By mentioning space, satellites, and orbits, the question is trying to convince you that your brain can't operate because there is no oxygen. Try thinking about the question this way: If it takes you 24 hours to travel around a circle, at the speed of 12 km/sec, then what's the radius of the circle ?
You don't have water because of two possible reasons:
Because of the summer and the little rain, the underwater supply goes low.
The slope in the hill you live makes the underground water goes down by the effect of gravity. Imagine the underground water like a small tank, when the water is reduced for any reason the bottom of the tank will have the remaining water, while the top part will be "empty".
