Some authorities believe that our space travel will be confined to our own solar system for a long time, perhaps forever. The trip to the moon, though now a tremendous project, would be relatively simple compared with a journey outside our system. Escape from the moon, for the return trip, would be easier than leaving the earth; because of its smaller mass, to escape the moon’s gravitational pull would take a speed of about 5,000 miles an hour, against 23,000 for the earth. Navigation would be much simpler. Our globe would loom up in the heavens, much larger and brighter than the moon appears to us. Radar beams would also be a guide. The greatest obstacle to reaching far-distant planet is the time required. In the Project “Saucer” study of space travel, Wolf 359 was named as the nearest star likely to have possibly inhabited areas. Wolf 359 is eight light-years from the earth. The limiting speed in space, according to Einstein’s law, would be just under the speed of light—186,000 miles per second. At this speed, Einstein states, matter is converted into energy. It is a ridiculous assumption, but even if atomic power, or some force such as cosmic rays, made an approach to that speed possible, it would still take eight years to reach Wolf 359. The round trip would take sixteen. There have been a few scientists who dispute Einstein’s law, though no one has disproved it. If the speed of light is not an absolute limit for space ships, then travel to remote parts of the universe may someday be possible. Otherwise, a trip outside our solar system could be a lifetime expedition. Most space travel would probably be limited to the planets of our sun—the moon, Mars, Venus, Jupiter, and the others. Although it may be many years before the first manned space ship leaves the earth, we are already at work on the problems the crews would face. I learned some of the details from a Navy flight surgeon with whom I had talked about take-off problems. “They’re a lot further than that” he told me. “Down at Randolph Field, the Aero-Medical research lab has run into some mighty queer things. Ever hear of ‘dead distance’?” “No, that’s a new one.” “Well, it sounds crazy, but they’ve figured out that a space ship would be going faster than anyone could think.” “But you think instantaneously,” I objected. “Oh, no. It takes a fraction of a second, even for the fastest thinker. Let’s say the ship was making a hundred miles a second—and that’s slow compared with what they expect eventually. Everything would happen faster than your nerve impulses could register it. Your comprehension would always be lagging a split second behind the space ship’s operation.” “I don’t see why that’s so serious,” I said. “Suppose radar or some other device warned you a meteorite was coming toward you head-on. Or maybe some instrument indicated an error in navigation. By the time your mind registered the thought, the situation would have changed.”