NEWTOWN, Conn. - An International Launch Services (ILS) Proton Breeze M successfully placed the Inmarsat-5 F1 (I-5 F1) satellite into a super-synchronous (geo-stationary) transfer orbit (SSTO) on December 9. The spacecraft was launched for Inmarsat. I-5 F1 is the first of three Inmarsat next-generation Global Xpress satellites scheduled to launch before the end of 2014.
A Proton carried Inmarsat-5 F1 into orbit
The Proton launch vehicle, carrying the I-5 F1 satellite, lifted off from Pad 39 at the Baikonur Cosmodrome yesterday at 6:12 p.m. local time (7:12 a.m. EST). The SSTO mission utilized a 5-burn Breeze M mission design to advance the orbital unit first to a circular parking orbit, then to an intermediate orbit, followed by a transfer orbit, and finally to a 65,000 km-apogee super-synchronous transfer orbit. After a 15-hour, 31-minute mission, the satellite was placed into the target orbit by the Proton launcher. SSTO missions provide increased heavy-lift performance over GTO mission designs, allowing our customers the capability to maximize spacecraft operational lifetime.
The satellite was manufactured by Boeing Satellite Systems International, Inc. and built on the 702HP platform. Weighing over 6 metric tons at lift-off, the I-5 F1 satellite has 89 Ka-band fixed beams and 6 steerable ones. I-5 F1 is designed to generate approximately 15 kilowatts of power at the start of service and approximately 13.8 kilowatts at the end of its 15-year design life. To generate such high power, the spacecraft's two solar wings employ five panels of ultra-triple-junction solar cells.
Once considered a reliable choice for carrying satellites into orbit, the Proton has experienced a number of failures in recent years. Since December 2010, four Proton rockets have failed to place their payload into the correct orbit. This has begun to raise doubts about the reliability of the Proton, and insurance rates for Proton customers have begun to rise.
Despite the recent rash of failures and future replacement, the Proton remains an important player in the launch industry, particularly in the commercial market. The Proton is one of the few large launch vehicles capable of carrying geosynchronous communications satellites into orbit.
The launch on December 9, along with recent launches in October and November will go a long way towards reassuring satellite operators about the reliability of the Proton.