1. Introduction

Life support systems (LSS) are engineered solutions designed to sustain human life in extreme or inhospitable environments, such as space, underwater habitats, or hazardous terrestrial locations. These systems provide essential elements including breathable air, potable water, food, waste management, and temperature regulation.

2. Historical Development

2.1 Early Concepts

  • Submarines (19th century): Early submarines used chemical scrubbers (e.g., potassium hydroxide) to remove carbon dioxide and compressed oxygen tanks for air supply.
  • High-Altitude Aviation (20th century): Pressurized cabins and supplemental oxygen systems were developed for high-altitude flights.

2.2 Space Age Innovations

  • Project Mercury & Gemini (1960s): Introduced closed-loop oxygen supply, CO₂ scrubbing, and humidity control.
  • Apollo Missions (1969–1972): Advanced LSS included lithium hydroxide canisters for CO₂ removal, water reclamation, and temperature control via liquid cooling garments.

2.3 Evolution in Underwater Habitats

  • Conshelf (1962–1965): Jacques Cousteau’s underwater habitats used compressed air, chemical CO₂ scrubbers, and desalination systems.
  • Biosphere 2 (1991–1994): Large-scale closed ecological system experiment in Arizona, testing the viability of self-sustaining habitats.

3. Key Experiments

3.1 Biosphere 2

  • Objective: Simulate a closed ecological system for long-term human habitation.
  • Outcomes: Demonstrated challenges in balancing oxygen, CO₂, and nutrient cycles; highlighted microbial and plant roles in atmospheric regulation.

3.2 MELiSSA (Micro-Ecological Life Support System Alternative)

  • Led by: European Space Agency (ESA)
  • Goal: Develop a regenerative LSS based on microbial bioreactors to recycle waste, produce oxygen, and grow food.
  • Progress: Multi-compartment loop tested with human crews; achieved closed-loop recycling of air and water.

3.3 ISS Environmental Control and Life Support System (ECLSS)

  • Components: Oxygen generation assembly (electrolysis), water recovery system (urine and humidity reclamation), trace contaminant control.
  • Significance: Demonstrated reliable operation in microgravity and provided data for future Mars missions.

4. Modern Applications

4.1 Space Exploration

  • International Space Station (ISS): Utilizes modular ECLSS for long-duration missions; includes Sabatier reactors for CO₂ reduction and water production.
  • Mars/Lunar Missions: Research focuses on in-situ resource utilization (ISRU), such as extracting oxygen from regolith or Martian CO₂.

4.2 Underwater Habitats

  • Aquarius Reef Base: Supports marine science with advanced air and water filtration, pressure regulation, and waste management.

4.3 Terrestrial Uses

  • Disaster Relief: Portable LSS for rescue teams in hazardous environments (e.g., collapsed mines).
  • Medical: Hyperbaric chambers and controlled-atmosphere rooms for patient care.

5. Practical Applications

5.1 Environmental Monitoring

  • LSS technologies inform air and water quality management in urban and industrial settings.

5.2 Closed-Loop Agriculture

  • Hydroponics and aquaponics systems use LSS principles for sustainable food production.

5.3 Bioluminescent Organisms in LSS

  • Research explores using bioluminescent algae for natural lighting and oxygen production in closed habitats, inspired by glowing ocean waves caused by dinoflagellates.

6. Teaching Life Support Systems in Schools

  • Secondary Education: Taught as part of biology, environmental science, and physics curricula; focus on respiration, photosynthesis, and human impacts on ecosystems.
  • University Level: Specialized courses in aerospace engineering, environmental engineering, and life sciences; includes hands-on experiments, simulation software, and design projects.
  • Interdisciplinary Approach: Combines engineering, biology, chemistry, and environmental science; often uses case studies like ISS ECLSS or Biosphere 2.

7. Recent Research

  • Citation: “Closed-loop life support systems for deep-space missions: Recent advances and future perspectives,” npj Microgravity, 2022.
    • Findings: Highlights progress in microbial bioreactor LSS, integration of bioluminescent organisms for multi-functional roles (lighting and oxygenation), and the importance of redundancy and automation for mission safety.

8. Glossary

  • Closed-Loop System: A system where all resources are recycled and reused with minimal external input.
  • CO₂ Scrubbing: Removal of carbon dioxide from the air, typically using chemical or biological processes.
  • ECLSS (Environmental Control and Life Support System): A suite of subsystems that provide life-sustaining resources in spacecraft or habitats.
  • ISRU (In-Situ Resource Utilization): Using local materials (e.g., Martian soil) for life support needs.
  • Bioluminescence: Light produced by living organisms due to biochemical reactions.
  • Sabatier Reaction: Chemical process that converts CO₂ and hydrogen into water and methane, used in space life support.

9. Summary

Life support systems are critical for enabling human survival in environments where natural life-sustaining resources are unavailable. Their development has progressed from basic chemical scrubbers to highly integrated, automated closed-loop systems used in space and underwater habitats. Key experiments such as Biosphere 2 and MELiSSA have provided valuable insights into the complexity of maintaining balanced life cycles in artificial environments. Modern applications extend to space exploration, underwater research, disaster relief, and sustainable agriculture. Recent research emphasizes the integration of biological components, such as bioluminescent organisms, and the need for robust, redundant, and automated systems for future deep-space missions. Education on life support systems is interdisciplinary, preparing students to address the challenges of sustaining life beyond Earth.

Reference:

  • “Closed-loop life support systems for deep-space missions: Recent advances and future perspectives.” npj Microgravity, 2022.
  • Additional sources: ESA MELiSSA Project, NASA ECLSS documentation.