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.