development gradually
encountered more problems and delays. a decision was made to use some of
the tests, which were intended solely for checking out the capabilities
of the final three-stage rocket, to try to carry at least physically a
minimum satellite into orbit. The satellite was to be a small 6.4 inch
magnesium sphere weighing less than four pounds and to contain only a short-life
battery operated Minitrack transmitter, which would prove that it actually
had made orbit. This announcement was made by the DoD in August 1957. It-sent
us at SRDL into high gear of technological and crusading activities.
Since the inception of the Silicon Solar Cell by the Bell Telephone Labs
(BTL) in 1954, the Signal Corps had become keenly interested in exploring
the utility of solar energy for its purposes. We at SRDL started immediately
a research program with the Radio Corporation of America (RCA - Princeton)
to search for possibly more efficient materials than silicon. We also initiated
new efforts for associated storage batteries. particularly of sealed configurations
which would not require maintenance. 1 was personally deeply involved and
had in November 1955 the privilege of accompanying our chief Signal officer,
Gen' O'Connell, to the first World Symposium on Applied Solar Energy at
Phoenix, Arizona.
We did not uncover major Signal Corps application potentials at that time,
but it was quite evident that solar power was the logical way to power
satellites and space probes; in fact, solar power had long been considered
standard equipment in science fiction stories.
Accordingly, in our Lunchbox report in 1955 as well as at the Michigan
Symposium in 1956, we had made a strong pitch for solar power for satellites.
But our hopes were dimmed when the Navy ruled out all unconventional and
not fully established concepts. among them specifically solar cells for
the IGY payloads. This seemed an inconsistent philosophy since the Navy
hinged the entire project on an unconventional not fully established vehicle
concept!
But we were not discouraged and continued both our work and our crusade
and in July 1956, the Navy agreed to assist us in the evaluation of our
developments through testing them on sounding rockets. These tests were
then successfully conducted to altitudes of 192 miles in April 1957 at
White Sands. The Navy also agreed to include at least one solar cell as
aspect indicator in the first two IGY satellites.
Now, in August 1957.
with the plan to launch some minimum payloads in the form of little spheres
with the available weight unused except for a Minitrack transmitter. we
saw a splendid new opportunity to give our solar power supplies a free
ride. After considerable debate, our idea was finally accepted and three
of these mini-satellites. often called grapefruits, were outfitted each
with six clusters of sixteen silicon cells of BTL vintage to power a second
Minitrack transmitter in addition to the originally planned battery operated
type.
Two of these satellites never reached orbit when the Vanguard vehicle tests
on 6 December 1957 and 5 February 1958 unfortunately ended in failure.
But the third was launched on St. Patrick's day 1958 and became, under
the designation Vanguard I, the first successfully orbited satellite of
the Vanguard program. Solar power, as we had expected, functioned perfectly
and kept the associated Minitrack transmitter on the air for more than
six years. whereas its battery powered companion gave up after the |
This sphere is an exact
replica of Vanguard 1, which was successfully placed in orbit on St. Patrick's
Day in 1958. Its estimated life span is 200 years. Its solar cell power
kept the Minitrack transmitter on the air for more than six years.
short battery life.
Although it was not endowed with any specific scientific instrumentation,
this satellite. through the opportunity to observe the orbit over many
years. produced valuable new information on the shape of the earth, correcting
the long assumed elipsoid configuration to that of a pear.
We at SRDL were immensely proud. After this first demonstration of its
utility, solar power quickly attained standard equipment status on satellites
and space probes.
The US demonstration came none too soon: on 15 May 1958 Sputnik III was
in orbit and it included the first Russian solar power system.
The Navy, when later writing the history of Vanguard, hailed the solar
power test as the only constructive historic space first of the entire
program (a second first was a lessons learned type and consisted in having
found an explanation for problems in rocket-stage separation which cause
orbit insertion failures). But besides some small print references to the
Signal Corps' general fine attitude of cooperation and SRDL's solar power
work, the Corps, in spite of proper news media coverage at the time of
the event, is not specifically credited as the organization whose technological
foresight and perseverance made possible our solar power first - a first
which otherwise would have been chalked up on the scoreboard of the USSR.
The unexpected appearance of Sputnik I in October 1957 also had some far
reaching impact on top level US government organizations.
NASA
To get a better grip on the three services' diversified competitive efforts
in the overall missile field. a Director of Guided Missiles was established
on 15 November 1957 as a special assistant to the Secretary of Defense
and given wide ranging directive powers.
In a second step, it was decided that the aspects of military satellite
programs beyond the involvement in the. |
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