Proton-K

Proton-K (Протон-К, GRAU: 8K82K, Sheldon: D-1, D-1-e, D-1-h, DoD: SL-12, SL-13), was a Russian, previously Soviet, carrier rocket derived from the earlier Proton. It was built by Khrunichev, and launched from sites 81/23, 81/24, 200/39 and 200/40 at the Baikonur Cosmodrome in Kazakhstan.

The maiden flight in 1967 carried a Soyuz 7K-L1 as part of the Zond program. During the Moon Race these Proton/Zond flights consisted of several uncrewed test flights of Soyuz spacecraft to circumlunar orbits with the unrealized aim of landing Soviet cosmonauts on the Moon.

During the 1970s and 1980s, Proton-K launched every interplanetary probe of the Soviet space program's Venera and Mars missions, using its Blok D fourth stage. In three-stage configuration, it launched the Zond program's circumlunar flights and all seven space stations of the Salyut program. The Soviet program also considered the Proton for launching the TKS crewed spacecraft and LKSspaceplane.

From 1986, the rocket launched six of the seven modules of Mir, the first modular space station, and from 1998, launched the Zarya and Zvezda modules of the International Space Station's Russian Orbital Segment. It was retired from service in favour of the modernised Proton-M, making its 310th and final launch on 30 March 2012.