The R-3 project was the first large-scale effort in the USSR, departing from the German rocket technology and developing complex approach toward rocket design.
In 1947, the first Soviet copy of the German A-4 missile, designated R-1, with the range of 280 kilometers was at least a year from its first launch, while its successor the R-2 with 600-kilometer range existed only on paper. Nevertheless, the USSR had already considered a missile capable of reaching England. Yaroslav Golovanov, Korolev's biographer, first revealed that in 1947, the Soviet rocket designer was already thinking of the future R-3 missile. (29) Describing events of 1947, but giving no exact dates, the author also mentioned Korolev's report on prospective designs of long-range ballistic missiles. This document reportedly summarized the experience from the R-2 development and laid foundations for more advanced concepts. (29) (Further in the book, however, Golovanov contradicts himself by saying that the R-3 capable of reaching 3,000 km range was conceived by Korolev in April 1948. (29)
The official history of RKK Energia released in 1996, (52) claims that the R-3 missile with 3,000 km range was a "one of the main subjects" of now famous meeting in Kremlin between Korolev and Joseph Stalin in April 1947. No doubt, the project has been favored by the Soviet government, as it would be the first time, when the investment into missile technology could pay strategic devidends. In fact, the R-3 program might have been approved in Kremlin even before much less ambitious R-2 was given a green light. According to Chertok, it was Korolev who insisted on R-2 development as a preliminary step in the R-3 program. (58) The post-Soviet sources (63, 58) date the beginning of the implementation of the R-3 project to the end of 1947.
It is clear (63, 52) that initially the R-3 project was evolving as a two-folded effort. On one hand, the NII-88 research institute conducted conceptual studies of different designs of a vehicle capable of reaching 3,000-kilometr range, including cruise and ballistic missiles, both in one- and multi-stage configurations. (63, 58) On the other hand, fundamental issues involved in the development of long-range missiles were studied. (52)
Very early on, the R-3 program involved a number of organizations besides NII-88. The problems of development of the radio control at long distance were addressed in the NII-20 research institute led by Boris Konoplev and alternatively in NII-885. (58) The engine development was assigned on a competitive basis to OKB-456 led by Valentin Glushko and to NII-1 of the Ministry of Aviation Industry, where the project was led by Polyarni. (52) One source claims that it was decided to replace alcohol with kerosene as fuel. (63)
By 1949, when preliminary design work on the R-3 reached its culmination, German rocket engineers detained on Gorodomlya Island all but lost their hope for productive work. None of the of the designs generated on the island were accepted by their Soviet bosses and Germans felt increasingly isolated from the real rocket development in the country. Yet, the Minister of Armaments Dimitry Ustinov, overseeing missile development program and who has been known for his suspicious view of Korolev's authority, apparently decided to have a "second opinion" on the R-3 project.
On April 9, 1949 Ustinov landed on Gorodomlya and gave Germans the same specifications set in NII-88 for the R-3: a missile with a range of about 3,000 kilometers, capable of carrying a three-ton warhead. Except for these basic requirements, Germans were free in their design decisions. Preliminary evaluation of possible configurations of such missiles, designated R-14 or G-4 (German-4), had to be completed in three months.
Western historians learned about R-14/G-4 missiles in the 1950s, soon after German rocket scientists returned from the USSR. (64, 10) However, only decades later, when Russian writers could touch the subject of the R-3 development (11), two projects could be linked and the G-4 effort like a piece of a puzzle could be put into a larger picture of missile development in the country. From several Western sources we know that in the initial phase of the project, the German team led by Helmut Gröttrup considered a variety of alternative concepts, including different propellant pairs, clusters of engines and multi-stage configurations. (64, 10) The final design, however, again employed an alcohol-oxygen propellant unit, a single engine and a single stage.
The rocket was shaped as a cone 24 meters tall and 2.74 meters in diameter. The weight of the rocket structure (empty weight) was about seven tons, including the warhead of the assigned weight. A fully fueled rocket would weigh 70.85 tons on the launch pad. Lack of any aerodynamic surfaces in the design helped reduce the mass ratio to only 0.1. Similarly to the R-10, thin pressurized propellant tanks made of stainless steel were part of the rocket's external structure; and, as in previous German designs, plywood was proposed for thermal protection of the warhead.
