The idea of exploring s.p.a.ce is, of course, nothing new. For many years, writers of imaginative fiction have described trips to the moon and distant planets. More recently, comic books and strips have gone in heavily for s.p.a.ce-travel adventures.

As a natural result of this, the first serious rocket experiments in this country were labeled screwball stunts, about on a par with efforts to break through the sonic barrier. The latter had been "proved" impossible by aeronautical engineers; as for rocket flight, it was too silly for serious consideration. Pendray, G.o.ddard, and other rocket pioneers took some vicious ridicule before America woke up to the possibilities.

Meantime, German scientists had gone far ahead.

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Their buzz bomb, a low-alt.i.tude semi-guided missile, was just the beginning. Even the devastating V-2, which soared high into the stratosphere before falling on England, was just a step in their tremendous s.p.a.ce program. If the n.a.z.is could have hung on a year or two more, the war might have had a grimly different ending.

When the Allies seized n.a.z.i secrets, some of the German plans were revealed. Among them was one for a huge earth satellite. From this base, which would circle the earth some five hundred miles away, enormous mirrors would focus the sun"s rays on any desired spot. The result: swift, fiery destruction of any city or base refusing to surrender.

First publication of this scheme brought the usual jeers. Many people, including some reputable scientists, believed it had been just a propaganda plan that even Goebbels had discarded as hopeless.

Then the Pentagon announced the U.S. Earth Satellite Vehicle Program, along with plans for a moon rocket, The artificial satellite is to be a large rocket-propelled projectile. In its upward flight, it will have to reach a speed of 23,000 miles an hour, to escape the earth"s pull of gravity. At a height of about 500 miles, special controls will turn the projectile and cause it to circle the earth. These controls will be either automatic or operated from the ground, by radar.

Theoretically, once such a vehicle is beyond gravity"s magnetism, it can coast along in the sky forever. Its rocket power will be shut off; the only need for such power would be if the satellite veered off course. A momentary burst from the jets would be sufficient to bring it back to its...o...b..t.

Circling the earth in about two hours, this first satellite is expected to be used as a testing station. Instruments will record and transmit vital information to the earth--the effect of cosmic rays, solar radiation, fuel required for course corrections, and many other items.

A second s.p.a.ce base farther out will probably be the next step. It may be manned, or it may be under remote control like the first. Perhaps the first satellite vehicle will be followed by a compartmented operating base, a sort of aerial aircraft carrier, with other rocket

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ships operating to and fro on the earth shuttle. The moon rocket is expected to add to our information about s.p.a.ce, so that finally we will emerge with an interplanetary s.p.a.ce craft.

The first attempts may fail. The first satellite may fall back and have to be guided to an ocean landing. Or its controls might not bring it into the planned orbit. In this case, it could coast on out into s.p.a.ce and be lost. But sooner or later, effective controls will be found. Then the manned s.p.a.ce ships will follow.

Once in free s.p.a.ce, there will be no gravitational pull to offset. The s.p.a.ce ship and everything in it will be weightless. Shielding is expected to prevent danger from cosmic rays and solar radiation.

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. Gr.i.m.m.i.n.ger, 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 sh.e.l.l our s.p.a.ce vehicles will undoubtedly have.

However, this applies only to the earth"s atmosphere. Longer studies, using remote-controlled vehicles in s.p.a.ce, may take years before it will be safe to launch a manned s.p.a.ce ship. Radar or other devices may have to be developed to detect approaching meteorites at a distance and automatically change a s.p.a.ce 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 s.p.a.ce travel.

Escape from the earth"s gravity is possible even now,

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according to Francis H. Clauser, an authority on s.p.a.ce 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 s.p.a.ce-travel problems, believes that pilots may have to accept temporary blackout as a necessity on the take-off. (Two of his books, Rockets and s.p.a.ce Travel and Outer s.p.a.ce, give fascinating and well-thought-out pictures of what we may expect in years to come.)

Some authorities believe that our s.p.a.ce 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 ma.s.s, 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

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s.p.a.ce 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 s.p.a.ce, 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 a.s.sumption, 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 s.p.a.ce 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 s.p.a.ce 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 s.p.a.ce 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 s.p.a.ce 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 s.p.a.ce ship"s operation."

"I don"t see why that"s so serious," I said.

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"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."

"Then all the controls would have to be automatic," I said. I told him that I had heard about plans for avoiding meteorites. "Electronic controls would be faster than thought."

"That"s probably the answer," he agreed. "Of course, at a hundred miles a second it might not be too serious. But if they ever get up to speeds like a thousand miles a second, that mental lag could make an enormous difference, whether it was a meteorite heading toward you or a matter of navigation."

One of the problems he mentioned was the lack of gravity. I had already learned about this. Once away from the earth"s pull, objects in the s.p.a.ce ship would have no weight. The slightest push could send crewmen floating around the sealed compartment.

"Suppose you spilled a cup of coffee," said the flight surgeon. "What would happen?"

I said I hadn"t thought it out.

"The Randolph Field lab can tell you," he said. "The coffee would stay right there in the air. So would the cup, if you let go of it. But there"s a more serious angle--your breath."

"You"d have artificial air," I began.

"Yes, they"ve already worked that out. But what about the breath you exhale? It contains carbon dioxide, and if you let it stay right there in front of your face you"d be sucking it back into your lungs. After a while, it would asphyxiate you. So the air has to be kept in motion, and besides that the ventilating system has to remove the carbon dioxide."

"What about eating?" I asked. "Swallowing is partly gravity, isn"t it?"

He nodded. "Same as drinking, though the throat muscles help force the food down. I don"t know the answer to that. In fact, everything about the human body presents a problem. Take the blood circulation. The