This is for a video game project.

In a future where living in the Earth's surface has become undesirable. People are building colonies in Earth's orbit.

If materials from Earth are used to build space ships or space colonies, aren't we killing Earth?

Those materials stay in space, they never return to Earth. This may be alleviated by some kind of return policy. But even in that case, the amount of returned materials will be less than the original amount that left Earth, because it's impossible to return the same amount.

If I use this to justify a conflict between Earth and the colonies, is this believable?

How many time needs to happen for this to be of concern to the people on Earth. I say 200 or 300 years, but its a completely arbitrary number. Any trick to calculate the time will be appreciated.

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    $\begingroup$ 100 tons of material hit the earth each day. You'd need a big space industry to exceed that. $\endgroup$ Nov 11, 2014 at 8:59
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    $\begingroup$ Please clarify the type of materials you are talking about - do you mean metals and composites or biomass and water/atmospheric gasses or all of the above? In most cases the amount of mass would be negligible and - in some ways be more beneficial than harmful (if the carbon composites your space station hull is made of are produced from atmospheric CO2 - for instance) $\endgroup$ Nov 11, 2014 at 9:01
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    $\begingroup$ There is a long running Anime seriese called GUNDAM, you are describing the plot of most of its incarnations. Pick any seriese and you will find the story you are trying to make in one form or another fully fleshed out, a great place to setal ideas from. $\endgroup$
    – Skeith
    Nov 11, 2014 at 17:23
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    $\begingroup$ The Moon Is a Harsh Mistress is about a conflict over the exact opposite situation: the removal of water from the moon $\endgroup$
    – flaviut
    Nov 12, 2014 at 1:02
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    $\begingroup$ Some resources are more credible for export than others, as many SF stories have documented. One thing Earth is likely to lead in, for a long time, is people. That could mean a lead in both number of experts and in degree of expertise, simply because there are more folks to work with and hence more top-level folks. Inventions/discoveries/techniques are very easy to export, though hard to copy-protect. The folks who can create them are a bit harder to export, but are potentially a very valuable resource. There are other possibilities once you widen your scope... $\endgroup$
    – keshlam
    Nov 12, 2014 at 1:04

6 Answers 6


You cannot use this as-is for justification for such a conflict.

Compare rocket size with the size of a mountain.

Now take earth's mountain ridges.

Clearly we could lose a mountain, of which many rockets could be made. (Gross oversimplification, but clearly in raw tonnes of material, this is not a problem).

But let's say you DO want this as a concept.

There's a movie that has in Earth-orbit colony and a kind-of conflict between Earth and the Colony. That movie is Elysium. Basically, people ruined earth, and now the rich live on the colony, whilst the poor slave away on earth.

If you place your colonies further away, you could argue that there is a resource (resource X) that allows fast rockets. Resource X is troublesome to excavate, polluting, rare, expensive... you name it. Imagine resource X to be of nuclear origin, but 10x all its factors and you get something that's pretty nasty.

You still need an opponent, though. If me donating you goods costs me a lot, I might just stop. What's preventing me from stopping with sending you goods? Death of a colony? Then why are the people angry? Surely they understand?

The idea is workable, but you need another source of conflict. Ecological conflict on a small scale is usually people not wanting to pay for getting rid of their trash properly, so they just dump it.

Maybe there's one continent responsible for the colonies and it's polluting the world with the constant rocket launches using Resource X. Background radiation levels are on the rise.

Radiation chart: https://xkcd.com/radiation/ (For better viewing, I recommend the original on XKCD)

Basically, the "daily dose" of 10 micro Sv is already increased to 50 micro Sv, and in the future it looks like it will go up to 100 micro Sv and 250 micro Sv. Now, this doesn't seem bad, but the radiation gets in the food, and the water, and slowly the whole world is poisoned.

Radiation is a scary thing, but it's just one example you could use. I don't think scarcity of resources will work out, unless you create some mystery "Resource X" that is A) Scarce and B) needed.

Iridium would do nicely if you want to use existing resources. Wikipedia lists Iridium consumption as 10 tonnes in 2010. That's not a whole lot, and if the rockets or the supplies needed it, you'd find Earth significantly lacking it.

But again, you run into the issues

  • Why do the rockets need it?
  • Why does Earth need it?
  • Why do the colonies need it?
  • And why would the people on Earth be upset if it's used/in low supply, enough to cause a conflict?

It can be done, but I feel you'll have to rely on some other, bigger threat (such as radiation).

