282 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1961 



physical Observatory of the Smithsonian would gain much by being 

 put in the academic atmosphere of Cambridge. 



Although Dr. Whipple's appointment did not become effective until 

 July 1, 1955, he began working part time for the Smithsonian in April, 

 and a provisional budget was drafted for the program to track the 

 satellite of Project Orbiter. 



The Astrophysical Observatory was officially transferred to the 

 grounds of the Harvard College Observatory on July 1. The pro- 

 fessional staff consisted of Dr. Whipple and Dr. John S. Rinehart, 

 half of whose time was to be devoted to scientific research and half 

 to assisting Dr. Whipple in the administration of the Observatory. 



Dr. Wliipple now enlarged the scope of the program of the Observa- 

 tory to "embrace not only research in solar activity and its effects upon 

 the earth, but also meteoritic studies and studies of the high atmos- 

 phere." He conceived the optical tracking of satellites as "a new and 

 startling tool of remarkable power in the study of solar-system and 

 geophysical phenomena." 



That summer Dr. Whipple went to Europe, still believing in the 

 strong possibility that some modification of von Braun's Orbiter proj- 

 ect would be adopted. When he returned and learned otherwise, he 

 immediately began to adapt his proposals for tracking Orbiter to re- 

 quirements of the Vanguard satellite, which at that time was planned 

 to weigh approximately 20 pounds and be 30 inches in diameter. 

 Making some a priori assumptions about the satellite itself and the 

 orbit it would follow, he calculated that the object would be as bright 

 as visual magnitude 5 to 7, that is, near the limit of naked-eye visi- 

 bility, but certainly easily observable under good atmospheric condi- 

 tions by means of binoculars or wide-field optical equipment. 



For this new tracking program he proposed that only the most rapid, 

 large-aperture Schmidt optical system would be suitable for observing 

 the satellite and that the telescope might be mechanized so that the 

 motion of the instrument would follow the apparent motion of the 

 satellite itself. He also outlined the value of teams of amateur visual 

 observers (later to be named "Moonwatch") for acquiring the satellite 

 in its first few orbits. In addition, he made provisions for a computa- 

 tions center to receive observational data and to prepare predictions of 

 satellite passages, and a communications network to and from the 

 various observing stations and teams and the suggested headquarters 

 in Cambridge. With imaginative foresight he envisaged what was 

 to become the optical tracking program of the Smithsonian Astro- 

 physical Observatory. 



His proposal for the Smithsonian to provide optical tracking of the 

 IGY satellites also involved at least two unrealistic factors that were 

 to have a crucial bearing on the events of the next few years. First, 



