Andrew Goetz

This is my personal website. I am a software engineer in the aerospace industry. My background is in pure mathematics, which I still love, but over the years I have slowly transitioned to the applied realm in my professional life.

Software

GitHub

I am on GitHub.

• penrose-turing - A command-line tool written in C which executes Penrose-style Turing machines as described in The Emperor's New Mind by Roger Penrose.
• poinsot - An animation of the motion of a torque-free top and the Poinsot construction. See the animation here!
• spacetrack-report-no-3 - Fortran code from the paper Spacetrack Report No. 3: Models for Propagation of NORAD Element Sets by Hoots and Roehrich, which is the origin of the algorithms used to propagate satellite two-line element sets today.

Open Source Contributions

I have contributed improvements and bugfixes to Hipparchus (a Java math library) and Orekit (a space dynamics library).

Textbook Notes/Solutions

One of my hobbies is reading through a math or physics textbook and trying to do all the exercises. I have a substantial library of notes, solved problems, and software routines that I've written for my own benefit. Once I've written the solution to a problem down, it prevents me from feeling like I need to solve it again later. Also, writing helps to clarify my thinking. I don't post most of my notes and solutions on the web, but here are the exceptions:

• What is Mathematics? (Second Edition) by Courant, Robbins, and Stewart
  • Elliptic billiards (p354)