ATLAS HISTORY April 2009
By: Ed Bock
Project
SCORE was the World’s first communications satellite. It was
launched by an Atlas rocket on December 18, 1958. SCORE, an
acronym for Signal Communications by Orbiting Relay Equipment, captured
world attention by broadcasting a Christmas message from President
Dwight D. Eisenhower. The SCORE satellite equipment was integral
with the Atlas Sustainer stage and became the largest object placed in
orbit up to that time. Launching the entire Atlas Sustainer stage
into orbit is the closest anyone has ever come to demonstrating
single-stage-to-orbit (Atlas had 1-1/2 stages; a jettisonable Booster
engine section and the Sustainer stage with Sustainer and Vernier
engines, avionics, an integral nose cone, and all the propellant
tankage).
March 1958 was the middle of the cold war with the
Soviet Union and the early phase of the space race. The USSR had
launched Sputniks 1 and 2 on October 4 and November 3, 1957, for a
total mass in orbit of 1304 pounds. The US had only managed to
orbit several Explorers on Jupiter rockets, while the Vanguard suffered
an embarrassing (and usually spectacular) series of failures.
Total US mass in orbit: 65 pounds. Then in May 1958 came Sputnik
III. The Atlas ICBM was in its early phases of development
testing. By June 1958, eight Atlas A vehicles (non-jettisonable
Booster engines and propellant tank with no Sustainer engine) had been
launched (3 successfully). Atlas B vehicles (jettisonable Booster
section and Sustainer stage) were just starting their flight tests.
Early Atlas flight test results indicated that it would
be theoretically possible to orbit the entire Sustainer stage if enough
non-flight-critical hardware (such as tracking, telemetry and range
safety equipment) could be removed. The 150 pounds of SCORE
electronics was developed over a six month period by the US Army Signal
Research and Development Laboratory (SRDL) at Fort Monmouth, New
Jersey, under the then new Advanced Research Projects Agency (ARPA),
the fore runner of DARPA. President Eisenhower was reluctantly
persuaded to “give it a try” as long as the attempt remained secret
until SCORE achieved orbit. If news of the project leaked, the
government people involved would lose their jobs.
Atlas flight
tests were ballistic trajectories, so the changes needed in vehicle
hardware and software (guidance equations) had to be achieved via
subterfuge and obfuscation by the smallest number of people. This
was accomplished by “Club 88”, the 88 people who were briefed on the
project to orbit an Atlas; including 22 military/government, 26 STL
(USAF technical advisors), and 19 General Dynamics Convair
engineers. The civilians were told that they would lose their
security clearances if any leaks occurred. To disguise what was
to be attempted, several flight sets of light weight conical nose cones
and adapters were ordered. Rocketdyne engine set acceptance test
firing data were screened to pick the highest performing engines.
A vigorous Atlas weight reduction effort was initiated under the guise
of demonstrating a 6000 NM ballistic trajectory. A single GD
Convair guidance engineer was selected to develop the equations for
orbiting Atlas. Atlas 10B was designated as the SCORE
vehicle.
At 17 November 1958, the Atlas B flight test record
stood at six attempts with three failures, including the last
two. President Eisenhower was very nervous and withdrew his
support, but an intensive lobbying effort by program personnel
turned him around. Fortunately, the Atlas 12B flight on November
28 was fully successful, demonstrating the full operational range
requirement of 5500 NM. The engines on 10B were switched out in
the San Diego factory with a higher performing set and the vehicle was
shipped to Cape Canaveral and erected on Complex 11. The Flight
Readiness Firing was accomplished with all the normal ballistic
trajectory hardware installed. Then two days before launch, the
equipment needed for SCORE was substituted and all non flight critical
hardware removed, including AZUZA tracking and Telemetry. All
unused brackets welded to the propellant tank were snipped off.
The wire carrying the signal for Sustainer Engine cutoff was cut,
taped, and hidden back into its harness. During the night before
launch, the reentry vehicle with dummy warhead was replaced with a
light weight conical nose fairing, and the Range Safety Receiver was
removed. All these changes were authorized by verbal orders
with no formal paperwork. Because President Eisenhower’s taped
Christmas message would not arrive until launch day, it would have to
be uploaded in the clear to the onboard tape recorder. This was
accomplished by a SRDL trailer parked several launch complexes away and
rumored to belong to the CIA.
Launch day weather was good, the
countdown was smooth, but the initial attempt was scrubbed by a ground
system interlock with the missing AZUZA equipment. A jumper fixed
the problem, countdown was recycled and Atlas 10B was launched.
Its initial trajectory during Boost phase was outside nominal and
almost reached the destruct limit line, but the Sustainer guidance
corrected back to near nominal. The Cape Canaveral Range Safety
Officer was a Club 88 member, and with the Atlas’ Range Safety Receiver
removed, he had no vehicle destruct capability. JPL in
California, who thought they were looking for a test ICBM, confirmed
that orbit had been achieved. The actual orbital parameters were
an inclination of 32.3 degrees, apogee of 787 NM and perigee of 98.5
NM. The orbit was more elliptical than planned due to larger than
predicted propellant residuals. The goal was 32.0 degrees, 550
NM, and 101 NM, respectively, with Atlas to remain in orbit a minimum
of 5 days, but it achieved 34 days.
President Eisenhower’s message played repeatedly for 12 days:
“This
is the President of the United States speaking. Through the
marvels of scientific advance, my voice is coming to you from a
satellite traveling in outer space. My message is a simple
one. Through this unique means I convey to you and all mankind,
America’s wish for peace on earth and goodwill toward men everywhere.”
The
Atlas’ 8660 pound 75 foot long Sustainer stage with SCORE electronics
was then the heaviest and largest object launched into orbit, and SCORE
was the world’s first communications satellite. The broader
significance was that it demonstrated the practical operation of a
satellite radio-relay system with intercontinental capability.
And, for a very brief period, we were ahead of the USSR in the space
race.
Sources and Resources
Atlas, The Ultimate Weapon -- Chuck Walker 2005
The Talking Satellite: A Reminiscence of Project SCORE -- Deane Davis
Published in the British Interplanetary Journal, Volume 52, 1999
Curt Johnston’s Atlas History - Atlas 50 Year Reunion, July 2007
Wikipedia, Project SCORE
Military Space Programs, SCORE http://www.fas.org/spp/military/program/com/score/htm