 All of the planets of the solar system, and many of the moons and asteroids, are suitable for life, and most are already occupied by humanoid extraterrestrial races.The initial adventures take place in the planets of the solar system but later stories (after the character invents the "vibration drive") take the hero to other stars, other dimensions and even the distant past and almost to the end of the Universe.For example, they visit the star Deneb, which is the origin of Earth humans, as well as many other humanoid races across the Solar System and beyond.