M u l t i b e a m s a t e l l i t e c o m m u n i c a t i o n s systems are expected to play an important role in constructing economical and highly reliable communications networks in combination with terrestrial networks. They will provide a t t r a c t i v e n e w c o m m u n i c a t i o n s s e r v i c e s promptly and widely.NTT is making intensive efforts in the research and development of multibeam satellite communications systems and is planning to carry out flight vcrification of the system using Engineering Test Satellite-VI (ETS-VI) which will be launched in 1992. This paper describes the configuration and characteristics of the experimental systems for fixed and mobile satellite communications.