Here's the best diagram I can find of Kodak's BIMAT P/N system used on early moon probes. The system used two lenses, a long focal length, and a wide angle (a Schneider Xenotar!) and two spools, one with film, the other with a "web". The web was damp with processing chemicals, and processed the film, which would also if desired produce a DTR positive onto the web.
The system shown in the diagram scanned just the negative with a flying spot scanner, a precursor to the drum scanner. A flying spot scanner uses a CRT-like electron beam to illuminate a spot that moves in a predictable way, and the intensity of the transmitted light can then be recorded or transmitted to a distant location.
Check out this shot.
Here is a link to the website discussing it, and if you look around you can see striped pictures of the moon shot with this system, which might have used Pan-X.