Passive intermodulation is a real threat to all types of payloads. In some cases, it could even lead to total lost of the spaceship. Despite of this, there is very weak understanding of the parameters that generate this unwanted interference as well as their influence in the amplitude of the interfering signal. In addition, there is a total lack of agreed testing techniques, procedures and methodologies as well as justified test margins, as has already been recently stated by the European community (National Delegations, satellite operators and Eurospace).

All satellites must have the ability to correct for the high rotational tip-off rates after initial release from the launch vehicle. On current navigation satellites, de-tumbling is usually achieved in short duration using the onboard chemical propulsion thrusters. With future Navigation satellites looking at using all-electric propulsion satellites, these manouevres are to be performed by xenon-fed auxiliary thrusters. COTS (xenon cold gas) auxiliary thrusters are limited in the max thrust level provided and the de-tumbling duration, in the absence of chemical thrusters, is a concern.

Control Moment Gyroscopes (CMGs) of compact size target the small satellite market, especially for agile attitude control of satellites with high-resolution optical instruments. With the ability to acquire high-resolution images, the swath width is typically limited by the narrow field of view of the instrument’s optics. In order to enlarge the field of view, an agile attitude control system is advantageous because the ground target area can be substantially expanded by pointing the entire satellite.

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