A Domestic Satellite Design

This paper deals with the design parameters of a communications satellite which would be capable of providing domestic telephony, data, and television distribution services. Certain important aspects of the design are discussed, including satellite antenna beam coverage, transponder bandwidth, and transponder radiated power for a given weight range. A baseline satellite design is then presented which has 24 transponders (with 4000 watts radiated power on-axis and 34-MHz radio-frequency bandwidth) fully accessible from the 48 contiguous United States. The design uses crossed linear polarization to reuse the satellite transmit and receive frequency spectrum.     

Possible Applications of Communications Satellites to Offshore Systems

Expanding offshore operations have generated an increased need for communications in both international and domestic areas. The capabilities of communications satellites are presented both as currently existing and as envisioned in the future. The possibilities of using these capabilities in offshore communications systems are discussed especially with regard to the potential of new services brought about by the latest generation of satellites currently under production. Two potentially new types of services are hypothesized. Lastly, progress on the development of a small earth station of low cost suitable for such services is reported. It is concluded that communications satellites hold potential both currently and in the future for various offshore operations.     

Polymerization under Microgravity: Results and Prospects

Frontal photopolymerization of polyacrylamide gel is theoretically and experimentally investigated under conditions of microgravity. With the help of optical methods, the conversion field of monomer is visualized in the course of the experiment, and the pattern of a reaction front motion is determined. The comparison of the properties of flight and laboratory samples of gel allows us to conclude that carrying out polymerization onboard an orbital station in order to obtain homogeneous polymeric materials is promising.