308 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1960 



time and by radiation contacts with objects having known locations 

 in terrestrial space or celestial space. Navigation progressed with the 

 perfection of chronometers and other instruments, and with improve- 

 ments in the means for sensing radiation-contact information, until at 

 the present time a state of development exists for these elements that 

 approximates their ultimate possibilities. It now remains for new 

 methods to overcome the problems in navigation that began to emerge 

 during the last half of the fifth decade of our century. These prob- 

 lems, which are not solvable by radiation-contact methods, originated 

 largely from needs associated with modern military operations and 

 flights by vehicles moving in the emptiness of space outside the earth's 

 atmosphere, although civilian applications will surely become impor- 

 tant in the future. The new difficulties in navigation appear because 

 the vehicles involved must operate in situations where it is undesirable 

 or impossible to maintain radiation contacts of any kind with outside 

 points. 



Bombers flying to attack targets deep within well-defended enemy 

 territory will surely not have an environment of cooperative ground 

 stations and can expect the enemy to take all possible measures for 

 interfering with the operation of such radiation-contact equipments 

 as radios and radars. Submarines designed for the underwater launch- 

 ing of ballistic missiles must have an accurate and continuous knowl- 

 edge of position during long periods of submerged cruising near 

 enemy shores. Ballistic missiles, which to be effective must be de- 

 signed for simultaneous launching in salvos of considerable numbers, 

 need to have self-contained guidance systems in order to keep ground 

 installations within feasible limits of size and cost. Satellites, lunar 

 craft, and interplanetary vehicles need navigational equipment de- 

 signed to make the most effective use of the available weiglit and vol- 

 ume capacity, so that there are strong reasons for working out designs 

 based on the best possible combinations of radiation-contact com- 

 ponents and inertial elements. 



These examples serve to illustrate the nature of the new require- 

 ments on navigation equipment that have developed during the past 

 10 years. These requirements reduce to the necessity for navigation 

 systems capable of giving high-quality performance during periods 

 that include a considerable number of hours without radiation 

 contacts. In terms of the basic geometry involved, this means that 

 navigation equipment must include a completely self-contained means 

 for providing geometrical references (fig. 6) . 



Inertial principles applied through the medium of gyroscopic action 

 (see bibliography) make it possible to realize geometrical reference 

 members, in the form of rigid bodies, that are capable of serving the 

 functions of celestial space in navigation. To be satisfactory, these 

 reference members must hold initially established orientations with 



