Power GaN on Silicon is an emerging technology that can contribute to space electronics development. The heavy-ions environment is one of the limiting factors on the use of this technology in space especially in regards to high voltage applications and significant margins are currently used to account for potential risk related to a harsh space environment. An improvement in the understanding of the sensitive cell characteristics shall help to better define those margins and potentially extend the use of this technology bricks in the power space landscape. The main idea is to develop a new characterization scheme to better scope this limitation, notably by extending the radiation safe operating area characterization with the use of tilted heavy ion beam. Based on those results, the sensitive volume of such technology shall be modelled and pave the way to build radiation risk assurance guidelines. This study shall complete the current European projects (H2020 Call, GSTP) that strive for developing an European independent access to key technologies such as wide band gap electronics that are identified in our technologies roadmap.