Interplanetary travel is now the only form of "conquest and empire" compatible with civilization. Without it, the human mind, compelled to circle forever in its planetary goldfish bowl, must eventually stagnate.


The Challenge of the Spaceship, The Challenge of the Spaceship (p. 7)


Interplanetary travel is now the only form of conquest and empire compatible with civilization. Without it, the human mind, compelled to circle...

Interplanetary travel is now the only form of conquest and empire compatible with civilization. Without it, the human mind, compelled to circle...

Interplanetary travel is now the only form of conquest and empire compatible with civilization. Without it, the human mind, compelled to circle...

Interplanetary travel is now the only form of conquest and empire compatible with civilization. Without it, the human mind, compelled to circle...