Word: tails
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...engines can lift much more than their own weight. The X-13, presumably, has a high-thrust power plant whose weight is as low as possible, but it must have many other novelties too. At the moment of takeoff, while it is still moving at negligible speed, its tail surfaces are useless. Some other system, such as secondary gas jets, is presumably provided to keep it under control until it has gained enough speed for the conventional control surfaces to go into operation...
Another difficult moment is the approach to the ground in tail-down attitude. The pilot has to watch the ground in some way. He may look over his shoulder with mirrors or other optical aids, but it is more likely that electronic instruments tell him his distance from the ground and the speed with which he is approaching it. An "automatic landing pilot'' may even control the whole operation...
...head grows bigger, some of the fine material is blown out of it by the pressure of sunlight, which has more effect than gravitation on particles of proper size. This fine material forms the tail, which always points away from the sun no matter how the head is moving. It may become many millions of miles long. The light from the head and tail is partly reflected sunlight; the rest of it comes from atoms or molecules made to fluoresce by solar radiation...
...Radical Tail. During its plunge toward the sun, Comet Arend-Roland developed a respectable head and tail, and there is good reason to hope that it will come through its solar ordeal without too much loss of substance. Astronomers have plenty of questions to ask it; their instruments and understanding have improved enormously since...
...important new technique will be to observe the comet's tail with radio telescopes. If it is really full of peculiar chemical fragments (free radicals), as astronomers suspect, the fragments should be excited by sunlight and made to broadcast on characteristic wave lengths. The Naval Research Laboratory in Washington has turned its 50-ft. radio disk on the comet in the hope of detecting waves from hydroxl (OH) radicals. If astronomers find this odd stuff in comets, they may be able to trace it back into interstellar space. This may lead them, in turn, to new knowledge about what...