Polaris Submarine Technology Aids the Space Race
Driven by the need for world dominance, the 20th Century brought some of the most revolutionary leaps in aerospace, computer, and mechanical engineering. One of the most critical inventions developed out of World War II was inertial navigation. A problem solver for the United States during WW II. The MIT Instrumentation Lab (now Draper) began by improving the accuracy of fire control systems on US Naval warships in the pacific fleet because they were getting pummeled by the Japanese air force.
Next came the development of an inertial guidance system for Naval submarines so that they could navigate under water for long periods of time, cutting down the frequent resurfacing that might otherwise give away a sub’s positioning. The Ship’s Inertial Navigation System (SINS) was developed by the Instrumentation Lab in 1954, and is still used in submarines today. It combined gyros and accelerometers with a computer that performed “dead reckoning” to navigate.
Once Doc Draper figured out the immense value of inertial guidance he began to look at other ways to transfer the use of this technology and began working on submarine-launched ballistic missiles. The critical new factor in these missiles was a computer that guided them -- the Polaris Missile Guidance Computer.
The Polaris Guidance Computer was the Instrumentation Lab’s first run at a digital computer, and came with similar constraints that would prepare the team for the future. It had to be small, focus only on essential tasks, and contain unique equations to help launch and track missiles. The accuracy of the missile was based heavily on the SINS; in order to fire at a target, they had to know their own location.
Eldon Hall and Dave Hoag were among the group of Apollo engineers who began their careers with the Polaris project. Dave Hoag was the Technical Director on the program, while Eldon Hall developed the Digital Differential Analyzer (DDA) architecture for the guidance equations. Hall was at the forefront of insisting on a digital computer, and the DDA architecture drew on mechanical computing technology that had already been developed at MIT almost twenty years prior and allowed for real-time control.
It was the work on the Polaris Guidance Computer and the success of this program that gave Doc Draper the idea he could take his guidance work from the seas to the stars and allow man to navigate through space without any help from the earth. Draper ultimately proved to NASA that the engineers at MIT had the groundbreaking technology to make a trip to the moon possible and landed the Instrumentation Lab the very first Apollo contract. Hardware and algorithms were transferred from the Polaris Missile Guidance Computer and expanded upon in the Apollo Guidance Computer.
Draper continues to work on guidance systems, keeping itself firmly rooted in the project that made it what it is today.