I have no inside information on Starflight but this is typical of Forth systems. They are an image structured environment. Unless you build your own data struc

I have no inside information on Starflight but this is typical of Forth systems. They are an image structured environment. Unless you build your own data structures that are external to Forth's memory image, called a dictionary, everything exists in that chunk of memory. Variables and arrays etc. exist where they are declared in the code sequence. So to save the game they opted apparently to just save the system image. It was the simple way out IMHO. It's trivial to create separate data area and write that out to a file in Forth.