MOSCOW. Feb 12 (Interfax-AVN) - An international body investigating an anomaly during the placing of the Yamal-402 spacecraft into orbit using a Proton-M launch vehicle and a Breeze M upper stage in December 2012 agreed with a Russian commission's conclusions regarding the cause of the malfunction and sanctioned the resumption of the Proton 2013 program, International Launch Services (ILS) reported on its website.
"The FROB [the Failure Review Oversight Board] analyzed the findings and recommendations of the Russian working group, which included participation from experts from TsNIIMash (Central Scientific Research Institute of Machine Building), M.V. Keldysh Research Center and Khrunichev State Research and Space Production Center (Khrunichev). The members of the FROB agreed with the findings of the Russian investigation that the most probable root cause of the failure was due to a combination of adverse conditions which affected the operation of the Breeze M main engine during the startup of the 3rd burn causing damage to a bearing on the oxidizer side of the turbo pump," it said.
"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, with subsequent separation of the spacecraft," it said.
The completion of the investigation makes it possible to resume the Proton mission program, ILS said. "The ILS Proton return-to-flight mission will be the Satmex 8 satellite for Satelites Mexicanos, S.A. de C.V. (Satmex) next month. Scheduling of this mission and of the remainder of the ILS Proton near term manifest for 2013 is currently being determined," it said.
The Proton-M coupled with the Breeze M upper stage and carrying the Yamal-402 satellite was launched from the Baikonur space center on December 8, 2012. The satellite was not placed into a geo-transfer orbit in a nominal mode, as the upper stage's 4th burn ended four minutes later than due. To maneuver the satellite into the planned orbit, its own engines were burned, and the spacecraft was eventually declared fully operational on January 8, 2013.
Specialists from a Russian group investigating the anomaly concluded that it was caused by mechanical destruction of a bearing in the upper stage's turbo pump.