Apollo Mission Simulators & Computer Control Company’s DDP-224

The exceptional work done by NASA personnel and by highly expert contractors from Computer Control Company and others helped bring the U.S. into a leadership role in the early manned space program. One of the secrets behind the success of NASA’s Moon missions was the usage of specialized training with the help of highly complex computer simulators.

In the Mercury, Gemini, and Apollo programs, Astronauts spent one-third or more of their training time in simulators. Early Gemini simulators were a combination of analog and digital components. The control panel of an Apollo simulator was controlled by highly-skilled NASA personnel. During the Apollo program, the use of digital computers to control simulators was essential. The Apollo guidance computer onboard the actual spacecraft was emulated using specialized software running on DDP-224 computers.

Apollo Mission Simulators

Apollo Mission Simulators – Command Module Mission Simulator (CMS) and Lunar Module Mission Simulator (LMS). You can find one CMS and one LMS at Kennedy Space Center (KSC). The other CMS and LMS are located at the Manned Spacecraft/Johnson Spaceflight Center (JSC). The picture below shows the two simulators located at KSC.

The Apollo mission simulator was 65 feet wide, 30 feet high, and over 100 feet long. It weighed 40 tons and was required for DDP-224 computers for simulation functions. By the time a human-crewed space mission is launched, flight crews and ground support crews have flown the mission hundreds of times thanks to the computerized simulators.

For astronaut training programs, systems planning engineers design both the hardware and the software to make the simulators very realistic. In the Apollo command module simulator, most spacecraft systems are represented. Digital computers perform real-time computations that put trainees into convincing spaceflight situations.

The sense of reality is heightened by simulated spacecraft characteristics, flight dynamics, and visuals. And sound effects from control panel lights to jet and rocket noise. The lunar module simulator is also an all-digital simulator with three computers using coordinates based on mathematical models to simulate the spacecraft and the lunar landing phase of a mission.

As in the command module trainer, the primary guidance navigation and control system simulation is the most significant part of the training procedures. In the lunar module itself, the controlling element in the system is an onboard digital guidance navigation and control computer.

DDP-224

DDP-224.
DDP-224.

The LINK GROUP of General Precision Systems Incorporated built the Apollo mission simulator under contracts with North American Rockwell and NASA. The lunar mission simulator was built under contracts with Grumman Aircraft Engineering Corporation and NASA. Simulators were installed at both the Houston, Texas facility and the Kennedy Space Center facility in Florida. Computers were used at each flight simulation installation. Model 224 was a faster and more powerful version of the model DDP-24.

Both used similar technology and components. Modular board design helped facilitate service and upgrades. The Computer Control Company was a pioneering microcomputer company formed by Dr. Louis Fain, Robert Massard, Bill Horton, and others who had worked on RAYDAC, Raytheon Digital Automatic Computer, for the Navy’s Bureau of Aeronautics in the late 1940s and early 1950s. Founded on October 30th, 1952, it moved from Wellesley to Framingham in 1959. It also established a West Coast office in Los Angeles, California.

DDP-224 Summary Overview

  • Type: General Purpose, Solid-State, 24-bit, mid-size.
  • Date of First Installation: December 1964.
  • Average Purchase Price: USD 94,000 -USD 96,000.
  • Average Monthly Rental: USD 3,300.
  • Total Numbers of Systems Installed (1964-1969): 60.
  • Manufacturer: Computer Control Company, Inc. (“3C”).

(Note: 3C was purchased by Honeywell, Inc. in 1966).

DDP-116

DDP-116
DDP-116.
  • The first 16-bit minicomputer.
  • Memory was available in either 4K or 8K 16-bit word configurations.
  • Speed 1.7 microseconds.
  • Cost about USD 28,000.
  • About 250 were sold worldwide.

Computer Control Company developed various custom-engineered special-purpose digital equipment for scientific and military applications, including top-secret projects. It became widely known for its highly successful DDP computers based on the innovative DDP-116 computer designed by Gardner Hendrie around 1964. In 1966 the company was acquired by Honeywell and became the “Computer Control Division” of Honeywell, incorporated that same year.

Honeywell won a 4.2 million dollar contract to supply DDP-224 computers to NASA. They became key components in NASA’s computerized flight simulation programs. In 1970 Honeywell acquired General Electric’s Computer Division and formed Honeywell Information Systems. It stops producing the DDP product line around that time. Existing DDP system installations continued in use for many years. More than 60 DDP- 224 computers were shipped worldwide, many to NASA and other government facilities.

Thank you for taking the time to read this article. Please feel free to browse my website for more exciting facts about the Apollo Program and the mission to the Moon.

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