Rocket Engineering Manned Space Flights Now Within Calculation

Press, Volume C, Issue 29566, 15 July 1961, Page 8

Rocket Engineering Manned Space Flights Now Within Calculation

IBv PROFtSSOR BXRMABN OBERTH] will come next in rocket engineering? asks Professor Hermann Oberth, the famous rocket engineer, in his third article in this series. Few people can answer this question with more authority than he. His own work in rocket engineering started in the twenties, and after the war he headed a department in Huntsville, Alabama, which had the particular task of examining what the next few years might bring in the form of new ideas and new developments. An automaton can only measure and record that which its inventor has planned it to measure and record. It will therefore be useful only for what is predictable. The human brain, on the other hand, observes everything—even the unexpected—and what is most important to science is that which no one has thought about

Sitting in an automobile that makes a sudden violent start, we are pressed against the back of the seat; if the car brakes suddenly or if it hits something, we are thrown forward. The force with which all these things happen, may be calculated in the following manner: when anyone is standing at rest, gravitation pulls him toward the ground, and since the ground does not yield, there will be a pressure of the soles of his feet against the ground, of bone against bone in his body, and a tension in sinews and muscles. This is what makes us feel that we have weight. More, over, there are in the ears small calcium crystals—so-

called Miniere corpuscles—which rest lightly on nerve filaments and by their changing position as we lean our heads this way or that they report immediately to the brain any change of direction of the the pressure or gravitational pull. Manned Space Travel This is why we are preparing rockets for manned space travel. All unmanned rockets which have flown higher than weather balloons have therefore carried automatic measuring devices and transmitters. And thanks to this, we are now quite well informed about what is lying in wait for us in space Already, space conditions as recorded by the rocket instruments, are being artificially created in the institutions of astronautics! medicine to examine their effect on the human body and the human mind, so that we may plan countermeasures and study their effect It is possible to say even now, that space has no dangers which our technical know-how cannot master, if we only know these dangers.

The first strain that a space traveller will experience is a tremendous pressure.

In an automobile we should be pressed against the back of the seat with the same force, if with every second the automobile accelerates by 35 km. an hour. If the acceleration is only one-tenth of that, or 98 cm.-sec. equals 3.5 km./ hour, then we should be pressed against the back of the seat with only one-tenth of the aforementioned force, which ia the same as onetenth of our own weight, since our weight is equal to 1 g. In a rocket which accelerates, by 70 km. an hour, we should be pressed against our aupport by twice our own weight, and, if the rocket rises vertically, by three times our own weight. Just after take-off a rocket does have a nearly vertical upward acceleration of 0.5 to

l. g. The passengers will therefore feel 1.5 or 2.5 times as heavy as on Earth. Just before the engine of the first stage cuts out the weight of the rocket will have become considerably smaller while, thanks to the greater altitude, there will be a greater exhaust gas velocity. Consequently the power of the engine will increase, and just before the stage is jettisoned the passengers will feel a pressure of 5 to 6 g. The second step of the rocket begins with an acceleration of 3 g. and also finishes with 5 to 6 g. and so does the third step. Human Reaction Examined To examine how the human organism can stand these conditions, the space doctors use a kind of giant centrifuge or merry-go-round with a long, powerful arm (the one at Randolph Field, Texas, has a length of 35 meters) carrying at its end a cell or cabin where the human guinea pig can sit or lie down. This arm will move around a vertical axis and at its other end there will be a balance weight. As the arm moves around its axis, the centrifugal force will press the man in the cabin outward from the centre at maximum speed this centrifugal force or pressure will equal 15 g., which is equal to 147 m. A weight connected to an elastic spring measures and records the pressure. To keep the device in motion, the man in the cabin must keep pressing his hand on a push button above his hand, —that is, he must press the button in the opposite direction of the pressure. When he can no longer do this, the ‘'carriage” stop* automatically. Apart from this, he is under constant observation by a doctor standing near the centre of the centrifuge. Observation is made possible by means of a mirror which even allows photographing the “guinea pig.” These experiments have demonstrated that in a sitting position a healthy man will stand up to 2 g. without injury, at accelerations above 2 g. there will be black-outs: blood will rush to the legs, the brain will be empty of blood. At 3 g. consciousness will be affected, and at 5 g. everyone will be unconscious in free air. But if the man sitting in a container with salt water from his feet up to above his diaphragm, the pressure of the salt water against the blood vessels of the legs and abdomen will prevent these vessels from admitting more blood than normally, and the man will be able to stand accelerations from 6 to 7 g. sitting or lying down Any man will stand high

pressures best lying down. Even without a salt-water container and other special preparations normal people will stand pressures up to 8 g. for a few minutes. With training (you can actually train yourself to stand these strains) ordinary, healthy people can stand up to 10 g. and a few have stood strains of 15 g. or more.

New Surprise For Passengers

The next surprise to the passengers will come when the rocket has flown beyond Earth’s gravitational pull and the engines of all the steps have exhausted their fuel. Since the rocket now flies at uniform speed and there is no gravity, every kind of pressure dissappears. The passengers may fly about in their cabin like angels; in fact they must hook their feet to rings in the wall to avoid hovering in mid-air, or even better, have magnets fastened to their shoes which will keep them "glued” to iron walls or steel ropes. On their backs they may have wings like giant moths to assist them in flying around the cabin. Or instead of magnets they may use hollow rubber soles on their feet. As they press their feet against the smooth surfaces of the floor or walls the soles will stick like the feet of a fly walking up and down a window.

In a state of weightlessness it would not be possible to pour water from a bottle into a glass. The passengers must use straws or tubes to be able to drink. If an open bottle is pulled away in a direction away from the bottleneck, the liquid content would remain in free air forming a big round drop, which can be sucked through a straw just as if it was in a bottle. Man's reaction to weightlessness could so far be tested only in the following manner. When a jet plane is flying at top speed as high as it can reach and the pilot pulls the elevator, the plane will climb a little higher, but as it then enters a layer of air which cannot carry it, it will sink back again. An experiment like this was made with a Bell X. First it flew at maximum speed in a layer of air that would carry it. then climbed almost vertically, and as it was near the peak of its trajectory it was made to dive (rockets and jet airplanes as everyone knows can be steered even in airless space.) Nose downward it rushed back into denser atmosphere where the fall was stopped. Climb and dive each lasted for one minute. At the beginning of this “free flight” the pilot held a matchbox at the level of his head. During the following two minutes this box hovered free in the cabin proving that there really was weightlessness. Ambitious Plans In the United States plans are in progress to make experiments with a new Bell X. the Bell X-15, which is to remain in free space for five minutes. The Russians have even more advanced plans. They want to send a manned space rocket into orbit around Earth within a year. As the rocket circles the Earth, the gravitational force is neutralised by the force of the rocket’s own speed, and one will be able to observe for hours, days or maybe weeks and months, how to stay in space will effect the pilot. The United States follow with similar experiments in 1962. Present experiments have shown that human guinea pigs react differently to weightlessness. The reaction

will depend fi’-st on whether the man ex-’er ences what is happening activelv or passively. A pilot who actively creates the sta’e of weightlessness generally finds it a pleasant experience, while a passenger may have a feeling of nausea or something similar to seasickness. Nor is it unimportant what feel, ings have preceded the state of weightlessness. On the whole, most people seem to accustom themselves very quickly to the new state of weightlessness after the first few moments of unpleasantness. (To Be Concluded)