NO. 2 METHOD OF REACHING EXTREME ALTITUDES 



A METHOD OF REACHING EXTREME ALTITUDES 

 By ROBERT H. GODDARD 



PART I. THEORY 

 METHOD TO BE EMPLOYED 



It is possible to obtain a suggestion as to the method that must be 

 employed from the fundamental principles of mechanics, together 

 with a consideration of the conditions of the problem. We are at 

 once limited to an apparatus which reacts against matter, this matter 

 being carried by the apparatus in question. Fo'r the entire system 

 we must have : First, action in accordance with Newton's Third Law 

 of Motion ; and, secondly, energy supplied from some source or 

 sources must be used to give kinetic and potential energy to the 

 apparatus that is being raised ; kinetic energy to the matter which, 

 by reaction, produces the desired motion of the apparatus ; and also 

 sufficient energy to overcome air resistance. 



We are at once limited, since sub-atomic energy is not available, 

 to a means of propulsion in which jets of gas are employed. This 

 will be evident from the following consideration : First ; the matter 

 which, by its being ejected furnishes the necessary reaction, must 

 be taken with the apparatus in reasonably small amounts. Secondly, 

 energy must be taken with the apparatus in as large amounts as pos- 

 sible. Now, inasmuch as the maximum amount of energy associated 

 with the minimum amount of matter occurs with chemical energy, 

 both the matter and the energy for reaction must be supplied by a 

 substance which, on burning or exploding, liberates a large amount 

 of energy, and permits the ejection of the products that are formed. 

 An ideal substance is evidently smokeless powder, which furnishes a 

 large amount of energy, but does not explode with such violence as 

 to be uncontrollable. 



The apparatus must obviously be constructed on the principle of 

 the rocket. An ordinary rocket, however, of reasonably small bulk, 

 can rise to but a very limited altitude. This is due to the fact that the 

 part of the rocket that furnishes the energy is but a rather small 

 fraction of the total mass of the rocket ; and also to the fact that 

 only a part of this energy is converted into kinetic energy of the mass 

 which is expelled. It will be expected, then, that the ordinary rocket 

 is an inefficient heat engine. Experiments will be described below 

 which show that this is true to a surprising degree. 



