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.)

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."

"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 space 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

amount of energy required to pump blood through the veins would be almost negligible. What would that do to your heart?"

"I couldn't even guess," I said.

"Well, that's all the Aero-Medical lab can do--guess at it. They've been trying to work out some way of duplicating the effect of zero gravity, but there's just no answer. If you could build a machine to neutralize gravity, you could get all the answers, except to the 'dead distance' question.

"For instance, there's the matter of whether the human body would even function without gravity. All down through the stages of evolution, man's organs have been used to that downward pull. Take away gravity, and your whole body might stop working. Some of the Aero-Medical men I've talked with don't believe that, but they admit that long trips outside of gravity might have odd effects.

"Then there's the question of orientation. Here on earth, orienting yourself depends on the feeling you get from the pull of gravity, plus your vision. just being blindfolded is enough to disorient some people. Taking away the pull of gravity might be a lot worse. And of course out in space your only reference points would be distant stars and planets. We've been used to locating stars from points on the earth, where we know their position. But how about locating them from out in space, with a ship moving at great speed? Inside the space ship, it would be something like being in a submarine. Probably only the pilot compartment would have glass ports, and those would be covered except in landing--maybe even then. Outside vision might be by television, so you couldn't break a glass port and let out your pressure.

"But to go back to the submarine idea. It would be like a sub, with this big difference: In the submarine you can generally tell which way is down, except maybe in a crash dive when you may lose your equilibrium for a moment. But in the space ship, you could be standing with your feet on one spot, and another crewman might be--relative to you--standing upside down. You might be floating horizontally, the other man vertically.  The more you think about it, the crazier it gets. But they've got to solve all those problems before we can tackle space."

To make sure I had the details right, I checked on the Air Force research. I found that the Randolph Field laboratory is working on all these problems, and many more.

Although plans arc not far enough advanced to make it certain, probably animals will be sent up in research rockets to determine the effect of no gravity before any human beings make such flights. The results could be televised back to the earth.

All through my check-up on space exploration plans, one thing struck me: I met no resistance. There was no official reticence about the program; on the contrary, nothing about it seemed secret.

Even though it was peacetime, this was a little curious, because of the potential war value of an earth satellite vehicle. Even if the Nazi scheme for destruction proved just a dream, an orbiting space base could be used for other purposes. In its two-hour swing around the earth, practically all of the globe could be observed-directly, by powerful telescopes, or indirectly, by a combination of radar and television. Long-range missiles could be guided to targets, after being launched from some point on the earth. As the missiles climbed high into the stratosphere, the satellite's radar could pick them up and keep them on course by remote control.

There were other possibilities for both attack and defense. Ordinarily, projects with wartime value are kept under wraps, or at least not widely publicized. Of course, the explanation might be very simple: The completion of the satellite vehicle was so remote that there seemed no need for secrecy. But in that case, why had the program been announced at all?

If the purpose had been propaganda, it looked like a weak gesture. The Soviets would not be greatly worried by a dream weapon forty or fifty years off. Besides that, the Pentagon, as a rule, doesn't go for such propaganda.

There was only one conventional answer that made any sense. If we had heard that the Soviets were about

to announce such a program, as a propaganda trick, it would be smart to beat them to it. But I had no proof of, any such Russian intention.

The date on Secretary Forrestal's co-ordination announcement was December 30, 1948. One day later, the order creating Project "Saucer" had been signed. That didn't prove anything; winding up the year, Forrestal could have signed a hundred orders. I was getting too suspicious.

At any rate, I had now analyzed the Gorman case and checked on our space plans. Tomorrow I would see Redell and find out what he knew.

CHAPTER XII

'WHEN I called Redell's office I found he had flown to Dallas and would not be back for two days. By the time he returned, I had written a draft of the Gorman case, with my answer to the balloon explanation. When I saw him, the next morning, I asked him to look it over.

Redell lighted his pipe and then read the draft, nodding to himself now and then.

"I think that's correct analysis," he said when he finished. "That was a very curious case. You know, Project 'Saucer' even had psychiatrists out there. If Gorman had been the only witness, I think they'd have called it a hallucination. As it was, they took a crack at him and the C.A.A. men in their preliminary report."

Though I recalled that there had been a comment, I didn't remember the wording. Redell looked it up and read it aloud:

"'From a psychological aspect, the Gorman incident raised the question, "Is it possible for an object without appreciable shape or known aeronautical configuration to appear to travel at variable speeds and maneuver intelligently?"'"

