The SPS reference design plan called for workers at LEO (500km), workers transferring to GEO and workers remaining at GEO (36,000km) for approximately 90 day terms. GEO has the highest amount of ionizing radiation intensity. So. How to protect SPS workers? Dr. Gerard K. O'Neill had a simple fix. His plan, based on significant research on SPS as a, dare we use the term, "Holistic" package made thick hulled habitats for workers out of the slag byproduct of the creation of solar cells from Lunar silica. No atmosphere poisoning launches of all that dumb mass from Earth, everything in a manageable deltaV, big and safe workspaces. But NASA even 50 years later and with their own Artemis Program can't allow themselves to consider using materials not dragged up from Earth so... using nearby tons of slag is still out. Sadly, this document could have come out this morning. And since it will surely come out again with a new set of names, we put it here so we can all get ahead of it.