Three dimensional model of a sail thrusted by Solar and Planetary Radiation Pressure

Solar sailing is by far one of the most intriguing and promising concepts for the space exploration since it is free from the need of carrying a propellant on board of the spacecraft. In literature, many studies have demonstrated the suitability of solar sailing for a wide range of different applications; however, up until now almost all of them have taken into account only the solar radiation pressure (SRP) to calculate the sail force. This assumption is acceptable for most of the missions but, since the planet emits radiation or reflects part of the one coming from the Sun, for planetary missions, a new contribution should be factored in the calculation of the total radiation pressure. Therefore, this work analysed the combined effect of both planetary radiation pressure (PRP) and SRP with a three-dimensional approach, extending a previous work developed for the two-dimensional case. The study has been focused, in particular, on the Earth and Venus; the first one for the remarkable amount of possible applications, the second one for the promising results obtained in the two-dimensional study. In the case of Venus, the PRP is the dominating contribution within a distance of about five planetary radii, while for the Earth this region is smaller and closer to the planet. Both for Venus and Earth, results show a potential increase in net acceleration and a change in optimal attitude to maximise the acceleration in a given direction; moreover, the PRP provides a force even in the eclipse area, where the planet blocks solar photons. Last part of the work analysed some manoeuvres with and without PRP, to compare the results on the change of semi-major axis, eccentricity and inclination of the orbit; furthermore, the effect of PRP on the capturing manoeuvre of Venus were studied. The results show that PRP has a positive effect on the performance of the sail, in particular for the changing of the orbital elements.