J. S. Mayo et al., “The Command System Malfunction of the Telstar Satellite,” _Bell System Technical Journal_, July 1963, page 1631. _Note_: The _Bell Laboratories Record_ is published by Bell Telephone Laboratories, Incorporated, 463 West Street, New York 14, New York. _The Bell System Technical Journal_ is published by the American Telephone and Telegraph Company, 195 Broadway, New York 7, New York. The Editor Ronald M. Foster, Jr., _was born in Plainfield, New Jersey, and received an A.B. degree from Harvard College in 1948. He joined Bell Telephone Laboratories in 1956, and is a member of the Educational Aids Department of the Public Relations and Publication Division. He is engaged in development of material for the Bell System Aid to High School Science Program._ Footnotes [1]This is obtained from _k_ = _gR_², where _g_ is the acceleration due to gravity and _R_ is the radius of the earth. (Here, we can use _k_ = 96,500 miles³ per second².) [2]Donald R. Herriott of Bell Labs had suggested using plane reflectors on satellites as long ago as 1957—although his idea was that this would increase their visibility, rather than aid in determining their attitude. [3]This method was developed by D. W. Hill of Bell Telephone Laboratories. [4]We will not attempt to go into all the details of semiconductor physics here. If you would like to know more about how solar cells work, refer to the Suggested Reading on page 88. [5]See pages 42 and 43. [6]Published as part of the Bell System Aid to High School Science Program. [Illustration: Wraparound cover image] Transcriber’s Notes —Silently corrected a few typos. —Modified some image references to reflect the pageless flowable eBook format. —Retained publication information from the printed edition: this eBook is public-domain in the country of publication. —In the text versions only, text in italics is delimited by _underscores_. End of Project Gutenberg's Satellite Communications Physics, by Various