Over the last decade, terms such as big data and IoT have become part of our everyday vocabulary, and as time goes by, more and more systems are collecting larger amounts of data in order to provide new services or improve quality, and aerospace sector is not an exception. Space probes and rovers, which originally communicated with ground stations using S-band, have moved to higher frequencies in order to be able to transmit more information per unit of time. As the frequency of the system increases, the optical band is reached, 40 years ago, the first experiment in aerospace to demonstrate laser communication, the Airbone Flight Test System (AFTS), was conducted. Numerous efforts have been made to demonstrate that optical communications are possible. When sending an exploration mission, the scientific community maximises the performance of the instruments by taking into account multiple criteria, such as whether the particular device has been previously tested in space and the likelihood of failure. Therefore, the use of new technologies requires a process of multiple demonstration missions prior to be accepted. This thesis compiles the state of the art, i.e. the knowledge acquired over the last four decades, and covers three main points: ground infrastructures, the flight terminal and the method of communication between both systems. In the first point, the study focuses on explaining the parameters that must be taken into account when designing an international ground station network, equivalent to its counterpart in the RF band, NASA’s DSN networks or ESA’s ESTRACK, among others. One of the most relevant variables that determines the location of a ground stations are the atmospheric conditions. For this reason, a series of files containing information about the planet’s atmosphere has been downloaded and processed from NASA’s LAADS DAAC database. Secondly, the link equation of a signal emitted in optical band has been studied. Each of the terms that make up the equation are presented in detail in several sections, in particular the obscuration losses in Cassegrain type antennas, the pointing losses and those due to atmospheric absorption and turbulence. Finally, two practical studies have been carried out in which it is possible to see how the mathematics described in the previous chapters have been applied to execute missions whose purpose is to communicate in deep space. To achieve this, the JPL library and toolkit called SPICE has been used in a fictitious but realistic Mars-Earth downlink mission. Thanks to the high reliability of SPICE, all the data related to the orbital mechanics of a space mission has been obtained and compared, in order of magnitude, with a mission called Psyche and DSOC, scheduled for launch in August 2022. Apart from didactically exemplifying the terms of the link equation in a specific mission, key elements such as capacity or bit rate have also been retrieved, which allow immediate conclusions to be drawn in favour of this technology and thus contribute to its consolidation in the field of deep space communications
