Forecast: A SKY FULL OF SATELLITES (Jan, 1958)
Forecast: A SKY FULL OF SATELLITES
By Richard F. Dempewolff
MAN’S GREAT DREAM of stepping off his island in the universe to explore the spangled reaches of space took a giant step toward realization on October 4, 1957. That date marks the exclamation point in history when a 184-pound moon, boosted by a mighty rocket smashing skyward from an airfield on the Caspian Sea, was programmed into an 18,000-mile-per-hour orbit around the earth.
Roaring unmanned space vehicles already capable of reaching up to splash visible blots of potassium or metallic sodium across the real moon’s face 239,000 miles away, and manmade baby satellites plaintively beeping back messages about temperature, cosmic rays, the intensity of meteorite showers and other unknown conditions “out there,” are advance scouts for man’s own expeditions into the void. But the day Earth’s first space “Viking,” clad in a still-to-be-designed “Buck Rogers” pressure suit, steps to the surface of another world from a still-to-be-designed spaceship capable of weathering still-to-be-discovered storms and hazards of outer space, is many moons (and many rockets) away.
Some of those moons and rockets, however, are already in the hardware stage and about to be fired into orbit. Parts of others â€” more elaborate space platforms with TV cameras aboardâ€”are under test in laboratories where they are being subjected to conditions of outer space to make sure they’ll stand up when subjected to the real thing. Still more advanced space stations and vehicles are on the drawing boardsâ€”proven in theory, but waiting for word from the “advance scouts” before money and manpower are thrown into their actual construction. During the next few months and years, according to experts involved in both the United States and the Russian space programs, we soon will witness a sky full of satellites, all orbiting around our globe like Jupiter’s moons.
At Vanguard headquarters in Washington’s Naval Research Laboratory, nearly half a hundred glittering satellites are already built. Most are being used for test in huge vacuum chambers simulating conditions of outer space. Many of the weird-looking spheres are covered with metal cups, beneath which heat or cold can be applied to any portion of the satellite’s skin, just as it will be in the burning sun and polar frigidity beyond the atmosphere. Of all this hardware, four baby spheres weighing 4-1/2 pounds and carrying only a tiny transmitter powered by solar batteries, may be orbiting by the time you read this. Four larger ones, measuring 21 inches in diameter and weighing 21-1/2 pounds, are scheduled for launching in March. Meanwhile the Russians have been launching heavier satellites. Their Sputnik II, sent aloft early in November, was reported to weigh 1120 pounds with maximum altitude of 1056 miles. This satellite carried the first living creature, a dog, into outer space.
In the labs along the Naval Research Laboratory’s off-limits corridors, you can see technicians at work on 10-pound plastic-encased instrument cores for the U. S. spheres. The cylindrical package, a masterpiece of miniaturization, looks like a stack of plump pancakes. “Unlike Russia’s first sputnik which, as far as we know, contained only a transmitter,” says Dr. John P. Hagen, Vanguard director, “ours has instruments to perform many jobs.” Some of the things our orbiting satellites will do: An ionization chamber in the sphere’s shell will pick up and record amounts and types of radiation from the sun; sensitive skin instruments will count particles of meteoric dust colliding with the sphere as it whisks along; a strip “thermistor,” stuck on the satellite’s magnesium hide like a Band-Aid, will record the outdoor temperatures of space; baby microphones will pick up and count sounds of collisions with larger meteoritesâ€”a hazard of space that may make it prohibitive for men to travel there; cosmic-ray counters will tally particle bombardments, and shoot each strike to an amplifier for boosting. A tiny electronic brain, regulated by solar power, will store all the data from these instruments, correlate it, send it to a coder and then out over the sphere’s minitrack transmitter for broadcast to earth. “The signal,” says a Vanguard technician, “is much more musical than that of Sputnik Iâ€” a series of high, low, long and short tones almost like a melody.”
