Speaker
Description
QARMAN is the "QubeSat for Aerothermodynamic Research and Measurements on AblatioN" of the von Karman Institute of Fluid Dynamics (Belgium). It is the world’s first CubeSat designed to survive atmospheric re-entry. The main aim of the QARMAN mission was to demonstrate the usability of a CubeSat platform as an atmospheric entry vehicle.
QARMAN is a 3U CubeSat whose thermal design is based on a front cork-based ablative thermal protection system, and on internal heavily-insulated survival units protecting key equipment. It was launched in December 2019 and deployed in orbit from the ISS on 19 February 2020. It was operated for 5 months, demonstrating proper functioning of the main subsystems. QARMAN unexpectedly stopped transmitting on 14 July 2020.
An extensive failure analysis has been carried out with the support of ESA experts. The last received beacons showed increasing temperatures for OBC, UHF, and ADCS. Mission analysis (ran with STK software) showed that this peak of temperature coincide with QARMAN being exposed to constant sunlight (instead of the typically alternating 60 min sunlight / 30 min eclipse). This pointed towards a thermal-induced failure caused by an extended sunlight period. This scenario was further investigated by running extensive thermal analyses with ESATAN-TMS software, including model correlations based on TVAC and orbital data, and prediction of thermal behavior over the period of interest. The thermal analysis did not permit to conclude with certainty on the root cause of the signal loss failure but batteries can be considered the most at risk, reaching the upper part of their nominal range and being a critical element of the system.
The proposed presentation will introduce QARMAN and its thermal design, before detailing the failure analysis. It will emphasize the post-mission thermal analysis process, which was based on sometimes scarce data and required strategies to overcome the limitations of ESATAN-TMS (not permitting the propagation of orbital elements). The conclusions will be shared and opened to discussions and suggestions.
