The ITU Radiocommunication Assembly, considering that the spectrum between 20 THz and 375 THz is available for communications in near-Earth and deep space environments; that for the proper planning of Earth-space systems operating between 20 THz and 375 THz, it is necessary to have appropriate propagation data; that methods have been developed that allow the calculation of the most important propagation parameters needed in planning Earth-space systems operating between 20 THz and 375 THz; that, as far as possible, these methods have been tested against available data and have been shown to yield an accuracy that is both compatible with the natural variability of propagation phenomena and adequate for most present applications in the planning of systems operating between 20 THz and 375 THz.