Spaceflight is exciting again Robotic space probes have recently explored the dwarf planets Ceres and Pluto; and a spacecraft has even landed on a comet. Commercial aerospace companies have successfully launched rockets to space and delivered cargo to the International Space Station. In the United States, new laws are being passed concerning the property rights on the Moon, and in anticipation of asteroid mining. In light of this surge in spaceflight activities, a basic appreciation of spaceflight issues would seem valuable to anyone wishing to better participate in discussions about this...