SATELLITE -TRACKING PROGRAM — HAYES 349 



for using satellite observations in geodetic studies. These and other 

 programs of research and analysis were to reach fruition after the 

 IGY when the Satellite-Tracking Program of the Observatory came 

 under the sponsorship of the National Aeronautics and Space 

 Administration. 



ACHIEVEMENTS DURING THE IGY AND IGC 



Wlien the Satellite-Tracking Program came under the National 

 Aeronautics and Space Administration on July 1, 1959, the Observa- 

 tory's direct participation in the International Geophysical Year and 

 the International Geophysical Cooporation ended. 



The changes, the progress, the achievements of the program during 

 those years had been momentous. 



The Observatory staff — most of whom were involved in the satellite 

 program in one capacity or another — grew from 3 when the 

 Observatory moved to Cambridge in 1955 to a cosmopolitan group 

 of more than 175 people. 



In 3 years, the Observatory built and manned a worldwide network 

 of 12 stations, each equipped with a specially designed and constructed 

 Baker-Nunn camera and Norrman time standard. The camera was 

 so sensitive and so accurate that it photographed the Vanguard 6-inch 

 sphere at a distance of some 2,400 miles ; the clock could display time 

 to one-thousandth of a second. By mid-1959 these 12 stations had 

 made more than 4,000 photographic observations of U.S. and U.S.S.R. 

 satellites launched during the IGY and IGC. 



A communications network linking the stations with headquarters 

 in Cambridge handled each month 400,000 words of information on 

 predictions and observations of satellite transits. 



More than 8,000 volunteers joined the Moon watch program of visual 

 observations of satellites. More than 200 teams were organized, not 

 only in the United States but also throughout the world. Together, 

 they made nearly 10,000 observations and were of unique value in 

 locating several "lost" satellites and in observing the demise of 

 Sputnik II. 



Techniques were developed for the precise reduction of the films 

 from the Baker-Nunn cameras, and by June 1959 the times and posi- 

 tions recorded on the photographs were being routinely determined. 



The computations group successfully evolved a series of programs, 

 among them the DOI, for the generation of predictions to the camera 

 stations and the Moonwatch teams and for the derivation of precise 

 orbits. They also created a number of other significant programs for 

 research and analysis. 



Scientists used the observational data to define several influences on 

 the motion of satellites and thereby made new estimates of atmospheric 



