We started class with the history of human space flight in a (very small) nutshell. The Mercury mission (smaller rocket) carried one person into suborbital and then orbital flight that lasted several hours. The Gemini missions (larger rockets) carried two people into Earth orbit for more complex operations that would last for several days (up to nearly two weeks in one case). The Apollo missions (largest rockets, amongst which the majestic Saturn V) took three people to the Moon, two who descended onto the surface in the lunar module, the third stayed in orbit around the Moon in the command module. The reason for the ever-larger rockets is the fact that we need to escape Earth's gravity to enter into Earth orbit and to sail to the Moon. We talked a lot about gravity, and what effect the weaker gravity of the Moon (1/6 that of Earth) has on people walking on the Moon. We watched a short video with real footage from the Apollo 11 mission that illustrated some of these aspects.