As we explore our solar system, we discover new and new reservoirs of water, some of them really large. But have you ever wondered about the behaviour of water in space? In what shape does it exist, can it be used for drinking and if so, how do we extract it for our space exploration purposes? The article below answers all of that and lists even more surprising facts about water in space, so dig in!
Not exactly, but the major problem is that it only exists as ice or iced vapour in open space. Chemically speaking, water is a combination of oxygen and hydrogen — the two elements that can be found in space. However, our planet is the only celestial body known to us where liquid can exist in a liquid state. In space, water naturally comes from comets and volcanoes that are also active on other planets, like Saturn. Their eruptions go higher, so all vapours immediately gasify and freeze, after which they are carried further into space. So, does water freeze or boil in space? Both because zero pressure first turns water into boiling vapour which freezes, or crystallizes, almost instantly.
Obviously, astronauts need to carry water supplies to the ISS, but how does it behave in ISS zero gravity conditions? This is where real wonders begin. Since gravity is not pulling water down, forcing it to spray over the surface, it forms into various-sized balls and floats. How to drink water in space, then? You probably know that astronauts carry most of their supplies in special tubes, including water. So, you sip any liquids from a special bag using a straw. Otherwise, you simply would be forced to chase floating liquid drops — and, let’s agree, as exciting as this may sound, such a game would not be much fun for a truly thirsty astronaut.
What about other processes on the ISS, like taking a shower? Once again, things are not what we’re used to on Earth. Astronauts have to wipe their bodies with wet showers and clean their hair with dry shampoos to solve the ‘escaping’ liquid problem. Technically, a classical terrestrial shower on the ISS could be made possible by some gravity-imitating shower cabin, but their another catch.
Water remains a precious resource in space, and its cost of delivery to the ISS is, quite literally, worth its weight in gold. And this leads us to the next point — if the water in space is plenty, why is it so precious for astronauts? Mostly because we have not yet figured out the best way to mine and recycle it in space. But steps are already taken in this direction.
Right now, ISS is recycling all liquids they have aboard; however, this cycle is not limitless. Captured moisture from the air can be restored at 100% of its original amount, but purifying liquid from urine gives back only 85% of the original amount. So, even if the total recycles’ efficiency rate stands at 93%, each new water recycling round in space is 7% lower than the original amount of liquid. So, several startups are working on technologies that could address this challenge.
Masten, Honeybee Robotics and MOXIE — three established companies that have a long history of collaborating with NASA — are now working on a ROCKET M project for a drill that would extract lunar ice and convert it into water. Looking back to our water in the space freeze or boil scenario, it is also important to have a hermetic dome above the drilling site. This way, water vapour will not turn back into ice and can potentially be converted to fresh water for supplying the future lunar station.
Another interesting project that involves space ice mining may potentially solve our refuelling needs. Modern liquid engines are mostly powered by hydrogen and oxygen — the exact two elements water consists of. The electrolysis process can potentially extract both lunar and Martian ice, giving astronauts a chance to refuel their rockets without relying on Earth supplies.
ESA has also been working on a very similar project that should split water into hydrogen and oxygen and send these two directly into the steam engine. As of now, the patent for an upcoming water engine has been bought by 50 countries worldwide! And it certainly seems this is only the beginning.
Now that you how does water behave in space and what challenges astronauts have to deal with, you understand how lucky we are with the resources available on Earth. Perhaps, one day, we may be able to find a way to make water as available in space as it is back on Earth.