HISTORY - Page 55
experienced during the trajectory. All information was
then fed into the control computer—attitude
information from the ST-90, angle-of-attack signals
from the angle-of-attack meter, and guidance signals
from the guidance computer—which assimilated the
information and signaled the hydraulic actuators for
such actions as swiveling the main and vernier
engines or operation of the jet nozzles
71
.
The target date to accomplish firm G&C plans was
November 1956, and this was met. Specifications were
furnished to the Ford Instrument Company for the
delivery of the ST-90 in January 1957. A testing program
was then under way until October 1957, when JUPITER
Missile 3 was used to flight test the ST-90 and related
components. It worked
72
.
Propulsion System
Perhaps one of the most difficult of the development
problems to resolve was in the propulsion area, an
item over which ABMA had the least control. The heart
of the system was the main engine, a component
commercially produced by NAA. As earlier mentioned,
the supply source was saturated in satisfying the
demands of four long-range missile systems. Since the
Air Force was in charge of the development of three,
ABMA's requirements had considerable difficulty in
being met. Also, ABMA thought that the NAA engine
was only marginal in satisfying JUPITER needs, yet
there was little opportunity for NAA to enter into a
large-scale research program. To ABMA's way of
thinking, the over-all engine program should involve
one
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71. Ibid.; JUP Dev Plan, FY 58, 29 Sep 56, Hist Off files.
72. JUP Prog Rpt for Nov 56, 8 Dec 58; JUP Prog Rpt for Oct 57, 8 Nov 57, Hist Off files. 73.
Study, Liquid Rkt Engine Dev Prog, 19 Jul 56, Hist Off files.