The Russian failure investigation into the Proton M Breeze M undershoot on 8 December 2012 which stranded the Yamal 402 communications spacecraft (the satellite later recovered itself albeit with some loss of projected lifespan) has found that found that “adverse conditions” affected startup of the 3rd burn of the Breeze M (Briz-M) upper stage resulting in damage being caused to a Breeze M engine bearing on the oxidizer side of the turbo pump. This ultimately resulted in the failure of the bearing during the 4th burn and caused the 4th burn of the Breeze M to end about four minutes early, The “adverse conditions” have not yet been disclosed.
The International Launch Servies (ILS) Failure Review Oversight Board (FROB) agreed with the conclusons of the official failure investigation. Proton launches are set to resume next month.
