Non-methane hydrocarbons in a controlled ecological life support system.

Area of Science:

• Environmental Science
• Space Exploration
• Atmospheric Chemistry

Background:

• Non-methane hydrocarbons (NMHCs) are crucial for human health and plant growth in controlled ecological life support systems (CELSS).
• Understanding NMHCs dynamics is vital for long-term space missions and closed-environment sustainability.
• CELSS environments require careful atmospheric monitoring due to potential pollutant buildup.

Purpose of the Study:

• To measure and analyze the concentration trends of 54 NMHCs within a CELSS.
• To identify the primary sources and contributing factors of NMHCs in a closed ecosystem.
• To provide data for managing the atmosphere in CELSS for future space exploration.

Main Methods:

• A 4-person, 180-day integrated experiment was conducted in a CELSS with dedicated plant growth and human activity cabins.
• Gas chromatography was used to measure concentrations of 54 different NMHCs.
• Atmospheric samples were collected and analyzed throughout the experimental period.

Main Results:

• Total NMHCs mixing ratios increased from 423 ± 283 ppbv to 2961 ± 323 ppbv over 180 days.
• Ethane and propane showed significant increases, becoming the most abundant alkanes.
• Alkenes like ethylene and isoprene fluctuated, while aromatic hydrocarbons decreased substantially.

Conclusions:

• NMHC concentrations undergo significant changes in long-term closed ecological environments.
• Biomass burning, sewage treatment, construction materials, and plants are identified sources of NMHCs within the CELSS.
• The findings offer critical insights for CELSS atmosphere management and understanding human-environment interactions in space.