Radiation Blind Atriums
Moon Town was created with the intention of long-term habitation from the beginning. Its mission included to find the way to become Earth independent and create a self sustaining closed ecosystem. The first step taken in this direction was to create sunken atriums that could be of great size, and admit enough sunlight for a wide range of plant life to grow.
The technique was to create great stone arches of local material, and place a series of them closely spaced all along the length of the glazed roof of the atriums. At the latitude of Lalande, only 4.5 degrees south of the equator, sun reached through the glazing all year round. All the arches were aligned precisely pointing east-west. On the first atrium built, they are 6 m tall (tapered to a ridge in the top 2.5 m), and are spaced 75 cm apart. The bottom 50 cm of each arch is a separate piece located inside the glazing. These pieces can slide across to cover the glazing open to the sky when there is a solar flare.
The result is that no matter where a person is inside the atrium, only a small portion of the field of vision sees the sky. The vast majority of their view has sight lines that intersect with either walls, or so much stone that subatomic particle cascades due to cosmic rays are blocked. A very small portion of their view looks at areas where the amount of material between them and the sky is enough that cosmic rays passing through there tend to hit something, triggering a particle cascade, and then that cascade has the energy to pierce the protection. To reduce the impact of that, the sides and bottoms of the inner beams are covered with slabs of plastic a few centimeters thick. That material absorbs some of some of this particle apray. Overall, this system reduces exposure in the atrium to ionizing radiation from cosmic rays to a level a person can sustain over decades without much risk. Blocking the gaps between the arches by sliding across the inner arches when there is a solar flare allows protection from this risk to the plants in the atriums, so they don’t have to all be moved to safety at such times. People should leave the area as during large flares this protection still wouldn’t be enough for them.
Only an approximate analysis has been done of this system. It needs to be properly analyzed using OLTARIS, a task that has been put off due to other priorities taking the time of the game dev staff. What exposure is acceptable can only be guessed at. See for instance Cucinotta’s paper Space Radiation Cancer Risk Projections and Uncertainties Some parameters for this will need to be chosen, and can be revised when better data becomes available.
This system can be revised to put beams closer together, make them taller, or supplement them, if it is considered that they are inadequate protection in the case of very long term exposure. For instance, once space development was mining enough water, conceivably a meter or two of water could go over the glazing to provide even more protection. Or the stone arches could be replaced with ones of materials and layers more capable of blocking radiation.
Current 3d models:
There is a channel on our Discord server for discussion of the design of this equipment. Come join if there is anything you’d like to comment on or ask – https://discord.gg/phbdWZaaa7
Also see the Projects page for general guidance on designing for Moonwards – materials, infrastructure, transport, practices, and main reference works.