Thermal design of the OUFTI-Next mission

OUFTI-Next is a CubeSat developed by the University of Liège
aiming to improve irrigation strategies. Thermal infrared imaging
is used to measure the temperature of crops and to assess their level
of hydric stress. OUFTI-Next is a technology demonstrator for an
ambitious project. The final objective is to launch a constellation
of satellites to achieve daily revisits over a particular location.
This Master’s Thesis focuses on the thermal modelling and
design of the satellite. Because of the early phase of the mission,
several spacecraft’s shapes and orbits have been considered
throughout this study. The goal was to determine the feasibility
form the thermal point of view and to guarantee that all the components
operate within their allowed thermal range. Various models
of increasing complexity have been implemented to analyze the
thermal behaviour of the satellite. The computation has mainly
been done with the Esatan software and the results have been
heavily post-processed by Matlab routines.
The thermal models highlighted the fact that some components
were not compliant with their permitted temperature range. To
solve this problem, several solutions have been implemented. Special
care has also been taken to maintain the payload as cold as
possible. Indeed, this critical element requires low temperatures to
operate properly.
Because the mission was only at its beginning, the different
thermal properties have not been fixed yet. Hence their influence
on the results has been determined and discussed at several stages
of the work thanks to sensitivity and uncertainty analyses.