Proton (rocket family)

Proton 8K82K
Proton Zvezda crop.jpg
Launch of a Proton-K rocket
FunctionOrbital launch vehicle
ManufacturerKhrunichev State Research and Production Space Center
Country of originSoviet Union; Russia
Height53 metres (174 ft)
Diameter7.4 metres (24 ft)
Mass693.81 tonnes (1,529,600 lb) (3 stage)
  • M: 4
  • K: 3
Payload to LEO23,700 kilograms (52,200 lb)[1]
Payload to GTO6,300 kilograms (13,900 lb)[2]
Launch history
Launch sitesBaikonur, LC-200 & LC-81
Total launches420
  • M: 105
  • K: 311
  • Proton: 4
  • M: 95
  • K: 276
  • Proton: 3
  • M: 9
  • K: 24
  • Proton: 1
Partial failures12
  • M: 1
  • K: 11
First flightProton: 16 July 1965
Proton-K: 10 March 1967
Proton-M: 7 April 2001
Last flightProton: 6 July 1966
Proton-K: 30 March 2012
Proton-M: 5 August 2019
Notable payloads
First stage
Engines6 RD-275
Thrust10,470 kN (2,350,000 lbf)
Burn time126 s
Second stage
Engines3 RD-0210 & 1 RD-0211
Thrust2,399 kN (539,000 lbf)[3]
Specific impulse327 seconds (3.21 km/s)
Burn time208 s
Third stage
Engines1 RD-0212
Thrust630 kN (140,000 lbf)
Specific impulse325 seconds (3.19 km/s)
Burn time238 s
Fourth stage – Blok-D/DM
Thrust83.4 kN (18,700 lbf)
Specific impulse349 seconds (3.42 km/s)
Burn time770 s

Proton (Russian: Протон) (formal designation: UR-500) is an expendable launch system used for both commercial and Russian government space launches. The first Proton rocket was launched in 1965. Modern versions of the launch system are still in use as of 2019, 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 factory in Moscow, transported to the Baikonur Cosmodrome, brought to the launch pad horizontally, and raised into vertical position for launch.[4][5]

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).[6] Geostationary transfer capacity is about 6.3 tonnes (14,000 lb).[7] Commercial launches are marketed by International Launch Services (ILS).[8]The rocket is intended to be retired before 2030.[9]

As of June 2018, production on the Proton rocket is ceasing as the new Angara launch vehicle comes on line and becomes operational. No new launch service contracts for Proton are likely to be signed.[10]


Proton[11] 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. The unusual appearance of the first stage results from the need to transport components by rail. The central oxidizer tank is the maximum width for the loading gauge of the track. The six tanks surrounding it carry fuel and serve as the attachment points for the engines. Despite resembling strap-on boosters, they are not designed to separate from the central oxidizer tank. The first and second stages are connected by a lattice structure. The second stage engine ignites shortly before separation of the first stage and the lattice allows the exhaust to escape.[12]

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.

Mass-production of guidance, navigation and control system for Proton has begun in 1964 on "Communard" Industrial Association (Kharkov, Ukraine).[13]

Proton launched the uncrewed Soviet circumlunar flights and was intended to have launched the first crewed 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 Zvezda modules 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.[14]

Between 1994 and mid-2010, Proton revenues were $4.3 billion, and were projected to grow to $6 billion by 2011.[15]

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.[16][17]

In June 2018, the state corporation Roscosmos announced that the Proton rocket would cease production as the new Angara launch vehicle comes on line and becomes operational. No new launch service contracts for Proton are likely to be signed.[10]

Other Languages
azərbaycanca: Proton (raket)
български: Протон (ракета)
català: Proton
français: Proton (fusée)
한국어: 프로톤 로켓
hrvatski: Proton (raketa)
Bahasa Indonesia: Proton (keluarga roket)
Lëtzebuergesch: Proton (Rakéit)
မြန်မာဘာသာ: ပရိုတွန်ဒုံးပျံ
Nederlands: Proton (raket)
Simple English: Proton (rocket family)
slovenščina: Proton (raketa)
srpskohrvatski / српскохрватски: Proton (raketa)
suomi: Proton
svenska: Protonraket