Push into Space

(See Cover) When the Soviet Lunik raced past the moon and free of the earth last week, it did more than win a triumph for its designers. It also marked a turning point in the multibillion-year history of the solar system. One of the sun's planets had at last evolved a living creature that could break the chains of its home gravitational field.

After a few more moments on the evolutionary time scale, earth's restless social primate, man, can almost surely make himself felt throughout the system. Earth's life will no longer be confined to the earth. This startling development took place with explosive suddenness. Boys still in high school remember a time when sensible citizens considered space flight as impractical as hunting leprechauns. Only ten years ago the altitude record for rockets, 250 miles, was held a brilliant achievement. Only two years ago, the earth satellite, that humblest of space vehicles, seemed an almost impossible project.

Newton's Rails. But the basic rules of space flight have been known for centuries. The Chinese, who invented rockets about 1200, did not theorize about them, but Sir Isaac Newton's laws of motion, published in 1687, not only explained the principle that makes rockets fly but gave the essential sailing directions for space ships of the future. When a U.S. Atlas or an even bigger (for the present) Soviet space rocket roars into the sky. it runs on rails devised by the ill-tempered Sir Isaac, who sat in his English garden nearly 300 years ago and wondered why things move as they do, and why things fall. When a rocket engine shoots a jet of gas out of its tail cone, Newton's third law takes over: For every action there is an equal and opposite reaction. Acting in the opposite direction to that of the racing gases, a mighty force lifts the rocket off its launching pad. As long as the engine fires, the rocket climbs faster and faster, obeying Newton's second law: An unbalanced force acting on a body makes it accelerate in the direction of the force . . . When the engine burns out, the rocket continues upward under the control of Newton's first law: . . . A body in motion continues to move at constant speed in a straight line unless acted upon by an unbalanced force. As it rises, it slows and curves because an unbalanced force, the earth's gravitation, keeps pulling at it in obedience to Newton's law of gravity: Each particle of matter attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Although the magic laws of Newton pointed clearly into the sky, no one apparently followed their lead until a shy, deaf, self-educated Russian schoolteacher, got to thinking about air travel in the 1890s. Konstantin Eduardovich Tsiolkovsky, born in 1857, wrote about space flight with amazing prescience. He chose the rocket as the only possible space engine and derived mathematically the speed that its exhaust gases would have to attain. He decided that it should burn liquid fuel. This conclusion he published in 1898, when not even an airplane had left the ground.

Extreme Altitudes. Almost as a foretaste of the current U.S.-Soviet rivalry, the next space pioneer was an American. Robert Hutchings Goddard, born in Worcester, Mass, in 1882, was not only a far-sighted theorist but the maker of the first well-engineered space hardware. In 1915, when he was an assistant professor at Clark University in Worcester, he built solid-propellant rockets, and won a $5,000 grant from the Smithsonian Institution. In 1919 the Smithsonian published a brief Goddard report which predicted, among other things, that a multistage rocket weighing only ten tons could land a small payload on the moon.

Suddenly Goddard had a kind of fame. Newspapers featured him, and the New York Times chastised him for the error (it is no error) of believing that a rocket engine can work above the atmosphere without "something better than a vacuum to react against." Goddard, a sensitive man, was appalled by this notoriety.

By 1922 he was bench-testing in secrecy the world's first liquid-fueled rocket. Four years later, he made his first flight tests. His tiny, ungainly gadget, launched from a relative's farm near Auburn. Mass., hardly got off the ground, but it was the true precursor of today's mighty rockets. Three years later, an 11-ft. rocket climbed 90 ft. Its noise attracted the local cops and stirred up so much opposition that Goddard left Massachusetts for thinly populated New Mexico. There his rockets climbed higher and higher. In 1935 one reached the sensational height of 7,500 ft.

Goddard's rockets remained small, but they were not crude. They had all the essential features that later rockets needed to fly out of the atmosphere, including gyroscopic guidance and combustion-chamber walls cooled by flowing fuel. The German V-25 that caused a sensation toward the end of the war followed Goddard's lead without basic innovations.

Soon after the publication of Goddard's 1919 report, rocket enthusiasts began to clot together in little societies. The science of celestial mechanics (motions of the planets) had been highly developed by the astronomers. The astronauts took it over, added some features of their own. Long before World War II, when no rocket had flown above buzzard altitude, they drew charts of imaginary voyages to Mars or Venus that match almost exactly those drawn today.

