Full thermal network model of the SMOG-1 picosatellite

This model was developed to conservatively estimate the thermal behavior of the SMOG-1 picosatellite using a thermal network model.

The SMOG program was launched in 2014 to build a successor to MaSat-1, the first entirely Hungarian satellite. The SMOG refers to electrosmog since the majority of broadcasting signals end up in space, becoming electromagnetic pollution. Since the primary payload, a spectrometer, does not consume much power, the picosatellite platform (5×5×5 cm or 2"×2"×2") was selected to cut all the launch and development costs and development time. The SMOG-P satellite was launched on December 6, 2019, to an elliptic orbit with 97° inclination, 353 km perigee, and 403 km apogee. Due to this low orbit, the satellite returned on September 28, 2020, completely burning in the upper atmosphere. The SMOG-1 satellite was launched on March 22, 2021, with an inclination of 97.6°, apogee: 567.6 km, and perigee: 537.6 km.

The MaSat-1 development team did not perform detailed thermal calculations; several operating satellites were orbiting without such problems. However, no fully operating picosatellite existed before the SMOG-P. Therefore, thermal modeling was treated as a critical issue due to its fractional total heat capacity, endangering the operation of the battery if the temperature fluctuations are excessive. The satellite was modeled in both Simulink (long-term operation, limited to 11 nodes) and ANSYS Workbench (short-term operation with detailed thermal behavior).

The model consists of one node for each of the six side panels and the five panels inside. Heat propagation is possible only via thermal radiation and conduction in space. Most model parts focus on the latter, considering the view factors between all sides. The model considers the angular velocity of the satellite besides the lit/shadow of the orbit. The model contains all parameters and is ready to run upon downloading. It also exports the temperatures of most PCBs and the battery.

This model is considered complete, and only critical errors will be corrected.