The first major challenge facing NASA with landing a man on the Moon was figuring out how to get there. If that sounds simplistic, look at it this way. Think about aiming at a fixed target from a fixed position. It’s a two dimensional targeting issue. Now, imagine hitting an orbiting target from an orbiting position…while rotating at the same time. It’s a bit more complicated.

Fortunately, the mathematics required to solve this problem was already well understood by the time of the Apollo program. The challenge was incorporating the math into a navigational device that could guide a spacecraft autonomously. Unlike the mariners of old, the Apollo astronauts were never intended to “steer” their spacecraft to its celestial destination.

Meet Doc Draper

Enter Charles Stark Draper. Better known among his colleagues as “Doc” — and to his childhood friends as Stark — he was best known as the man whose genius created a technology that, as Draper himself described it, “does for geometry what a watch does for time.”

On a Sunday in early February 1953, a B-29 Superfortress took off from Bedford, Massachusetts on a non-stop flight to Los Angeles International airport — back before there was non-stop airline service between those two locations. On board the flight were two air force pilots along with nine scientists, engineers, and air force officers as observers. Among these passengers was Doc Draper, who at the time was the 51-year old head of MIT’s aeronautical engineering department as well as the head of an MIT Division that he had created, the Instrumentation Lab (IL) — an academic organization that would play a critical role in the Apollo mission.

Some 13 hours after takeoff, Doc Draper’s B-29 (the plane actually belonged to MIT) approached LAX, 10 miles off course out of the 2,590 miles it had flown. The remarkable thing about this fact is that neither pilot in the cockpit had touched the plane’s controls. The plane had instead been flown by a device the size of a washing machine, weighing 2,700 pounds and mounted toward the rear of the plane’s fuselage.

The device was an inertial guidance navigational unit, capable of sensing every movement of the airplane: its velocity, altitude, and any changes in direction, however slight. Through a combination of gyroscopes, accelerometers, a clock, and in this case even a pendulum, an inertial guidance system could fly an aircraft without the need for radio signals, beacons, or a compass. You told it where you were and where you wanted to go, with no input from any other technology (or human). It was the creation of Doc Draper, a man whose intellect was uniquely suited, in the words of Apollo historian and writer, Charles Fishburn, “to connecting the curves and equations of advanced math to physical problems in the real world, and…invent or refine the technology to take advantage of those equations.”

Doc Draper grew up in Missouri and entered the University of Missouri as a mere 15-year old. He transferred to Stanford two years later and completed his BA in psychology. On a trip to Boston with friends in 1922 he discovered MIT, which had recently moved to Cambridge. He was captivated by the school and enrolled that fall, eventually earning a second bachelor’s degree in electrochemical engineering. A love of flying led Draper to research engines and aircraft instruments, and he went on to a PhD in physics at MIT. He became a full professor by 1939, holding a school record for the most courses for credit as an MIT student.

The Story of Inertial Guidance

During World War II, Draper and his colleagues and students developed what would become known as the Mark 14 gun sight, which took all the motions of a shipboard anti-aircraft gun into account when aimed at an attacking plane, and automatically smoothed and adjusted the gun so that a gunner was actually aiming at a point where a plane would be when the bullets arrived. As one naval officer described it, the Mark 14, “did four hours of differential calculus in a split second.”

At MIT, Doc Draper’s Instrumentation Lab proved an excellent training ground for graduate students and future engineers to combine math and physics with advanced engineering and manufacturing to create new tools that applied advanced science to solving hard problems with real technology. The Mark 14 gun sight, which had been developed in partnership with Sperry Gyroscopes, was the result of the culture Draper created at IL, and Doc led its efforts to apply its technology to rockets following World War II and America’s acquisition of German rocket technology through captured weapons and scientists — one of whom, most notably, was Wernher von Braun.

Over time, Doc Draper’s efforts at IL became key to U.S. nuclear strategy and closing Kennedy’s vaunted “missile gap” with the Soviet Union as improved and miniaturized inertial guidance systems were installed on a series of U.S. nuclear missiles, including Thor (the first U.S. nuclear missile), Atlas (the first U.S. nuclear ICBM), and eventually the submarine-launched Polaris…a Cold War game changer.

The guidance system for Polaris weighed 225 pounds, including a digital computer. Two years later the unit’s weight was reduced to 140 pounds, while its accuracy was improved by a factor of four. To create an inertial guidance system that would enable a trip to the Moon, with a subsequent landing by a separate craft, Doc Draper and MIT’s Instrumentation Lab would ultimately have to design a system for a computer that would occupy a one cubic foot space. Pulling off this engineering feat would involve yet another industrial collaboration. This one would be with a company called Raytheon…the subject of the next episode in our series.