Though the United States Air Force refuses to deny or admit it, an elaborate space-platform program called Project Pied Piper (also known as Big Brother because of its watchdog implication) is reported well under way. A globe-circling reconnaissance satellite, orbiting at an altitude between 300 and 1000 miles, Pied Piper would carry TV cameras and transmitters, and radar or infrared scanning systems which could sweep all corners of the earth once every 24 hours, monitor global events such as weather, atom-bomb tests, undue massing of ship or aircraft fleets, and so on. Taken with telephoto lenses, pictures would carry detail as sharp and clear as an aerial photo taken at 5000 feet. Target date for an unmanned version of Big Brother is estimated about 1960; manned version, about 1965. Some of the tough problems that still need solving: Electronic coding of picture data so it can be transmitted to earthlings, some kind of motorized gimbal mount to keep the camera pointed at earth while the satellite spins its way through space, a rocket powerful enough to get the big satellite up there.
What keeps a satellite in the sky anyway? Why does our four-stage Farside rocket fall back after penetrating 4000 miles into space, while a sputnik can get a mere 170 miles up and stay put? The secret lies in speed and direction. Farside goes straight up until gravity stops it. Earth’s gravitational field extends infinitely. Dr. Fred Whipple, director of Harvard’s Smithsonian Astrophysical Observatory, explains it simply, graphically: “The sputniks were steered to a flat course at 18,000 miles per hour. They keep trying to shoot off at a tangent to the earth with exactly the same force that gravity is tugging them downward. Hence, they orbit around and around the globe, forever falling earthward but never getting there.” Put any object above earth’s atmosphere, traveling horizontally at a speed great enough to offset gravity (18,000 miles per hour at 600 miles; less speed at higher altitudes), and presto! â€” you have a satellite.
Easier to Hit Moon
Shooting a powerful rocket straight up to slap the moon’s face is headline material, but takes less tricky rocketry than precisely steering a satellite into orbit. Our Navy’s project Farside, a four-stage complex of rockets with one stage nested inside the other, is lifted 20 miles by a helium-filled polyethylene balloon. There, above most of earth’s atmosphere, the rocket takes offâ€”right through the balloonâ€”to soar thousands of miles, collecting data and radioing it back to earth via 3-1/2-pound transmitters in each stage’s nose cone. The name Farside, according to the project’s liaison officer, Comdr. Tom Wilcox, has nothing to do with the other side of the moon and never did. “It was thought up by a secretary in my office, and everyone liked it, that’s all,” he says. A few alterations to Farside’s assembly, according to American rocket expert Willy Ley, are all that’s necessary to give it an escape velocity of 25,000 miles per hour and make it a moon rocket. The job of converting Sputnik I for moon-target practice is even simpler, since a 30-pound reduction in weight and slight increase in final speed would do the job.
But to send a satellite into orbit is something else. Our 21-1/2-pound sphere needs a three-stage rocket with 27,000 pounds of thrust to get up there, and must be fired eastward to take advantage of the earth’s spin. Russia’s Sputnik I, if her rocketry resembles ours, had to have a massive, multistage vehicle weighing 150 tons and capable of a 300,000-pound shove to throw the 184-pound sphere into orbit. Intricate self-contained guidance systems of gyroscopes, pendulums and computers steer the big rocket, and program it into a course parallel to the earth’s surface. Delicate plumbing and instruments, sandwiched between the rocket’s glowing 4000-degree skin (from friction with air) and tanks of liquefied gas at 350 degrees below zero, must still function perfectly or the launching is a bust. “The trouble with liquid fuels,” grumbles a noted rocket engineer, “is you’ve got to tote along both fuels and oxidizerâ€”a touchy combination.” The advantage is the ability to control the flow of fuel, changing thrust to keep the rocket going in the right direction. Solid propel-lants, though easier to handle, burn erratically. Farside rocket components, using solid fuel in a new form, however, have restored hope for solid propellants in future rocketry.
Future Propulsion Fantastic
Some of tomorrow’s rocket-propulsion systems may be truly fantastic. In laboratories of the National Advisory Committee for Aeronautics, scientists are poring over ion engines that they predict will propel and control future satellites in their orbits. In these tiny motors, charged bits of atoms formed in an electrical discharge are accelerated by a magnetic field, producing a high-speed jet-stream of ions at temperatures up to 20.000 degrees F. NACA engineers see the day when that little jet will be used, in the vacuum of outer space where air-breathing engines can’t operate, to move a satellite from its orbit and send it on a course to other worlds.
An atomic rocket, already designed by the Atomic Energy Commission, carries a supply of liquid-hydrogen propellant that explodes into voluminous mass as it circulates through a uranium furnace in the nose.
