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Birth of Proton: The Iconic Rocket That Almost Wasn't
Previous chapter: The A-600 project
By 1961, the Soviet strategic roadmap into space hit a serious snag. The Soviet Ministry of Defense "rebelled" against the burden from the overly ambitious space program adopted by the Soviet leader Nikita Khrushchev in June 1960, largely at the expense of military projects. A new decree signed on May 13, 1961, scaled down the space effort. In particular, the development of the previously approved A-600 rocket was limited to a preliminary design, while pushing the deadline for its completion to 1962. (509)
Perhaps responding to a reduced appetite of the military, in the second half of 1961, engineers at Vladimir Chelomei's Branch No. 1 at OKB-52 conceived of a somewhat smaller, 500-ton, two-stage rocket designated 8K82. (134) To ensure military support, the rocket was promised to carry a powerful nuclear warhead and to be deployed in underground silos.
One proposed design for the 8K82 involved clustering four UR-200 ballistic missiles (then in development at OKB-52) and adding an upper stage derived from the second stage of the same predecessor. However after testing dynamics of such an architecture on a scale model, the idea was rejected as grossly inefficient. Instead, two competing concepts apparently emerged. A group of veterans transferred from Myasishev design bureau and now led by Viktor Bugaisky proposed a so-called monoblock design, featuring stages placed "in-line," one above the other. However in order to lift the required payload using a body diameter that would be constrained by existing railway standards, the rocket would become unacceptably tall and thin. (355) Alternatively, a group of engineers led by E. Radchenko proposed to split the first stage into a core tank carrying oxidizer and six skinnier propellant tanks strapped around it. (210) Comparative studies favored this second option. Interestingly, authoring certificate No. 36616 for this rocket's ultimate architecture was given on July 26, 1966, to a group of engineers, including both Radchenko and Bugaisky. (209)
According to the initial design, the first stage of the UR-500 would borrow engines with a thrust of 50 tons each from the first stage of the UR-200 missile. However, to achieve the required lift capability, the first stage would need 15 or even 16 such engines. Instead, it was proposed to install just six 11D43 engines with a thrust of 150 tons each, which had been originally designed by Valentin Glushko for the N1 rocket. (209) The basic design of the first stage was apparently finalized in January 1962. (134)
The second stage of the UR-500 would be fashioned from the first stage of the UR-200. (209) It would employ engines borrowed from the first stage of the UR-200 upgraded for high-efficiency operations in vacuum and equipped with four steering mechanisms designed to move them in flight to adjust the flight trajectory.
In April 1961, Deputy Aviation Minister Kobzarev approved the development plan for the 8K82 project with following milestones:
1962: Khrushchev approves UR-500
According to one account, Chelomei first introduced the 8K82 rocket to Soviet leader Nikita Khrushchev during his "working vacation" in Pitsunda in February 1962. Chelomei advertised his new creation as a "versatile rocket" or UR for short. With a launch mass of around 500 tons, the UR-500 would be the carrier for a 30-megaton super-bomb (according to another source the warhead could have a yield of up to 150 megatons) asd well as a space launcher capable of delivering from 12 to 13 tons into orbit. It could also serve as a so-called orbital ballistic missile, whose nuclear warhead reaches orbit and then reenters on its way to its target. (355)
One veteran of Chelomei's team later claimed, the Minister of Armaments Dmitry Ustinov, Chelomei's key adversary, had only learned about the proposal at this meeting and, obviously, was not pleased. However, Khrushchev liked what he saw (210) and on April 29, 1962, the Soviet government approved the development of the three-stage 8K82 ballistic missile, orbital missile and launcher of military and scientific satellites with Decree No. 409-183. The document allocated three years for the project, with the first test launch scheduled for the 4th quarter of 1963. (209, 210)
In May 1962, the project engineers now led by Yuri Trufanov finalized the architecture of the rocket which featured the first stage comprised of a central tank and six strap-on tanks. The second stage of was installed above the first. The diameter of 4.1 meters chosen for the core of the rocket was the absolute maximum for cargo transportable by rail even with the help of custom-designed carriage. As a result, costly air transportation of stages to the launch site was avoided. (112) However, two-way railroads would have to divert incoming traffic in order to provide enough clearance for outbound trains carrying oversized stages of the UR-500.