  • $\begingroup$ I think this answer my question. Earth's concern about getting empty is not believable, but note that the fact that Earth is an open system and is gaining materials not only losing them is also important, not only the amount it has now compared to the amount needed to build the colonies. And thank you for suggesting a fix, the Resource X may work for this game. Good answer. $\endgroup$ Nov 11, 2014 at 9:28
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    $\begingroup$ @HatoruHansou Don't forget to make Resource X sound cool or mysterious. Actually calling it Resource X is a bit silly. =) $\endgroup$
    – Pimgd
    Nov 11, 2014 at 9:30
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    $\begingroup$ Of course, I'm using Resource X as "The resource still to be given a name". I still like the scarcity idea, but contamination may work too. Also fighting for control of Resource X may work too. $\endgroup$ Nov 11, 2014 at 9:42

There is no scientific rational for saying the space industry is taking material away from earth. There are good reasons for space industry to start using materials sourced in space (for example mining The Moon, or asteroids) but that's just because it avoids the costs of lifting those materials out of The Earth's gravity well.

There is a sci-fi short story though about colonists on Mars and a politician on earth started drumming up FUD about the fact that they were taking water away from Earth each time they launched and to keep their colony running, and trying to tax the water and generally rabble rousing on the subject.

The story is The Martian Way, it's a Novella by Isaac Asimov.

They went to the rings of Saturn, harnessed a huge chunk of ice there brought it back to Mars and then offered to sell water to the politician at the same rates he'd been trying to charge them.

My point being that you don't need to have a real objective cost for someone to start drumming up fear on it. Lets say there is a shortage of a certain element - immediately politicians can start blaming the space industry for taking that element away from earth and making everyone back home run short.

Whether it's true or not politicians love having someone to blame.

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    $\begingroup$ Nice approach. The FUD may work here. $\endgroup$ Nov 11, 2014 at 9:31
  • $\begingroup$ Do you remember the name of the movie? $\endgroup$ Nov 11, 2014 at 9:47
  • $\begingroup$ It's a short story, not a film. I've added some more information on it to the answer. $\endgroup$
    – Tim B
    Nov 11, 2014 at 9:57
  • $\begingroup$ Thank you. I love Asimov's Fundation trilogy but I don't know a lot about his other works. $\endgroup$ Nov 11, 2014 at 10:23
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    $\begingroup$ You might be interested to hear about: slashfilm.com/foundation-tv-series then $\endgroup$
    – Tim B
    Nov 11, 2014 at 10:43

Gains from meteors

According to NASA, 100 tons of material hit the earth each day. See here:


You'd need a big space industry to exceed that. Perhaps you have such an industry.

However, you are probably interested in available and valuable material, aluminium, titanium, steel. Short of mining the core we have a limited amount of concentrated, easily extractable material.

Loss of light material

On the other hand, we lose approximately 250 tonnes of hydrogen and helium into space each day, a phenomenon known as atmospheric escape.


This represents an approximate net material loss of 150 tonnes per day.

Mass of the earth

The earth weighs in at approximately 5.97219 × 10 to the 21 tonnes so we have a way to go before it disappears altogether. Could it be depleted? Well readily available material could be mined out making materials much more expensive and environmentally damaging to produce.

  • $\begingroup$ I know that the Earth is an open system, but I didn't know the numbers. So, If Earth is gaining materials, and the amount is known, then I have something to work with. I will have to modify my game's story. $\endgroup$ Nov 11, 2014 at 9:18
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    $\begingroup$ @HatoruHansou: While I like looking at those numbers too, the thing here is availability. Lithium, for example, is quite common in the earth's crust, but only a few places on earth have high enough concentrations of it to make mining feasible. Gold is a very common element, but unfortunately most of it is dissolved in the molten core where we cannot really get at it. Plenty of more examples. Simply looking at "oh, we got plenty, all told" doesn't really do it justice... $\endgroup$
    – DevSolar
    Nov 11, 2014 at 12:08

As others have noted, it would take a huge space industry before you were shooting any appreciable percentage of Earth's resources into space.

My first thought parallels Tim B -- in fact I was thinking of the same story. A fear or complaint doesn't have to be rational for people to get very excited about it. For example, in the U.S., offshore drilling for oil has been banned along most of our coastline because people are afraid of oil leaks polluting the ocean, even though every study I've heard of has found that the amount of leakage is less than the amount of oil that leaks into the oceans naturally, and would make little measurable difference.

Or to take everyone's favorite villain, Hitler said that Germany lost World War 1 because the country was betrayed by the Jews and look how far he was able to take that. (This one has nothing to do with natural resources, but is an example of getting many people to believe a pretty irrational story for political purposes.)

My second thought is that, even from a completely rational perspective, you don't have to suppose that the space program is consuming ALL of Earth's resources. What if it is just consuming a substantial percentage of one important resource?

Like, I read years ago that some group or other was complaining that an excessive percentage of the Earth's helium was going to fill party balloons. As helium is lighter than air, once it's released it floats to the upper layers of the atmosphere where there's no way to recover it. It's an element so there's no way to make it from something else short of hugely expensive nuclear reactions.