"Hallucination might sound like a logical answer," I said, "until you check all the testimony. But there are just too many witnesses who confirm Gorman's report. Also, he seems like a pretty level-headed chap."

Redell filled his pipe again. "But you still can't quite accept it?"

"I'm positive they saw the light--but what the devil was it? How could it fly without some kind of airfoil?"

"Maybe it didn't. You remember Gorman described an odd fuzziness around the edge of the light? It's in this Air Force report. That could have been a reflection from the airfoil."

"Yes, but Gorman would have seen any solid--" I stopped, as Redell made a negative gesture.

"It could be solid and still not show up," he said.

"You mean it was transparent? Sure, that would do it!"

"Let's say the airfoil was a rotating plastic disk, absolutely transparent. The blurred, fuzzy look could have been caused by the whirling disk. Neither Gorman nor the C.A.A. men in the tower could possibly see the disk itself."

"Paul, I think you've hit it," I said. "I can see thc rest of it--the thing was under remote control, radio or radar. And from the way it flew rings around Gorman, whoever controlled it must have been able to see the F-51, either with a television 'eye' or by radar,"

"Or by some means we don't understand," said Redell. He went on carefully, "In all these saucer cases, keep this in mind: We may be dealing with some totally unknown principle--something completely beyond our comprehension."

For a moment, I thought he was hunting at some radical discovery by Soviet--captured Nazi scientists. Then I realized what he meant.

"You think they're interplanetary," I murmured.

"Why not?" Redell looked surprised. "Isn't that your idea? I got that impression."

"Yes, but I didn't think you believed it. When you said to check on our space plans, I thought you had some secret missile in mind."

"No, I had another reason. I wanted you to see all the problems involved in space travel. If you accept the interplanetary answer, you have to accept this, too--whoever is looking us over has licked all those problems years ago. Technically, they'd be hundreds of years ahead of us--maybe thousands. It has a lot to do with what they'd be up to here."

When I mentioned the old sighting reports, I found that Redell already knew about them. He was convinced that the earth had been under observation a long time, probably even before the first recorded sightings.

"I know some of those reports aren't authentic," he admitted. "But if you accept even one report of a flying disk or rocket-shaped object before the twentieth century, then you have to accept the basic idea. In the last forty years, you might blame the reports on planes and dirigibles. But there was no propelled aircraft until 1903.  Either all those early sightings were wrong, or some kind of fast aerial machine has been flying periodically over the earth for at least two centuries.

I told him I was pretty well convinced, but that True faced a problem. There was some conflicting evidence, and part of it seemed linked with guided missiles. I felt sure we could prove the space-travel answer, but we had to stay clear of discussing any weapons that were still a secret.

"I can't believe that guided missiles are the answer to the Godman Field saucer and the Chiles-Whitted case, or this business at Fargo. But we're got to be absolutely sure before we print anything."

"Well, let's analyze it," said Redell. "Let's see if all the saucers could be explained as something launched from the earth."

He reached for a pad and a pencil.

"First, let's take your rotating disk. That would be a lot simpler to build than the stationary disk with variable jet nozzles. With a disk rotated at high speed you get a tremendous lift, whether it's slotted or cambered, as long as there's enough air to work on."

"The helicopter principle," I said.

Redell nodded. "The most practical propulsion would be with two or more jets out on the rim, to spin your rotating section. But to get up enough speed for the jets to be efficient, you'd have to whirl the disk mechanically before the take-off. Here's one way. You could have a square hole in the center; then the disk launching device would have a square shaft, rotated by an engine or a motor. As the speed built up, the cambered disk would ride up the shaft and free itself, rising vertically, with the jets taking over the job of whirling the cambered section.

"The lift would be terrific, far more than any normal aircraft. I don't believe any human being could take the G's involved in a maximum power climb; they'd have to use remote control. When it got to the desired altitude, your disk could be flown in any direction by tilting it that way. The forward component from that tremendous

lift would result in a very high speed. The disk could also hover, and descend vertically."

"What about maneuvering?" I asked, thinking of Gorman's experience.

"It could turn faster than any pilot could stand," said Redell. "Of course, a pilot's cockpit could be built into a large disk; but there'd have to be some way of holding down the speed, to avoid too many G's in tight maneuvers."

"Most of the disks don't make any noise," I said. "At least, that's the general report. You'd hear ordinary jets for miles."

"Right, and here's another angle. Ram jets take a lot of fuel. Even with some highly efficient new jet, I can't see the long ranges reported. Some of these saucers have been seen all over the world. No matter which hemisphere they were launched from, they'd need an eight-thousand-mile range, at least, to explain all of the sightings.