Since the days of Archytas, rocket propulsion has been the Holy Grail of aeronautics. Thanks to Galileo's inertia, Newton's laws of motion, and the "father of modern rocketry," Goddard, space is not a complete mystery anymore. Rocket-powered aircrafts have evolved from the first liquid fuel rocket in 1926, to the Soviet R-7 which launched Sputnik, to NASA's Saturn V that propelled Apollo 11 to the moon. Today, even billionaire tourists can enjoy space, like Microsoft's Charles Simonyi and...