SECRETARY'S REPORT 85 



Pedro E. Zadunaisky has begun an analysis of the motion of 

 Halley's Comet in order to check current theories about the forces 

 perturbing the elliptic motion of a comet. 



Opening a new field for study, Dr. Tilles will construct a high- 

 sensitivity mass spectrometer and from recovered satellite samples 

 will measure the isotopic composition of the gases in solar winds and 

 flares. He will also study the stable isotopes of noble gases in 

 meteorites and terrestrial rocks. 



Satellite-tracking program. — The optical tracking of artificial satel- 

 lites with NASA support continues to provide data for the prediction 

 of orbits and for basic research in the space sciences. The program 

 comprises a worldwide organization of Moon watch teams, the oper- 

 ation of 12 precision photographic stations in various parts of the 

 world, the calculation of satellite ephemerides, photographic image 

 reduction, detailed analysis by electronic computers, and precise 

 reduction of satellite positions. 



From May 1, 1960, to May 1, 1961, Moonwatch observations of 57 

 satellites and their orbiting components provided data for correcting 

 ephemerides and for acquiring and reacquiring satellites. The sta- 

 tions also conducted a number of searches for orbiting objects. 



Dr. Gustav A. Bakos's analysis of Moonwatch observations indicates 

 that they compare favorably with those made by radar and with field 

 reduced observations by SPOT. 



Major developments in operational techniques of the Baker- Nunn 

 camera stations were accomplished in two fields — the automation of 

 matched-track and off-culmination observing methods, and the design 

 and development of auxiliary equipment that enables the entire 

 network to be synchronized to within a few milliseconds of time. 

 These developments will prove extremely valuable in the forthcoming 

 research in geodesy using direct triangulation methods. 



Specifications were drawn for a new electronic time standard for 

 the stations that would be capable of maintaining uniform and precise 

 time to an accuracy of one-half millisecond. This clock, which will 

 greatly improve observational accuracy, is unique in its field. 



Five stations in the Baker-Nunn network worked in conjunction 

 with the Jodrell Bank Kadio Telescope in making optical observations 

 of flare stars. 



Of 13,556 films received from the Baker-Nunn camera stations, the 

 photoreduction center completed reductions of 8,961. From July 

 1960 through April 1961 the computations center sent 32,592 pre- 

 dictions to the 12 Baker-Nunn camera stations, 11,160 transits of 

 satellites were observed, and 14,361 reduced positions were reported. 



The communications center cleared more than a million words per 

 month, 95 percent of which represent satellite data received or sent 

 throughout the world. 



