Abstract
In this chapter, the spacecraft charging effects that lead to ESD events, as well as the associated immunity testing required, are presented in detail and compared to the human-induced discharges, mainly simulated by most commercial ESD generators. Additionally, design guidelines for mitigating the effects of these ESD occurrences, essential for every space application designer, are discussed. Finally, the measurement requirements, as well as the test setups, regarding the immunity testing to power leads transients are described thoroughly. This chapter aims at reviewing the current international standards and the recent bibliography, summarizing and commenting on the EMC requirements, regarding the transient phenomena, pinpointing the differentiations of these standards and their effects on the design procedure and testing creditability.
TopIntroduction
Spacecraft in synchronous or lower orbits often experience a buildup of charge on the exposed and the internal materials as a result of geomagnetic storms. The resulting large potential differences can lead to insulator breakdown events and the generation of electrostatic discharges with peak values of a couple kilovolts. The generated electric current is coupled, in turn, to the electronic equipment ports disrupting sensitive digital and analog electronics with probably disastrous effects and potential system failure. Over the last decades, space engineers have introduced many ESD mitigation methods (selection of specific surface materials, grounding techniques etc.) on modern spacecrafts; nevertheless, the equipment-level immunity testing to ESD still remains the most reliable mechanism of failure prevention. International Standardization provides testing specifications which simulate as accurately as possible the flight ESD phenomena. In this chapter, the different test methods are described in detail.
Later, this chapter describes the phenomena of power bus transients induced by the switching on/off of loads on the bus presenting and commenting on the suggested measurements and immunity test methods by the associated Standards. Some of the Standards mentioned herein are the Military Standard MIL-STD-461, and its most recent version (G), the ISO 14302 Standard, specifying the Electromagnetic Compatibility requirements for Space systems, as well as the ECSS-E-ST-20-07C European Standard on Electromagnetic Compatibility for Space engineering by the European Cooperation for Space Standardization.
Summarizing, the scope of this chapter is to present the types and causes of transient electromagnetic phenomena encountered in the space environment, review and comment on the recent standardization efforts by the various associated bodies and suggest sufficient protection measures for a robust and electromagnetically compatible space system design.
More specifically, in the “BACKGROUND” section the electromagnetic phenomena expected to occur in the space environment and affect the aerospace systems, as well as their causes are described. The “INTERNATIONAL STANDARDS: TESTING AND MEASUREMENT PROCEDURES” section presents earlier and current testing methods according to different International Standards trying to establish the most accurate simulation and testing of the aforementioned phenomena. Differentiation points as well as the authors’ comments on the preferable methods are presented herein. Finally, the “SOLUTIONS AND RECOMMENDATIONS” section includes design guidelines and mitigation techniques against those types of electromagnetic disturbances crucial during the design process of every aerospace system.