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DRAFT Soil/Regolith Air Filter

Project

Highlights

    Overview

    Here's what the DRAFT Project is all about.

    • State of the Art Filters are Insufficient

      The Trace Contaminant and Control System used to keep air clean on the International Space Station only monitors and manages 30 compounds - but we know there are more than a hundred.

    • Trace Contaminants Accumulate

      In a closed environment, people and equipment emit many mild pollutant gasses that build up over time. This can cause sickness over prolonged periods.

    • Soil Air Filter

      A technology from the early 1900s, blowing contaminated air through soil captures pollutants so microbes can eat them, converting toxins into H20 and CO2.

    • In-Situ Resource Utilization

      Can we convert abundant regolith into a soil-like substrate capable of supporting a robust microbiome for filtration?

    Introduction

    Our experiment aims to address a crucial challenge in maintaining a safe and habitable environment for lunar exploration missions—the effective removal of trace volatile organic compounds (VOCs) from the habitat's atmosphere. We suggest a bioregenerative approach of using soil air filters to reduce VOCs, drawing inspiration from successful applications in controlled environments like Biosphere 2. It also incorporates elements of In-Situ Resource Utilization by testing the efficacy of a bioremediated lunar regolith simulant as a prospective filter substrate. The experiment is planned to take place on the Asclepios IV analog astronaut mission in Switzerland in the summer of 2024.

    Location of Asclepios IV Mission: San Gottardo, Switzerland

    Rationale for Experiment

    The longevity and success of lunar exploration missions hinge on the ability to maintain a safe and habitable environment for astronauts. One of the critical challenges in environmental control and life support systems (ECLSS) is the effective removal of trace volatile organic compounds (VOCs) from the habitat's atmosphere. Current air filtration systems, like those on the International Space Station (ISS), are effective in removing a limited number of potentially harmful gasses, but do not address the majority of the broad spectrum of potential VOCs produced by humans and their activities. Over extended missions, the accumulation of VOCs can pose serious health risks to the crew.

    The experiment involves two investigations. The first component is confirming the hypothesis that a soil air filter is effective at
    reducing toxins present in the analog’s atmosphere. Standard potting soil will be used to validate the concept, as it is known to host a rich microbial community capable of  metabolizing a wide range of organic compounds. The second component seeks to integrate in-situ resource utilization by attempting to make filters with  bioremediated and untreated lunar regolith simulant.

    Hypothesis:

    The hypothesis is that soil air filters are effective at removing VOCs because of their microbiome. Native lunar regolith lacks microbes and thus should not be effective at filtering. Bioremediating lunar regolith will make it more effective.

    Example of atmospheric pollutants generated by crew and activities. "Dynamic Sampling of Cabin VOCs during the Mission Operations Test of the Deep Space Habitat, 2013."
    "Status of the International Space Station Trace Contaminant Control System, 2009"

    How do soil air filters work?

    The DRAFT Team

    The minds behind the project!

    • Patrick Grubbs Science Lead
    • Jorge Galvan Lobo Aerospace Engineer

    Gallery