68 ANNUAL REPORT SMITHSONIAN INSTITUTION, 195 6 



teorite craters. A long-term objective of the program is to arrive 

 at a better estimate of the rate of accretion of meteoritic material 

 by the earth. 



Design and construction of a fluorescent X-ray micronanalyzer have 

 likewise been initiated and are now well under way. When completed 

 this instrument can be used to determine within a microscopic (5- 

 micron) area the concentration and distribution of the various chemi- 

 cal elements within a meteorite, without destruction of the sample. 

 The method will be applied first to the determination of nickel-iron 

 percentages in meteorites that have Widmanstaetten figures. A 

 knowledge of the distribution of nickel will be of considerable cos- 

 mological significance as related to the origin of meteorites. 



Satellite Tracking Program. — The United States National Com- 

 mittee of the International Geophysical Year under the National 

 Academy of Sciences and through the National Science Foundation 

 has assigned to the Smithsonian Institution the responsibility, and 

 also a grant of funds, for initiating and executing an optical research 

 program involving the tracking of the planned artificial earth's satel- 

 lite. Dr. J. Allen Hynek has joined the project as associate director 

 in charge of the Optical Observing Program and will join the perma- 

 nent Smithsonian staff in July 1956. 



The Satellite Tracking Program consists of two distinct parts : the 

 visual search and tracking program, of low-order accuracy, and the 

 photographic tracking program, of extremely high precision. The 

 two have a common denominator in the needs for a communication 

 system and a central computing bureau to provide ephemerides and 

 for the later analysis of scientific results attained from the tracking 

 of the satellites. 



The precision optical program will be carried out by means of 

 special Schmidt cameras of aperture 20 inches, mirrors of aperture 

 30 inches, and focal length of 20 inches, for which a newly developed 

 optical system is being designed by Dr. James G. Baker. A unique 

 drive system for these cameras is being designed by Joseph Nunn 

 and associates to make possible the photography of a 15-inch sphere 

 at a distance of a thousand miles and a 3-foot sphere at the moon's 

 distance during hours of deep twilight or darkness when the satellite 

 is illuminated by the sun. A tracking accuracy of some 2 seconds of 

 arc normal to the path of the satellite on the sky and some 6 to 10 

 seconds along the direction of motion with a time precision of one- 

 thousandth of a second is anticipated in the operation of these cameras. 



A number of observing stations, possibly 12, each of which will 

 include one of these cameras and a precise crystal-clock system, will 

 be established at intervals around the globe. Observations of artificial 

 earth satellites from such a system of stations, combined with an 



