GERMAN SECRET WEAPONS

Greymouth Evening Star, 6 October 1945, Page 8

GERMAN SECRET WEAPONS

ISLANDS IN SPACE. From Germany correspondents sent reports of. the discovery of plans among the papers of the German General Staff of what would have been one of the most incredible of secret weapons—a huge mirror, floating in space 5000 miles above the earth (.writes Noel Hush in the “Sydney Morning Herald”). This would have been used to concentrate the sun’s days on enemy cities to produce an intense heat that no living organism could endure, so intense that it could make oceans boil. Is such a construction theoretically possible? The physicist’s answer is that it is.

The notion of constructing an island in space between the earth and the moon is quite sound. If an object were shot'out from the earth’s surface to the height of a few mile-, it would fall back again when the driving force was expended; but,' according to the inverse square law for gravitational attraction, if this distance were increased tenfold the gravitational attraction would drop to one-hundredth of its former value. And as a result of this, a heavy object if shot out about 100 miles above the earth’s surface would not fall back, but would do precisely what another heavy object, which we call the moon, does—revolve around the earth in a regular orbit. It would be possible, then, if we had the necessary force available for the propulsion, to create as many artificial moons —islands in space—as we pleased. But. would it be possible to concentrate heat in such enormous quantities? Again, the answer is that there is no theoretical objection to this.

The radiation of heat also follows an inverse square law, which means that the sun’s heat is rapidly dissipated as the distance from the sun increases; so marked is this that while the face of the moon permanently turned away from the earth receives blistering heat, some of the farthest planets are so cold that it is conjectured that they have cores of solid ice and solid carbon dioxide—substances which are liquid or gaseous at earth surface temperature. If, then, we constructed a large mirror at some distance from the earth, we would have a source of abundant radiant energy. GIGANTIC MIRROR.

According to the cabled reports, the Germans planned to construct a mirror 1.86 miles square, with a surface of metallic sodium. The area seems rather small for the purpose, but a metallic sodium surface would be an excellent reflector.

At the earth’s surface, the metal sodium has a dull, tarnished appearance; this is because it has been attacked by the air. So readily does the metal combine with oxygen that it will burn in water, liberating hydrogen from the water molecule. But at a height of 5000 miles there is no air, so the sodium would exhibit its natural brilliant lustre.

| There would, of course, be many i' difficulties in the way of ccncentratl ing the power obtained on a given | spot. Not the least of these is the j! speed at which the island would re'i volve, which would make necessary a complicated mechanism to focus the rays. The point cf most interest at the i moment is that such knowledge is not new at all, and not very start- , ling. It has been available for years i in the published works of the men !(interested in the possibilities of ’ rocket propulsion for space travel—i the sc-called “astronauts”; the idea I of constructing islands in space is a ' commonplace in such writing. ■ Of the most recent writers in this I field, who have contributed many i mathematical treatises, the most pro- ' minent are Robert Esnault-Pelterie, i Walter Hohmann, Count Guido von Pirquet, Count Potocnic, and Herman Oberth.

Potocnic, Oberth and von Pirquet j considered that if rocket trips were ?to be made from the earth to the moon or to Mars, it would be necessary to create intermediate refuelling .stations—“islands” —which would store the liquefied gases needed to continue the journey. Von Pirquet, a consulting engineer, saw nothing fantastic in the idea of constructing |i such bases in space. He found that yif a rocket-ship had an exhaust ' velocity of 4000 metres per second, for every ton of useful load the ship 1 would have to consume 70 tons of fuel. One refuelling island he did not consider sufficient; and so he planned three islands at distances from the earth of about 470, 470-3105 and 3105 miles. These would, like I the moon, have definite periods of rotation; but, unlike that of the moon these periods would be at most of a few hours’ duration. Actually the islands would revolve around the earth in periods of 100, 150 and 200 minutes respectively. Count Potocnic, who wrote a book on the subject of the construction of islands in space, under the pseudonym Hermann Noordung, was perhaps the most thorough in his treatment. He envisaged the pos-

sibility of using the islands as trappers of power for the earth. He saw the difficulty of using an island | which circled the earth in a few hours to concentrate the sun’s rays on one spot; so he suggested that the island be placed in an orbit distant 23,000 miles. An island in such an orbit would circle the earth only once in 24 hours, and this would enable the beams to be easily concentrated on the one spot. The manner of construction of the islands was gone into most ingeniously by the astronauts. In order to obviate unnecessary journeys from the earth with materials, it was pronosed to build the island around the ship as nucleus. More ships could be added until the island was complete. It was. incidentally, never suggested that the islands should I have permanent inhabitants; so great is their faith in machinery that the astronauts get along without celestial lighthouse-keepers. The perusal of this material leads one into speculation concerning the source of the “secret” plans recently discussed so excitedly by Army officers and correspondents. It is, I thtnk, very likely that the works of von Pirquet and nf Potocnic have been unearthed, and have become “highly confidential.” Army information in the hands of innocent investigators!