78 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1962 



Robert J. Davis, astrophysicist in charge, with other Observatory 

 scientists, have concentrated on "Celescope," the series of telescopes 

 intended for orbiting in artificial satellites above the earth's atmos- 

 phere. Equipped to provide television images in four colors of the 

 entire celestial sphere, this vital new technique, when completed and 

 in operation, will vastly extend astronomical observation to the far ul- 

 traviolet region of the spectrum and prepare the way for further 

 detailed studies of objects and areas revealed by the survej'^s. Con- 

 tracts have been completed for fabrication of two Aerobee-Hi rocket 

 payloads carrying a prototype Celescope of simplified design to test 

 critical electronic equipment and the brightness of stars in the ultra- 

 violet. These stars, found in recent observations by NASA and others 

 to be 10 times fainter than supposed, require more sensitive television 

 camera tubes ("uvicons") and larger optics than were originally 

 available for the experimental flight. Now that better uvicons are 

 available, the rocket payloads will be rebuilt to accept them. Contract 

 for the satellite payload has been awarded, and construction is 

 proceeding. 



In connection with this problem Dr. Om P. Rustgi has set up a 

 laboratory for absolute calibration of uvicons, a matter of highest im- 

 portance to the project for measuring stellar and interstellar radiation. 



Rocket failures and the insufficiently sensitive tubes have delayed 

 the program, but successful orbit is expected in 1964. The Celescope 

 project is being conducted in cooperation with NASA's Orbiting 

 Astronomical Observatories Program, which provides auxiliary equip- 

 ment and support, but the scientific management of the experimental 

 payload and analysis of the results remain the Smithsonian's responsi- 

 bility. The long-range plan is for development of even more power- 

 ful celescopes and equipment. 



Dr. G. Colombo, professor of theoretical mechanics at the University 

 of Padua, Italy, during his 2-year stay at the Observatory has analyzed 

 the stabilization of a satellite at the point of equilibrium between the 

 earth's and the moon's gravitational forces and is exploring the feasi- 

 bility of a high sensitivity device for detecting displacement which 

 would significantly affect techniques of space navigation and com- 

 munication. He has also completed an analysis of the motion of Ex- 

 plorer XI (1961 Gamma) around its center of mass and demonstrated 

 qualitatively that variations of its angular momentum are explicable 

 only by the interaction of the earth's magnetic field and the body of 

 the satellite. 



Dr. Colombo has recently initiated a study of numerical integration 

 in the semirestricted three-body problem (including radiation pres- 

 sure from a fourth body) to investigate the possible use of such pres- 

 sure for transferring earth-aromid-moon orbits of satellites with large 



