Space applications and technology in the 100¿1000 GHz frequency range

This paper reviews the key applications areas for spaceborne systems operating in the 100¿1000 GHz spectral range. The strong interaction between the atmosphere and e.m. radiation at these frequencies is discussed and its consequences in terms of applications stated. For radio astronomy the heavy absorption by the atmosphere forces space-borne telescopes to be employed and the primary radio astronomy objectives in this frequency range are reviewed. The presence of atmospheric molecular transitions at these wavelengths allows extensive atmospheric studies to be conducted especially by the limb-sounding of important trace gases in the upper atmosphere. The possible application of this frequency range to inter-satellite communication links is also described. A detailed account of the present development status of receiver hardware technology is given with special reference to the importance of heterodyne techniques for tuneable, high resolution high sensitivity receivers.