Next success of International Launch Services – Proton-M was launched at 07:10 GMT from Baikonur cosmodrome.
Second launch of Proton-M in 2016 was postponed from yesterday due the technical issues with cable connectors leading from ground infrastructure to the rocket. Service team managed to check cables and launch today was possible at 07:10 GMT. Breezy weather did not interrupt flight-punctually at 07:10 GMT Proton-M started to rise over Launch Pad 24 in Baikonur cosmodrome. At T+10″ rocket performed roll maneuver to align with correct north eastern trajectory. At T+1’02” rocket reached point when maximum aerodynamic stress is act on rocket structure. This moment appeared when rocket reached speed of 1.06 Ma with visible condensation cloud. At T+1’19” rocket disappeared from view of cameras. At T+2’3″ first stage of the Proton-M separated from second stage. Long for 21 m oxidizer tank surrounded by six smaller tanks with one RD-253-14D14 engine each filled with unburned N2O4/UDMH propellant started to fall to drop zone. Proton-M was continuing its flight with nominal parameters. Second stage started its propulsion shortly before separation; three RD-0210 and one RD-0211 with thrust at 2399 kN were operating through first stage structure. It was confirmed by Baikonur control center at T+3’11”-engines would operate for next three minutes. Separation of the second and third second was performed a T+5’26”. After next 17 seconds of flight at T+5’43” payload fairing was jettisoned when rocket was flying with speed at 16000 km/h on altitude of 147 km over central Russia. At T+9’41” third stage separated and Briz-M upper stage started its propulsion (S5.98M engine with 19.6 kN of thrust) for the first time. It was 1.5 minute after separation at T+11’15”. After MECO at T+15’32” Briz-M and Intelsat-31 were on parking orbit on altitude of 173 km over Amur Oblast in eastern Russia. According to Russianspaceweb.com engine of Briz-M was operating about 34.57 seconds longer than it was planned (it was spotted during live broadcast) but ground control center did not confirmed any problems during flight of the third stage. Briz-M spent on parking orbit enough time to fly around Earth and then it started its engine for the second time for twenty minutes at T+1h50’30” over Japan to T+2h10’17” when Briz-M was flying over South Pacific. It was necessary to reach transfer orbit with apogee on altitude of 6000 km. Next two hours of ballistic flight helped in increasing altitude until next burn which started during flight over China at T+4h23’49” and finished over South China Sea at T+4h32’47”. Next Briz-M jettisoned the toroid Auxiliary Propellant Tank which held 14.6 t of N2o4/UDMH propellant and was attached to Briz-M fuselage. It was performed at T+4h33’37” over Malaysia. Next burn started at T+4h35’04” and last until T+4h44’07” when Briz-M passed Australia. It was penultimate burn-Briz-M will continue ballistic flight to climb gradually to orbit with apogee of 65000 km. Deploying satellite from this altitude will help in saving fuel which normally would be used for apogee kick motor of Intelsat-31. Last burn will be performed before deploying Intelsat-31 at T+15h31′. Engine of Briz-M will start at T+15h15’05” and finish at T+15h18’09”. Thirteen minutes later from SSTO orbit from altitude of 65000 km and inclination to equator at 29.6° Intelsat-31 will be deployed by Briz-M flying with speed of 25000 km/h.