Another follow-Up to this question.

If you exclude earth as source, which means you can use all other planets and all celestial bodies within neptunes orbit range.

Just how hard it is to get your hands on clean / useable or drinkable water? Can it be harvested? Or somehow manufactured out of other elements that are more readily available? Dynas had the idea to use water as a currency. Is it valuable enough?

I believe comets could be a source (since they are made of ice?). If you have a better idea for a currency, please answer the other question here. Thanks!

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    $\begingroup$ There is loads of it. Water is the most common non-single atom molecule in the universe. en.wikipedia.org/wiki/Extraterrestrial_liquid_water $\endgroup$ – Erik Aug 18 '15 at 20:14
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    $\begingroup$ It is believed that the moon of Europa alone contains more water than Earth does. $\endgroup$ – Erik Aug 18 '15 at 20:15
  • $\begingroup$ This question may be trivial, but it's well-intended and well formulated. The downvotes it's received seem unfair. $\endgroup$ – Nich Del Aug 18 '15 at 23:42
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    $\begingroup$ @Nich Del The site rules says to downvote questions that shows a lack of research. Additionally (and that's something that annoys me a lot about WB) questions like this call on 'facts' based on faith in the answers. $\endgroup$ – Mystra007 Aug 19 '15 at 21:14
  • $\begingroup$ Well after thinking over it, I have to admit, that @Mystra007 is kinda right. I was in a train of thought and was not thinking/researching long enough before posting the question. I did not understand you second sentence, Mystra. Could you explain it? $\endgroup$ – user6415 Aug 19 '15 at 21:51

The solar system is swimming in water. Europa alone is thought to have 3X the amount of water in the Earth's oceans, and it is only one moon in the Jovian system (Ganymede and Callisto are ice moons even bigger than Europa, and Jupiter has at least 67 other bodies of various composition in orbit).

If that is not enough, Saturn's rings are thought to be made of small chunks of ice, and may Saturnian moons are also icy bodies. Uranus and Neptune not only have flotillas of icy moons in orbit, they themselves are considered to be "ice giants" rather than "gas giants".

Going farther out, the distant bodies of the Kuiper belt and Oort cloud are all considered to be made of ices of various sorts. Asteroids are also known to have water trapped or embedded in them, and they alone have something like 4% of the mass of the Earth, while the Oort cloud is estimated to have anywhere from 5 to 300 time the mass of the Earth (the estimates are very wide due to the lack of direct observation of the cloud).

So water, in the form of ice, is very common and abundant in the Solar System. Getting it requires enough deltaV to leave Earth orbit and match orbits with the body of interest, but some Near Earth Objects (NEOs) require less deltaV than needed to get to the Moon, so you can start small and work your way outwards. Once you get to the ice, you will certainly need enough energy to melt it, and most likely some process to remove trapped gasses and filter out impurities like bits of rock, salts and carbon that may have been trapped in the ice, but after that, fill your glass and enjoy!


Water is composed of elements that are very common in the universe : Hydrogen (rank #1) and Oxygen (rank #3). This makes water (H2O) one of the most common molecule in the universe. So from an economic standpoint, its choice as currency is definitely not a good one.

In the solar system, most water will be found as ice. It may contain other organic molecules in comets or asteroids, or some other components on planets & satellites (salt, etc.). If you need it to be pure, you'll probably have to refine it somewhat.


Water is common enough, but getting access to it can be expensive. All the major sources exist at the bottom of gravity wells while sources such as comets are usually traveling at very high relative velocities. The actual cost really depends on the intended purpose. On most parts of the Earth you can sit back and wait and it will come to you, but if you wanted to collect some so you could irrigate a field on the moon, the price goes up a lot!


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