Still, the rocket's transportability and easy-to-assemble design demonstrated salient advantages over the similar-class Saturn-1 rocket developed in the US. (355)
Making the UR-500
The preliminary design of the UR-500 rocket was completed in 1963 and it was immediately rushed to the manufacturer. First attempts to build UR-500 out of the new aluminum alloy known as AMTs caused a lot of grief for the engineers. They discovered that the material was too inflexible and brittle, leading to failures of new tanks during static tests. Cracks reportedly appeared in areas were tanks were welded together. Some components even cracked during prolonged storage. As a result, developers fell back to the heavier but more familiar AMG-6 alloy. The main designer of Plant No. 23 B.G. Britkov then led an effort to lighten various components of the rocket in order to bring the total mass of the vehicle back down to the original design specifications.
The use of the older alloy also imposed temperature limitations on the UR-500, making it impossible to keep it fueled for extended periods under very high heat. In addition to manufacturing problems, specialists at Plant No. 23 were still struggling to complete major upgrades of their production lines in order to switch from aircraft and helicopter to rockets.
While most of the development and manufacturing work on the UR-500 was conducted at Branch No. 1 in Fili, Chelomei's original core team at OKB-52 in Reutov also got some responsibilities. They were designing warheads, a targeting system, an integration of the rocket with a silo launch facility, and were preparing related experiments at the bureau's test facilities. (662)
Finishing the development
As various development problems were pushing the first launch of the UR-500 farther and farther behind schedule, it was decided to start flight testing with a two-stage version of the rocket.
On July 24, 1964, a two-stage UR-500 equipped with mockup engines arrived to Tyuratam. Exactly two months later, Khrushchev, during his visit to the launch site, personally viewed the largest Soviet space vehicle to date standing on its launch pad. (233) He also saw the rocket's transport trailer and a scaled mockup of the UR-500's giant underground launch facility. Although Khrushchev was very positive about the new rocket, as a sign of things to come, he reportedly asked a rhetorical question, after glancing at the silo mockup: "So what are we going to build -- communism or silos for UR-500?" (209)
Birth of Proton-K (8K82K)
In parallel with the development and testing of the original two-stage version of the UR-500 rocket, Chelomei's engineers worked on a three-stage rocket designated 8K82K. The upgraded vehicle featured a significantly stretched second stage and a redesigned lattice structure connecting it to the first stage. Moreover, a third stage was added to the vehicle. It was created by shortening the original version of the second stage and leaving only one main engine instead of four. These modifications enabled increasing the rocket's payload up to 22 tons in low Earth orbit. (660)
Again, Chelomei considered military applications for the rocket. In 1963, his team issued a preliminary design of the 8F117 warhead compatible with Proton-K and with the AB-500 maneuverable aviation warhead.
The preliminary design of the UR-500K vehicle was completed in 1964. (210) On August 3, 1964, the Soviet government finally gave its formal go-ahead to a full-scale development of the three-stage 8K82K rocket. However it would be developed only as a space launcher in a belated effort to catch up with the US in the Moon Race. At the time, Chelomei's circumlunar mission was planned for the end of 1966 or the first half of 1967. (509)
However, while the UR-500 rocket had already appeared in metal, Chelomei's LK spacecraft, conceived for a circumlunar mission, existed only on paper. Chelomei would not be able to approve its preliminary design until June 30, 1965. Instead, by the beginning of 1964, the scientific community led by Keldysh had already begun development of large scientific detectors designed to measure the flux of heavy subatomic particles in space, as the UR-500's first payload. The resulting 12.2-ton satellite called "Proton" would ride the UR-500 rocket during its risky test flights. OKB-52 fashioned cylindrical instrument compartments for Proton satellites out of UR-500's third stage. (660)
As with a number of other Soviet space launchers, the satellite's name was announced in the open Soviet press immediately after its first launch in 1965, and it would eventually become the public name of its launch vehicle. (210)
Building the flight control system
The development of the flight control system for the UR-500 rocket was started by Nikolai Pilyugin's collective, however in 1964 SKB-897 at the Kommunar plant in Kharkov took over Pilyugin's initial concept. There, Abram Ginzburg, Deputy Chief Designer and Sergei Ryabtsev, head of Department No. 70, led the project. From 1971, Anatoly Doroshenko led this work in Kharkov. (661)
Fall of Khrushchev: Proton's last hurdle
By the fall of 1964, most technical issues with the 8K82 rocket had been largely resolved, but politics intervened in a major way in the project. On October 14, Khrushchev was ousted in a bloodless coup, leaving Chelomei without his ultimate benefactor. The work on Chelomei's UR-200 missile was quickly canceled in favor of the R-36 missile, whose developer was based in Dnepropetrovsk, Ukraine, coincidently once the home town of the new Soviet leader Leonid Brezhnev. The UR-500 was clearly next to go on the chopping block.
