You may find the European Space Agency's specifications more elegantly organized and easier to understand than NASA SPEC. The ESA spec includes nearly all the details of the NASA and applicable U.S. military specs, but benefits from being able to take a fresh look at how to organize and present the data.
The primary drawbacks to the ESA specs are their devotion to (and inconsistent use of) the French system of units and some rough spots where the authors seem to emphasize style over utility. So as always when working with specifications and especially with the metric system, be careful.
See notes at the bottom of this page for information on how to acquire copies of these documents. They are generally published as bound pamphlets on standard metric paper at a price of 10 euros each.
Space engineering: Policy and principles
System engineering process
Requirements def. and analysis
Spacecraft launcher interface
Human factors and ergonomics
Electrical and electronic
Verification and validation
Transfer, operations, and maintenance
Spacecraft data interfaces
Rendezvous and docking
Altitude and orbit control
Ground systems and operations
Mission operations requirements
Enginering aspects of ILS
"ECSS" stands for "European Cooperation for Space Standardization"
These specifications are controlled by:
Requirements and Standards Division
Noordwijk, The Netherlands
These specifications are printed in The Netherlands and published by:
ESA Publications Division
The price of each specification document is typically 10 euros.
ESTEC, P.O. Box 299
2200 AG Noordwijk,
For further information, refer to the ECSS web site.