The Hook:
	"...interstellar exploration... may require a revolution in our
	way of life not only socially but biologically if we are ever
	to become a galactic people."
	 
	Rationale:
	"Humanity dispersed over many worlds would appear more secure
	than humanity crowded on one single planet." - Shepherd
	 
	Large Scale of the Project:
	"In other words we are concernted with the problem of getting
	small colonies across the almost endless interstellar gulfs,
	safely, but no matter how or in what time." - Shepherd
	 
	"...getting an adequate community to another system.  In is
	important to stress this point because this profoundly
	affects our interpretation of what is possible and what is
	impossible." - Shepherd
	 
	The Very Long Travel Times Involved:
	"Indeed, interstellar colonization may call for the sacrifice
	of whole generations in the lonely reaches of space." -Shepherd
	 
	Mindset of the "Astronauts":
	"..he will never again see his native planet,"
	"...he will not even see the planet of his destination."
	"...for him there can be no personal gain, only the dying
	knowledge that some will survive to benefit from his action."