Arthur C. Clarke is mostly known as the “2001 A Space Odyssey” author but he was much more. One of my high school term papers was taken from his book “Interplanetary Flight.” In it, he was the first in semi-popular literature to discuss such things as escape velocity, orbital velocity and the concept of a geostationary satellite orbit. Interestingly enough, I cannot find reference to that book in his Wikipedia entry and Amazon.com had a later publication date than I remember. Maybe there was a second edition. Anyway, he was a great mind and we are better for his having lived.