To the Moon and Back: Developing
an Inertial Guidance System

Charles Stark Draper 1901-1987

How does a pilot navigate an airplane in stormy weather? How is a rocket guided through the sky? How did the Apollo 11 spacecraft land on the moon, then return its crew safely to Earth in 1969? Dr. Charles Stark Draper developed solutions to these real-world problems.

Draper, a professor in the Department of Aeronautics and Astronautics at MIT, established a teaching lab in the 1930s through which many advances in guidance, navigation, and control for all kinds of vehicles-ships, submarines, airplanes, spacecraft, and missiles-were made for U.S. military and space programs. The lab separated from MIT in 1973 and became a nonprofit, research and development laboratory-The Charles Stark Draper Laboratory, Inc., still located in Cambridge.

Draper's research resulted in the development of a complete inertial guidance system for manned and unmanned vehicles. These guidance systems use highly precise gyroscopes which measure changes in vehicle direction/orientation and accelerometers which measure changes in velocity. From this information, calculations can be made about location and whether course correction is necessary. Before Draper developed his inertial guidance systems, navigators depended on celestial and radio navigation.