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PRESENT DAY SOVIET LAUNCH VEHICLES
Although most observers of the exploration of space are quite familiar
with the various US launch vehicle families (Atlas, Titan, & Saturn),
their Soviet counterparts are still a mystery to most Western analysts.
This shroud of secrecy is encouraged by the Soviet government which, for
various reasons, has released little information on these launch
vehicles. However, given the few tidbits of data available from news
photos, orbital elements, and the rare Soviet publication, it is now
possible to describe the history and capability of the Soviet present
arsenal.
The following is a summary of the known major Soviet rocket engines and
their major characteristics. (Vacuum thrust is given in metric tons).
Number of Vacuum Chamber Specific Principal
Name Chambers Thrust Pressure Impulse Propellents Use
------------------------------------------------------------------------
RD-100 1 30 234 Alcohol/LOX R-1
RD-103 1 55 28 245 Alcohol/LOX SS-3
RD-107 4 102 60 314 RP-1/LOX A Class
RD-108 4 96 52 315 RP-1/LOX A Class
RD-111 4 166 80 317 RP-1/LOX SS-10??
RD-119 1 11 80 352 UDMH/LOX B Class
RD-214 4 74 45 264 RP-1/Nitric Acid B Class
RD-216 4 177 75 290 UDMH/Nitric Acid C Class
RD-219 2 90 75 293 UDMH/Nitric Acid SS-9??
RD-253 1 ? 400 ? UDMH/N2O4 D Class
As is well known, the Soviets began rocket research on their own
before the Second World War. The first liquid fueled engine developed
by Gird, an amateur rocket club, was called the ORM-1, and had the
distinction of being able to use both cryogenic and storable fuels, an
ability the Soviets utilized in later vehicles. This small program was
greatly aided by the capture of German V-2 rockets and scientists in
1945. The Soviets, as did the US, gained much experience studying the
German effort. The first post-war Soviet rocket, the R-1, a V-2 clone,
was launched in 1947, and was powered by the RD-100 engine, the first in
a long line of large German-influenced engines. In the early 1950's,
the Soviets developed the Shyster vehicle (dubbed the SS-3 by the US Air
Force), basically an improved copy of the V-2, for testing Soviet-built
components in ballistic flights. During this period, the Soviet
government decided that in order to send 10,000 lb. atomic bombs to the
US mainland, it would be necessary to develop a large booster, with much
greater capacity than the Shyster. Thus, Soviet scientists developed
the techniques of clustering and parallel staging simultaneously. This
entailed the use of a single turbo-pump per cluster, which led to the
Soviets adopting a distinct definition of an engine from the Americans.
The single 50,000 lb thrust engine of the V-2 was clustered in groups of
4, with a single set of turbopumps for each group. The core cluster of
4 (called the RD-108 engine, although it used 4 combustion chambers and
4 exit nozzles) was surrounded by 4 strap-on clusters (the RD-107, but
basically identical to the RD-108), for a total of 20 first stage
engines. After the vehicle left the lower atmosphere, the four
strap-ons were jettisoned, and the core cluster was to carry the warhead
on a ballistic flight to the US. This vehicle, known to the Air Force
as the SS-6, and referred to as the A-class launcher by the Library of
Congress classification system, became the first Soviet satellite
booster, launching Sputnik in 1957. With a single 12,000 lb thrust
engine added as an orbital stage, the A class booster was used to launch
the Vostok capsule. In the mid 1960's, a four chambered, LOX/RP1 fueled
engine was developed by the design bureau of the late C.A. Kosberg.
This 50,000+ lb. thrust engine replaced the earlier orbital stage on the
Soyuz booster.
Soon after the conception of the A class vehicle, the development of
the hydrogen bomb enabled much smaller warheads to be built, making the
large booster obsolete soon after its first launch. The core cluster
was immediately reconfigured into a missile in its own right, with the
engine now dubbed the RD-214. In order to decrease launch preparation
time, the Soviets converted the engine to use storable propellents,
nitric acid and kerosene, (as in the pre-war ORM-1). This combination
is much less efficient than the RD-107/108's LOX/RP-1 fuel, resulting in
a lowered thrust of about 150,000 lbs for the RD-214. The new launcher,
was deployed in Cuba and Eastern Europe as an intermediate range
ballistic missile and was dubbed as the SS-4 by the US Air Force.
