Evening Republican, Volume 23, Number 202, Rensselaer, Jasper County, 21 August 1920 — “SHOOTING AT THE MOON”: Verne – Schroeder-Goddard [ARTICLE+ILLUSTRATION]

“SHOOTING AT THE MOON”: Verne - Schroeder-Goddard

by Robert H. Moulton

authorized /I by the Smithsonian InstituI tion th»t Prof. Robert H. V I Goddard of Clark college fir U has Invented and tested a I new type of multiple-charge, A efficiency rocket of an enI tirely new design, for ex- ■' ploring the unknown regions of the upper air. will recall the two adventurers in Jules Verne’s novel, “De la Terre a la Lune" (1865). Of course “A Trip From the Earth to the Moon” was a literary Joke, so to apeak, but it was no more so than Verne’s "Twenty Thousand Leagues Under the Sea" —all of which came true a few years later with the submarine. Then here Is Maj. R. W. Schroeder of Chicago, chief test pilot at McCook field, who flew up 36,020 feet the other day, said to be 5,020 feet higher than man ever ascended before. He says he’s going higher next time. Anyway, the claim is made for the rocket that It will not only be possible to send it to the layers of air beyond the earth’s atmosphere, but even to the moon itself. Briefly, the principle involved in this latest space-demolishing marvel is that of multiple discharge. The rocket leaves the earth under force of an explosion in the lowest of a series of chambers loaded with smokeless powder. After reaching a certain altitude chamber No. 2 is shot, giving impetus for a few more thousand feet upward. Then, nt accurately timed and measured Intervals, there are further discharges. which spur the rocket on its way. The atmosphere surrounding the earth extends outward about two hundred miles, while thus far the highest level reached by recording instruments is 19 miles. Rockets such as are used as signals of distress nt sea have a range of only a quarter of a mile, with the highest point of trajectory less than five hundred feet. Their initial speed is about 1,000 feet per second, while that of Prof. Goddard records 8,000 feet per second. This. Incidentally, is the most rapid velocity In practical use, the muzzle velocity of projectiles from the greatest guns being only about 3.000 feet per second. The most important feature of the new device is that it includes a nozzle, constructed of the toughest steel, through which the gas is ejected. This concentrates the force, instead of its being dissipated in the air, as in the old types.

It Is argued that when the rocket emerges from the earth’s atmosphere a vacuum will be encountered in the upper regions, in which exploding gases will lose their power of propulsion. Experiments by Prof. Goddard have demonstrated this feature is no drawback. He fired his rocket in a tank from which the air was drawn, and found greater efficiency in the matter of propulsion than in the air. The quantity of powder required has been calculated. The experimenter takes one pound as his unit mass, and to send this up 1,228.000 feet 9.8 pounds are needed, and to reach beyond the earth’s influence of attraction only 1,274 pounds initial mass. When once the influence of gravitation, or rhe earth’s attraction, has been passed, the rocket theoretically goes forward through space at a uniform speed—through infinite space—and eternity. unless it should bump Its head against some distant star, or encounter a flying meteor or body of atmosphere out somewhere in ether. Naturally the curious will ask: “How are you going to know when you score a hit on Luna?” Professor Goddard has worked out this feature by exper-

intent. He proposes to aim at the dark area of our satellite and in the nose of his rocket place a large charge of flash powder, which will be Ignited by. impact. The flare of this can be observed by powerful telescopes on the earth. But. remark the skeptical, how does he know at what distance flashes of magnesium powder can be seen? He knows, as he knows other details, by exact experiments and mathematical calculations based on them. Briefly, his experiment consisted of exploding a given quantity of flash powder in a glass tube, from which the air had been drawn. The exact quantity was weighed and measured, and the resultant flash was observable at, say, two miles. From this he ..could figure just how much would be required to make light enough on the dark side of the moon so that It could be noted on the earth with the proper kind of telescope.

Professor Goddard’s experiments with flash powder demonstrated that if the powder were exploded on the surface of the moon, distant 220,000 miles, and n telescope of one foot aperture were used —the exit pupil being not greater than the pupil of the eye—we should need a mass flash of 2.67 pounds to be just visible, and 13.82 pounds or less to be strikingly visible. The quantity required could, of course, be much reduced by the employment of a larger telescope. For example, with an aperture of two feet, the masses would be reduced to onefourth of those just given. The use of such a large telescope would, however, limit considerably the possible number of observers. In all cases, says Professor Goddard, the magnification should be so low that the entire lunar disk is in the field of the telescope. Another facto? is presented in the form of itinerant meteors. One of these might come in contact with the rocket and an expensive experiment would be shattered. Professor Goddard has looked into the subject of meteors and found that the probability of collision Is negligible. Sir Isaac Newton estimates that the average distance apart of meteors is 250 miles, so that with the vast areas of space it is fairly safe to conclude that a rocket traveling 220.000 miles is not likely to have an unpleasant encounter enroute. The subject of meteors suggests another difficulty In connection with the rocket as a. means of observing the upper strata of the air. It is popularly known that when meteors strike the earth they do so with such force as to be imbedded often 16 to 20 feet in the soil. Should they strike water or a harder substance than soil, they are virtually vaporized by the terrible Impact. Now when the observation rocket comes down from Its lofty flight, would It not be blasted and broken, like visiting meteors? Professor Goddard has devoted thought to this detail, so there need be no worry about the rocket and its freight of scientific instruments. Meteors enter the earth’s atmosphere at tremendous speed, which is but little slowed before terra flrma Is touched.

The rocket ascends to a point of rest; the Instant of time when Its limit of upward motion is reached. From this point it descends, hence would have nothing like the downward velocity of a meteor. Still the fall would be sufficient to do damage, and to obviate this Professor Goddard proposes a parachute which will decrease the velocity as denser air is reached. If the parachute is so large that the velocity will be decreased greatly when the denser air Is reached, the descent will be so slow that finding of the apparatus will not be so easy as would be the case with a more rapid descent. For this reason part of the parachute device must be lost automatically when the apparatus has fallen Into air of a certain density, with additional parachute devices rendered operative as the rocket nears the ground. Such devices have not been fully worked out by Professor Goddard, but he says they would be of simple and light construction. Professor Goddard’s experiments show that the time of ascent of his rocket would be remarkably short. For example, a height of over 230 miles is reached in less than six and one-half minutes. The- reason is, of course, that this form of rocket possesses the advantage of the bullet in attaining a high velocity, with the added advantage of starting gradually from rest. In fact the motion fulfills closely the ideal conditions for extremely rapid transit —namely, starting from rest with the maximum acceleration possible, and reversing this acceleration in direction at the middle of the Journey.

The short time of ascent and descent is, of course, highly advantageous as regards following the apparatus during ascent, and recovering it on landing. The path can be followed by day by the ejection of smoke at intervals, and at night by flashes. Any distinctive feature, as, for example, a long, black streamer, could assist in rendering the instruments visible on the return. Not since the Germans sprung the long-distance gun with which they killed children and women in Paris, by means of a shell fired 72 miles, has the world had so spectacular a proposltfon in the field of explosives presented as that of Professor Goddard’s rocket. It opens fields of speculative thought whose limits are not confined by things terrestrial. What may not be developments to follow on sending of earth’s material to the moon?