There were a handful of people who worked on that regularly and I was also working on the successor, but even in 2003-2006 they were selling star trackers that had a 20 year old CPU with a hardware-implementation of a Forth interpreter built into the CPU itself. I wasn't actually working on that part, so only dabbled in Forth after some conversations with a couple of the guys that actively worked on that part of the system. It was actually pretty easy to learn because of my experience with Reverse Polish Notation on my college HP calculator.