333x800 (30 485 bytes)		Principal characteristics of rocket R-7
		Maximum firing range, km (not considering the Earth rotation) Launch mass, t Warhead mass, t Mass of filled in propellants (LOX, kerosene, hydrogen peroxide, gas, etc.), t Velocity at the moment of PU burn, m/s: stage I stage II PU ground thrust (of stages 1 and 2), tf	8000 280 5.3 - 5.5 253   2170 6385 403.4

The Government Decree of February 13, 1953 obliged to work out a preliminary design of a two-stage ballistic rocket 170 t in mass with a separable warhead 3000 kg in mass capable to be launched to a range of 8000 km. In October 1953, the design assignment was changed: a fire charge mass was increased to 3000 kg (a total mass of the rocket warhead - to 5500 kg) with a flight range remained unchanged, i. e. the design had to be modified radically.
In January 1954 the Board of Chief Designers among which were S. P. Korolev, V. P. Barmin, V. P. Glushko, B. M. Konoplev, V. I. Kuznetsov, N. A. Pilyugin took place with the participation of M. I. Borisenko, K. D. Bushuev, S. S. Kryukov, and V. P. Mishin to discuss further work on the rocket with regard to increased mass of its warhead. The board made a resolution to use a standardized engine of a comparatively small size for all stages, to limit overall dimensions of the stages to allow their railway transportation. Because of the operation environment, stationary ground equipment had to be designed to employ a unique method for the rocket suspension on application specific deflectable trusses that allowed to keep the rocket unloaded during stoppage and to reduce its mass.
To achieve the specified firing accuracy, scattering of engine thrust aftereffect impulse should stay within a strictly fixed range, however, in the preliminary design phase OKB-456 (V. P. Glushko) did not manage to solve this problem. At that time it was decided to use steering verniers in the capacity of control members to generate finite thrust after the main engine has been shut down and a required aftereffect impulse. In so far as V. P Glushko refused to develop vernier thrusters, S. P. Korolev charged M. V. Melnikov to do this work. The vernier thrusters containing gimbals combined with fuel delivery lines were sized to a 2.5 tf thrust. Each strap-on booster contained two and a core stage contained four vernier thrusters.
In designing the vernier thruster many problems have been solved and new structures developed. These structures found application and further evolution.
In February 1954 the rocket development milestones were agreed to and on May 20, 1954 a Decree enacted development of two-stage ballistic rocket R-7. In the order of Minister of Defense it was particularly underlined that the development of rocket R-7 was a matter of national importance and all work had to be accomplished within the specified time limits.
The R-7 design was radically distinguished from all previous rockets by its configuration and structural arrangement, overall dimensions and mass, propulsion capacity, a number and purpose of systems, etc. It consisted of four strap-on boosters attached to a core stage. By their interior arrangement, both the strap-on boosters and the core stage were similar to a single-stage rocket design with a front location of an oxidizer tank. Fuel tanks of all stages also served as structural elements. Engines of all five stages were ignited from ground. Each stage accommodated a standardized four-chamber liquid-propellant engine sized to a 80-90 tf thrust. A control system incorporated a stabilization automatics ensuring normal and lateral stabilization, an apparent velocity control system, and a range and direction radio control system. On the core stage a fuel tankage simultaneous depletion system was provided because a lack of this system caused a large range loss.
In conclusions on the R-7 design it was noted that in the engineering design phase it will be required to carry out serious experimental work on the rocket warhead, study and test engine control systems, verify combustion chambers with high power characteristics, verify control system hardware, vernier thrusters, and separation systems.
The R-7 rocket preliminary design was reviewed by a Commission of Experts headed by Academician M. V. Keldysh. The commission included prominent scientists and the Customer representatives. The commission recognized that the submitted preliminary design could serve as a basis for further work. On November 20, 1954 the preliminary design of rocket R-7 was approved by the Board of Ministers of the USSR.
Work on rocket R-7, up to its full completion, was split into three phases:

• Phase 1: the design completion relying on critical comments of the Commission of Experts, manufacturing of two lots of rockets for bench tests and one lot of rockets for flight tests;
• Phase 2: testing of a series of rockets under a complete program, modifications to the rockets relying on the testing results;
• Phase 3: manufacturing of a series of rockets with updated characteristics for flight tests.

In Phase 1, a good deal of difficulties were posed for testing a vernier thruster.
A theoretical drawing of rocket R-7 was approved by S. P. Korolev on March 11, 1955 and on July 25, 1956 the updated preliminary design documentation was signed. Development of design documentation on rocket R-7 started as early as in 1953.
In 1956 two sets of stage A (a core stage) and two sets of stage B (one of the strap-on boosters) have been manufactured for bench tests and three mockups - for ground tests. In parallel, the first flight prototype has been made late in 1956 and delivered to the launch site.
In the second half of 1956, it was decided to involve the Kuibyshev plant "Progress" in the rocket R-7 mass production. At the plant the first rockets were assembled of parts and units made at Plant 88. Further, the third branch office of OKB-1 headed by the deputy Chief Designer D. I. Kozlov was set up at the "Progress" plant. To this branch office reformed in 1974 into an independent organization - the Central Specialized Design Office - technical documentation on rocket R-7 and its modifications was passed on by our enterprise to start mass production at the "Progress" plant.
The rocket design novelty, new approaches to a launch pad structure required a large amount of experimental development of certain systems and the rocket as a whole. For this purpose an integrated test program has been worked out and implemented.

