A secretive Russian military communications satellite arrived in geostationary orbit Sunday after a successful liftoff aboard a Proton rocket, the Russian defense ministry said.

United Launch Alliance’s 50th mission for the U.S. Air Force lifted off at 12:15 a.m. EDT (0415 GMT) Wednesday. An Atlas 5 rocket launched from Cape Canaveral with the Air Force’s fourth Advanced Extremely High Frequency communications satellite.

Riding on its side aboard a rail car, a Proton rocket trekked to its launch pad Tuesday at the Baikonur Cosmodrome in Kazakhstan with a Eutelsat television broadcast satellite ready for liftoff Friday.