# Lunar and Martian Regolith Simulants Desorb and Weather after Exposure to Bioregenerative Life Support System Effluent

## TL;DR

Lunar and Martian soil simulants release essential nutrients when exposed to waste from life support systems, suggesting they could help sustain agriculture on these planets.

## Contribution

This study demonstrates that extraterrestrial regolith simulants can desorb and weather when exposed to bioregenerative life support system effluent, offering new insights into nutrient cycling in space agriculture.

## Key findings

- Lunar and Martian regolith simulants desorbed significant amounts of sulfur, calcium, and magnesium when exposed to BLiSS effluent.
- XPS analysis revealed elemental bonding of carbon, nitrogen, phosphorus, and calcium on the regolith surface after reaction.
- SEM-EDS showed pitting in lunar simulant and nanoparticle coverage in martian simulant after exposure to BLiSS effluent.

## Abstract

The extraction of
plant essential nutrients from extraterrestrial
regolith will be necessary to ensure the sustainability of lunar and
martian agriculture. An essential instrument of these outposts will
be bioregenerative life support systems (BLiSS) that attempt to fully
recycle nutrients from organic wastes. While BLiSS may not be fully
efficient and lead to a reduction in the quantity of some elements,
it is necessary to explore if regolith can be used to fortify the
composition of BLiSS effluent. Lunar (JSC-1A) and martian simulants
(MGS-1) were reacted with a high-fidelity BLiSS effluent from NASA’s
Kennedy Space Center (KSC) in a 24 h batch experiment and compared
to reactions with an inorganic nutrient solution and water. Net sorption
and dissolution of elements were determined by quantification of reacting
solutions using inductively coupled plasma-optical emission spectroscopy
(ICP-OES), with P demonstrating Langmuir and Zn and K demonstrating
Freundlich
sorption isotherms. The lunar simulant desorbed sizeable quantities
of S, followed by Ca and Mg, while the martian simulant desorbed S,
followed by Mg, Ca, and Na. Elemental bonding of C, N, P, and Ca was
observed on the simulant solid phase with X-ray photoelectron spectroscopy
(XPS) after reaction with BLiSS solution. Minerals after experimentation
were
observed using scanning electron microscope−electron dispersive
spectroscopy (SEM-EDS), revealing pitting in JSC-1A and covering of
nanoparticles in MGS-1. There were marked differences between the
reactions of the inorganic nutrient solution compared to BLiSS effluent,
indicating the necessity to study high-fidelity solutions over single-element
model systems. Overall, lunar and martian regoliths contain highly
soluble components that may fortify BLiSS effluents with valuable
metals and plant essential nutrients.