The Proton-K, also designated Proton 8K82K after its GRAU index, 8K82K, was a Russian, previously Soviet, carrier rocket derived from the earlier Proton. It was built by Khrunichev, and launched from sites 81 and 200 at the Baikonur Cosmodrome in Kazakhstan.

Launch of a Proton-K carrying the Zvezda module of the International Space Station
FunctionHeavy-lift launch vehicle
Country of originUSSR
Height50 metres (160 ft)
Diameter7.4 metres (24 ft)
Stages3 or 4
Payload to LEO19,760 kg (43,560 lb)
Record: 22,776 kg (50,212 lb) with Zvezda[1]
Associated rockets
FamilyUniversal Rocket
Launch history
Launch sitesBaikonur Sites 81 & 200
Total launches310
Successes275 (89%)
Partial failures11
First flight10 March 1967[2]
Last flight30 March 2012
First stage
Length21.2 metres (70 ft)
Diameter7.4 metres (24 ft)
Empty mass31,100 kilograms (68,600 lb)
Gross mass450,510 kilograms (993,200 lb)
Engines6 RD-253-14D48
Thrust10,470 kilonewtons (2,350,000 lbf)
Specific impulse316 sec
Burn time124 seconds
Second stage – 8S811K
Length14 metres (46 ft)
Diameter4.15 metres (13.6 ft)
Empty mass11,715 kilograms (25,827 lb)
Gross mass167,828 kilograms (369,997 lb)
Engines4 RD-0210
Thrust2,399 kilonewtons (539,000 lbf)
Specific impulse327 sec
Burn time206 seconds
Third stage
Length6.5 metres (21 ft)
Diameter4.15 metres (13.6 ft)
Empty mass4,185 kilograms (9,226 lb)
Gross mass50,747 kilograms (111,878 lb)
Engines1 RD-0212
Thrust613.8 kilonewtons (138,000 lbf)
Specific impulse325 sec
Burn time238 seconds

The maiden flight on 10 March 1967 carried a Soyuz 7K-L1 as part of the Zond program. During the so-called "Moon Race" these Proton/Soyuz/Zond flights consisted of several uncrewed test flights of Soyuz spacecraft to highly elliptical or circumlunar orbits with the unrealized aim of landing Soviet cosmonauts on the Moon.

It was retired from service in favour of the modernised Proton-M, making its 310th and final launch on 30 March 2012.

Vehicle description

The baseline Proton-K was a three-stage rocket. Thirty were launched in this configuration, with payloads including all of the Soviet Union's Salyut space stations, all Mir modules with the exception of the Docking Module, which was launched on the United States Space Shuttle, and the Zarya and Zvezda modules of the International Space Station. It was intended to launch Chelomey's crewed TKS spacecraft, and succeeded in launching four uncrewed tests flights prior to the program's cancellation. It was also intended for Chelomey's 20-ton LKS spaceplane that was never realised.

Like other members of the Universal Rocket family, the Proton-K was fuelled by Unsymmetrical dimethylhydrazine and nitrogen tetroxide. These were hypergolic fuels which burn on contact, avoiding the need for an ignition system, and can be stored at ambient temperatures. This avoids the need for low-temperature–tolerant components, and allowed the rocket to sit on the pad fully fuelled for long periods of time. In contrast, cryogenic fuels would have required periodic topping-up of propellants as they boil off. The fuels used on the Proton, were, however, corrosive and toxic and required special handling. The Russian Government paid for the cleanup of residual propellent in spent stages that impact downrange.

Proton components were built in factories near Moscow, then transported by rail to the final assembly point near the pad. The first stage of the Proton-K consisted of a central oxidiser tank, and six outrigger fuel tanks. This separated as one piece from the second stage, which was attached by means of a lattice structure interstage. The second stage ignited prior to first stage separation, and the top of the first stage was insulated to ensure that it retained its structural integrity until separation.

The first stage used six RD-253 engines, designed by Valentin Glushko. The RD-253 is a single-chamber engine and uses a staged combustion cycle. The first-stage guidance system was open-loop, which required significant amounts of propellant to be held in reserve.

The third stage was powered by an RD-0210 engine and four vernier nozzles, with common systems. The verniers provided steering, eliminating the need for gimballing of the main engine. They also aided stage separation, and acted as ullage motors. Ducts built into the structure channelled vernier exhaust before stage separation. The third stage guidance system was also used to control the first and second stages earlier in flight.

