Research has been carried out in the THz region for several decades. Until fairly recently, the main drive came from applications such as radio astronomy, later followed by planetary, cometary and atmospheric science. Arguably, without these driving influences it is unlikely that many of the recent technological breakthroughs would have occurred. This paper presents an overview of space related applications and technologies, divided into three main areas: terrestrial science, astronomy and planetary/cometary science. The more traditional and some most likely future space applications will be treated.