Design and development of a 1-axis attitude control testbed for functional testing of EIRSAT-1

The performance of the Attitude Determination and Control Subsystem (ADCS) of a CubeSat relies on consistent and robust inputs from sensors to provide the actuation to manoeuvre and stabilise the satellite orientation in space. This paper details the design and manufacture of a 1-axis motorised testbed to perform pre-flight ADCS functional testing of a nanosatellite based on the CubeSat Standard. This testbed has been developed to support the Educational Irish Research Satellite, EIRSAT-1, a 2U CubeSat being developed in University College Dublin (UCD) as part of the European Space Agency (ESA) Fly Your Satellite! (FYS!) Programme. EIRSAT-1 is a student led project to develop, build, test and launch Ireland's first satellite. The project is a collaborative effort of staff and students across a range of disciplines including physics, engineering and maths. The design of the testbed allows all axes of the CubeSat to be tested individually. The design can be adapted easily to accommodate individual subsystem boards, such as an ADCS motherboard, in addition to larger CubeSat sizes, thus making it applicable to other missions. This testbed will be used to fully assess the functionality of the EIRSAT-1 ADCS motherboard, its inertial measurement unit, sun sensors, and magnetorquer actuation, first testing the Engineering Qualification Model (EQM) and then the Flight Model (FM). The testbed allows for polarity and performance checks of the sensors by comparison with known good reference sensor values. A controllable motorised rotating testbed allows for automated testing of the gyroscope and magnetometer. The performance of the five magnetorquers required for actuation is evaluated by an external magnetometer for each actuator. An easily adjustable artificial sun source allows for characterisation of the fine and coarse sun sensors response to change in angle relative to source. The testbed allows the satellite sensor and actuator outputs to be compared pre and post test procedures including ambient, vibrational and environmental test campaigns, in order to confirm full functionality or clearly indicate any issue