The Research Background of the Telstar Experiment

For several years before the launch of the Telstar satellite, research effort was directed toward an experiment with an active satellite capable of relaying a broadband communication channel. The intention was to utilize and test a number of novel techniques which had become available, to explore those areas in which the current technology was lacking, and to demonstrate the feasibility of this means of communication. This paper describes some of this work, the background of facts and beliefs on the basis of which a number of important choices were made, and the general slate of the radio art upon which the Telstar program was built. L. I N T R O D U C T I O N The Telstar satellite communications experiment, like all achievements in technology and engineering, has many roots. Some of these roots are as broad and old as science itself; others are rather recent and include modern rockets, missile guidance, and general space technology. Other more modest but essential roots grew from an early appreciation of the potential of satellite communication and the steps taken in the area of communication technology to foster its growth. Bell Telephone Laboratories interest in the possibility of using artificial earth satellites for communication purposes began in 1955 with the publishing of the article on "Orbital Radio Relays" 1 by J. R. Pierce. It is significant, however, that some of the research which was relevant to the success of the satellite predated this publication by a decade or more.