Abstract: The effect of the natural space environment on the design, development and operation of spacecraft is discussed by a series of NASA reports compiled by Electromagnetics and Aerospace Environments Branch, Systems Analysis and Integration Laboratory, NASA Marshall Space Flight Center. Among these reports, NASA RP-1390 contains a detailed discussion of seven major environmental issues, including their definitions, related design concerns, and their influence on spacecraft subsystems. Typical cases of more than one hundred spacecraft failures and anomalies that took place during 1974~1994 related with natural space environment are provided in NASA RP-1390, with statistic analyses which may help spacecraft designers and managers to minimize the risk and optimize the design in reduced cost to better accomplish the target flight mission.