Proton / UR-500·Russian Federal Space Agency (ROSCOSMOS)
Proton is a Russian hypergolic propellant expendable launch system operated by Roscosmos for commercial and state payloads. Developed by the Soviet space program, its first launch, a Proton-K variant, was in 1965. The modernized Proton-M is in use as of 2026, making it one of the most successful heavy boosters in the history of spaceflight.