This standard includes selected environmental exposure tests for hardware operating in earth orbit. The tests included are generally regarded as the most critical and the ones having the highest cost and schedule impact. This standard also includes functional demonstration tests necessary to verify the capability of the hardware to perform its intended function (with and without environmental exposure as appropriate). This standard specifies test levels, factors, margins, durations, and other parameters where appropriate. In some cases, these specifics are expressed statistically or are referenced in other NASA standards. The document defines a standard set of flight hardware test requirements, which provide the necessary verification of design adequacy and flight worthiness of NASA spacecraft.