SATELLITE-TRACKING PROGRAM — ^HAYES 333 



hand at this operation when I have time." He had been sent by 

 mistake a packet from the Smithsonian U.S. National Museum. 



By mid-1958, excellent routines for the exchange of satellite in- 

 formation had been worked out. Tapes were cut and ready for im- 

 mediate transmission to all stations giving the news that a satellite had 

 been launched. 



Another tape was cut stating that the satellite went into orbit at a 

 particular time, and this mformation was then sent to the station. 

 Following this second message, still another gave all the latest 

 information received on the satellite itself — its size, weight, revolution, 

 perigee, apogee, etc. 



There was constant improvement of the system and efforts to over- 

 come annoying delays. By early 1959, the communications center was 

 already beginning to tie into the services of the National Aeronautics 

 and Space Administration. Thus, the teletype services to South 

 Africa were put through NASA facilities, and similar arrangements 

 were being discussed for lines to Australia and Peru. By March, a 

 privately leased teletype line was in operation between the head- 

 quarters in Cambridge and the Space Control Center in Washington, 



D.C. 



PHOTOREDUCTION 



The first Baker-Nunn fihns of satellite transits were tediously re- 

 duced at the stations, and information on the time and coordinates of 

 the satellite image was rushed to Cambridge by cable. The time 

 shown on the slave clock was, of course, directly photographed on the 

 film. The position of the satellite image was determined in relation 

 to the background of stars. These measurements were sufficiently 

 good for the generation of new predictions of satellite passages and 

 for preliminary estimates of atmospheric density and other phe- 

 nomena. They did not, however, provide nearly so precise information 

 as the Baker-Nunn camera was capable of offering. In fact, these 

 measurements of position were inaccurate on the average between 60 

 and 90 seconds of arc, which might represent for a low-orbiting satel- 

 lite as much as 1,000 feet in space. 



There arose, therefore, the necessity for finding a much more ac- 

 curate, reliable, and rapid means of reducing the films. As early as 

 March 1957, an experimental machine for measuring Baker-Numi film 

 was constructed; it incorporated a fihn backup plate similar to that 

 used in the camera so that angular distances could be measured 

 directly. In the ensuing months, however, as construction of the first 

 Baker-Numi camera was rushed to completion, and then as the first 

 satellites were launched and tracked, this aspect of the program re- 

 ceived relatively little attention. It was not until early 1958 that the 

 staff of the Observatory formally outlined the possible equipment and 



