- how an off-Earth base could quickly become self-sufficient -


What is Earth Independence? Dr. Doug Plata explains what exactly Earth independence is, its two types, how it is measured, why it is so important, and how soon we might expect it to be achieved.

Earth independence is the use of off-Earth resources, recycling, and other means to decrease or eventually eliminate the need for supply deliveries from Earth. Right now, if we were to establish a permanent lunar or Martian base, we would need to ship everything from Earth in order to build it and sustain it. This would cost many billions of dollars each year. This isn't the best approach. Rather, it is now widely recognized that we need to use local resources (i.e. "live off the land") to reduce the amount that we need to ship.

Over the years, various orbiting craft looking down on the Moon, Mars, the asteroids and elsewhere have identified locations where very valuable resources are located which could be used while developing off-Earth bases and colonies. From industrial process over the centuries, we also have ideas about how to extract, process, and utilize those resources to make the things that we need to live at those locations.

Earth independence can come in various types. For starters, there is "partial independence". This means that some but not all of the items needed for a growing colony are being produced locally. But ultimately, it is the goal of space advocates that all of the items needed would be produced locally. On the one hand, the difference between partial and complete Earth independence seems obvious and not very profound. Yet the difference between these two levels of Earth independence are quite significant. Many space advocates understand that it is one of the major goals of space settlement to eventually become completely Earth independent. Only when this point is reached will humanity be securely located at two different locations in the solar system.

But another way of looking at Earth independence is whether a colony is specifically being built to be Earth independent or whether Earth independence is an unintentional outcome of space settlement in general. Some have termed the first type of colony as being a "survival colony" whereas the second approach could be called "general space settlement".

The objective of a Survival Colony would be to achieve complete Earth independence as soon as possible. It would take the approach of identifying exactly what the survival needs are and then developing protocols for providing for those needs while only using local resources.

Yet another way of looking at Earth independence would be to understand that one could become independent of Earth in different ways such as technically, economically, or politically independent. Some space advocates speak as though it is an absolute truth that a settlement cannot become Earth independent unless it becomes economically independent. So they often ask, "What resource could a settlement trade which would produce enough of a profit to fund the development, maintenance, and growth of the settlement"? But this is limited and incorrect. For example, there are self-sustaining tribal groups on Earth that are so isolated that they don't trade with anyone else. Yet they survive for centuries because they know how to use local resources to meet all of their needs. So fundamentally, it is technical independence that is needed to achieve full Earth independence. That doesn't mean that trade or profit cannot be allowed to play any role. But if a Survival Colony is to become completely Earth independent, it has achieve technical independence. It is the focus of these pages to describe how technical independence can be achieved at the earliest point possible. It is a fascinating question to address.

So, why is Earth independence a good thing? There are two basic reasons:
   - To reduce costs
   - To ensure the survival of humanity

These two reasons are fairly obvious. The more stuff one produces locally, the less you have to ship and hence the lower your shipping costs. Since each launcher is capable to launching a specific amount of mass to space, one doesn't save much at all by reducing any given payload mass. Likewise, if one reduces the frequency of rocket launches with full payloads, one still has to pay the "standing army" of aerospace engineers and various overhead costs so the savings would not be as great as one might expect (unless launches are shared by other customers). Yet, another benefit of local production would be that the full payloads may no longer include those items that one is producing for the colony those items one is not yet producing locally so as to grow the colony faster. A related reason has to do with being able to produce one's needs in case one runs out of stockpiles in the event that there was a disruption of shipped supplies.

The second reason, survival of humanity, is also fairly obvious. If something really, really bad were to happen to Earth, it would seem prudent to have humanity in another "basket" somewhere else in the solar system. These pages suggest that the Moon would be the first location that a completely Earth independent colony could be located. Those of us working on the subject of achieving Earth independence believe that a Survival Colony is technically possible within several years of first crew arrival on the Moon. Please read all of the pages on this site before deciding for yourself how possible it is.

Now, people often think of a really big asteroid as how Earth might be destroyed. That's a poor example. We have telescopes large enough to identify Earth-crossing asteroids big enough to cause extinction (>> 10 km diameter) and none of those is a risk. Rather, it is recognized by the experts in the field of global catastrophic risk that the far, far greater risk comes from future technology likely to mature in the near future. Specifically this includes: biotech, self-replicating chemicals, and nanotech. A biotech and chemical ecophage event could occur soon with nanotech becoming more of a risk in the latter part of this century. AI is a totally difference risk which space colonization cannot address.

Yes, the degree to which a colony is Earth independent can be measured and a number placed on it. It is the amount of mass that no longer has to be shipped from low Earth orbit (LEO) because of the measures being taken by the colony. It is fairly easy to understand:

  • 0% - The colony is producing nothing and is recycling nothing and so everything has to be shipped.
  • 50% - The colony is producing enough and/or recycling enough such that only half as much needs to be shipped per year in order ot maintain the colony.
  • 100% - No further shipment needs to be sent to the colony in order for it to survive indefinitely.

So, this is "Earth independence by mass". We believe that majority Earth independence (i.e. >50%) can be achieved early on -- perhaps even before the first crew arrives.

It is challenging to calculate exact figures on how Earth independent a base would be as the local production of each resource was mastered. But the graph to the left is the current best guess. We believe that water (and hence propellant), organics, and metals could possibly be produced even prior to crew arrival. Just these four items would result in about an 85% Earth independence by mass. So, it's a big deal -- perhaps as big a deal as achieving fully-reusable launchers.

There is one more important and interesting concept to consider. Normally one would think that complete Earth independence would be achieved once a colony was producing everything that it needed. This is actually not quite correct. A colony becomes Earth independent the moment nothing more has to be shipped from Earth to sustain it. But aren't these two the same thing? Not actually. If for example, one were to oversupply a base with electronics, and before that supply were to run out the colonist were to implement technology protocols to produce good-enough electronics from local resources, then the shipping from Earth could stop when the base was "sufficiently supplied" and hence would become Earth independent at that moment. For this reason, we believe that a completely Earth independent colony could be established within several years of initial crew arrival on the Moon.

By using local resources, a base could reduce the amount that is needed to be shipped to it even to the point of achieving complete Earth independence.

Next: Resources