In 1953, an Air Force bomber took off from Boston carrying with it a new type of mechanical device, which, without reference to any external landmarks, would attempt to navigate the airplane to Los Angeles.  A few minutes after takeoff, the pilot got out of his seat and walked toward the back of the plane, where the device’s inventor, a scientist at MIT, was observing his device being tested for the first time—and it was now in control of the aircraft’s auto-pilot and guiding the flight.  From the perspective of the people on board, they were flying deaf and blind as far as navigation was concerned. The scientist called his device an Inertial Guidance System.  It consisted of a number of gyroscopes and instruments for measuring changes in direction.  The system was based on a principle that when a gyro is set spinning it remains on a fixed axis, whatever happens around it, and provides a known baseline, or platform, against which to calculate movement.  On that platform are a separate kind of instrument called accelerometers, which detect whether the aircraft is moving forwards or backwards, left or right, up or down, relative to the fixed platform.  By keeping a record of these movements, you’ll always know where you are.  A simple electro-mechanical device would read the data from the gyros and turn it into flight instructions.  For the first few hours of the flight, all was going well.  Then, towards the end of the flight, the guidance system suddenly appeared to lose its way.  It began commanding a turn to the right, causing a bustle among the people in the back trying to determine what was happening and what they should do.  Yet as the plane emerged from the clouds, they saw beneath them the city of Los Angeles, even at a point within sight of the airport–it was precisely on course!  The guidance system had simply been correcting for side winds, having recognized that it was being pushed off course and resisting that, and doing just what it was supposed to do.  A television reporter who was on board the flight covering the event said to his audience, “maybe one could say that this is one small step towards the age of space travel.”  The reporter’s observation would prove to be correct, but he probably erred in calling it a “small step”.  In 1961, just after John F. Kennedy made the speech that set in motion the Apollo program, with the goal of landing on the moon before the decade was out, the first contract that was awarded was for a system that would guide the rocket to the moon.  That is the measure of importance that NASA saw in guidance, and that contract went to the Massachusetts Institute of Technology, or MIT, due to the extraordinarily clever device that was developed in their laboratory 10 years earlier, before the age of computers.  This purely mechanical device was able to achieve its very high level of precision by implementing the physical laws of science.  And it was this technology that NASA hoped could be developed, not to take humans a few thousand miles across America, but the half million miles to the moon and back.

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