• Tests of rocket-7 radio control system on a basis of rocket R-5R. From May 31 to June 15, 1956 three successful launches of Rocket R-5R have been implemented.
• Flight tests of the R-7 control systems: the core stage fuel tankage simultaneous depletion system, the apparent velocity control system, the normal and lateral stabilization system, the telemetry system. In a period from February 16 to August 18, 1956, ten launches of rocket M5RD have been carried out.
• Tests of shockless ejection of the rocket out of the launch pad at the Leningrad Metallic Plant. The tests were run on the R-7 mockup яN that allowed to fill the tanks with distilled water containing anticorrosive agent.
• Firing tests of the rocket stages and the integrated rocket in a period from July 1956 to March 1957 on 2 NII-88 testing facility.
• Tests of the launch pad service tower and verification of its mating with aft compartments of the rocket stages. The work was carried out at 2 NII-88.
• Tests of the rocket strap-on boosters separation system on a dedicated setup at 2 NII-88.
• Verification of the rocket pre-launch processing technology and interaction between the launch site services.

In March 1957 the first rocket R-7 № M1-5 has been delivered to the pre-launch processing facilities for flight tests.

Rocket R-7 800x621 (160 800 bytes)

Launch of rocket R-7 702x800 (96 374 bytes)

On April 10, 1957 the first meeting of the State Commission chaired by V. M. Ryabkov (a Chairman of the Military-Production Complex) took place to decide on flight tests. S. P. Korolev (a technical manager). Results of the R-7 experimental development and processing for flight tests were reported by S. P. Korolev.
On May 5, 1957 rocket R-7 № M1-5 has been delivered to the launch site.
The first launch has been carried out on May 15, 1957, at 19:01 Moscow time. Visually, the flight seemed to run normally, but then, changes in the engine exhaust gas flame of the aft compartment became apparent. Processed telemetry showed that strap-on booster D fell off at the 98-th second and the rocket lost stability. The accident cause turned to be leakage of its fuel line. This launch have permitted to obtain test data on the lift-off and stage 1 flight dynamics.
The second launch planned for June 11, 1957 failed despite of three trials: in the first two trials, because of freezing of the main oxygen valve disc in strap-on booster B, the launch sequence was reset; the third trial failed because of the propulsion emergency shutdown in the preliminary thrust stage mode caused by an error made when installing a nitrogen purging valve of the core stage oxygen line. The rocket was dismounted from the launch pad and returned to the processing facility.
The third launch took place on July 12, 1957. At 33s the rocket lost stability. The accident resulted from a closure on the shell of the integrating device control signal circuits via a roll channel.
The forth launch of rocket R-7 carried out on August 21, 1957 was successful and the rocket reached its destination point for the first time. The main drawback of this launch was a destruction of the warhead in atmosphere in the trajectory descent leg. On August 27, 1957, the TASS report was published on the intercontinental ballistic rocket tests.
The next launch of rocket R-7 carried out on September 7, 1957 mainly verified the previous launch results.
Positive results of rocket R-7 flight in the ascent phase of trajectory justified its use for launching the first two artificial Earth's satellites (of the Pя type). Rockets № 1Pя and №2Pя were used in the capacity of launchers modified with the consideration of flight test results and specified tasks.
Relying on results of six launches of rocket R-7, its warhead was replaced with a new one, the separation system was modified, and slot antennas of the telemetry system were used.
A launch of rocket R-4 was successful for the first time on March 29, 1958 (the warhead reached the target without destruction). Flight tests of the second cycle have been completed with launches of rockets R-7 on May 24 and July 10, 1958.
The third cycle of flight tests have been carried out from December 24, 1958 to November 27, 1959. 16 rockets have been launched of which 8 were made at the Progress mass production plant. On rockets of the third version the inter-tank instrumentation compartment was removed from the core stage (instruments were accommodated in a single section of the core stage nose), vernier thrusters of higher capacity and improved power supply system were introduced among other modifications.
In parallel with the flight tests, space launch vehicles based on rockets R-7 of the third version were being launched (September 1958 - November 1959). Seven automatic space stations have been launched.
On January 20, 1960 intercontinental ballistic rocket R-7 entered service.
From December 24, 1959 flight tests of rocket R-7A without a radio control system and with a newly designed warhead were commenced. Rocket R-7, with a launch mass of 276 t and a warhead mass of 3 t, was capable to fly to a range of 12 000 km. During flight tests eight rockets have been tested of which seven rockets implemented their task.
Rocket R-7A entered service and replaced rocket R-7.