Encyclopedia Astronautica
Zenit


Russian military surveillance satellite. Study 1956. Work began on the original Zenit spy satellite on 30 January 1956. After the success of Sputnik Sergei Korolev advocated that manned spaceflight should have first priority.

After bitter disputes, a compromise solution was reached. Korolev was authorized to proceed with development of a spacecraft to achieve manned flights at the earliest possible date. However the design would be such that the same spacecraft could be used to fulfill the military's unmanned photo reconnaissance satellite requirement. The military resisted, but in November 1958 Korolev won, and the Council of Chief designers approved the Vostok manned space program, in combination with Zenit spy satellite program. This was formalized in a decree of 25 May 1959 that authorized development of the Zenit-2 and Zenit-4 spacecraft based on the Vostok design. This marked the end of the original Zenit configuration.

On 30 January 1956 work began in the Soviet Union on defining the requirements for satellites for military purposes. The system was defined incrementally throughout 1956 in a series of specification documents. In April the specification for a redundant restartable engine system for use in a variety of maneuverable satellites was released. The same month the requirements for research and development of an appropriate satellite guidance and control system were released. In May the technical requirements document was issued for a satellite that could be oriented in orbit by OPM MIAM. In July tests began of appropriate heat shield materials able to resist temperatures of 1,000 to 2,000 degrees C. A decree in August 1956 authorized design of a military reconnaissance satellite. In October the specification was issued for a comprehensive research program leading to maneuverable spacecraft, including investigations into launch methods, re-entry capsules, hypersonic aerodynamics, heat shields, thermodynamics, and parachute systems. By April 1957 the military issued a requirements document for experimental solar cell panels.

Design bureau work on the reconnaissance satellite began in 1957 in Section 3 of OKB-1 (Tikhonravov and Ryazanov). The first version designed consisted of an equipment section and a re-entry capsule. The equipment section included the camera, ELINT receivers, and control systems for orbital flight. The conical re-entry capsule contained the film cassettes to be returned to earth and the recovery systems. The capsule was deorbited by a separate TDU braking rocket. This spacecraft was initially sized at 1.5 metric tons total for launch by the basic R-7 rocket.

But early on it was decided that a long focal length camera (1.0 m) would be required, which tripled the estimated weight of the spacecraft.

By 2 July 1957 Tikhonravov had defined the necessary development tasks for the Zenit reconnaissance satellite as follows:

  • Development of a three stage version of R-7, with improved engines for higher specific impulse in the first and second stages, and improved guidance and engine cut-off systems for better precision in orbital insertion.
  • Research and development of the satellite on-board guidance and control systems of the precision required for photography from orbit
  • Development of satellite control equipment, ELINT sensors, guidance systems, film cassette return systems
  • Development of radio tracking and active broadcasting system for recovery of the re-entry vehicle with the film cassette.

Gross mass: 1,500 kg (3,300 lb).

More... - Chronology...


Associated Countries
See also
Associated Launch Vehicles
  • R-7 Russian intercontinental ballistic missile. The world's first ICBM and first orbital launch vehicle. The 8K71 version was never actually put into military service, being succeeded by the R-7A 8K74. More...
  • Soyuz Russian orbital launch vehicle. The world's first ICBM became the most often used and most reliable launch vehicle in history. The original core+four strap-on booster missile had a small third stage added to produce the Vostok launch vehicle, with a payload of 5 metric tons. Addition of a larger third stage produced the Voskhod/Soyuz vehicle, with a payload over 6 metric tons. Using this with a fourth stage, the resulting Molniya booster placed communications satellites and early lunar and planetary probes in higher energy trajectories. By the year 2000 over 1,628 had been launched with an unmatched success rate of 97.5% for production models. Improved models providing commercial launch services for international customers entered service in the new millenium, and a new launch pad at Kourou was to be inaugurated in 2009. It appeared that the R-7 could easily still be in service 70 years after its first launch. More...

Associated Manufacturers and Agencies
  • Korolev Russian manufacturer of rockets, spacecraft, and rocket engines. Korolev Design Bureau, Kaliningrad, Russia. More...

Bibliography
  • Semenov, Yuri P Editor, Raketno-kosmicheskaya korporatsiya 'Energia' imeni S P Koroleva, Moscow, Russia, 1996.
  • Harvey, Brian, "Some Details on Project Zenith (1957 Onwards)", Spaceflight, 1993, Volume 35, page 382.
  • Vetrov, G S, S. P. Korolev i evo delo, Nauka, Moscow, 1998.
  • Melnik, T G, Voenno-Kosmicheskiy Siliy, Nauka, Moscow, 1997..
  • Siddiqi, Asif A, The Soviet Space Race With Apollo, University Press of Florida, 2003.

