LAUSR

When we think about structural design on Earth, one of the first aspects a structural designer investigates is local loads. In order to build mathematical models and simulations, structural engineers must have an appropriately defined load case scenario to work with. Earthquakes, hurricanes and floods are some of the extreme natural disasters a structural engineer needs to account for. However, here on Earth, we are an intergalactically safe heaven. We have access and sufficient time to understand and adapt the diverse planetary situations. Now, let us imagine two scenarios: (a) moving humans to approximately 384,400 km above the Earth’s surface, and (b) offsetting the Earth’s Goldilocks Zone by at least 55 million kilometres. All of our load cases would drastically change. The reader may have already noticed that we are referring to the Moon or Mars respectively. Some of the structural constraints of building infrastructure for humans on the Moon and Mars are as follows: On scenario a, because we have gone beyond our magnetic field, we lose our precious atmosphere. With no air, we have no air pressure. On scenario b, with the disappearance of a magnetic field that has stripped the atmosphere over time, some pressure remains. However, the atmosphere is approximately 100 times thinner. One survival factor for humans is the right combination of gases under the ideal pressure and therefore there is a need for an artificial atmosphere. That gives us a peculiar force to account for – outwards pressure. Exposure to isotropic and anisotropic radiation determines life, or the lack of it. With an active sun and deprived of proper atmosphere, infrastructure needs to provide sufficient protection, regardless of being underground, partially buried or overground. For the latter, thicker protection increases self-weight. For the former, retention walls may be necessary. Radiation protection will consequentially form and influence the load case. In both scenarios, a benefit may be that we reduce gravity by a sixth or a third respectively, but we may need to make construction adjustments. For scenario a, with vacuum, sun radiation has no obstacles. Temperature fluctuations can oscillate within a range of nearly 300°C between above and below 0°C. For scenario b, with a much greater distance from the sun, our scale translation brings us to an yearly average of −60°C. In extreme cold, or with huge temperature differentials, materials and some structures do not behave in the way they would on Earth. Therefore, extreme temperatures is another constraint. As celestial bodies age, their cores change and reflect on more superficial layers in the form of a quake, which can last longer than the ones we usually model for. Without, or even with a thinner atmospheric shield, impact from bodies travelling at intergalactic high speeds is a force that may interact with our partially buried and overground structures. Wind may not be a problem for our scenario a, however charged particles have already proven to be an obstacle during past missions. For the scenario b, wind and toxic particles cause sandstorms that could disrupt basic life, construction and structural resilience. Other factors will also influence the form of our extraplanetary infrastructure, such as the wellbeing of users. From abundance to scarcity: Learning from the past and designing future structures for hazardous conditions utilising limited resources