We do not have to wait until someone produces "antigravity" before we can travel to the planets: the means is already at hand. It is the rocket.
The Exploration of Space, Chapter 2 (p. 16), Harper & Brothers Publishers. 1951
We do not have to wait until someone produces "antigravity" before we can travel to the planets: the means is already at hand. It is the rocket.
The Exploration of Space, Chapter 2 (p. 16), Harper & Brothers Publishers. 1951