systems of technical and launch site and launch “Soyuz-U” carried out in accordance with operational documentation.

    The start and flight of the first and second stages of the launch vehicle took place normally, the control system to ensure sustained flight of a rocket to the desired path. Separation of the first two stages went well for the standard scheme at the estimated time without any problems.

     On the basis of analyzing the behavior of the parameters characterizing the operation of the propulsion system the third stage, and results telemetry data it is concluded that reducing consumption of fuel in the gas generator due to contamination tract of its submission. This led to a breach of working conditions and reduce the engine parameters, it shut down on command “Emergency engine shutdown.”

    Commission members concluded that this new manufacturing defect is random. However, the decision on his skills as a unit, should be taken only after cross-checking and follow-up of a special program just grazed manufactured propulsion.

    The Commission recommended the development of a coherent program to control this type of brushed motors and give opinion on the possibility of using each of them for other purposes.

    Commission proposed to develop and implement additional measures to control the status of units of new engines in their design and manufacturing, including install CCTV in the workplace in the final assembly shops.

    The result of the Russian Federal Space Agency director of the Interdepartmental Commission requested a timetable for improvements and determine the readiness of carrier rockets of the “Union” to start, based on which the program will be planned future launch of spacecraft, including manned subjects.

No information has been released so far about when the Soyuz rocket will resume its flying schedule.