On active and passive CETI from an earth satellite orbit

Abstract

Scientific and technical problems of the project (Subotowicz, 1976) were discussed in detail (e.g., single- or multiantenna system, frequency range, kind of orbit, corrections to antenna shape, role of thermal heating, gain of antenna, possible perturbations of the orbit, undesirable motion of the antenna, possibilities of long-term and exact pointing at a particular star, optimal dimensions of the antenna for different frequencies and distances in active and passive communication, modulation modes, etc.). Problems of the CETI antenna coupling with the solar power station (noise level, screening of the antenna from the power station, role of antenna mechanical oscillations, etc.) are discussed, as well as the shape and nature of the beacons and that of the S N ratio; the laws of pulse distortion in the interstellar medium, and the role of Doppler shift of the signal.