So what do you remember about the moon landing Besides being the only moon landing ever attempted, of more importance is that this happened almost 50 years ago. So here is what I remember about the whole thing
- Neil Armstrong and Buzz Aldrin
- “One small step for man, a giant leap for mankind”
- President Nixon’s speech announcing the moon mission
- NASA probably
But does anyone remember the scientists who worked behind the scenes to make this happen? I certainly do not. What about the technology platform that allowed them to do so? I tried googling and couldn’t get far. But one thing did stand out in the whole search – the one concept that probably helped more than anything else to help man land on the moon.
It is the concept of Kalman Filters – a mathematical / control concept that was proposed by Rudolf Kalman and subsequently adapted by Staley Schmidt of NASA for the Apollo Space Program. The principles put forth by Kalman allow the scientists to work with “Trajectory Estimation” problems – figuring out where the spacecraft is at any point of time. This is a crucial problem to solve in space because of the lack of any fixed points of reference and you are dependent on instruments for navigating.
If the instruments are off even by a tiny margin, then this error adds up until the space shuttle is way off from where it intended to be. Kalman’s hypothesis which was subsequently developed into an application called Kalman Filter allows the scientists to estimate the errors that have been introduced in the calculations and remove the errors ultimately.
What makes this remarkable is the fact that the computer that the Apollo Space Program carried had a clock speed of 100hz and around2MB of RAM. This is what makes the Kalman filter truly valuable – it can deliver great results even on less powerful computing platforms. Something that modern-day Machine Learning and AI algorithms can never claim to possess.
To know more about Kalman Filters, please check out our course videos on Control Systems.