The danger from meteorites has been partly discounted in one scientific study. (“Probability that a meteorite will hit or penetrate a body situated in the vicinity of the earth,” by G. Grimminger, _Journal of Applied Physics_, Vol. 19, No. 10, pp. 947-956, October 1948) In this study, it is stated that a meteorite is unlikely to penetrate the thick shell our space vehicles will undoubtedly have. However, this applies only to the earth’s atmosphere. Longer studies, using remote-controlled vehicles in space, may take years before it will be safe to launch a manned space ship. Radar or other devices may have to be developed to detect approaching meteorites at a distance and automatically change a space ship’s course. The change required would be infinitesimal, using power for only a fraction of a second. But before we are ready for interplanetary travel, we will have to harness atomic power or some other force not now available, such as cosmic rays. Navigation at such tremendous speeds is another great problem, on which special groups are now at work. A Navy scientific project recently found that strange radio signals are constantly being sent out from a “hot spot” in the Milky Way; other nebulae or “hot” stars may be similarly identified by some peculiarity in their radio emanations. If so, these could be used as check points in long-range space travel. Escape from the earth’s gravity is possible even now, according to Francis H. Clauser, an authority on space travel plans. But the cost would be prohibitive, with our present rocket motors, and practical operations must wait for higher velocity rocket power, atomic or otherwise. (“Flight beyond the Earth’s Atmosphere, “_S.A.E. Quarterly Transactions_, Vol. 2, No, 4, October 1948.) Already, a two-stage rocket has gone more than 250 miles above the earth. This is the V-2-Wac Corporal combination. The V-2 rocket is used to power the first part of the flight, dropping off when its fuel is exhausted. The Wac Corporal then proceeds on its own fuel, reaching a fantastic speed in the thin air higher up. Hundreds of technical problems must be licked before the first satellite vehicle can be launched successfully. Records on our V-2 rockets indicate some of the obstacles. On the take-off, their present swift acceleration would undoubtedly kill anyone inside. When re-entering the earth’s atmosphere the nose of a V-2 gets red-hot. Both the acceleration and deceleration must be controlled before the first volunteers will be allowed to hazard their lives in manned rockets. Willi Ley, noted authority on space-travel problems, believes that pilots may have to accept temporary blackout as a necessity on the take-off. (Two of his books, _Rockets and Space Travel_ and _Outer Space_, give fascinating and well-thought-out pictures of what we may expect in years to come.)