Zenit Chronology


1956 January 30 - .
  • Work began in the Soviet Union on military satellites. - . Nation: USSR. Spacecraft: Zenit. Design work starts on the Zenit, the first military photo-reconnaisance satellite. The necessary subsystems were defined incrementally throughout 1956 in a series of specification documents. In April the specifications for a redundant restartable engine and appropriate satellite guidance and control systems were released. In May the technical requirements document was issued for a satellite that could be oriented in orbit. In July tests began of appropriate heat shield materials.

1956 June - . LV Family: R-7. Launch Vehicle: R-7.
  • Zenit preliminary design complete - . Nation: USSR. Class: Technology. Type: Navigation technology satellite. Spacecraft: Zenit. Summary: Design was original concept of Zenit reconnaisance spacecraft. The effort would later be included in the Vostok program under the name of Zenit..

1956 August - .
  • Soviet decree authorised design of a military reconnaissance satellite - . Nation: USSR. Spacecraft: Zenit. The decree formally authorised design of a military reconnaissance satellite. In October the specification was issued for a comprehensive research program leading to manoeuvrable spacecraft. By April 1957 the military issued a requirements document for experimental solar cell panels. Design bureau work on the reconnaissance satellite began in 1957 in Section 3 of OKB-1 (Tikhonravov and Ryazanov). This spacecraft was initially sized at 1.5 tonnes total for launch by the basic R-7 rocket.

1957 Spring - .
  • Soviet reconnaisance system designs continue - . Nation: USSR. Spacecraft: Zenit; Zenit-2. Summary: Studies were undertaken for military reconnaissance satellites. Code names for these studies were: Shchit - military reconnaissance systems; Osnova - military reconnaissance equipment; Ediniy KIK - military reconnaissance control systems..

1957 July 2 - . LV Family: R-7. Launch Vehicle: R-7A.
  • Tikhonravov defined the development tasks for the Zenit reconnaissance satellite. - . Nation: USSR. Spacecraft: Zenit. These included development of a three stage version of R-7, development of satellite guidance and control systems of the precision required for photography from orbit, satellite control equipment, ELINT sensors, guidance systems, film cassette return systems, and tracking systems for recovery of the re-entry vehicle with the film cassette.

1958 November 1 - .
  • Vostok spacecraft and Zenit spy satellite authorised. - . Nation: USSR. Related Persons: Korolev. Spacecraft: Vostok; Zenit; Zenit-2; Zenit-4. Council of Chief Designers Decree 'On course of work on the piloted spaceship' was issued. Council of Chief designers approved the Vostok manned space program, in combination with Zenit spy satellite program Korolev was authorised to proceed with development of a spacecraft to achieve manned flights at the earliest possible date. However the design would be such that the same spacecraft could be used to fulfil the military's unmanned photo reconnaissance satellite requirement. The military resisted, but Korolev won. This was formalised in a decree of 25 May 1959.

1959 May 22 - .
  • Production of Vostok and Zenit-2 authorised. - . Nation: USSR. Spacecraft: Vostok; Zenit-2; Zenit-4; Zenit. Central Committee of the Communist Party and Council of Soviet Ministers Decree 569-264 'On work on a reconnaissance satellite and piloted spaceship' was issued. Due to a bitter fight with the military over the nature and priority of the manned spacecraft and photo-reconnaissance space programs, the final decree for the Vostok manned spacecraft was delayed until seven months after drawing release began. This authorised production of a single design that could be used either as a manned spacecraft or as a military reconnaissance satellite. These were the Zenit-2 and Zenit-4 spacecraft based on the Vostok design. This marked the end of the original Zenit configuration. The military had to develop the recovery forces and techniques for both spacecraft, including appropriate aircraft, helicopters, and handling equipment. At that time it was felt that there was a 60% chance on each launch of an abort requiring rescue operations for the cosmonaut.

1959 May 22 - .
  • Vostok / Zenit-3 decree issued. - . Nation: USSR. Spacecraft: Vostok; Zenit-2; Zenit-4; Zenit. Due to a bitter fight with the military over the nature and priority of the manned spacecraft and photo-reconnaissance space programs, the final decree for the Vostok manned spacecraft was delayed until seven months after drawing release began. This authorised production of a single design that could be used either as a manned spacecraft or as a military reconnaissance satellite. These were the Zenit-2 and Zenit-4 spacecraft based on the Vostok design. This marked the end of the original Zenit configuration.

Home - Browse - Contact
© / Conditions for Use