SATELLITE-TRACKING PROGRAM — HAYES 341 



RESEARCH AND ANALYSIS 



Once satellites bad been launcbed and tracked, and observations of 

 them reduced to precise statements of time and position, there re- 

 mained the most important job — the use of these data for scientific 

 purposes. Satellite orbits are sensitive to a nmnber of influences — the 

 earth's gravitation, atmospheric density (which changes with both 

 electromagnetic and corpuscular solar radiation), and the pull of the 

 sun and the moon. By means of powerful mathematical tools, includ- 

 ing computer programs especially developed for the purpose, scientists 

 are able to separate these influences from one another and to measure 

 them individually. From this study have come some of the most 

 exciting and significant discoveries of the space age. 



Late in 1957 Dr. Allen Hynek, associate director of the Observatory, 

 outlined such a program of satellite research and analysis. He pro- 

 posed to reduce and analyze the data from visual and photographic 

 observations of earth satellites : "Data are now being received at the 

 Smithsonian Astrophysical Observatory from stations and observa- 

 tories on a worldwide basis. . . . The project would extend the present 

 work to future satellites, conduct basic research on the reduced data 

 with the objectives of determining values of upper atmosphere density, 

 geodetic parameters, and the value of gravity in geopotential. Pre- 

 liminary results will be published in special project reports for rapid 

 dissemination among the scientific community and final results will 

 be published in standard scientific journals." 



Already the Observatory had undertaken such a program, and had 

 issued six Special Reports on Sputniks I and II, including a prelimi- 

 nary estimate on upper atmospheric density derived from observa- 

 tions of Satellites 1957 Alpha and Beta. The call now was for a 

 greatly expanded project that could adequately handle the many data 

 and derive maximimi scientific results from them. 



By mid-1958, when the project was well under way. Dr. Whipple 

 wrote to Mr. Odishaw : "I want to underscore the real need for more 

 scientists and money for rapid reduction and interpretation of the data 

 obtained. In my opinion this problem will reach crucial proportions 

 not only in the rocket and satellite fields but also in other IGY areas 

 where you are faced with the accumulation of a considerable amount 

 of raw data in very complex form." More scientists and more monies 

 were forthcoming, and the Observatory developed a major program of 

 research and analysis. 



The plan of the IGY was to launch satellites that could contribute 

 to the gathering of information about the earth during those 18 



