From Wikipedia, the free encyclopedia.
The Proton rocket (formal designation: UR-500) is a Russian unmanned space vehicle design first launched in 1965 and still in use as of 2003.
Proton initially started life as a 'super ICBM'. It was designed to throw a >10MT nuclear warhead over a distance of 12,000km. It was, of course, hugely over-sized for an ICBM and was never used in such a capacity. Its real purpose was as a launch vehicle.
Proton launched the unmanned Soviet circumlunar flights and would very likely have launched the first humans to circle the moon had the flight of Apollo 8 gone as originally planned. It launched the Salyut space station, Mir core segment, and both Zarya and Zevezda of the ISS. It also launched many probes to the Moon, Mars, and Venus.


