This study presents verification and validation methods for the power supply system of the Fine Guidance System experiment of the ARIEL satellite. Risk and reliability analyses were performed to assess the safety of the design. These include Derating alongside Part Stress Analysis, Worst Case Analysis and Failure Mode and Effects Analysis. Based on the results, recommendations for the power supply design are presented.Moreover, an active load compliant with the SpaceVPX standard was designed to efficiently verify the power supply. The proposed test system design is characterised by low cost, small dimensions and high accuracy. The required electronic modules were designed and tested, with the results discussed. Possibilities for further automation of test procedures and improvement of flaws and shortcomings in the developed electronic equipment are also discussed.

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