All these items are, actually, a prelude to the day when man himself steps off into the void beyond the atmosphere â€” a day that, until last October 4, was considered a pure fantasy coddled by a few fanatics. Today, it is frighteningly close to reality. Prof. Kirill Stanyukovich, who is a leading Russian rocket expert, has casually predicted manned flight to the moon in three years; to Mars in 13 years. Willy Ley more conservatively sees a manned spaceship six years away, a big manned space station in a dozen years, and a manned moonship assembled at the station a few years later.
The Goodyear Corporation has released plans for a three-man satellite designed to orbit at a maximum altitude of 500 miles. This satellite would be launched by a three-stage ferry rocket developed by the company and called Meteor Junior.
One of the biggest problems of space travel is getting people back safely. Their vehicles, traveling at 18,000 to 20,000 miles per hour, would melt down to a glowing lump of tubing if they plunged into the atmosphere at such speeds. Dr. Wernher von Braun, chief of development at the Army’s guided-missile center in Hunts-ville, Ala., has suggested a winged-glider arrangement that would enable the vehicle to orbit through the atmosphere, slowing gently and finally landing like any aircraft. Actually, the first men to fly into space probably will get there not in satellites, but in craft similar to our present ramjet and rocket-driven high-altitude research planes. In fact, it’s a good bet North American Aviation’s test pilot Scott Crossfield will be the world’s first space pilot this year, if he flies the nearly completed X-15 rocket plane to its design potential of 4500 miles per hour at 100 miles altitude. While Crossfield won’t get into orbit, he will be a mere 70 miles from sputnik’s track at perigee (point of orbit nearest to the earth) and higher than any human has ever been. Flights like this will pave the way for tomorrow’s spaceship pilots.
Space Stations Seen
Most fascinating of all satellite prospects for the near future are the manned space stations, due within a dozen years according to experts. Such a massive satellite, capable of housing a crew of 50 to 75 men, might be a huge cylinder with a vast disk of solar batteries at one end or, as Ley and von Braun have visualized it, a doughnut-shaped affair in which men work and live in corridor-type rooms filled with instruments. The station, Ley says, would orbit at an altitude of about 1000 miles.
First, according to von Braun, spaceships carrying half a dozen men at a time will enter the orbit. Other rockets from earth will ferry structural parts, prefabbed sections and nylon bags full of small equipment up to them each day. All these things, dumped out into the orbit on arrival will actually be individual satellites larruping around the earth like the sputnik’s final-stage rockets. Lashed together to keep them from kiting all over the universe, they will comprise a loose stockpile from which the builders can construct their home in the sky. Men in space, wearing pressure suits, will propel themselves in any direction by tiny rocket motors.
Once the big satellite is finished and a crew installed, assembly of moonships and outer-planet ships will be accomplished the same way. Advantage of launching spaceships from such an island in space is great. Fantastic speeds can be achieved, Ley points out, since a rocket in space accelerates continuously at phenomenal rates as long as its fuel holds out. Using earth as a launching pad, most of the fuel is burned pushing the massive vehicle through the atmosphere.
No Friction in Space
Since friction is no problem in space, interplanetary spaceships need no streamlining. They will, according to Ley and von Braun, consist mostly of one huge spherical or cylindrical fuel tank. Small rocket motors and living quarters will be tied to the tank by metal girders. Spidery legs will provide something to land on. Taking off from the space station, they will move through the solar system like monstrous insects at six-figure speeds.
The men, says Willy Ley, will probably stay out only six weeks or so before returning to earth. Most of their work will be done aboard the space station, which probably will be man’s most valuable space tool for years to come. Most of us will be around to see it in operation. But in the next few years, dozens of unmanned platforms will provide plenty of interesting surprises. Some of these satellites will be sent aloft soon to study aurora, to forecast weather, to learn the mysteries of radiation in the upper layers and to photograph the surface of other planets in the clear unfuzzy light of outer space. Dr. Hagen wants to see a telescope-observatory satellite circling the earth every three hours at an altitude of 2500 miles. There probably will be a microwave-relay satellite, operating on solar batteries, to bounce TV signals to anyplace in the world.
If everyone who should know is right, we will see a sky full of satellites in short order.