Archive for the ‘habitat’ tag

Jan 30, 2012

The Difference Between a Lunar Base and Colony

Posted by in categories: existential risks, habitats, lifeboat, space, sustainability

Recently, Newt Gingrich made a speech indicating that, if elected, he would want 10% of NASA’s budget ($1.7 billion per year) set aside to fund large prizes incentivizing private industry to develop a permanent lunar base, a new propulsion method, and eventually establishing a martian base.

Commentators generally made fun of his speech with the most common phrase used being “grandiose”. Perhaps. But in 1996 the Human Lunar Return study estimated $2.5 billion from NASA to send and return a human crew to the Moon. That was before SpaceX was able to demonstrate significant reductions in launch costs. One government study indicated 1/3 of the cost compared to traditional acquisition methods. Two of SpaceX’s Falcon Heavies will be able to launch nearly as much payload as the Saturn V while doing so at 1/15th the cost of the same mass delivered by the Shuttle.

So, we may be at the place where a manned lunar base is within reach even if we were to direct only 10% of NASA’s budget to achieve it.

I’m not talking about going to Mars with the need for shielding but rather to make fast dashes to the Moon and have our astronauts live under Moon dirt (regolith) shielding while exploiting lunar ice for air, water, and hence food.

But the point of this post is this. If a small lunar base is within our reach, how much more would it take to achieve something that most of us realize would be the single most important step in ensuring the survival of the human species should a truly existential event strike Planet Earth. So I’m describing a small, self-sufficient colony. I would say that the difference between a base and a self-sufficient colony is fairly small. Small enough to make it worth our while to attempt to achieve.

So, what are the requirements for a self-sufficient colony? The most critical would be air, water, and food. But understand, oxygen and water can be produced from the 600 million metric meters of water ice estimated to exist at the north lunar pole. So there’s no shortage. And with recycling, the amount of daily required input could be pretty small — small enough to easily be within a day’s task for mining. But food also requires fertilizer. Fortunately for us, the LCROSS results showed that there is also methane and ammonia in the ice and the regolith contains other minerals such as phosphorus and potassium. So, the most critical components for a colony would already be present with a manned base at a lunar pole.

Besides this, the colony would also need protection from the vacuum and cosmic radiation — i.e. a sealed habitat. This should not be too difficult. For a base, options include inflatable habitats and using fuel tanks as durable, sealable compartments. Radiation protection is as simple as piling regolith over the structures or even digging trenches or caves into the sides of hills or craters. That’s fine for a base. But a self-sufficient colony requires that future colonists be able to construct their own habitats. This could be achieved in the intermediate term by simply caving out habitats, supporting them, and then inflating a liner. Many such liners could be delivered in a single 5,000 kg payload. In the long term, such liners could be produced as plastics from volatiles resulting from the production of water from lunar ice. Broken liners could be patched or even melted to produce new liners. Alternately, metals can be fairly easily produced from the regolith. Run a permanent magnet through the soil, extract iron, melt it using solar concentrating mirrors and then process the molten metal to sheets, wires, cast forms, etc. Glass could be made the same way along with fiberglass. Natural lighting could supplement electrical power by using aluminum mirrors and glass. Supplemental heat could be provided in a similar manner along with locally derived insulation.

Thin film solar panels can provide > 1,000 W/kg. So a 5,000 kg payload could provide a very large amount of onging power (if my math is correct, enough for perhaps 500 colonists). Excessive solar panels could be stored under ground and then used as needed thereby giving the colony decades of power. Eventually, a self-sustaining colony would need to produce its own power from silicon in the regolith. Storage of energy during the lunar night could be accomplished through the use of electrolysis of water to oxygen and hydrogen. These could then be recombined in a fuel cell to produce electricity and heat. Alternately, the colonists could simply travel every two weeks to the other side of the hill near the pole to another sunlit habitat.

Again, to buy the colony time to be able to develop the ability to produce its own space suits, many years’ worth of thin airproof liners to space suits could be delivered in a single 5,000 kg payload. Again, a self-sustaining colony would need to eventually produce their own. Between the use of fiberglass, metals, and locally produced plastic or silicon sealants, eventually the colony could produce their own. Of course plants could be grown to provide fibers for clothing.

To avoid day-long exposure to cosmic radiation while mining surface ice, mining could either be conducted underground or telerobotically. But regolith is very gritty and can wear out teleoperated mining equipment. But if a colony is able to produce its own metals and had machining equipment which could be used to produce more machining equipment, then the colony could stay ahead of equipment wearing out.

High-tech equipment (computer chips, cameras, and radio equipment) is certainly useful but I believe that there are ways around needing them. Still, in the interim, a single 5,000 kg payload delivery could provide centuries worth of computer chips, camera chips, and critical radio equipment components. For example, the Voyager craft have been exposed to 30+ years of 360 degree space radiation yet still work fine. So, an apple box worth of computer chips could last centuries. Eventually the colony would need to produce its own high-tech equipment. Perhaps they could use 1940’s technology such as vacuum tubes.

The Moon’s 1/6 gravity is probably not enough to prevent bone and muscle loss. Experiments on the international space station (ISS) show that an exercise program can do much to prevent bone loss. A recent study indicates that Fosamax prevents bone loss in astronauts. A 5,000 kg payload could give 83 million doses of Fosamax. Stored in a permanently shadowed area, it could provide for a very large number of future colonists. But also, a basic centrifuge or even a tether ball-like contraption could provide artificial gravity for colonists for part of the day. Trenches dug along its path could provide partial protection from cosmic rays. Alternately, space forums have discussed completely underground centrifuges using various ingenious approaches.

Of particular concern is how fetal children would develop given limited gravity. Studies of animals on the ISS indicates that this is a real concern. We don’t know enough about this issue. Perhaps pregnant women would need to spend significant amounts of time in a centrifuge perhaps in all trimesters.

I have started with the most essential requirements and have worked down. I propose that there are technologic solutions for each of the requirements but perhaps I have been unrealistic in one or more areas or perhaps have neglected to address an important requirement. Feel free to comment below.

For a truly self-sustaining colony, for humans, the Minimum Viable Population (MVP) is in the realm 1,000. I personally suspect that it is actually less than that but a solution here could be for a single payload delivery of frozen embryos for surrogate parenting to be frozen long-term in permanently shadowed areas. Although this may strike some as being unethical, these would only be needed in the event of a truly existential event on Planet Earth.

I envision the colony as not only securing the human species but a good representation of Earth’s entire biosphere. But discussing the details of that topic would extend this post much longer than it has already become. More on that later.