/specialCollection/MissileGap/1961/1961-04-25.pdf

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takeoff but four of the five engines, and per-
haps fuel tanks as well, are jettisoned at alti-
tude. The vehicle itself is probably of heavy,
airframe-type, welded aluminum construction.
108. Nosecone and Payload. The Soviets have
developed and tested ICBM nosecones of two
different weight classes, one extremely heavy
and the other somewhat lighter. Both are
designed for high speed re-entry. The pay-
load is protected from the heat of re-entry by
a type of ablative material which is different
from that used on any current US nosecone.
The very heavy nosecones, varying in weight
from 13,000 to 15,000 pounds and capable of
carrying maximum payloads of 6,000 to 10,000
pounds, were used on ICBMs launched from
Tyuratam in the first two phases of the firing
program. This class of nosecone was tested
extensively in firings to Kamchatka in 1959,
and was probably proof tested to 4,700 n.m.
Into the Pacific in October of that year. Most
of the firings in the 1960 phase of the pro-
gram used a lighter nosecone weighing ap-
proximately 8,000-9,000 pounds, capable of
carrying about 6,000 pounds of payload. This
nosecone was proof tested to 6,700 n.m. into
the Pacific in July 1960.
109.It is probable that the initial development
of a very heavy nosecone was made necessary
by the great weight required for high-yield
nuclear warheads when the Soviet ICBM was
first on the drawing boards, and by the Soviet
state of the art in re-entry techniques at that
time. Subsequent advances in Soviet nuclear
technology probably provided a high-yield war-
head suitable for use in a lighter weight nose-
cone."
110. Range. Nosecone weight is critical to
the range of the Soviet ICBM. Given the basic
similarity of the boosters used in all Tyuratam
launchings, Soviet ICBM with a very heavy
nosecone would have a nominal maximum
range of about 5,000 n.m. This range is sub-
ject to variations of some hundreds of miles
depending on missile trajectory, the latitudes
of launching sites and targets, and direction
" For a discussion of warhead yields, see Annex E,
"Estimated Present Nuclear Warhead Capabilities."
(Limited Distribution)
of fire in relation to the earth's rotation. So-
viet ICBMs with heavy nosecones could
achieve extensive coverage of US territory only
if they were deployed in northwestern USSR
or in the Soviet Far East. An ICBM with
lighter nosecone, however, would have a nomi-
nal maximum range of about 7,000 n.m., sub-
ject to the same variations. Soviet ICBMs of
this type could achieve full coverage of the US
from deployment areas virtually anywhere in
the USSR, including Tyuratam itself.
Performance Under Operatic:Inc-A Candit:ons
111. The data available for estimating Soviet
ICBM accuracy and reliability under opera-
tional conditions are far from adequate or ex-
act. We have taken into account the growing
body of evidence on Soviet test range results
and on Soviet state-of-the-art in critical sys-
tem components, at the same time attempting
to minimize the use of analogies to US mis-
siles. But even if we had exact data from the
test range and had examined the Soviet com-
ponents, the estimate of system performance
under actual wartime conditions would still re-
quire assumptions as to the capabilities of the
troops, the readiness of the units at the time
of firing, and the precise circumstances of em-
ployment, none of which can be known with
certainty in advance.
112. Accuracy. The Soviet ICBM guidance
system uses radio and inertial elements, in a
manner which differs in some respects from
US techniques. Inertial components within
the missile control most of the powered phase
of the missile's flight, with corrections made
by ground-based radio command only in the
last seconds before burnout. The data avail-
able to us are not sufficient to permit more
than an approximate determination of the
CEP of the Soviet ICBM system. We estimate
that with the present type of guidance, Soviet
ICBMs would have a CEP of about two n.m.
under operational conditions in mid-1961, but
the actual figure could be considerably greater
or somewhat less. The figure given is in-
tended as an approximation for an entire
ICBM force, with crews of various levels of
competence firing against targets at various
ranges.
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