Man must at all costs overcome the Earth's gravity and have, in reserve, the space at least of the Solar System.
Konstantin TsiolkovskyThe Earth is the cradle of Humanity. But one doesn't always live in the cradle.
Konstantin TsiolkovskyFor me, a rocket is only a means--only a method of reaching the depths of space--and not an end in itself... There's no doubt that it's very important to have rocket ships since they will help mankind to settle elsewhere in the universe. But what I'm working for is this resettling... The whole idea is to move away from the Earth to settlements in space.
Konstantin Tsiolkovsky