Patenting in the space sector is not as common as in other sectors, as commercial discretion and institutional confidentiality are often still priorities for some space systems. There are only a few hundreds patents a year. Still, the number of space-related patents has almost quadrupled in 20 years, as revealed by the applications filed under the Patent Co-operation Treaty (PCT). The space application areas (i.e. satellite navigation, earth observation, telecommunications) have also gained in importance in a decade.