268 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1961 



The NASA experimental program for developing operational sys- 

 tems includes, as already stated, communication and meteorological 

 satellite projects. Our communications satellite program encom- 

 passes a coordination of passive experiments as well as investigations 

 with active repeaters at medium altitudes — 2,000 to 4,000 miles — and 

 at synchronous altitude. NASA has arranged for two experimental 

 projects at medium altitudes, one under Government contract and one 

 financed by private industry. Both experiment satellites will include, 

 in addition to the communication payload, instruments for measuring 

 the effects of radiation on performance and life expectancy of the 

 payload. Ground stations in this comitry, Europe, and South Amer- 

 ica will be employed for both projects. 



A synchronous orbit system may provide world coverage, with 

 fewer satellites, thus avoiding large costs and complexities of tracking 

 and switching. We face technical difficulties, however, in placing and 

 maintaining satellites in such orbits for long periods. NASA is 

 initiating a series of experiments that will employ 40- or 50-pound pay- 

 loads in synchronous orbits. The ground facilities which the Army 

 has been developing for its Project Advent have been made available 

 to NASA for the synchronous satellite experiment. 



The Tiros series of meteorological experiments will be followed by 

 a series using an earth-stabilized spacecraft — called Nimbus — in polar 

 orbit. The Weather Bureau of the Department of Commerce, the 

 responsible organization for United States weather- forecasting activi- 

 ties, is following through on an operational meteorological satellite 

 system based on Nimbus. As agent for the Weather Bureau, NASA 

 will specify the launch vehicles and spacecraft, conduct the launch 

 operations, and control the satellites in space. 



MANNED SPACEFLIGHT IS ESSENTIAL 



Frequently I have been asked why we are preparing to send men 

 on hazardous spaceflights when instrumented satellites and probes 

 have proved so versatile and have returned such quantities of infor- 

 mation on the near-space environment of the earth and on conditions 

 in the vast reaches of deep space. 



First, integration of a human pilot into an onboard spacecraft sys- 

 tem greatly improves reliability. The man can make not only in- 

 flight tests but also in-flight repairs. We have striking examples of 

 this in missions of NASA's X-15 rocket airplane which has been flying 

 to the fringes of space and has achieved a speed of over 4,000 miles 

 per hour. In at least 8 out of 38 X-15 flights to date, flights would 

 have failed without a pilot in the cockpit to correct malfunctions of 

 equipment, instruments, or powerplant. In at least as many other 

 cases, if X-15 missions had been unmanned, we would have obtained 