Many launches used an upper stage to boost the payload into a higher orbit. Blok D upper stages were used on forty flights, the majority of which were for the Luna and Zond programmes. Ten flights used the Blok D-1, mostly to launch spacecraft towards Venus. Blok D-2 upper stages were used three times, with the Fobos 1, Fobos 2 and Mars 96 spacecraft. The Blok DM upper stage was used on 66 launches. The most commonly used upper stage was the Blok DM-2, which was used on 109 flights, mostly with GLONASS and Raduga satellites. Fifteen launches used the modernised Block DM-2M stage, mostly carrying Ekspress satellites, however other satellites, including Eutelsat's SESAT 1, also used this configuration. Two Araks satellites were launched using Block DM-5 upper stages. The Block DM1, a commercial version of the DM-2, was used to launch Inmarsat-3 F2. The Block DM2 upper stage was used to launch three groups of seven Iridium satellites, including Iridium 33. This configuration was also used to launch Integral for the European Space Agency. Block DM3 stages were used on twenty five launches, almost exclusively carrying commercial satellites. Telstar 5 was launched with a Block DM4. The Briz-M upper stage was used for four launches; three carrying payloads for the Russian Government, and one commercial launch with GE-9 for GE Americom.[3] One launch was reported to have used a Block DM-3 upper stage, however this may have been a reporting error, and it is unclear whether this launch actually used a DM-3, DM3, or DM-2.

