Preliminary Thermal Analysis with MATLAB

Preliminary thermal analysis was performed using in-house MATLAB code developed during the thermal analysis of Iris. This transient model assumes no active thermal control system, and approximates each module as a lumped mass experiencing radiation and conduction. A 3U CubeSat with deployed wings, similar to Iris, was placed in a 550 km sun-synchronous orbit. A 6U CubeSat was not used for this preliminary analysis as the MATLAB model was already set up and tested for a 3U, and the differences between the two sizes are expected to be relatively minor. The satellite was assumed to never enter eclipse, as LI Bus will see very short eclipses very infrequently. Additionally, due to the relatively high structural mass of LI Bus, it is expected that the temperatures will not drop significantly during the short eclipses. The periods of constant exposure which were modelled provide the 'hot' steady state temperatures across the satellite. 

The results of the preliminary thermal analysis are shown in the chart above, with each solid coloured line corresponding to a different node in the spacecraft model, and the two dashed lines emphasizing the bounds of the stead state temperatures. These temperatures vary between approximately 55°C and 66°C. The model was analysed with both black and clear anodization applied to the bus, and a difference of only a couple degrees was seen across all nodes. As such, clear anodization will likely be used to improve the optical visibility of the CubeSat.