Placid Space. The best way to think of space as a navigable medium is to imagine the frictionless surface of a calm, glassy pond. Small objects drift across it easily, propelled by feeble forces. Scattered at wide intervals over the mirror surfaces are deep, sucking whirlpools. If a floating leaf drifts close to one of them, it plunges down to the bottom. A self-powered object, say a water insect, that gets sucked into a whirlpool has a terrible time battling back to the surface.

Deep space, far from stars or planets, is like the pond's smooth surface. An object becalmed in its emptiness floats like a galleon in the doldrums. If the object is a spaceship with propulsive power, it can cruise in any direction, meeting practically no resistance. But it must keep away from the whirlpools: the gravitational fields that surround stars and planets. If it plunges into one of them, it may end as a puff of gas in a star or a brief streak of fire in a planet's atmosphere.

Looking at it from the other end. a spaceship that starts its voyage on the surface of a planet has a hard time climbing out of its gravitational pit. Once it has reached untroubled space, it can coast for millions of miles on its unopposed momentum.

To fight free of the earth, the space navigator must reach a speed called escape velocity. Figured at the surface of the earth, this is 25,000 m.p.h. But rockets do not start suddenly. They accelerate gradually, keeping their speed fairly low while still in the atmosphere, then spurting quickly. If a rocket is moving 24,000 m.p.h. when it is 300 miles above the surface, it will escape from the earth's gravitation. When the Russian Lunik launchers, watching their bird with Doppler (speed-measuring) radios, saw it pass the critical speed, they knew it would never return to earth. A lesser speed than escape velocity sets a satellite revolving around the earth just free of the atmosphere. A satellite can be compared to a chip or leaf circling around the sides of a whirlpool without escaping from it or immediately being swallowed.

Near the rim of the earth's gravitational pit is a much smaller pit belonging to the moon. An object shot away from the earth at 24,800 m.p.h. will reach the boundary, about 34,000 miles short of the moon, where the moon's pull is as strong as the earth's. If it reaches this point with a small velocity, it will fall on the moon. If it crosses the line at good speed, it will shoot past the moon, its course merely deflected. This is what happened to the Lunik.

Solar Orbit. The earth and moon, whirling around each other, are not alone in space. They also orbit around the sun, and so do the other planets. A gravity chart of the solar system shows an enormously deep pit, the sun's, with much smaller pits in its slope, one for each planet. When a spaceship has climbed out of the earth's gravitational pit, it is still deep in the sun's pit. This does not mean that it will fall into the sun. Besides the comparatively small speed contributed by its own engine, it also has the earth's speed in its travel on its orbit. If the ship has only barely escape velocity, it will circle around the sun indefinitely on an orbit close to the earth's--just as bombs, in the newsreel pictures of a decade ago, seemed to hover in space just below the plane that released them.

To go to Mars, whose orbit is outside the earth's, the spaceship must climb up the side of the sun's gravitational pit--by speeding up. To reach Venus it must climb down--by slowing down.

For a voyage to Mars the space navigator takes his departure from earth in the same direction that the earth is moving around its orbit (see chart). His ship must have a speed of only 870 m.p.h. over escape velocity. The excess speed is added to the earth's orbital speed (66,600 m.p.h.) that the spaceship had before it was launched. This is enough to offset the sun's gravitational pull, allows the ship to swing outward in an ellipse. If the timing is right, it makes a rendezvous with Mars on its orbit.

For a voyage to Venus, which revolves nearer the sun, the space navigator starts his ship in the direction opposite to the earth's orbital motion. Its net departure speed above escape velocity is subtracted from the orbital speed. This makes it move too slowly to stay on the earth's orbit, so the sun's gravitation curves it inward to Venus.

Perhaps the most striking thing about space navigation is the ease of longdistance travel after successful launching. Mars never comes closer to the earth than 34.5 million miles, Venus never closer than 25 million miles. To cover these great distances, it takes more time (146 days to Venus, 260 days to Mars), but only slightly more speed than is needed to go to the moon, which is only 230,000 miles away. This is because space between the planets is comparatively smooth. It is only slightly affected by planetary gravitation, and the great pull of the sun is countered by the orbital speed that a spaceship inherits from its home planet.

Interstellar Escape. Full escape from the gravitational pull of the sun would be tougher. Starting from the earth's surface, a ship would need 36,800 m.p.h. Soaring past Mars, Jupiter, Saturn, Uranus, Neptune and Pluto, it would reach the outer limits of the solar system with almost no speed left. Then, like a chip on a glassy lake, it could drift for millions of years before it approached the nearest star, Proxima Centauri, which is 25 trillion miles away from the sun. Man's spaceships can probably reach interstellar escape velocity in a generation, but there will be little profit in interstellar voyages. They will take too long. The barrier that protects the stars and their planetary systems from human invasion is not space but time, and the shortness of man's life.

