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Proton (rocket family)

Proton 8K82K
Launch of a Proton-K rocket
Function Orbital launch vehicle
Manufacturer Khrunichev State Research and Production Space Center
Country of origin Soviet Union; Russia
Height 53 metres (174 ft)
Diameter 7.4 metres (24 ft)
Mass 693.81 metric tons (1,529,600 lb) (3 stage)
Stages 3 or 4
Payload to LEO 22.8 metric tons (50,000 lb)[1]
Payload to
6.3 metric tons (14,000 lb)
Launch history
Status Active
Launch sites BaikonurLC-200 & LC-81
Total launches

  • M: 102
  • K: 311
  • Proton: 4

  • M: 92
  • K: 275
  • Proton: 3

  • M: 9
  • K: 24
  • Proton: 1
Partial failures

  • M: 1
  • K: 12
First flight Proton: 16 July 1965
Proton-K: 10 March 1967
Proton-M: 7 April 2001
Last flight Proton: 6 July 1966
Proton-K: 30 March 2012
Proton-M: 11 September 2017
Notable payloads
First stage
Engines RD-275
Thrust 10.47 MN (1.9 million pounds)
Burn time 126 s
Fuel N2O4/UDMH
Second stage
Engines RD-0210 & 1 RD-0211
Thrust 2.399 MN (539,000 lbf)[2]
Specific impulse 327 s
Burn time 208 s
Fuel N2O4/UDMH
Third stage
Engines RD-0212
Thrust 630 kN (140,000 lbf)
Specific impulse 325 s
Burn time 238 s
Fuel N2O4/UDMH
Fourth stage – Blok-D/DM
Engines RD-58M
Thrust 83.4 kN (18,700 lbf)
Specific impulse 349 s
Burn time 770 s
Fuel LOX/RP-1

Proton (Russian: Протон) (formal designation: UR-500) is an expendable launch system used for both commercial and Russian government space launches. The first Proton rocketwas launched in 1965. Modern versions of the launch system are still in use as of 2017, making it one of the most successful heavy boosters in the history of spaceflight. All Protons are built at the Khrunichev State Research and Production Space Center plant in Moscow, transported to the Baikonur Cosmodrome, brought to the launch pad horizontally, and raised into vertical position for launch.[3][4]

As with many Soviet rockets, the names of recurring payloads became associated with the Proton. The moniker “Proton” originates from a series of similarly named scientific satellites, which were among the rocket’s first payloads. During the Cold War, it was designated the D-1/D-1e or SL-12/SL-13 by Western intelligence agencies.

Launch capacity to low Earth orbit is about 22.8 tonnes(50,000 lb).[1] Geostationary transfer capacity is about 6.3 tonnes (14,000 lb).[5] Commercial launches are marketed by International Launch Services (ILS).[6] The rocket is intended to be retired before 2030.[7]

In January 2017, the Proton was temporarily grounded due to the manufacturer, Voronezh Mechanical Plant, having substituted a heat-resistant alloy in the engines with a cheaper metal.[8][9]


Proton[10] initially started its life as a “super heavy ICBM“. It was designed to launch a 100-megaton (or larger) thermonuclear weapon over a distance of 13,000 km. It was hugely oversized for an ICBM and was never deployed in such a capacity. It was eventually used as a space launch vehicle. It was the brainchild of Vladimir Chelomei‘s design bureau as a foil to Sergei Korolev‘s N1 rocket, whose purpose was to send a two-man Zond spacecraft around the Moon; Korolev openly opposed Proton and Chelomei’s other designs for their use of toxic propellants.

A rushed development program led to dozens of failures between 1965 and 1972. Proton did not complete its State Trials until 1977, at which point it was judged to have a higher than 90% reliability.

Proton’s design was kept secret until 1986, with the public being only shown the upper stages in film clips and photographs, and the first time the complete vehicle was shown to the outside world happened during the televised launch of Mir.

Proton launched the unmanned Soviet circumlunar flights and was intended to have launched the first Soviet circumlunar spaceflights, before the United States flew the Apollo 8 mission. Proton launched the Salyut space stations, the Mir core segment and expansion modules, and both the Zarya and Zvezdamodules of the ISS.

Proton also launches commercial satellites, most of them being managed by International Launch Services. The first ILS Proton launch was on 9 April 1996 with the launch of the SES Astra 1F communications satellite.[11]

Since 1994, Proton has earned $4.3 billion for the Russian space industry, and by 2011 this figure is expected to rise to $6 billion.[12]

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