TABLE OF CONTENTS In closing this chapter, it is advantageous to reflect on certain engineering principles and trends for aerospace systems, taking into account the advent of MEMS technology.
MEMS designs by their very nature intimately merge structure and function. This merging suggests that at the smallest scales, mechanical structures should not be designed separately from electronics. In the distant past, the concept of merging electronics and mechanics did not exist, because there was no electronics. As electronics came into being, its applications to aerospace systems, which also did not exist, influenced the design of both. Significant amounts of structural attention must be given to electronics. For example, bulk real estate must be allocated. In aircraft, cooling plenums must be routed. Large electric generators must be co-integrated with engines. In spacecraft, similar facilities must be provided, but they are of a fundamentally different form. Thermal management is achieved through conduction, not forced air. And while the typical aircraft generates enough electricity to run many residences, many spacecraft operate on less power than a hairdryer. The requirements of reliability and maintainability in aircraft translate into special types of structures to permit the servicing and replacement of electronic components, and logistics is a significant expense for operational fleets. By contrast, space logistics is a far more limited concept, currently applicable only to the rare space station. From a serviceability (but hopefully not an operational) standpoint, most satellites are fire and forget .
The ability to dramatically...
