I give you three examples: first, medical space research may open up new understanding of man's relation to his environment. Examinations of the astronaut's physical, and mental, and emotional reactions can teach us more about the differences between normal and abnormal, about the causes and effects of disorientation, about changes in metabolism which could result in extending the life span. When you study the effects on our astronauts of exhaust gases which can contaminate their environment, and you seek ways to alter these gases so as to reduce their toxicity, you are working on problems similar to those in our great urban centers which themselves are being corrupted by gases and which must be clear.

President John F. Kennedy's last formal speech and public words, 21 November 1963, San Antonio, Texas