The Exploration of Space

acceleration already asteroids astronautics astronomers atmosphere body bricks build carry certainly Chapter chemical completely course crew degrees F difficult direction distance Earth energy enormous escape velocity EXPLORATION OF SPACE extremely fact Figure free orbit fuel Galaxy giant gravitational field gravity heat Hermann Oberth hundred miles idea imagine important interplanetary flight interplanetary travel interstellar involved ionosphere journey Jupiter landing light light-years lunar Mars and Venus Martian means Mercury meteors million minutes missile Moon Moon's motors never observed oxygen payload perhaps planetary planets Pluto possible pounds pressure pressurised probably problem produce propulsion Proxima Centauri R. A. Smith radar radiation radio reach reason refuelling return to Earth rocket power satellite Saturn scientific ship Solar System space-flight space-station space-suits space-travel spaceship speed spinning stars stations surface take-off telescope temperature terrestrial thousand thrust tion trolley Uranus voyage weight