On December 13 at 12:07 UTC, a Russian Proton-M/Briz-M launched the Ekspress AMU3 and AMU 7 spacecraft into near geostationary orbit from Site 200 at the Baikonur Cosmodrome in Kazakhstan.

After an incredible eighteen hours of flight time and five burns of the Briz-M upper stage, the two payloads were separated into a very eccentric geostationary transfer orbit with a perigee of 18,700 kilometers and an apogee above the geostationary belt of 52,000 kilometers. This gets them closer to geostationary orbit than most launchers.

Both Ekspress AMU-3 and AMU-7 were built by Russian company ISS Reshetnev with communications payloads from Italian company Thales Alenia Space. According to ISS Reshetnev: Express-AMU3 and Express-AMU7 satellites will provide advanced communications, television, and radio broadcasting services for millions of users in Russia and other countries.

Just like the Soyuz, the Proton is assembled horizontally. It’s brought to the launch pad via a special slow-moving train, where it is raised vertically into its launch mount. The advantage of this assembly method is that it requires less ground infrastructure at the pad to support the rocket and reduces processing time when actually at the pad. SpaceX’s Falcon 9 also uses horizontal integration and often only needs a handful of hours at the pad before launch, occasionally rolling out on launch day.

Along with the Chinese Long March 2, 3, and 4 rocket families, Proton is one of the few rockets today that still uses toxic hypergolic propellants that spontaneously ignite when combined. Initial fueling of these vehicles requires workers to be in hazmat suits, but the use of unsymmetrical dimethyl hydrazine and dinitrogen tetroxide means that rockets can spend days at the pad without having fuel continually topped off. Like the Soyuz, Proton was originally designed to be an ICBM. All of these rockets are on their way to retirement, being replaced with better performing and less toxic launch vehicles like the Angara for Russia and the Long March 5, 6, and 7 families for China.

Proton-M also has an abysmal launch reliability rating – only 90%. This is another reason why it is being retired.

More Information

ISS-Reshetnev press release