Cast Iron Habitat Pressure Hull

Version 1.4 June 9 2021

Lunar Iron Habitat Project Overview

Lunar Iron Habitat Project at a glance – No frills description.

Lunar Iron Habitat Project Outline – Details what I’ve learned and what I still need to work on.

Lunar Iron Habitat Project Goals – The goals of the project.

Lunar Iron Habitat Project Posts – All the posts involving the SPORE Project.

Lunar Iron Habitat Project Updates – All the updates I have posted.


Why is researching iron habitats my first project for Lunar Homesteading you ask (written before I started other projects)? Because the most critical component (aside from the people) is pressurized shelter. Sure, a functioning Homestead needs lots of other technology but no pressure hull equals no people. And you can’t have a Homestead without people. Besides, we need a cool container to put all the other nifty gadgets into.

We can build pressure hulls out of many other materials besides iron. But iron has a unique combination of qualities that makes it the obvious (at least to me) first choice for Lunar, and most other, Homesteaders.

Other options for Lunar habitat construction (basalt, sintered regolith, aluminum, titanium, lunar concrete, etc.) just don’t have all the advantages of iron. At least that’s what my preliminary research shows. Part of this project is to quantify all of iron’s advantages and prove my hypothesis that iron should be a primary resource for Lunar Homesteaders. 


Lunar iron can serve as the primary construction material for Lunar Homestead habitat pressure hulls.


Habitable space is at the core of manned space settlement. Without it, we might as well stick to sending robots. And very few people are interested in permanent robotic Lunar settlement.

  • I’m not stating that this is a completely original idea. A lot of very smart people have spent decades thinking about this topic. There are loads of papers that talk about using Lunar iron in a THEORETICAL sense. There has been very little actual WORK to make this hardware a reality.

Why iron?

Some of the characteristics of Lunar iron that make it highly desirable are:

  • Iron is a fairly common element on Luna. It is found as a free metal in very small concentrations everywhere and as an iron oxide bound in rocks.
  • With some research it should be possible to build working scale prototypes of equipment to mine and refine iron sources.
  • We know iron. Humans have been using it for thousands of years. We know how to make tools, parts, and even pressure hulls with it.
  • Elemental iron is pretty strong and durable. Alloyed with other elements (carbon, nickel, etc.) it becomes even more useful. Nature has already alloyed some of the Lunar iron with nickel (asteroids smashing into the Lunar surface). We just have to pick it up.
  • Iron is a common resource both on Luna and throughout the solar system. The Lunar regolith contains significant amounts of iron, both free and in minerals. Nickel-iron asteroids are abundant. Even the iconic red Martian regolith is composed of rusting iron minerals. If we can master iron beyond the Earth, we can build almost anything almost anywhere. And we can standardize common hardware because they can all be constructed from the same material.
  • Lunar iron should be relatively easy to obtain (needs experimentation). Free iron can be found throughout all of the Lunar surface. See all those craters covering the Lunar surface? All of them were caused by things hitting Luna at high velocity. This resulted in quite a lot of free iron being generated (through reduction of the regolith) as well vaporized iron from the impactor being scattered all over the place. We don’t need to mine or refine this iron. All we need is a magnet. Well, we actually probably need to process it a bit before it’s usable.
  • Refining iron from the iron oxides found in Lunar regolith is a relatively simple process (at least on Earth!). Doing it on Luna will be trickier but it will still take less energy and chemicals than aluminum, titanium, and most other elements bound up in the Lunar regolith. And iron oxides are fairly common in mare basalt.
  • Iron makes a decent radiation shield. Sure, it’s not as efficient as lead. But a reasonable thickness will get the job done. Mass matters a lot less once we are already on the Lunar surface. Throw some regolith on top and radiation becomes much less of a problem.
  • Iron is easy to build with and repair. Again, we’ve been doing it for a very long time. We know how to cast, forge, weld, and sinter iron. We can even use it in 3D printers. Of course, we’ll need to learn some new tricks to do all that on Luna.
  • Homesteads are going to need storage tanks before we start extracting oxygen, hydrogen, and all the other stuff we need. Even simple water tanks are going to be important. Storing pressurized gas is much easier than dealing with cryogenic liquids. We can make both pressurized and non-pressurized storage tanks from iron.

Here’s some more applications for iron.

Iron applications
From Space Resources: Vol 3 Materials, page 283.


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