Differently from geostationary satellites, all the other types of space orbits, including Low Earth Orbits, Medium Earth Orbits, High Elliptical Orbits, or orbits for interplanetary navigation, communicate with ground stations with radio links through slant paths in the troposphere with a time-variable elevation angle. At frequencies greater than 10 GHz, all these radio links are faded by rain. I have investigated how rain attenuation changes in slant paths to a spacecraft located at the Sun-Earth Lagrangian point L1. The results are valid also for communications with spacecrafts orbiting Mercury, such as the ESA Bepi Colombo spacecraft. The time distribution of the rain events during the 24 h is an important factor when the observation time is only during the daylight; therefore, the prediction of rain attenuation must consider only the rain rate collected during the contact time, according to the local climate.