TABLE OF CONTENTS O great computer, the task we have designed you to perform is this: We want you to tell us the Answer.
Lunkwill in Hitchhiker's Guide to the Galaxy, 1981
In general two groups may be seeking a computer "answer" to support spacecraft design and development. Spacecraft designers and developers need models and simulations to see how they can apply them throughout a space system's lifecycle in order to benefit its design, development, testing, and operation. But these models and simulations often aren't available to support designing, developing, and integrating the payload and spacecraft bus, so developers must create them to meet this need. The second group, models and simulations developers, must build tools the first group needs and therefore must understand what their capabilities and characteristics should be.
In the 1970s spacecraft modeling and simulation (M&S) focused on interfacing software for detailed design and analysis tools so planners also could use it to support trades on conceptual designs. For example, NASA's Langley Research Center developed the Aerospace Vehicle Integrated Design (AVID) approach, which interfaced inputs and outputs between analysis applications for structural, thermal, and control subsystems. Their next advance was M&S for Large Advanced Space Systems, by which users could interact through menus to do "top-down" design and analysis of spacecraft (Farrell 1982). Langley also sponsored other efforts, including a...