The R-14 was to be powered by a 100-ton engine. Its combustion chamber was enveloped into a spiral of pipes through which super-cold oxidizer was running before reaching the injection system. The hot exhaust gas was collected from the combustion chamber to drive turbo pumps. In their turn, exhaust gases generated by the turbo pumps were directed into the system of nozzles, which prevented rotation of the rocket around its longitudal axis. To control the rocket in flight, the main engine of the R-14 could be gimbaled by pneumatic or hydraulic system to up to 4 degrees. For this purpose, two different systems of the engine's suspension were proposed -- so called "double knife edge" or "ball and socket." The retro-thrusters employed for the warhead separation in the previous German project -- the R-10 -- gave the way to the more weight-efficient explosive bolts in the R-14.
Like all other early Soviet projects in missilery, the R-14 was conceived as a mobile weapon, with all service and launching equipment placed on road vehicles. However, Gröttrup suggested that in the case of the R-14 project, the increase in range made mobility redundant. Instead, Heinz Jaffke and his assistant Anton Narr, launching equipment engineers at Gorodomlya, designed a unique underground complex for the rocket. It included an assembly plant, the facility extracting oxygen from the air, a storage for ethyl alcohol and, finally, a silo, from which the R-14 would be launched.
In parallel with the work on the R-14, another group at Gorodomlya proposed a completely different vehicle, able to meet Ustinov's requirements. Albring and his associates proposed an unmanned bomber designated R-15 (G-5) and equipped with a ramjet engine. The vehicle would be launched by the R-10 or A-4 booster rocket, and upon reaching the height and speed necessary for the ignition of the ramjet, it would separate from the launcher. Then, the R-15 would level off at the altitude of about 15 km, from which it would cruise to the target.
On October 1, 1949, the Scientific Technical Council of the NII-88, including Gonor, Pobedonostzev and Korolev arrived to Gorodomlya. The Germans presented their work on the R-14 to the Russians, who left with all the drawings and technical papers generated on the island. In November 1949, Gorodomlya group received an assignment to redesign the R-14's warhead module so it could use its kinetic energy to increase the destructive effect on the target. In addition, Germans were asked to redesign the structure of the rocket to utilize aluminum instead of steel. All modifications were completed by February 1950. After that, Germans had no word on the fate of the R-14 and R-15 projects. (10)
Many years later, B. Chertok, Korolev's deputy, was the first Russian author, who mentioned the existence of G-4 (R-14) and G-5 (R-15) projects. He didn't describe what influence if any, this work had on the R-3 development in NII-88, however, he did say that these projects had never gone any farther than conceptual drafting and basic calculations. (58)
According to Russian sources, the R-3 project was finalized in June 1949, but not until Gorodomlya Germans finished their work on the G-4 were blueprints of the R-3 delivered for the critique by the Scientific Technical Council. Almost two years of research conducted at NII-88 resulted in 10 volumes of reports plus dozens of more volumes prepared by other organizations involved in the project. Most of these reports were subdivided into two parts: one containing fundamental data relevant to long-range missiles in general and second dedicated solely to the R-3. (52)
Whatever German influence on the R-3 project could have been, the final version of R-3 missile presented at the special sessions of the Scientific Technical Council during November and December 1949, bore some resemblance to the German G-4. One should not forget that Germans from Gorodomlya had no information on the R-3 development, while Korolev saw all the drawings done by the Germans for the G-4 project.
There are speculations (28) that Korolev and Kurchatov met Stalin in 1949 to discuss a wide range of defense issues, including prospects of development of a nuclear bomb and its delivery systems. There were discrepancies on when exactly this meeting took place and who its participants could have been. What certain is that Korolev met Stalin at least once, sometimes between 1948 and 1949. (29) The results of the R-1 tests and works on the R-2 and R-3 were apparently discussed.