Launch failures

Flight numberDate (UMC)Vehicle modelPayloadPayload mass, kgOrbit (intended)Orbit (actual)Notes
7September 27, 1967Proton K/DZond5375Moon?One first-stage engine did not start at liftoff due to a rubber plug accidentally left inside during assembly, causing control to gradually fail during ascent. The cutoff command was issued at T+97 seconds and the booster crashed downrange, but the LES pulled the Zond descent module to safety.
8November 22, 1967Proton K/DZond5375MoonnoOne second-stage engine failed to ignite at staging. The remaining three engines were shut down automatically and the booster crashed downrange. Once again, the LES pulled the capsule away to safety. Cause was determined to be premature release of fuel into the second stage, resulting in overheating and engine failure.
10April 22, 1968Proton K/DZond5375Moon?A malfunction in the LES accidentally shut down the second stage at T+260 seconds and triggered an abort. The capsule was successfully recovered.
14January 20, 1969Proton K/DZond5375MoonnoSecond stage turbopump failure at T+313 seconds. The LES once again lifted the Zond capsule to safety.
15February 19, 1969Proton K/DLuna probe2718MoonnoPayload fairing collapsed at T+51 seconds. Flying debris ruptured the first stage and caused leaking propellant to ignite on contact with the engine exhaust, resulting in the explosion of the launch vehicle.
16March 27, 1969Proton K/DMars probe4650Heliocentric?Third stage turbopump failure at T+438 seconds. The upper stages and payload crashed in the Altai mountains.
17April 2, 1969Proton K/DMars probe4650Heliocentric?A fire in one of the first stage engines caused an almost immediate control loss at liftoff. The booster reached an altitude of 300m and began flying horizontally before the cutoff command was issued, causing it to plunge nose-first into the ground. Launch complex personnel were unable to leave the Baikonour Cosmodrome due to one exit being blocked by the still-intact second stage and the other by a large puddle of nitrogen tetroxide. They had no choice but to remain there until a rain came and washed the spilled fuel away.
18June 14, 1969Proton K/DLuna probe2718Moon?Blok D stage failed to ignite and the probe reentered the atmosphere
18September 23, 1969Proton K/DLuna probe?Moon?Blok D LOX valve failure. The probe remained in LEO until reentering.
18October 22, 1969Proton K/DLuna probe?Moon?Blok D control malfunction. Probe failed to leave LEO.
23November 28, 1969Proton K/DSoyuz???Pressure sensor malfunction caused first stage cutoff at T+128 seconds
24February 6, 1970Proton K/DLuna5600MoonnoAt T+128.3 s, flight safety system automatically shut off first-stage engine because of false alarm from pressure gauge.
30May 10, 1971Proton K/DKosmos 4194650HeliocentricLEOBlock D flight sequencer programmed incorrectly, resulting in failure to perform second burn or payload separation. Reportedly the coast time between burns was set to 1.5 years instead of 1.5 hours.
36July 29, 1972Proton KDOS-218000LEOnoAt T+181.9 d second-stage stabilization system failed because of short circuit in pitch and yaw channels of the automated stabilization system.
53October 16, 1975Proton K/DLuna?MoonLEOFailure of fourth-stage oxidizer booster pump.
62August 4, 1977Proton KAlmaz?LEOnoAt T+41.1 s, a first-stage engine steering unit failed, causing loss of stability and automatic thrust termination at T+53.7 s.
66May 27, 1978Proton K/DMEkran1970GEOnoVehicle stability loss at T+87 s because of an error in first-stage No. 2 engine steering unit. Fault attributed to fuel leak in second-stage engine compartment, which caused control cables to overheat.
68August 17, 1978Proton K/DMEkran1970GEOnoLoss of stability at T+259.1 s caused flight termination. Hot gas leak from second-stage engine because of faulty seal on pressure gauge led to failure of electrical unit for automatic stabilization.
71October 17, 1978Proton K/DMEkran1970GEOnoAt T+235.62 s, second-stage engine shut off with resultant loss of stability caused by a turbine part igniting in turbopump gas tract followed by gas inlet destruction and hot air ejection into second rear section.
72December 19, 1978Proton K/DMGorizont 11970GEOGEO, inclination 11.0Block DM was misaligned for GEO injection burn, resulting in non-circular orbit with 11 deg. inclination
95July 22, 1982Proton K/DMEkran1970GEOnoFirst-stage engine No. 5 suffered failure of hydraulic gimbal actuator because of dynamic excitation at T+45 seconds. Automatic flight shutdown commanded. This would be the last first-stage malfunction of a Proton until 2013.
100December 24, 1982Proton K/DMRaduga1965GEOnoSecond-stage failure T+230 seconds due to high-frequency vibration.
144November 29, 1986Proton KRaduga1965noSecond stage control failure due to an electrical relay becoming separated from vibration
145January 30, 1987Proton K/DM-2Kosmos-18171965incorrect LEOFourth stage failed to start because of control system component failure.
148April 24, 1987Proton K/DM-2Kosmos 1838-1840 (Glonass)3x1260MEOLEOFourth stage shut down early and failed to restart. Failure occurred in control system because of manufacturing defect in instrument.
158January 18, 1988Proton K/DM-2Gorizont2500GEOnoThird-stage engine failure caused by destruction of fuel line leading to mixer.
159February 17, 1988Proton K/DM-2Kosmos 1917-1919 (Glonass)3x1260MEO, inclination 64.8noFourth-stage engine failure because of high combustion chamber temperatures caused by foreign particles from propellant tank.
187August 9, 1990Proton K/DM-2Ekran M?GEOnoSecond-stage engine shutoff because of termination of oxidizer supply due to fuel line being clogged by a wiping rag.
212May 27, 1993Proton K/DM-2Gorizont2500GEOnoSecond- and third-stage engines suffered multiple burn-throughs of combustion chambers because of propellant contamination.
237February 19, 1996Proton K/DM-2Raduga 331965GTOnoBlock DM-2 stage failed at ignition for second burn. Suspected causes were failure of a tube joint, which could cause a propellant leak, or possible contamination of hypergolic start system.
243November 16, 1996Proton K/D-2Mars 966825Heliocentrictoo low LEOBlock D-2 fourth-stage engine failed to reignite to boost spacecraft into desired transfer orbit; injection burn did not propel spacecraft out of Earth orbit. Spacecraft and upper stage reentered after a few hours. Root cause could not be determined because of lack of telemetry coverage, but suspected cause was failure of Mars 96 spacecraft, which was controlling Block D stage, or poor integration between spacecraft and stage.
252December 24, 1997Proton K/DM3PAS-223410GTOinclined GTOBlock DM shut down early because of improperly coated turbopump seal, leaving spacecraft in high-inclination geosynchronous transfer orbit. Customer declared spacecraft a total loss and collected insurance payment. However, Hughes salvaged the spacecraft using spacecraft thrusters to raise orbit apogee to perform two lunar swingbys, which lowered inclination and raised perigee. Apogee was then lowered to achieve a geosynchronous orbit inclined 8 deg. Spacecraft has become available for limited use.
265July 5, 1999Proton K/Briz-MRaduga 1-51965GTOnoMaiden flight of Briz-M upper stage. Contaminants from welding defect in the turbopump caused the second-stage engine No. 3 to catch fire, destroying the rear section of the stage.
268October 27, 1999Proton K/DM-2Ekspress 1A2600GEOnoArticulate contamination caused the turbine exhaust duct of second stage engine No. 1 to catch fire at T+223 s, resulting in rapid shutdown of the stage. This and the previous failure in July were attributed to poor workmanship at the Voronezh engine plant. Both engines were part of the same batch built in 1993, during a period when production decreased significantly.
295November 26, 2002Proton K/DM3Astra 1K2250GTOnoA failed valve caused excess fuel to collect in the Block DM main engine during the parking orbit coast phase after the first burn. The engine was destroyed.

See also


  1. "Zvezda Service Module". Khrunichev. Retrieved June 11, 2017.
  2. McDowell, Jonathan. "Proton". Orbital and Suborbital Launch Database. Jonathan's Space Page.
  3. Krebs, Gunter. "Proton". Gunter's Space Page.
  4. International reference guide to space launch systems, Fourth Edition, pp. 308-314, ISBN 1-56347-591-X
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