A Soviet space rocket introduced in 1965, used to launch heavy satellites, space probes, and the Salyut and Mir space stations.

Proton is a three-stage rocket that can lift 22 tonnes into low Earth orbit; a fourth stage is added for higher orbits.

Six Proton rockets launched Soviet missions to Mars from 1971 to 1973, and a Proton-K (with a Pizza Hut logo on its side) launched the Zvezda module to the International Space Station in July 2000. The latest in the series, the more powerful Proton-M, was first launched in April 2001; its latest launch occurred in September 2017. While the Proton series has never been used to launch humans into space, it continues to launch, making it one of the most successful heavy boosters in the history of space flight.

The Soviet Proton 1 rocket was originally designed to launch atomic bombs, though the weapons-carrying version was never built.

Credit: Research Machines plc