By Robert Duncan Enzmann
1. Basic requirements:
Perception that it is possible – such as writing, flying, radio, water pipes, and telegraph.
(ISP) specific impulse demand fission, fusion, or devolution of matter and the conversion of these energies into momentum.
Either a long trip on a slow boat, or a long passage on a fast ship there is no escape.
Star flight is unique in that unlike travel across the earth which in the writer's time shortened from 6 weeks to cross overland from Manchuria to Poland (on a very pleasant train) to hours on a jet, cannot be equaled for travelers between stars.
Star flight is extraordinarily unique in that time for the traveler can be shortened. This is the nature of the long passage.
The possibility of (FTL) faster than light ships would end both long trips and long passages.
Self-sufficiency and true independence, not just ideally, but quite necessarily, must be attained. If this is not so, a ship might reach its destination only to be marooned for generations.
2. Motivations to go:
Commercial profits, information, entertainment.
Power of a nation being itself, developing itself, throwing off shackles of superpowers, of international organizations.
Freedom - of religion, of regulation of all aspects of life, to be an ethnic group, to develop science.
Escape dissent, crime, war.
Off-planet species survival.
Immortality of the long passage travelers, of mankind.