The CCIR, considering that suitable operating frequencies and required radio-frequency bandwidths for near-Earth space research missions are determined by propagation factors and technical considerations; that two-way communication is required for many near-Earth missions, and is vital for manned missions.
ITU-R SA.364-5 SPANISH-1992 history
1992ITU-R SA.364-5 SPANISH-1992 PREFERRED FREQUENCIES AND BANDWIDTHS FOR MANNED AND UNMANNED NEAR-EARTH RESEARCH SATELLITES