International Launch Services, Russian and American joint-venture company, is getting ready for their latest mission-delivering to orbit Intelsat-31 (DLA-2) broadcasting satellite on atop of their flagship, Proton-M launch vehicle. Launch is scheduled for 8th June 2016 for 07:10 GMT from Baikonur cosmodrome, Launch Pad 24. It will be second launch of Proton-M operated by ILS in 2016.
Intelsat-31, broadcasting satellite designed and manufactured by Space Systems/Loral for Luxembourg based company Intelsat S.A., was delivered to Baikonur cosmodrome at May 2, 2016, along with Proton-M rocket. Payload and launch vehicle were delivered by rail to Building 92A-50 and next for further processing they were transported to Hall 111. At 16 May, 2016, satellite was already tanked with NTO/NMH propellant, (satellite is equipped with R-4D engine providing 490 N of thrust) by propulsion service team. At 2 June 2, 2016, Briz-M upper stage was started to be loaded with propellant- N2o4 and UDMH. Finally after almost one month of unpacking, testing and preparing for launch, rocket, upper stage and payload were ready to roll out. Yesterday, on June 5, 2016, at 00:30 GMT (06:30 local time at Baikonur) Proton-M was rolled out to Launch Pad 24. Next rocket was moved from horizontal position (which is ordinary position for assembling Proton-M) to vertical position. All additional launch systems were connected to Proton-M and specialists and engineers started to perform last tests before start readiness. Information was officially confirmed by Roscosmos with official statement:
"On June 5, 2016, at the Baikonur cosmodrome, to the launch system has been installed the Proton-M carrier with Briz-M booster and the Intelsat DLA-2 satellite,"
Intelsat-31 is one from two (Intelsat-30 and Intelsat-31) satellites contracted in 2011 by Intelsat S.A. to Space Systems/Loral. Intention of the Intelsat was improving their range over Latin America and Caribbean region with high power Ku/C band broadcasting satellites. Satellites will extend range of present offer in Direct-to-Home services over Latin America. Both satellites are based on proven SSL-1300 bus; Intelsat-31 weighs 6450 kg and with folded solar panels satellite has following dimensions: 8.6 m x3.4 m x 3.1; after deploying solar panels span of spacecraft will be 32.4 m. Both spacecrafts are powered with two deployable solar arrays and onboard lithium batteries providing up to 20 kW of power, enough to keep 4 C band and 72 Ku band transponders operating. They will operate for at least 15 years being allocated with Intelsat-30 and Intelsat Galaxy-3C at same slot 95° west.
Delivering satellite to designated orbit will take approximately 15h 31'. According to announced mission plan, first three stages of Proton-M will deliver Briz-M to sub-orbital trajectory with payload fairing separation at T+5'46". Next Briz-M will start its propulsion and continue flight to circular parking orbit. In the next phase of flight it will place Intelsat-31 to intermediate orbit, then it will reach transfer orbit and finally it will put Intelsat-31 to supersynchronous transfer orbit with perigee at 3503 km, apogee at 65000 km and inclination at 29.6°. From SSTO satellite will be deployed at T+15h 31'.
Proton-M with Briz-M upper stage are manufactured by Moscow based Khrunichev State Research and Production Space Center. Proton-M has its origins in construction of UR-500 heavy ICBM designed in the early sixties; conception of super heavy ICBM with possibility of serving as launch vehicle was developed in following years but ultimately in this shape rocket was not put into service. It was used only as launch vehicle since 1965 but it still remained classified military project until first launches under Mir program. Proton-M in present shape was launched for the first time in 2001 and comparing to previous versions has improved avionics, modified structure for reducing weight and increased pressure in engine chambers. It is designed to lift up to 22000 kg to International Space Station (LEO with inclination at 51.6°), 3200 kg into geostationary orbit or 5500 kg to geostationary transfer orbit. Payload fairing is manufactured from composites and has diameter of 4.35m with length up to 15.26 m (13.31 m in shorter version-during Intelsat-31 longer payload fairing will be utilized). Proton-M is based on three stages with Briz-M upper stage-all stages and upper stage are liquid fueled (dinitrogen tetroxide and unsymmetrical dimethyl hydrazine). Weight of the rocket is 712800 kg with height of 58 m and diameter at 7.4 m in the first stage. First stage is designed in general as long for 21 m oxidizer tank surrounded by six smaller fuel tanks (top of the every fuel tank is covered with conical fairing) and consisting one engine each. Engines are able to move with 7 degree range for thrust control. Six RD-253-14D14 are providing up to 10532 kN of thrust with specific impulse lasting 285 seconds. Second stage (with height at 14 m and with diameter at 4.1 m) is powered with three RD-0210 and one RD-0211 and are providing thrust at 2399 kN. Third stage length is 6.5 m and it is equipped with one RD-0212 with thrust at 613.8 kN. Briz-M is powered by one S5.98M with thrust at 19.6 kN and its length is 2.61 m.