How close is interplanetary voyaging? The great weight (2,925 lbs. of instrumented payload) of Sputnik III proved to the space-wise that the Russians had practically licked the initial problems of interplanetary flight. U.S. scientists reckon that the Soviets' Lunik, with only a little more speed, would have swooped past Mars and soared out toward the asteroids. George Paul Sutton, professor of aeronautical engineering at M.I.T., believes that present propulsion systems with a little refinement can send a space vehicle as far as Jupiter or even to Saturn, 750 million miles from the earth.

Astronomers can hardly wait for the day when these first space scouts are launched. For oddly enough, they know less in many ways about the planets, the earth's neighbors, than they do about far-distant stars. The reason is that stars shine in their own light, revealing much about themselves to astronomers' spectroscopes. The solar system's planets are visible only in the reflected light of the sun. Their spectra carry little firm information, and the details that can be seen on their surfaces are clear enough to excite but too vague to satisfy human curiosity.

Controversial Moon. The moon is an exception. It is so close that it shows a wealth of detail that astronomers have studied for centuries. They have also argued bitterly over many questions presented by its serene face, e.g.: Are the ring-shaped craters the result of volcanic activity or meteor impacts?

Dutch-born Astronomer Gerard Kuiper (rhymes with hyper), head of the University of Chicago's Yerkes and McDonald observatories, thinks the moon was formed at the same time as the earth (5 1/2 billion years ago), but at first it revolved only about 20,000 miles from the earth's surface. Beyond it were a lot of smaller satellites arranged in a disk somewhat like the rings of modern Saturn.

This situation did not last. When the earth acquired oceans, the great tides aroused in them by the nearby moon made the earth rotate more slowly. This made the moon spiral outward. As it moved, it crashed into the lesser satellites, each of them blasting an impact pit in its surface. The bigger pits punched through the moon's crust and were filled with lava from the molten interior. The biggest satellite of all, about 100 miles in diameter, hit the present site of the lunar plain called Mare Imbrium--the right eye of the "man in the moon."

Crunchy Snow. After this climactic event Astronomer Kuiper thinks the moon led an increasingly peaceful life. It picked up the rest of the small satellites, which made the fresh-looking pits on its surface. Cosmic rays and other high-speed particles bombarded its surface, riddling the material with microscopic holes. This beaten-up stuff is only an inch or so thick, says Kuiper, and it is not dust. He thinks it would feel underfoot "like crunchy snow."

Nobel Prizewinner Harold Urey of the University of California at La Jolla, another leading moon authority, agrees with Kuiper about there being lava on much of the moon's surface, but he does not think that it welled out of a molten interior. Instead, he contends, it was formed on the spot by the energy of great meteors that hit the moon and melted both themselves and the local lunar rock. He thinks that the present surface material may be something like sand or gravel.

Radiation Erosion. The newest and most radical moon theory was developed by British Cosmologist Thomas Gold, now at Harvard. Professor Gold agrees that the moon was pockmarked long ago by large meteors, and it may have been built up entirely by such accretion. But he does not think that the smooth, dark areas that are called maria (seas), because early astronomers thought they were exactly that, are filled with lava. He thinks that they are low places full of fine dust that was removed by a kind of erosion from the moon's highlands. In some places it may be more than a mile deep.

There is no water on the moon, so Gold's erosion cannot be like the kind that wears down earth's mountains. He thinks that the chief eroding agent is high-energy radiation from the sun helped by cosmic rays and meteorites. They slowly chewed a flour-fine dust from the moon's exposed rocks and kept it stirred up so that it gradually flowed into low places like the interiors of old craters and the maria.

Whether Gold's theory is correct or not, it threw something of a scare into space-minded military men who hope some day to land on the moon and do not like the idea of sinking into a mile of loose dust. Their fears were calmed by simple tests made in the laboratories of their contractors. North American Aviation, Inc., for instance, shows two sealed glass tubes. One of them contains air as well as fine dust, and a small steel ball sinks deeply below the surface. The other has a vacuum. The dust particles, no longer lubricated by air between them, pack tightly and prevent the ball from sinking. On the airless moon, it is likely that dust has compacted in the same way.

