-
Computers in Spaceflight: The NASA
Experience
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- - Chapter Four -
- - Computers in the Space Shuttle
Avionics System -
-
- Conclusion
-
-
- [133] The DPS on the
Shuttle orbiter reflects the state of software engineering in the
1970s. Even though the software was admittedly the key component
of the spacecraft, NASA chose the hardware before the first
software requirement was written. This is typical of practice in
1972, but less so now. NASA managers knew that time and money
spent on detailed software requirements specification and the
corresponding development of a test and verification program would
save millions of dollars and much effort later. The establishment
of a dedicated facility for development was an innovative idea and
helped keep costs down by centralization and standardization. A
combination of complete requirements, an aggressive test plan, a
decent development facility, and the experience of NASA, Rockwell,
Draper, and IBM engineers in real-time systems was enough to
create a successful Shuttle DPS.
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- Even as the system took shape, NASA
managers looked to the future of manned spacecraft software.
Increased automation of code and test case generation, automated
change insertion and verification, and perhaps automated
requirements development are all considered future necessities if
development costs are to be kept down and reliability increased.
In the 1980s, a new opportunity for software development and
hardware selection presents itself with NASA's long-awaited Space
Station. NASA has another chance to adopt updated software
engineering techniques and, perhaps, to develop others. Success in
space is increasingly tied to success in the software
factory.
