ESA Study of Water Extraction from Lunar Regolith


Composite map of the near-side of the Moon. The blue shows the signature of water (at higher latitudes), and the red shows high pyroxene concentrations. Captured from NASA’s M3 instrument on Chandrayaan-1. Credit: ISRO/NASA/JPL-Caltech/Brown Univ./USGS


The Moon is becoming the proving ground for many space organizations. The European Space Agency (ESA) has awarded a contract to study and prepare for an all-European mission to the Moon. If developed, this would be ESA's second mission to the Moon and first lunar lander. The most exciting aspect of this proposal is ESA’s intent on demonstrating the extraction of water and other volatiles from lunar regolith. Importantly, this recent award further demonstrates Europe's commitment to space resources.

The ESA contract is for a one year study covering a future landed mission to the Moon before 2025. A key component for the mission is the processing of lunar regolith, with the aim to extract water and oxygen. Being able to extract water in space is required for building a sustainable presence off Earth. With available water, it is possible to perform a variety of chemical reactions including making rocket propellant, air to breathe, and potable water (for human and plant consumption).

Lunar regolith is the term to describe the loose top layer of dust and broken rocks. Lunar regolith generally forms through mechanical disintegration of rocks by continuous meteoric impacts. Without humidity, wind, or biological processes, the material is very rough and abrasive. The main mineral composition of lunar regolith includes oxygen, silicon, iron, calcium, aluminum, magnesium, and titanium. However, the silicon base material can contain hydroxyl (-OH) that can be processed to pull out water.

The side of this young crater on the far-side of the Moon has a high concentration of water-rich minerals (blue in right image). Credit: Credits: ISRO/NASA/JPL-Caltech/USGS/Brown Univ.

The concentration of hydroxyl group elements varies greatly around the Moon, but is generally a few fractions of a percent by mass of regolith. The NASA Moon Mineralogy Mapper (M3) instrument on the Chandrayaan-1 lunar orbiter detected hydroxyl absorption lines at high latitude locations and in several feldspathic craters [Pieters et al. 2009]. High concentrations of hydroxyl and even water ice have been observed in a few of the Moon’s polar permanently shadowed craters.

The focus of this ESA study is on hydroxyl rich areas. One of the approaches for extracting water from hydroxyl is to heat the material, causing the out-gas of the OH that will recombine into water (H2O) when cooled. Such a system would require a material collection system, a heater, a condensation unit, and a final water storage system (heated to prevent freezing). For concept testing, a system like this could use a lander and rover based system.

The ESA contract was awarded to ArianeGroup, who is partnering with PTScientists and Space Applications Services. ArianeGroup is a European joint venture between Airbus and Safran, both of whom are aerospace firms focused on aerospace and defense contracts. ArianeGroup is the main contractor for the Ariane family of launch vehicles, including Ariane 5 and Ariane 6. The Ariane 6 launch vehicle is a likely choice for launching this potential mission.

PTScientists is developing their own lunar lander and rover that is expected to land on the Moon by late 2019 or early 2020. They are providing insight on lunar landers to ArianeGroup for the ESA regolith processing study. Credit: PTScientists

PTScientists is a German aerospace startup who was a competitor in the now cancelled Google Lunar X-Prize. They will be providing the partnership with a lunar lander. The lander they provide will be similar to the one they plan to land for their Mission to the Moon, set to launch by late 2019 or early 2020.

Space Applications Services is a Belgium firm who will provide the ground control facilities and communications for the potential mission.

Even though this contract is only for a study of a lunar regolith water processing system, it holds promise for becoming a real mission. The European partnership formed by ArianeGroup has a wide skill set to develop a system that should achieve feasible water extraction. We eagerly await their results, and hope ESA continues work on space extraction missions.