Roscosmos has cleared the Proton-M rocket and the Breeze-M upper stage for flight after an inquiry found that the recent loss of a communications satellite was caused by a programming error in the third stage’s guidance system.
“Following analysis of information, the commission has concluded that over formation of the mission profile for the Briz-M upper stage, the time interval of sub turning of the gyro-stabilised platform was cut unreasonably. This caused the incorrect orientation of the upper stage and, consequently, failed to bring the satellite to the designed orbit,” Roscosmos said in a press release.
The failure stranded the Express-AM4 satellite in a useless orbit. Controllers have been unable to contact the satellite, which was designed for digital television broadcasts. Russia has suffered four launch failures in less than nine months.
“The rest of the booster worked without any problems,” Roscosmos said. “The result of the commission lifted the ban on the preparation of ‘Proton-M’ with RB ‘Breeze-M’ and prepare the necessary recommendations to be implemented before the next launches.”