uHETsat small Power System for high demanding payloads

Coming right after the launch of the ESEO spacecraft, uHETsat will be the second mission based on the use of SITAEL S-50/75 microsatellite platform for IOV/IOD purposes. In this case the subject of the In Orbit Validation will be SITAEL HT100 Hall Effect Thruster (HET) -one of the smallest of its kind-that for the first time will be embarked and operated onboard a small platform. Starting from its predecessor, the spacecraft has undergone a series of updates and upgrades necessary to comply with the new set of mission requirements. Although some of the AODCS equipment has changed compared to ESEO [1], most of the efforts in the adaptation of the Power System (PS) were spent to handle the power required by the propulsion subsystem for its proper functioning. The PS re-design included a new set of deployable Solar Arrays (SA), a revised Power Management Board (PMB) and Power Distribution Unit (PDU), and a larger battery that will allow the mission to accomplish its goals: 2000 ignitions and 1000 hours of firing for the propulsion subsystem. Main objectives for this re-design activity have been the improvement of the overall reliability through a meticulous review of the components selection, at the same time preserving the single failure tolerance and the low cost approach (hybrid automatic-manual) in terms of manufacturing. The uHETsat PS is currently being accepted for flight and all its components have been tested as EQM showing the capability of the system to support both platform and payload operations. After a brief overview of the uHETsat mission, the focus will be moved to the PS architecture description, redundancies strategy and the single point failure free design approach.