Rocketeering

So unobtrusively does Professor Robert Hutchings Goddard of Clark University, Worcester, Mass., work on his study of the air's upper miles by means of rockets that to many a Clark student he is only a tradition. They call him the moon man, in the inaccurate belief that he is trying to reach the moon with his missiles. Last week, Tradition Goddard detonated very loudly. From a 40-ft. steel tower he fired his latest rocket, a huge steel cylinder 9 ft. long by 2 1/2 ft. diameter. A new propellant sent it whizzing from the ground. It rose straight up about a quarter-mile. There the fuel seemed to ignite all at once, instead of in a stream, as planned. The roar sent Worcester ambulances and police hunting for tragedy. They found Professor Goddard and assistants inquisitively studying his rocket shell, which had landed near the side of its propulsion.

Carrying objects, and perhaps eventually persons, by means of rockets is an engineering phase of physics in which Professor Goddard, 47, has been experimenting for 17 years. The principle of rocket motion is simple--action and reaction. Escaping gases act in one direction, the rocket body in the opposite. The ground is not necessary for the rocket gases to push against in order to propel the rocket. Nor is the air. Such action and reaction can take place in a vacuum, a fact which has driven Professor Goddard on his experiments. His objective is not to see how far he can shoot a rocket but to investigate the physics of the earth's third and outermost blanket of air.

Earth's atmosphere is only seven to eight miles thick. Aviators have been able to reach the top and hover there a few moments. Outside is the tenuous stratosphere, about 70 miles thick. Man has not entered that yet, although small balloons bearing measurements have done so.

Of the third and outer blanket, the Heaviside layer, very little is known, and that only inferentially. Pressure 100 miles up is calculated to be 1/300,000 of the pressure at sea level, practically a vacuum. Highly tenuous though that upper medium is, it is nonetheless dense enough to burn up meteors by its friction. Like the lower atmosphere it carries electrical charges. Proof of that is the great heights from which the curtains of Aurora Borealis, an electrical phenomenon, hang. If Professor Goddard, or anyone else, can learn the exact nature of that high zone it is conceivable that man will be able to put it to some purpose.

Rockets have already been used for motive power. A rocket car driven by Fritz von Opel attained 120 m. p. h. in eight seconds (TIME, June 4, 1928).

Fuel is the great handicap against sending rockets to great heights. No known fuel is sufficiently light and energetic to be useful.