A mathematician behind the moon landing

In the wake of the 40th anniversary of the Apollo 11 landing, here’s a nice piece from the Vanderbilt University News Network about Richard Arenstorf, professor emeritus of mathematics, who solved a major piece of the theoretical puzzle that made that landing possible. Excerpt:

In order to determine the path that the Apollo spacecraft would take in its journey from the earth to the moon, NASA scientists had to come up with a new solution for a difficult mathematical problem, called the three-body problem, that had been studied for more than 300 years by a number of famous mathematicians, including Euler, Lagrange and Poincare. [...]

Using a computer, [Arenstorf] solved a special case of the three-body problem that provided the mission with the information it needed. His solution consisted of a set of closed figure-eight trajectories that pass arbitrarily close to two celestial objects. These are now known as “Arenstorf Periodic Orbits.” In 1966, he was given the NASA Medal for Exceptional Scientific Achievement for his contribution.

I’ve mentioned Prof. Arenstorf here before, since he is not only a famous and prolific mathematician, he was also my Complex Analysis professor in grad school and had a near-miss proof of the Twin Prime Conjecture a few years ago. One of my favorite memories of grad school was sitting with Prof. Arenstorf at our weekly grad student teas — which he regularly attended, because he loved being around graduate students — talking about the space program and comparing his NASA stories with those of my dad, who was an engineer contracted from General Motors working on the Apollo project at around the same time Prof. Arenstorf was at NASA. It’s nice to see him get the recognition he deserves.