Radioactive Moon. Russia's Lunik carried an instrument to measure the radioactivity of the moon's surface. Neither Kuiper nor Gold believes that it could have worked at the distance (4,660 miles) at which the Lunik swept past the moon, but they would be grateful for any information that the Russians choose to release. Dr. Kuiper believes that the moon's surface is blazing with radioactivity. On the earth, he says, the thick layer of air is the shielding equivalent of 3 ft. of lead or 33 ft. of water, protects the surface from many kinds of tough radiation beating down from space. Kuiper believes that the moon is radioactively contaminated to a depth of 30 ft. below the surface.

The Planets. Nearest planet to the earth is Venus. It is about as big as the earth and has an atmosphere, but it seems even less attractive as real estate than the airless, sun-seared moon. Its atmosphere is so cloudy that outsiders, peering from the earth, can see only its slightly yellowish cloud deck, which sometimes shows faint, impermanent markings.

The Venusian atmosphere contains carbon dioxide. This information does not mean (as many science-fiction writers seem to think) that Venus under its clouds is covered with lush jungles. Earthside plants need carbon dioxide, but their flourishing presence on earth is the reason why the earth's modern atmosphere contains only a trace of CO2. This abundance of carbon dioxide in the Venusian atmosphere is excellent proof that the planet has no earthlike plants on it.

Probably it has no life at all. Dr. Kuiper thinks that it has no water or free oxygen. Radio waves, which penetrate the murky atmosphere, hint that the temperature of the invisible surface is something like 500DEG F., which is much too high for the earth's kinds of life. Venus rotates only once in several weeks, making the sunlit side much hotter than the dark side, and causing violent storms that sweep perpetually over its hot, dry deserts.

Dr. Urey still thinks that the clouds in the Venusian atmosphere may be made of water droplets like clouds on earth, but few astronomers agree with him. Dr. Kuiper thinks they are made of fine dust particles of carbon suboxide (0302). In an attempt to prove this theory, he made a mixture of carbon dioxide and carbon monoxide and exposed it to assorted radiation at the Argonne National Laboratory. Sure enough, carbon suboxide formed, and its molecules stuck together to make particles of yellowish polymer.

Optical Canals. Mars is more interesting than Venus because its atmosphere is transparent enough to permit its surface to be seen. But astronomers do not agree about what they see on it. All of them see white patches at the planet's poles, which they accept as thin layers of ice or hoarfrost. All of them see irregular light and dark markings that change with the Martian seasons. Only a few of them still see the network of straight, artificial-looking lines that was widely believed a generation ago to be a system of irrigation canals built by highly civilized beings to distribute the failing water supply of their aging planet.

Even stern astronomers regret to see the Martians abolished, but they can do nothing to save them. They have to insist that even if Mars is really covered with fine lines at the limit of vision, they cannot be irrigation canals, since they are not arranged in a way that would distribute water from the icecap, and they follow no logical contour lines. With this notion lost, there is no further support for the civilized Mars theory.

The Martian atmosphere is thin (8% of the pressure on earth) and may have no oxygen. It contains a little carbon dioxide and probably nitrogen and argon. The daytime temperature may occasionally rise above 86DEG F., and at night it may fall to minus 150DEG F.

These are tough conditions for life, but life is tough. Mars's seasonal changes of color suggest strongly the growth of something like vegetation in the Martian spring when the polar icecap melts or evaporates and spreads its scanty moisture over the nearby surface. And only this year new evidence was found that some kind of life exists on Mars--perhaps at the level of lichens. Dr. William M. Sinton of Lowell Observatory took spectrograms of Mars in infra-red light, found dips in three places where infra-red waves are absorbed by chemical compounds containing hydrogen atoms bonded to carbon. Earth's living plants and animals are made almost entirely of such compounds.

Small Star. There is little chance that life as known or imagined on earth can exist on any other solar system planet. Mercury is so close to the sun that its sunlit side (it always shows the same face to the sun) is hotter than molten lead. Its dark side, which gets no heat except from the stars and distant planets, is probably the coldest place in the solar system, only a few degrees above absolute zero ( -- 273DEG C.).

Jupiter, the biggest planet, has a turbulent atmosphere thousands of miles deep made of unpleasant gases like hydrogen, methane and ammonia. In its upper levels float clouds of ammonia crystals. Jupiter is marked with conspicuous bands roughly parallel to its equator. They may be storm belts, but no one really knows. A great oval red spot about 25,000 miles long in its southern hemisphere is unexplained. Dr. Kuiper thinks that the great planet is exceedingly hot inside ("really a small star") and that it has a peculiar surface made of solid hydrogen. Gigantic volcanoes bursting from below may send shock waves through the atmosphere, stirring it into raging storms and inducing great electrical discharges.