Topped by an orbital stage, the hydrazine fueled 24,000 lb thrust RD-119
engine, this launcher, known as the B class vehicle, is the equivalent
of of the US Thor/Delta.
The RD-214 engine was later refined by the use of UDMH instead of
kerosene for fuel. This new storable fuel increased specific impulse
for the engine from 264 to 290 seconds. Thrust was increased to 380,000
lbs. through increase in chamber pressure from 45 to 75 atmospheres.
The engine was renamed the RD-216, and was installed in the first stage
of the C class booster. This new vehicle, the equivalent of the Atlas
launcher, replaced the earlier B class vehicle, and is now the third
most used space launcher in the world.
The primitive SS-6 ICBM was ineffective as a weapon. The Soviet
Union, faced with the need for a storable ICBM, developed a new missile.
The result was the SS-9, a 2 stage ICBM with 6 thrust chambers, using a
common turbopump, for the first stage. It is reasonable to suppose that
the tried and true V-2 design was again used in this new configuration
with hypergolic fuels for quick launch reaction and storability. It can
be expected that first stage thrust is greater than the 300,000 lbs that
the original LOX/Kerosene combination would have produced, due to higher
efficiency of the Hydrazine/UDMH fuel and Nitrogen tetroxide oxidizer,
and advances in turbopump technology that the Soviets can be expected to
have achieved in the 8 year period between the introductions of the A
class and the F class vehicles. The F class vehicle is roughly
equivalent to the US Titan missile in payload capacity.
The Soviets felt that the need existed for a larger space payload than
the A class, which was limited to 14,000 lbs. in low orbit, could
provide. A new engine, the RD-253, was developed. One of these engines
was used in the air-launched core vehicle for the new Proton vehicle,
with six RD-253 strap-ons as the first stage, giving a total thrust of
2.5 to 3 million lbs., and a payload capacity of 40,000 lbs. in orbit.
Details on the upper stage of the Proton are lacking, but it is possible
to provisionally state that the RD-219 could be a candidate. As the
RD-219 is claimed to be a second stage engine, with thrust of almost
200,000 lbs, a probable application for this engine is as the second
stage of the Proton, if one considers the external strap-ons as a zero
stage. The tentative configuration of the Proton is thus:
Zero stage (6 strap-on RD-253) 3,000,000 lbs (approx)
1st stage (one cluster) 500,000 lbs (approx)
RD-219 2nd stage 180,000 lbs
The Proton rocket is used to launch the Salyut space station, as well as
heavy military payloads.
It is well known that the Soviets maintain a heavy launch schedule.
Given the serial production of many thousands of the V-2 class engines,
which entailed little developmental costs (thanks to the Germans), it is
reasonable to assume that great economies of scale prevail in their
space effort. Whereas the US will spend hundreds of millions to develop
a launch stage that may be used less than ten times (as with the Centaur
G stage), the USSR has spent little on a family of boosters that
apparently utilize the same engine design. The U.S. at the beginning of
the Space Age also developed several boosters from a single engine
design, the H-1, which grew from 135,000 lbs to 205,000 over twenty
years. However, the H-1 family was soon superceded by many more
powerful and more efficient designs, and is now far from being the
leading edge of engine technology in the U.S. Apparently, the Soviets
have been content to stay with their basic original design, which has
grown from less than 40,000 lbs to now over 500,000 lbs of thrust. This
same paucity of engine research could explain the mysterious lack of a
liquid hydrogen engine in the Soviet arsenal. Although payload size
could be greatly increased with even the smallest of cryogenic stages,
the Soviets are apparently willing to forego the developmental costs in
favor of keeping program costs to a minimum. Given this low priority
for engine research, rumors of several new Russian launch vehicles seem
unfounded, as all of the rumors presuppose Soviet development of liquid
hydrogen engines that surpass US engines in efficiency. Given the
present advantage in engine R & D by the US over the Russians, it would
be highly doubtful that the Soviets will surpass us in engine technology
in the near term. Making these rumors more dubious is the fact that
present Soviet launch vehicles can launch all payloads that the Soviets
have announced for the foreseeable future, including the 1993 asteroid
flyby. Thus, one can probably count on seeing (or reading about) the
present group of Soviet vehicles for many years to come.