The primary source is bubbles of helium trapped in natural gas beneath the surface of the Earth, and that are recovered as a by-product of drilling for natural gas. Not all natural gas drillers capture it, so much of the helium just escapes.

Anyway, I'm not saying that a space program would use up a lot of helium specifically, but it could be anything. Pick one resource, find some plausible (or at least, plausible sounding) explanation of how large quantities of this resource are used to build or propel your space ships, come up with a way for this to be a measurable percentage of Earth's total production, and there you go. It doesn't have to be 90% or anything like that. If it hits 5 or 10% it would be a reasonable cause for concern.


Please let me know if this is off-topic.

You have great answers for your first question, but I would like to address your second question:

If I use this to justify a conflict between Earth and the colonies, is this believable?

The first thing I thought when I read your description of farming the Earth for materials is resentment brewing in the people left on Earth who have to farm these materials. Why should I work hard in terrible conditions only for other people to profit off my labor and live in nice colonies when I can't escape myself?

Note, I have no understanding of how the system works in Gundam, as mentioned by Skeith in the comments. I imagine this is how one series may have originated a conflict between two factions.

  • $\begingroup$ Marion, +1 good answer. $\endgroup$
    – Jim2B
    Apr 2, 2016 at 3:35
  • $\begingroup$ As you said they are all great answer and all of them are useful to me. The reason an edit was proposed (and accepted by me) to my original question is that, in the end, I chose and answer that fits more to the edited version of the question. OK, I see the point, I think. If people on Earth feel that the colonies aren't giving something valuable enough in exchange for the resources going to space then we have there a reason for conflict. "Don't help them, they don't help us". $\endgroup$ Apr 2, 2016 at 8:50
  • $\begingroup$ If life in the colonies contrasts enough with life on the planet people may start suspect the colonies (I mean, something in the line "aren't we getting a bad deal here?"). I wonder if the opposite can work too, rich people on the planet and poor in the colonies (this is not the case of the world I imagined. The colonists aren't specially rich either). $\endgroup$ Apr 2, 2016 at 9:05
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    $\begingroup$ @HatoruHansou, people are suspicious. If you create enough isolation between the groups and someone nasty, petty, and jealous starts a rumor on one side about how the other group is living in luxury, it could escalate and cause a civil war. $\endgroup$
    – Marion
    Apr 2, 2016 at 18:01

No. Most of the materials for building space structures would be cheaper and simpler to get from off-Earth sources, like mines on Moon or asteroids.

Just the opposite would be true. Likely, space colonies would provide materials to Earth.

There was a sci-fi about disagreement between Earth and mars colony about the amount of water lifted to supply Marsians. Resolved (by Marsians) by getting ice from Saturn's rings.

Added: Two very useful ways to orbit material from Moon can be build, and both would be simpler to operate from moon than Earth because of lower gravity and lack of atmosphere:

Both are reusable (do not burn/spend any parts on launch) and can run on electricity, not using any valuable fuel.

Rocket sled ramp from Moon is simplest to build. Should be your first choice, especially if your technology is not too advanced. Big advantage is that Moon is tidally locked with Earth, so ramp will be pointing to approximately same place in Earth's orbit (subject to small wobble).

  • $\begingroup$ In this scenario the colonies does not have off-Earth mining yet. They are in the orbit of the planet, not very far away. The sci-fi you mentioned is The Martian Way by Isaac Asimov. $\endgroup$ Dec 5, 2014 at 14:25
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    $\begingroup$ It still will be cheaper and faster to develop off-Earth mining. Mine stuff on Moon and build electricity-powered space ramp to launch material to Earth orbit. Will be easier from moon because of lower gravity and lack of atmosphere and its resistance. $\endgroup$ Dec 5, 2014 at 14:37
  • $\begingroup$ I will think about it. Asimov's story does not only mention the amount of water needed by each launch but also some of the materials needed to build the spaceships: tungsten, magnesium, aluminum, and steel according to Asimov calculations. Also the politician shows concern about they being "gone forever from Earth" as the scavengers from Mars collect them but for Mars not for Earth. Even being estimated as hundred thousand tons of materials, people of Earth do not really care about those materials, only the water is of concern. $\endgroup$ Dec 5, 2014 at 14:43
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    $\begingroup$ Read also "Moon is harsh mistress" by Heinlein, if you haven't already. Deals with (a penal colony on Moon) mining stuff on Moon and shooting it to Earth orbit. Such ramp is cheapest vehicle to place stuff on the orbit because does not need chemical fuel, just electricity, and all parts are reusable. $\endgroup$ Dec 5, 2014 at 15:21
  • $\begingroup$ That title is in my list. I will read it soon. I didn't know it presents such interesting concept. $\endgroup$ Dec 5, 2014 at 15:26

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