EMC testing of Expert Payloads
The Qualification Models (QM) and Flight Models (FM) of the payloads on board Expert have undergone an extensive EMC test campaign to verify the adequacy of their designs. The tests were performed in the Maxwell facility in ESA’s ESTEC research and technology centre in The Netherlands.
The EMC & ESD facility.
The tests were performed in the EMC & ESD facility in ESTEC. The chamber consists of a shielded enclosure, commonly called a Faraday cage, with continuously conducting metal walls, floors, and ceilings. The walls and ceiling are lined with an absorbent, anechoic material designed to attenuate the reflected electromagnetic energy. The floor is lined with ferrite absorbers and mobile resistive absorbers. The wall opposite the main door is lined with air-cooled high-power resistive absorbers capable of dissipating up to 3 Watts per square centimetre. Ceiling and floor absorbers are specially coated to prevent particle release so as to preserve the class 100 000 cleanliness level.
The EMC test campaign
The EMC test campaign involved the payloads that have a data acquisition unit connected via a serial link to the Data Handling Unit (DHU) of the main on board computer. Those payloads are Payload 2 a set of pyrometeters for measuring temperature of Thermal protection System, Payload 3 a set of Pyrometers devoted to investigation of gas surface interaction and catalytic phenomena, Payload 6 devoted to the instrumentation of a flap, Payload 8 an IR camera and Payload 10 a spectrometer for chemistry characterization of plasma during re-entry.
The QM units underwent a complete EMC test campaign to reach full qualification of the proposed designs, which covered:
- Electrical Bonding
- Grounding & Isolation
- Conducted Emissions (CE)
- Conducted Susceptibilities (CS)
- Radiated Emissions (RE)
- Radiated Susceptibilities (RS)
- Electrostatic Discharge (ESD) (conducted and radiated).
During the EMC testing of the Qualification models the following points were identified, improving the payloads Flight Models design:
- The inrush current to the DC/DC converters was over the requirement for some payloads.
- Susceptibility from radiated electric field of the link between the camera and the computer of Payload 8 for some frequencies.
- Bonding measurements showed that some components had a bigger value than the requirement.
- Radiated emissions of electric field over the required limit were detected during the test for some frequencies.
Conducted susceptibility of differential mode on the main power cables of the payloads was over the required threshold.
Actions were taken in order to solve such issues. As a result the EMC test campaign of the Flight Model, performed from June till October 2009 was fully successful.
After the acceptance campaign, the payload FMs have been shipped to the Prime Contractor’s premises for integration in early autumn 2010.
The availability of a state-of-the-art EMC facility at ESTEC not existent at the Principle Investigator’s premises was a key for the success of the Expert Payloads EMC test campaign. This allowed an efficient coordination of the campaign and provided the Payloads providers with feedback in order to solve EMC issues and increase the reliability of the instrumentation.
For further information contact:
Nickolaos Panagiotopoulos,
Expert Avionics Engineer
Nickolaos.Panagiotopoulos@esa.int
