Computers in Spaceflight: The NASA
Experience
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- Part III: Ground-Based
Computers For Spaceflight Operations
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- Introduction
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- [205] NASA's ground
computer systems are characterized by large size, by the
implementation of real-time programming, and by the use of may
computers connected together. The need for these three attributes
has caused NASA and its contractors to devise new techniques for
computer applications, such as operating systems for mainframe
computers capable of handling real-time processing and
sophisticated networking. Through these developments NASA has had
its largest impact on computing in the commercial world.
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- Differences between ground-based computers
and on-board computers center on the relative ease of hardware
procurement with the continued difficulty of software development.
On-board computers evolved from custom-made systems to the largely
off-the-shelf Skylab and Shuttle computers. Ground computers
followed a more conventional line, as they could be, from the
beginning, commercially available systems, though applied to
noncommercial tasks. NASA examined many existing computer systems
each time it needed a machine. In fact, the government's bidding
process gave NASA a larger mix of different vendors' equipment
than most commercial enterprises, causing occasional difficulties
in connecting computers together. This problem and that of
adapting business machines to real-time processing were largely
solved by software. Contractors received invaluable experience in
large systems development and networking in the process of
achieving NASA's goals.
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- Ground-based computer systems are used for
preflight checkout and the launching of space vehicles,
controlling both unmanned and manned missions, creating
simulations of rocket flight for vehicle development and of space
flight for crew training, processing telemetry data from launch
vehicles and space probes, and in basic research. In the following
chapters these functions are grouped into launch processing,
mission control, and support tasks. Chapter 7 develops the concept
of launch processing from the manual era to the fully automated
Shuttle flight preparation. The chief result from this effort was
a large integrated network of computers that proved to be highly
innovative. Chapter 8 presents computer systems in both the manned
Mission Control Center in Houston and the unmanned control [206]
centers at the Jet Propulsion Laboratory (JPL) and Goddard Space
Flight Center. In Chapter 9, the uses of computers in simulations
and data reduction are discussed.
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