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UR-500

Proton 8K82K
Proton Zvezda crop.jpg
Launch of a Proton-K rocket
Function Orbital launch vehicle
Manufacturer Khrunichev State Research and Production Space Center
Country of origin Soviet Union; Russia
Size
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
Capacity
Payload to LEO 22.8 metric tons (50,000 lb)
Payload to
GTO
6.3 metric tons (14,000 lb)
Launch history
Status Grounded
Launch sites Baikonur, LC-200 & LC-81
Total launches 412 (9 June 2016)
Successes 365
Failures 47
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
Notable payloads Salyut 6 & Salyut 7
Mir & ISS components
ViaSat-1
First stage
Engines 6 RD-275
Thrust 10.47 MN (1.9 million pounds)
Burn time 126 s
Fuel N2O4/UDMH
Second stage
Engines 3 RD-0210 & 1 RD-0211
Thrust 2.399 MN (539,000 lbf)
Specific impulse 327 s
Burn time 208 s
Fuel N2O4/UDMH
Third stage
Engines 1 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 rocket was launched in 1965. Modern versions of the launch system are still in use as of 2016, 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.

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

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.

Proton 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.


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