According to Korolev's deputy Boris Chertok, at the end of 1949, the progress on the R-3 project was reported to Stalin by Minister of Armaments Dimitry Ustinov. (27). The long-term implication of these meetings, Chertok believed, had been Stalin's conclusion that ballistic missiles are far from being a serious player in the arm race with the U.S. and the development of a new generation of anti-aircraft defense was required. (27)
The final R-3 design envisioned a one-stage ballistic missile with the length of 27.1 meters, and maximum diameter of 2.8 meters. Fully fueled it would weigh 65-70 tons. (52) The rocket would be powered by a single engine with the trust of 120-140 tons.
At the same time, the Council saw unprecedented complexity facing the R-3 designers and, as a result, recommended the development of the R-3A experimental rocket, as yet one more intermediate step toward the R-3. While inheriting dimensions of the smaller R-2 rocket, the R-3A would test some of the concepts proposed for the R-3, first of all, a brand-new 40-ton engine. This engine was apparently designed by Isaev design bureau in Zagorsk. (28) The R-3A rocket with a dry mass of four tons and fueled mass of 23.4 tons could have a range of 935 km. (52) The first test flight of the R-3A missile was planned for October 1951.
However, soon after initiation of the R-3A development, more radical plans have emerged in NII-88, which would allow to use more concepts from the R-3 project in the design of the new ballistic missile. By October 1951, the R-5 project was prepared, which called for development of a 1,200-km range missile. In appearance the R-5 looked like a "skinny" R-3.
R-3 and Sputnik
Enthusiasts of space flight within a narrow circle of people informed of developments in NII-88, eyed the R-3 for their own "agenda." It is clear from the Soviet sources (11) that as early as 1951, hopes to launch an artificial satellite rested on the R-3 project. The two-stage booster was envisioned as a "pack" of three R-3-based rockets assembled in parallel configuration.
The R-3 project was based on the new engine --RD-110 -- with the trust of 120 tons developed at Valentin Glushko's OKB-456 bureau. (28) However, the development of the engine run into problems, when in 1950-51 test firings demonstrated that the engine's large combustion chamber was unable to survive internal pressure and temperatures. Glushko solved the problem conceptually. Since everybody tried to avoid multiple engines, due to higher risk of turbo pump failures, he decided to multiply only combustion cambers, feeding them with the help of a single high-power turbo pump. Such approach allowed to achieve higher trust with relatively small combustion chambers, and with no additional pumps. At the same time, Glushko's progress in engine development raised serious doubts in Korolev's mind about practical value of the R-3 configuration. The size and weight of the rocket was dictated primarily by the amount of propellant necessary for 3,000-kilometer range seemed too big for practical military use. With implementation of the second stage, however, the range of the vehicle would easily go beyond 3,000 km range.
In 1951, immediately upon successful defense of the project before the state commission, Korolev proposed to cancel the R-3 and go ahead with even more ambitious design of the multi-stage intercontinental rocket based on a concept of multi-chamber engine. (11) This proposal was reportedly met not without controversy within the government. (28) As a result, Minister of Armaments Ustinov established a commission headed by his deputy Konstantin Rudnev. Eventually, Korolev was able to convince the government that R-3 was too bulky and ineffective within given configuration, while much more capable rocket was becoming feasible. The R-3 project was canceled around 1952. (7) The project of the first ICBM was given green light around 1954.
While R-3 had never left drawing board, the project had long-lasting effect on the Soviet rocketry. It challenged Russian designers with a new level of technical complexity and prepared unprecedented expansion of the Soviet rocket industry, which was soon used in its full capacity to develop the first ICBM. Ironically, the R-3 design was the last to be influenced by German engineering from Gorodomlya Island.
The R-3-based launch vehicle. Credit: TsNIIMash
Artist rendering of the separation between first and second stage of the R-3-based launcher. Copyright © 2001 by Anatoly Zak
The RD-110 (Version 1) engine, which was inteneded for the R-3 missile. Copyright © 2002 by Anatoly Zak
The later modification of the RD-110 engine, which was inteneded for the R-3 missile. Copyright © 2002 by Anatoly Zak