Ironically, just a day after Khrushchev's fall, a mockup of the Proton rocket intended for critical fueling tests was shipped to Tyuratam. After assembly and various checks at its Technical Complex at Site 92, the vehicle finally reached its launch pad in December. Along with fit tests of the launch complex, the rocket was to be filled with water to simulate all fueling procedures, however freezing temperatures in Tyuratam made the operation too dangerous. Instead, the project managers resorted to the second best -- 40-percent alcohol, essentially vodka. A total of 15 rail cisterns had to be delivered to the launch pad to fill the entire rocket.
The first flight-ready version of the rocket appeared at the launch site in March of 1965 and, after four months of risky, trouble-plagued preparations and delays finally lifted off on July 16, successfully delivering the Proton-1 satellite into orbit. Despite this remarkable success, the creators of the UR-500 were not out of the woods either on the engineering or on the political front.
Korolev still hoped to kill the UR-500 project in its infancy, in order to focus limited industry funding on his lunar program built around the N1 Moon rocket. In a letter dated Aug. 14, 1965, Korolev recommended that the Soviet government cancel "all" work on the UR-500 and use the freed resources and hardware for the main task of the N1 development. His letter, however, did not explain how abandoning the already-built hardware and launch infrastructure for the UR-500 would benefit the N1 project. Korolev never sent this particular letter, but, apparently, around the same time, Chelomei directed his leading engineer at Branch 1 V.M. Volokhin to go to the Military Industrial Commission, VPK, of the Soviet of Ministers. According to Chelomei's sources, a very important document was traveling up the chain of command of the Soviet government. Upon arrival at the VPK offices, Volokhin was shown a draft of a government decree prepared by Korolev on the cancellation of the UR-500. To his horror, Volokhin realized that the decree had already been signed by powerful industry officials, including Deputy Chairman of the Government Leonid Smirnov, Secretary of the Central Committee Dmitry Ustinov and a new head of the industry Sergei Afanasiev, who had been appointed to his position on March 2, 1965. (355)
The UR-500 would probably have been killed if not for the powerful head of the Soviet Academy of Sciences Mstislav Keldysh. Keldysh saw little use for the UR-500 as a ballistic missile, but did value its orbital launch capabilities. He decided to bank on the UR-500 as a vehicle that could carry Soviet cosmonauts around the Moon before the Americans could do the same.
In August 1965, Keldysh chaired a commission tasked with scrutinizing the activities of Chelomei's OKB-52 and downsizing his projects when possible. As a result, the UR-500 was officially "relieved" of its military duties (355), but the commission ultimately recommended that Chelomei continue the development of the UR-500K version as a space launcher and even spared his lagging LK circumlunar spacecraft, even though it clearly duplicated Korolev's L3 lunar landing project.
Focus on the Moon
On Sept. 6, 1965, the Minister of General Machine Building, Afanasiev issued an official order to submit to the ministry a schedule for the production of UR-500K vehicles. By October, the Soviet government reconfirmed its commitment to the development of the UR-500K, but it would now launch Korolev's stripped down version of the 7K (Soyuz) spacecraft to circumnavigate the Moon. (209) Chelomei's LK project was relegated to history.
On Oct. 25, 1965, the Soviet government issued a decree formally consolidating the industrial efforts on the circumlunar mission with UR-500K-7K-L1 complex. On November 13, the head of the industry officially ordered Korolev and Chelomei to finalize the plan before the end of the year. Korolev's OKB-1 formally finished initial phase of the preliminary design of the 7K-L1 spacecraft on November 30.
(To be continued)
Next chapter: Proton flight history
The UR-500 (Proton) development team:
Specifications of the original UR-500 rocket (a two-stage version):
Chronology of the development of the UR-500 (Proton) rocket:
1960 beginning of April: Engineers at OKB-52 design bureau draft plans for a A-series of launch vehicles.
