A sampling of items related to human settlements off earth:

** Cylindrical homes on Mars created via 3D printing from local materials have made the AI SpaceFactory team a finalist in NASA’s 3-D Printed Habitat Challenge competition to design viable habitats for living on Mars: AI SpaceFactory builds 3D printed Mars habitat prototype, green-lighted by NASA for final phase – SpaceFactory

Using state of the art robotics and their proprietary polymer, AI SpaceFactory is contending for the final top prize of $500,000 given to the highest scoring team to print a sub-scale habitat in the third and final phase of the construction competition. The 1:3 scale prototype will be printed in front of a live audience at Bradley University in Peoria, Illinois, from April 29 to May 4.

AI SpaceFactory was one of only four teams awarded among six who submitted entries, placing 2nd overall on the basis of 3D-printed samples that were tested for strength, impact resistance, and durability in extreme temperatures. In contrast to other teams, which used concrete as their construction material, AI SpaceFactory formulated their own material – a “Martian polymer” that can be made from matter found or grown on Mars. The polymer was validated by a third-party lab and proven to outperform concrete in every important way: superior tensile and compressive strength, extreme durability in freeze-thaw cycles, and enhanced ductility. The polymer also provides superior cosmic radiation absorption and thermal resistance (insulation) and can be made without water: essential characteristics in the construction of off-world habitats

In five weeks, AI SpaceFactory progressed from basic tests to an autonomously-printed large-area slab validated by NASA in November 2018. Four weeks later the team successfully printed, in only 24 hours, a large cylinder designed to hold twelve-hundred gallons of water complete with prefabricated wall penetrations robotically placed and sealed “on the fly”.

AI SpaceFactory describes MARHSA as a first-principles rethinking of what a Martian habitat could be — not another low-lying dome or confined half-buried structure, but an airy, multi-level environment filled with diffuse light. This innovation challenges the conventional image of “space age” architecture by focusing on the creation of highly habitable spaces tuned to the demands of a Mars mission. 

The MARSHA approach could work well with SpaceX’s Mars settlement goals: 3D-printed Mars habitat could be a perfect fit for early SpaceX Starship colonies – Teslarati.

You can follow AI Factory and other finalists in the contest at Latest Updates from NASA on 3D-Printed Habitat Competition | NASA.

** Lavatube caves on the Moon and Mars could be excellent locales for early settlements. Bob Zimmerman writes about an opening that appears at the top of a long canyon: The location for a future Martian colony? | Behind The Black

My first reaction was, “Whoa! That tiny pit is at the head of an increasingly growing canyon!” To a caver on Earth, this instantly implies that water has flowed out of that pit and down the canyon, carving it out as it flowed. It also implied that the possible underground passage under the pit’s north rim might conceivably be extensive.

Reinforcing this first impression were the numerous dark streaks flowing down the canyon’s cliff walls to the south. They all seemed to originate at about the same elevation as the pit itself, suggesting they all come from the same contact between two geological layers, a contact where water tends to gather. On Earth, when water seeps downward through water-soluble limestone and then gets blocked at a contact of more resistant material, it then starts to flow horizontally, creating a cave at that contact. The Martian dark streaks and pit in the image to the right suggest a similar process is occurring here.

Bob goes on to discuss the region around the above canyon and what role water may have played in forming the features there.

Nonetheless, the data illustrated by these images makes that tiny pit most enticing. It not only appears to be relatively easy to access its interior, there is visual evidence that suggests the presence of water.

If I was a future settler of Mars, I would give this pit a very high priority for exploration. In fact, I think someone (maybe Elon Musk?) should already be considering a probe to delve its depths.

** Rotating in-space habitats can provide artificial gravity and don’t require that space transports go in and out of deep gravity wells. The Gateway Foundation initiative aims to develop a wheel-shaped station as the first large in-space habitat. This video lays out some of the design features: SpaceX Starship and The Von Braun Rotating Space Station –

Scott Manley gives a brief critique of the Gateway group’s approach: A Realistic Look At The Gateway Foundation & Von Braun Station –

Manley emphasizes that funding is the biggest challenge. I agree and believe that the only viable financial approach to such an orbital facility is one that allows for incremental growth. That is, devise a design that can start small and simple and grows step-by-step, just as happened with most towns on earth. For example, start with two Bigelow habitats connected with a tether and rotating. Prove that this works technically and then show it works commercially by attracting a constant stream of paying visitors. This will then provide the basis to attract more investment to expand to more modules and a more elaborate structure.

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The High Frontier: An Easier Way