Ensuring small satellite compatibility with EMI and EMC testing

EMI and EMC testing is intended to ensure that no electromagnetic interference will exist between:

• The launcher and the satellite 
• The satellite and the GSE 
• Different satellites in the same launcher  
• Different pieces of equipment with a given satellite

EMI/EMC testing consists of 5 kinds of tests:  

• Radiated emissions: Radiated emissions from the EUT are not more than a given level 
• Radiated immunity: The EUT is immune to radiated emissions from the environment 
• Conducted emission: Conducted emission is below a given level. In the case of a satellite, this refers to intra-satellite emissions from one subsystem to another.   
• Conducted immunity: A given subsystem is immune to emissions from other subsystems.  
• Self immunity: All subsystems working simultaneously do not produce interference with each other.  

EMI/EMC testing indicates to engineers whether a device is compatible with its electromagnetic environment and determines whether it will produce electromagnetic interference, or EMI, in real-world situations.

Electromagnetic Compatibility (EMC) tests are performed in an anechoic chamber for radiated emission/immunity (to avoid reflections) and using grounded planes (for conducted emission/immunity).  

An anechoic chamber is a room designed to absorb reflections of either sound or electromagnetic waves completely. They are also often isolated from waves entering their surroundings. This combination means that a person or detector exclusively hears direct sounds (no reverberant ), simulating being inside an infinitely large room. Electromagnetic Compatibility (EMC) testing of flight models needs a cleanliness level of ISO 8.  

ISO 8 is the least clean cleanroom classification. A cleanroom must have less than 35,200,000 particles/m3 particles > 0.5 µm and 20 HEPA filtered air changes per hour.