Word in Space. For the moment, most scientists are concentrating on sending not man but "black boxes" into space. Humans are too heavy, bulky, ineffective and delicate to pay their way in the space vehicles of the near future. Instruments will do much better with far less demand for accommodation. Best of all, the black boxes need not get home alive. If they have radioed their findings back to earth, they can vaporize in a planet's atmosphere or wander into space never to return.

The simplest kind of instrumented space probe can gather much valuable information without landing on the moon or a planet. A picture of the back of the moon is one of the easiest prizes. Interplanetary space is by no means empty. It contains a very thin gas of unknown composition, and through it a "wind" of high-speed particles blows outward from the sun. This wind may be dangerous; it should be studied carefully before manned ships are launched deeply into space.

As the space art improves, instrumented vehicles will make soft landings on the moon, braked gently to the airless surface by retrorockets. Once they get there, they can look around with television eyes, telling the earth what they see. When the probes get good enough to tackle the planets, they can swoop into the atmosphere of Venus for a look at its unknown surface, swing around Mars looking for signs of life.

An unsolved problem is communication. It will do no good to send a space probe to Mars if communication with it is lost, as happened to Lunik soon after it passed the moon. Radio signals can cover any desired distance if given sufficient power, but the only power sources now available are heavy, short-lived chemical batteries or feeble solar batteries. To tell its story properly from the distance of Mars, a probe needs as much power as an earth-side radio station. One possibility is a nuclear battery getting its energy from radioactive materials. Another (one form of which was invented by Professor Gold) is a solar battery of gossamer-light plastic film whose large area will catch several kilowatts of solar power.

Men in Space. But instruments can never bring back as much information as a spaceship with a human crew. The difficulties of manned space flight are still enormous, and they seem to increase the longer they are studied. The recently discovered belt of Van Allen radiation that rings the earth is a serious hazard that was not dreamed of a few months ago.

But man will fly through space, hazards or no hazards. The Russians are known to be planning to put a man up in a satellite. Astronomer Alexander A. Mikhailov, director of Pulkovo Observatory near Leningrad, told a TIME correspondent last week that they are also planning a manned voyage to the moon. The biggest problem, he said, is safe return, and they do not intend to risk a man until they are sure of getting him back alive.

The U.S. program is roughly similar. A "soft" instrument landing on the moon may be accomplished in 1960. Putting a man in space will take longer. A protected capsule to bring him back alive is already under development. One of the preliminary research tools toward this project is the X-15 rocket-plane, which will meet its first tests in a month or so. It is designed to start its flights in the atmosphere, then shoot out of it to a probable height of 150 miles. Its descent on stubby wings will build experience for controlled returns from deeper space.

What is the motive for the push into space? This question gets many sharply conflicting answers. Some military strategists believe that a U.S. rocket base on the moon, which could never be destroyed by surprise attack, would provide the supreme deterrent to any earth aggressor. Most scientists do not agree. Nor do they think much of the idea of armed satellite bases. They see little reason to shoot from a satellite when a rocket shot from solid ground can hit any target on earth. But satellites may prove to have value as "eyes in the sky" over enemy territory.

They can also serve as communication relays and act as aids for navigation.

But the rivalry with Russia is not a simple propaganda battle. Says one spaceman: "We could concentrate entirely on our military developments and let the Russians have space to themselves. Would we thus make ourselves impregnable? No, because the rest of the world simply would not believe that we were impregnable. It would look to Russia as the clear leader--and the battle would be lost before it was fought."

Challenge & Response. Simplest and most basic motivation of the drive into space is man's enduring and insatiable drive to explore and know his environment. Space is a challenge simply because, like Mount Everest, it is there. Hundreds of millions of years ago, earth's life ventured from the shelter of the oceans, crept slowly and painfully out on land, into the hostile air and searing sun. Man is venturing forth again into a new element. From the bottom of the air ocean where he has lived so long, the emptiness overhead looks almost impossibly hostile. Its vacuum kills a soft-bodied human in a few seconds; its radiation and heat and cold are almost as quickly fatal. But man has his daring and his intelligence. His body will not have to change. He can take with him into space an artificial environment that simulates the familiar bottom of the atmosphere.

It is supreme adventure for man's spirit as well as his rockets. The stars and the moon have long been symbols of a remote and indifferent universe, a reproach to man's insignificance. Now man for the first time is challenging the planets themselves.

Ultimately, man cannot refuse the challenge, if he is to keep alive the essential spirit that distinguishes him from animals. After all, man's ancestors that stayed in the sea are still fish.

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