NASA and ESA Specification Systems for EEE Parts

Specification Systems for High Reliability E.E.E. Parts

A specification document is often referenced by a contract or procurement document. It provides the necessary details about the specific requirements.
Specifications may be written by government agencies, standards organizations and others (i.e. end-user normally referred as “Custom spec”)
The U.S. National Aeronautics and Space Administration (NASA) adopt MIL-STD-975 as Standards Electrical, Electronic and Electromechanical (EEE) Parts List, consisting of selected standard military specification part numbers approved for usage in NASA Space Programs, with the exception of Goddard specification used for thermistors, and are divided into two quality level classifications, Grade 1 & Grade 2 components which vary enormously between commodities and between individual specifications.

The European Space Agency (ESA) uses its own specifications for electronic parts. Two testing severity levels B and C are available where level B is the highest grade.
The ECSS-Q-ST-60C standard defines the requirements for selection, control, procurement and usage of EEE components for space projects.
This standard differentiates between three (3) classes of components through three different sets of standardization requirements (clauses) to be met.