We have had space to describe only a few of the things involved in designing a solar cell power plant that would work unattended out in space. We have not mentioned a good many of the tough problems that had to be worked on. But we are glad to report that we could find answers to almost all our questions. And the most significant answer is shown in _the figure below_, where you can see how the Telstar I solar power plant slowly diminished in power almost exactly as we predicted it would. [Illustration: _Very gradual decay due to radiation effects of the Telstar I solar cell plant in the first months after the satellite went into orbit; it was extremely close to the predicted rate (solid line)._] Kenneth D. Smith _was born in Galesburg, Illinois, and received a B.A. from Pomona College in 1928 and an M.A. from Dartmouth College in 1930. He joined Bell Telephone Laboratories in 1930, and has worked on the development of proximity fuzes, radar bombing systems, broadband microwave radio systems, and various semiconductor devices, including radiation-resistant solar cells for the Telstar satellite._ CASE HISTORY NO. 5 Would Time Delay Be a Problem in Using a Synchronous Satellite? Peter D. Bricker _Psychologist—Member of Staff, Behavioral Research Laboratory_ THE PROBLEM _One of the satellite communications systems that has been proposed would make use of stationary synchronous satellites. These would be precisely located above the earth’s equator in orbits 22,300 miles high, where they would circle the earth once every 24 hours, and thus appear to remain stationary over a point on the earth. There are several advantages to this type of system—the most important being that we would need only three satellites for communications between almost all the inhabited regions of the earth._ _On the other hand, there are several problems in establishing a synchronous system. Just getting the satellites into exactly the right places and keeping them in position is a formidable one. We also have something of a mystery to contend with, because of the tremendous distances that would be involved. Although we can communicate at speeds close to that of light—186,000 miles per second—we cannot go any faster than that. You might think that 186,000 miles a second was fast enough for us, and most of the time it is. However, if you send signals 22,300 miles up into the sky, transmit them back to earth, perhaps send them up again to a second satellite, and finally bring them 22,300 miles back down to earth, even the speed of light may not be fast enough. The delay will be only about a second or so, but it may—for some kinds of communications—be long enough to cause trouble. How much trouble, we don’t yet know._