Ok folks, here is yet another game for everyone. The rules are simple. Each post states the next natural number in sequence, along with an astronomy/space flight connection. I will start off with the first 3 so that the idea is clear, and thereafter each post will be a single number. It should be easy in the beginning. As the numbers get larger, it should become rather difficult (and more fun)
1 - the Earth is 1 AU from the Sun ( I know that's almost cheating since an AU is defined that way)
2 - The number of stars in a binary system, and the number of moons of Mars
3 - The number of astronauts on an apollo moon mission.