1961: Vladimir Chelomei's OKB-52 design bureau begins work on the preliminary concept of the UR-500 rocket. (660)
1962 February: Vladimir Chelomei introduces the UR-500 project to the Soviet leader Nikita Khrushchev during his meeting with military and defense industry official in Pitsunda on the Black Sea.
1962: Vladimir Chelomei's OKB-52 design bureau issues the preliminary concept (avant-project) of the UR-500 rocket.
1962 April 16: The Central Committee of the Communist Party and the Soviet of Ministers issues a Decree No. 346-160 approving the UR-500 project. (209)
1962 April 29: The Central Committee of the Communist Party and the Soviet of Ministers issues a Decree No. 409-183 assigning the OKB-52 design bureau to develop the two-stage UR-500 (8K82) rocket. (210)
1963: Vladimir Chelomei's OKB-52 design bureau completes the preliminary design of the UR-500 (8K82) rocket.
1964 July 24: A full-scale mockup of the UR-500 rocket arrives at the launch site in Tyuratam. (233) The construction of the first launch pad (known today as "left" or Pad 23) for the UR-500 rocket in Area 81 is completed around that time.
1964 Aug. 3: The Central Committee of the Communist Party and the Soviet of Ministers issues Decree No. 655-268 assigning the OKB-52 design bureau to develop the three-stage UR-500K (8K82K) rocket for the LK circumlunar mission. (509) The development of a UR-500 ICBM is discontinued.
1964 Oct. 14: A bloodless coup in the Kremlin overthrows Khrushchev.
1964 Oct. 15: The fueling prototype of the UR-500 rocket is shipped to Tyuratam.
1964 December: The fueling prototype of the UR-500 rocket is installed on the "right" pad at Site 81 in Tyuratam for fit tests.
1965 March: The first flight-ready version of the UR-500 rocket arrives at its launch site in Tyuratam. (233)
1965 June 30: Chelomei approves the preliminary design of the LK complex for the circumlunar mission around the Moon.
1965 Aug. 5-19: The military industrial commission chaired by Mstislav Keldysh reviews the activities of OKB-52. (209)
1965 Sept. 8: The Military Industrial Commission of the Presidium of the Soviet of Ministers issues Decision No. 201 allocating 18 launches of the 8K82K rocket for the L1 test flight program.
Page author: Anatoly Zak; Last update: January 9, 2017
Page editors: James MacLaren and Alain Chabot; Last edit: November 16, 2013
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Eduard Radchenko, a key architect of the Proton rocket. Credit: GKNPTs Khrunichev
Dynamic testing models illustrate the development history of the Proton rocket. On the right is the early concept of the Proton rocket which would be comprised of four UR-200 missiles, also seen separately on the left. The model in the center represents UR-500K rocket (not to scale). Copyright © 2000 Anatoly Zak
Chelomei's design bureau had proposed the MP-1 hypersonic vehicle, which was undergoing testing until 1965. Credit: NPO Mash
The 11D43 engine proposed by Valentin Glushko around 1960 for the first stage of the Proton rocket. It had low-expansion ratio and could be gimbaled to control the rocket in flight. Four such engines along with four 8D43 engines would be used on the first stage, if this configuration was ever approved. Click to enlarge. Copyright © 2000, 2011 Anatoly Zak
A decorative scale model of the UR-500 launcher apparently showing the early configuration of the booster designed to carry LK-1, a manned spacecraft intended for a lunar fly-by mission. OKB-52, the Proton developer, presented this model to its rival OKB-1, which was developing its own version of the circumlunar spacecraft. Ironically, it was OKB-1's L1 spacecraft for circumlunar mission, which ultimately rode Proton into space, while LK-1 project was abandoned. Copyright © 2001 Anatoly Zak
Soviet leader Nikita Khrushchev visits Tyuratam during preparation of the first UR-500 rocket for launch. Credit: GKNPTs Khrunichev
An early Proton rocket during its assembly in Moscow. Credit: GKNPTs Khrunichev
One of the early Proton rockets sits on the launch pad in Tyuratam. Credit: GKNPTs Khrunichev
Stills from the film footage, documenting the launch of the two-stage version of the UR-500 rocket. Credit: Khrunichev
Vladimir Chelomei's proposal for the UR-500MK rocket, burning oxygen and kerosene propellant and possibly capable of supporting circumlunar missions. Click to enlarge. Copyright © 2001 Anatoly Zak