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Burroughs Mod I Guidance Computer
Display location: Museum blockhouse
Related exhibits:
- Atlas F and Transporter
- Atlas Booster Engine
- Atlas Vernier Engine
- Atlas Radio Guidance System
- Titan Guidance Computer
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At right is the operator's console, with the bank of plotters and paper tape readers and punches. |
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The large bank on the left is the main processor and memory modules. The unit in the foreground contains the power supply regulators. Power is fed from a motor-generator in a separate room. |
The Mod I version of this computer was the first in a series of computers built under contract by Burroughs Corporation as part of the WS-107A-1 Atlas ICBM program. There were four Mod I computers built by Burroughs, each designated by a "J" number. Computers J-1 and J-3 were installed in June 1957 at the General Electric Radio Guidance Center at Cape Canaveral Air Force Station. Computer J-2 was installed downrange in September 1957 at the San Salvador, British West Indies tracking station and used primarily by Range Safety. Computer J-4 remained at the Burroughs Military Field Service Division in Pennsylvania for engineering purposes.
The computer on display at the museum is the J-4, donated by Burroughs Corporation. It was one of the earliest exhibits to be placed on display at the museum arriving in May 1965. The Mod I is one of the earliest transistorized computers built and the very first entirely transistorized guidance computer built. Only 17 of these guidance computers were ever built. The Mod I and II versions were for research and development purposes. The Mod III was deployed with the first operational Atlas ICBMs of the Strategic Air Command and quickly gained a reputation for their extremely high reliability.
Computer J-3 was removed from the Cape and returned to Burroughs in 1959. It was replaced by an updated Mod III (A-1) computer credited with supporting hundreds of launches at the Cape. The J-1 and J-2 computers were removed from service in 1961. The J-1 computer was donated to the Smithsonian Air and Space Museum but is not on display at this time.
Over their operational lifetime, the Mod I and Mod III computers
supported 378 missile launches with guidance, range safety, or both
functions.
Not one single mission failure or premature mission
termination was attributed to the computers. They were used to
control the powered flight of all Atlas rockets during the research
and development (R&D) phase of that ICBM program, including the
Atlas D units used on the NASA Mercury man-in-space program. Other
supported launches included selected Titan I, Titan II, Nike-Zeus
and Thor Able rockets.
Before guidance computers were sufficiently miniaturized to be placed inside the rocket (see the Titan Guidance Computer), a ground-based computer was necessary to provide those commands. Tracking radars provided rate and position data to the computer which then sent course correction information back to the rocket. The computer also provided additional commands for events such as staging and engine shutdown. A simplified diagram of this closed-loop type of guidance system (left) was provided by Burroughs Corporation.
The Radio Guidance Center at the Cape used an array of five receiving dishes, four of which were located in a 90 degree configuration to the line of flight. The fifth antenna was located just outside of the building and served as both a transmitting and receiving antenna. The transmitting function sent guidance commands to the rocket during powered flight.
During the Mercury manned space program, the Burroughs computers, in addition to serving the guidance needs, sent 1002 bits per second of tracking data to the Mercury Control Center. There the data stream was merged with Eastern Test Range tracking data and forwarded to Goddard Space Flight Center for processing by their IBM 7094 computer complex.
A more complete historical summary of the Burroughs guidance computers with a focus on the museum's Mod I is available for download and viewing in Adobe PDF form. This document is large and, depending upon your internet connection speed, may take significant time to download for viewing.
