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Vostok (A-1/SL-3) - A-l with Lunar Upper Stage

Soyuz-UThe Vostok (A-1/SL-3) class of launch vehicles is based on the original Soviet ICBM, the SS-6 Sapwood, which was first tested as a missile on 2 August 1957. Its first use as a space vehicle was only two months later, suggesting concurrent development as an ICBM and SLV. This ICBM provided, in various forms, the initial stages of a whole family of SLVs including the operational Vostok, Soyuz and Molniya SLVs.

The original version, the A vehicle (or SL-1/2) is classified as a one and one-half stage vehicle. It consists of a central core with four strap-on boosters. The Russians classified this as a two-stage assembly, but since the engines of the strap-ons and the central sustainer ignite simultaneously at lift off, this parallel staging arrangement is generally regarded as a one and one-half-stage vehicle. This vehicle launched the first three Sputnik satellites in 1957 and 1958. The third and largest Sputnik had a mass of 1327 Kg and was delivered to a 122 by 1016 nm orbit. All three A launches were conducted from TT.

To satisfy the need to launch bigger payloads, the Vostok (A-1/SL-3) was introduced in 1959. With an SS-6 first stage, the Vostok had a second stage attached by a trellislike structure. The initial version of the A-1 vehicle was used to launch the Luna moon payload. The payload fairing was then enlarged to launch the manned Vostok as well as the first-generation recoverable Kosmos satellites. With a larger and more sophisticated payload fairing used on the Vostok, the overall length of the booster increased to 38m from about 34m. Initially the Vostok was launched from TT and later from PK. PK no longer launches the Vostok, although the capability still exists.

Three or four weeks before the launch, the components of the A-class SLV are delivered to the Space Vehicle Assembly Building (MIK) assembly complex in up to seven parts (4 strap-on boosters, first, second and third stages). In a few days, the separate parts are horizontally mated. After a successful integration test, the entire SLV, with its payload, is carried on a rail transport-ererector car to the launch pad, then tilted up to sit on a stand over a huge flame deflector pit.

The payload or satellite is also delivered to the launch facility by rail. The prospective satellite first goes to the MIK for initial pre-launch check-out. It is then carried by a special transport to the fueling facilities several kilometers from the launch site. Once fully fueled, the spacecraft is transported back to the MIK for horizontal mating with the SLV and final pre-pad checkout. The launch structure for the vehicle employs four releasable support beams which accept the weight of the SLV. The SLV is suspended over the gas deflecting trough with its tail portion 7m below the level of the platform.

After ignition, the four support beams are initially held in place by the weight of the booster. Counterweights cause these four beams to fall back and allow the climbing SLV to clear the structure. The A-class SLVs are normally brought to the pad less than 48 hours before liftoff. They are capable of launching in severe weather conditions including dense fog, wind, rain and snow.

The view from the West

Considering the lead times involved in developing space vehicles, it is likely that well before the time of Sputnik, the Russians were designing and building an upper stage to fit on their original model ICBM, and this raised its orbital capacity to 5,000 kilograms, though its first use was for direct flights to the Moon with a net payload weight of about 400 kilograms.

This upper stage used for the Luna 1, 2, and 3 flights was the first Soviet spacecraft to be put on public display in replica. Mounted on top of the sustainer core by an open truss structure, it measures about 3.1 meters long and has a diameter of 2.58 meters. Strangely to this date the Russians have not announced the designator for the single nozzle engine or given its thrust. Its thrust should be on the order of 5 metric tons. We are left with a mystery in the Soviet accounts. They reported for some years that the total thrust of all the engines was 600 metric tons. Having then told us that the five engines of the core and boosters had a thrust of 102 metric tons each, by subtraction the upper stage thrust should have been 90 metric tons, which would have put a heavy G load on this stage when it fired. This is the amount of thrust of the Soviet RD-219 upper stage engine, but it has two nozzles, and the lunar stage engine has only one nozzle. When this rocket was used for the direct flights to the Moon, the lunar stage was accelerated to a speed sufficient to send it to the Moon along with the payload. The combined weight of spent rocket and payload was on the order of 1,500 kilograms. The lunar version of A-l is shown in figure 9. Another hypothesis considers these launches to be precursors of F-launched ocean surveillance satellites.

When the Russians were ready to begin test flights leading toward placing man in orbit, they used this same upper stage on the original launch vehicle. It was not until 1967 that a replica of Vostok 1, shown in figure 9b, was put on public display (Paris Air Show), and indeed, the upper stage of that assembly was essentially the same as the earlier unveiled lunar stage of 1959.

It was mentioned that at first Western analysts thought a much smaller rocket had been used by the Russians for the launch of Sputnik 1 because that payload weighed only 84 kilograms, and people at first were unaware of the great weight of accompanying rocket stage also in orbit. A second factor in the underestimation was the difference in design philosophy. For example, the early U.S. Atlas missile has such light construction that it had to be kept pressurized all the time to keep it from collapsing of its own weight in relation to skin thickness. This was done to maximize performance for a given size of vehicle. By contrast, when the Soviet launch vehicle arrived by ship at Rouen, France, observers were fascinated to note that the core and boosters were unloaded with cables attached at opposite ends, and workmen could walk the length of the empty rockets. The implication was the Russians did not feel weight-limited, and had built rugged vehicles which still permitted them to carry the payload they wanted, within reasonable limits.

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Page last modified: 03-06-2018 19:18:01 ZULU