SECRETARY'S REPORT 81 



12,073, fumisliing basic data for correcting ephemerides and for ac- 

 quiring and reacquiring nonbroadcasting satellites. During the year 

 tlie teams conducted a number of searches for orbiting objects. 



In the same period the Computations Division distributed to the 

 12 Baker-Nunn stations 73,466 predictions that yielded 26,446 obser- 

 vations reported by cable to Cambridge. This amounts to approx- 

 imately twice the activity of the previous year. 



The Photoreduction Center received 25,060 successful films (arcs) 

 and completed 15,409 reductions of satellite positions. 



Through the Communications Center, 1.5 to 2 million words were 

 cleared each month, 95 percent of these representing satellite data 

 received or sent throughout the world. This compares with approx- 

 imately 1 million words per month in the previous year. 



The Eesearch and Analysis Division has derived valuable conclu- 

 sions based on the data drawn from the several tracking activities (see 

 Space Science). For example, the variations of density in the high 

 atmosphere for altitudes of 200 to 750 km. have been determined 

 with respect to solar activity, ultraviolet and corpuscular radiation. 

 The data on atmospheric drag obtained by optical observation are now 

 used as basic information by most investigators in the field of 

 atmospheric studies. 



The geodetic applications of satellite observations continue to be 

 studied. Knowledge of station coordinates has been improved by 

 means of a program of simultaneous satellite observations from se- 

 lected stations. The Baker-Nunn stations are now well equipped for 

 this type of observation, and a prediction program for simultaneous 

 obsers^ations is working satisfactorily. Good results have been ob- 

 tained already from the stations in Peru and Argentina working 

 simultaneously. 



To further this work, studies are being conducted of the adapta- 

 bility of modified aerial reconnaissance cameras for use as semimobile 

 cameras for geodetic use, both independently and in conjunction with 

 the fixed-position Baker-Nunn network. The Observatory is coop- 

 erating with the Department of Defense and NASA in establishing 

 an international program for a flashing-light geodetic satellite. 



Following a decision to continue operations of the optical satellite 

 tracking program for a number of yeare, steps are being taken to do 

 major maintenance and overhaul work on the cameras. 



This work is complicated by the fact that facilities for handling the 

 optical components of the cameras do not exist in most of the countries 

 where the cameras are located. 



PUBLICATIONS 



Publications of the Smithsonian Contributions to Astrophysics in- 

 cluded numbers 9 through 11 of volume 5. 



