The OD Project
In 1956, while the Object D and its launcher 8A91 were being developed, a programme started oTn designing of the first Soviet reconnaissance satellite [1], named Object OD (that in Russian stands for Orientirovanny D, or in English for Oriented D). At the outset Object OD was conceived as a spacecraft consisting of the main instrument module and a cone-shaped re-entry capsule [2]. The launcher project for orbiting OD satellites received the number, 8A92, as its designation. Up to the beginning 1957 these efforts went into two projects. The first was a satellite, designated Object 0D-1, with a passive orientation system and the second, Object OD-2, was equipped with an active system of attitude control and stabilisation [3]. This advanced project was developed during 1955-1956 by the NII-1 headed by academician M.V. Keldysh [4]. Korolyov planned to place the OD satellites in orbit during 1958-1960 [5].Launchers for OD Satellites
The Object D's launcher 8A91, based on the ICBM R-7 (details of which appeared in Part 1, Spaceflight, August 1995, pp.260-263) could have orbited a payload of up to 1400 kg. Preliminary studies, conducted by a group headed by E.F Ryazanov of the OKB-1's project department, had showed that Object OD satellites would have a weight of no less than about 1500 kg, the final weight of Object OD-1 together with the R-7's Stage 2 in orbit being 400 kg more than Object D with its stage. There was an obvious need to design a more powerful R-7 based launch vehicle. Early in 1957, from its outset, the Object OD-1's launcher 8A92 was conceived as a two-stage vehicle based on the R-7 (8K71) ICBM which was have to put a payload of about 1500-1700 kg in orbit. To construct this R-7 version, it was necessary [6]:The OD-2 Spacecraft
During 1958, as the OD project progressed on the definitive aspects of the design, the Object OD-2 matured as a two-unit spacecraft consisting of a big instrument/service module of cylindrical shape and a small cone-shaped re-entry capsule [7]. But early in 1958 another team, headed by K.P. Feoktistov, of the OKB-1's project department No. 9 started preliminary work on the development of an Object OD-2 intended for manned space flight [9]. In June 1958 this team gave Korolyov a report on the results of this work [10]. The descent module of the manned version of Object OD-2 would be a big sphere 2.3 m in diameter. Moreover this report envisaged an unmanned OD-2 version where the place for a man in the spherical module would be occupied by photo-reconnaissance equipment [11], Korolyov liked this idea and approved the concept The earlier designs of a reconnaissance satellite carrying a cone-shaped capsule were abandoned, and the decision was taken to develop unmanned satellites of the same design type as a manned spacecraft, i.e with a large spherical re-entry capsule. In November 1958 the Council of Chief Designers took the important decision to first develop the manned version of the OD-2. So, work on the unmanned reconnaissance version was somewhat pushed aside [11]. In summer 1959 the OD-2 programme received a new name -Vostok. The programme envisaged building a few versions of the Vostok spacecraft The R&D experimental version (developed under a government decree dated 22 May 1959 [12]), which was intended for tests of hardware both for manned and reconnaissance satellites, received the name Vostok-1 (designation Object 1K). Other designations were: • A reconnaissance satellite - Vostok-2 (Object 2K); • A spacecraft for manned missions - Vostok-3 (Object 3K); • The forthcoming high-resolution photo- reconsat - Vostok-4 (Object 4K) [13]. 8A92 - The Launcher of the Zenit-2 Spacecraft By a decree of the Soviet Government passed on 25 May 1959, OKB-1 was authorised to design the reconnaissance satellite [14], Object 2K, based on the Object 1K, and launch vehicles for launching it into orbit However, throughout 1959 and the first half of 1960 this programme proceeded slowly due to pressure of work on the manned space programme. At that time three-stage launchers 8K72 had flow a few times with Moon probes of the E-series, but the 8A92 and 8A93 launchers continued to remain on paper only. In the end, project 8A93 shared the same fate as 8K73, where due to problems with the development of Glushko's engine 8D711 (RD-109) for Stage 3 the project was cancelled. At the beginning of 1960, the programme for the first Soviet reconnaissance satellite was renamed once more when Vostok-2 became Zenit-2 and Vostok-4 became Zenit-4 to distinguish them from the manned spacecraft Vostok. During 1960-1961, project 8A92 underwent some changes. The final design of the launcher 8A92, completed in the summer of 1961, envisaged use of the improved ICBM 8K74 (R-7A) as the basic assembly of Stages 1/2 instead of the earlier 8K71 missile. The third stage (Block E) would be basically the same unit as used in the 8K72K vehicle, i.e. the launcher of the manned Vostok spacecraft (Spaceflight, June 1996, p.207) but equipped with an improved inertial control system and a new telemetry system. The control system would ensure a high level of accuracy of placing a satellite in orbit The third stage was powered by the 5.56 t thrust Kosberg engine 8D719 (RD-0109). In March 1962 the first 8A92 launcher was assembled at OKB-1's Experimental Plant No. 88 in Podlipki (near Moscow) and then went through tests together with its pay-load, satellite Zenit-2 (Product 11F61) No. 3 (the first two spacecraft had been luanched by the 8K72K launcher due to a delay in designing and building the 8A92 vehicle). Also, just as the 8K71 ICBM was earlier adapted to receive Stage 3 (Block E) and become the launcher 8K72 (Spaceflight, February 1996, p.51), so the basic ICBM 8K74 was modified in the same way to become the combined Stages 1/2 of the 8A92. In early April 1962 the 8A92 launcher was sent off to the Tyura-Tam Test Range for the first launch.
References
íà îñíîâå ñòàòüè Soviet Rocketry which conqured space èç æóðíàëà
Spaceflight, Vol. 40, January 1998
äàííûé ìàòåðàë ðàçìåù¸í ñ ñîãëàñèÿ àâòîðîâ..