# Capture protons from solar wind

Could it be possible ( using a reasonable amount of energy and ressources ) to capture protons from solar wind on (ex. the moon) in order to produce water for a long term self-sufficient mission. The amount of water should compensate for system losses.

You are free to make assumptions and improve my question as english is not my native language

EDIT: Assuming a proton flux of 2e12 m^-2 s as provided here (https://astronomy.stackexchange.com/questions/18829/composition-and-proton-flux-from-the-solar-wind) we would need to capture an area of 10^6 m^2 in order to get 0.11kg of protons per year ( the mass required to make 1 liter of water )

• To make hydrogen of protons you need electrons too. To make water of hydrogen you need oxygen too.
– Uwe
Mar 3, 2019 at 20:00
• @Uwe there’s plenty of oxygen on the moon, but what could be a source of electrons? Could we get it from solar wind too ? Mar 3, 2019 at 22:00
• density of solar wind: [the density of the solar wind [...] is usually on the order of just a few protons per cubic centimeter][1] [1]: en.wikipedia.org/wiki/Atmosphere_of_the_Moon#Composition
– Kav
Oct 21, 2021 at 15:40