EPISODE 10: MUSHROOMS ON MARS
MELiSSA PROJECT
The MELiSSA project (Micro-Ecological Life Support System Alternative) is a long-term research initiative led by the European Space Agency (ESA) with the goal of developing a regenerative, closed-loop life support system for long-duration space missions. The project aims to create a sustainable system that can recycle waste, provide oxygen, produce food, and purify water—essentially mimicking Earth's natural biosphere on a smaller scale—allowing humans to live and work in space for extended periods, such as on missions to the Moon, Mars, or beyond.
Key Objectives of MELiSSA:
1. Recycling Waste into Resources: MELiSSA aims to recycle all waste products generated by humans, including carbon dioxide (CO₂), organic waste, and human waste, turning them into usable resources such as oxygen, water, and food. This reduces the need for resupply missions from Earth, making space missions more sustainable and self-sufficient.
2. Producing Oxygen and Purifying Water: Plants, algae, and bacteria are key components of MELiSSA, as they can convert CO₂ into oxygen through photosynthesis and purify water through biological processes.
3. Producing Food: MELiSSA includes the cultivation of higher plants and algae, which can provide astronauts with a renewable source of fresh food. This system can produce essential nutrients needed for long-duration missions.
4. Supporting Human Life in Space: The ultimate goal is to develop a life support system that is fully self-sustaining and capable of supporting human life in space for extended periods, reducing the need for resupply from Earth.
Structure of MELiSSA:
MELiSSA is divided into five interconnected compartments, each serving a specific function in the life support system. These compartments work together to recycle waste and produce oxygen, water, and food.
1. Compartment I: Liquefying Compartment
- This compartment handles the initial breakdown of organic waste (human waste, inedible plant matter) through anaerobic fermentation. The organic material is decomposed into simpler compounds, such as volatile fatty acids, gases (like CO₂ and methane), and water, which are used by the other compartments.
2. Compartment II: Photoheterotrophic Compartment
- In this compartment, photoheterotrophic bacteria, such as Rhodospirillum rubrum, convert organic acids and other byproducts from Compartment I into simpler compounds like ammonia. These products can be used as nutrients for plants in later stages of the system.
3. Compartment III: Nitrifying Compartment
- Nitrifying bacteria in this compartment convert ammonia (produced in Compartment II) into nitrates, which are essential for plant growth. This step helps manage the nitrogen cycle within the system, providing nutrients for the higher plants.
4. Compartment IV: Photoautotrophic Compartment (Plants and Algae)
- This compartment contains higher plants (such as wheat, spinach, and other food crops) and algae that use photosynthesis to convert CO₂ into oxygen and produce edible biomass. The plants absorb the nutrients provided by the previous compartments and, in return, release oxygen, contributing to the life support system.
5. Compartment V: Human Compartment
- The human compartment is where astronauts live and work. It is connected to all the other compartments, receiving oxygen and food while producing CO₂ and organic waste. The waste generated by the humans is fed back into the system, where it is processed and recycled.
Key Components and Technologies:
1. Microbial Bioreactors: The heart of the MELiSSA system includes bioreactors that house microorganisms, which are responsible for breaking down waste, purifying water, and recycling nutrients. Different bacteria perform various tasks, such as converting ammonia into nitrates or organic matter into simpler compounds.
2. Plants and Algae: Higher plants, such as wheat, potatoes, and leafy greens, are grown to produce food, while algae like Spirulina can provide both food and oxygen. These organisms are critical in converting CO₂ into oxygen through photosynthesis and producing edible biomass.
3. Waste Recycling and Water Purification: MELiSSA aims to recycle all forms of waste, including human waste and inedible plant parts, turning them into valuable resources. The system also includes water purification technologies that ensure astronauts have access to clean water.
4. Environmental Monitoring and Automation: To keep the MELiSSA system running smoothly, it relies on advanced environmental monitoring systems that measure CO₂ levels, oxygen levels, humidity, temperature, and more. The system can adjust conditions automatically to maintain a balance between all compartments and ensure human safety.
Progress and Achievements:
- Ground-Based Research: Much of the MELiSSA research has been conducted on Earth, in laboratories designed to simulate space environments. These experiments allow researchers to fine-tune the various components and interactions between the compartments.
- Space-Based Experiments: Several components of MELiSSA have been tested on the International Space Station (ISS) to study how the system functions in microgravity. These experiments have focused on how plants, algae, and bacteria grow and interact in space environments.
- Food Production Experiments: MELiSSA has been involved in experiments growing plants such as lettuce, wheat, and algae in space. These tests provide valuable insights into how these organisms can be integrated into a life support system for long-duration missions.
Potential Benefits for Earth:
- Sustainable Agriculture: The technologies developed for MELiSSA, such as waste recycling and efficient water purification, can be applied to Earth to create more sustainable agricultural systems. Closed-loop systems similar to MELiSSA could help reduce the environmental impact of farming on Earth.
- Water and Waste Management: The water purification and waste recycling technologies used in MELiSSA could be adapted for use in areas with limited access to clean water or waste treatment facilities, improving access to essential resources in remote or underdeveloped regions.
Applications for Space Exploration:
- Long-Duration Missions: MELiSSA’s closed-loop life support system is essential for long-duration space missions, such as those to Mars or establishing lunar bases. These missions will require systems that can recycle waste, produce oxygen, and grow food autonomously, as resupply from Earth will be limited.
- Lunar and Martian Bases: Future human settlements on the Moon or Mars will rely heavily on closed-loop systems like MELiSSA to provide the necessities of life. MELiSSA could enable astronauts to live and work on other planetary bodies for extended periods by providing a continuous supply of fresh food, oxygen, and clean water.
Future Goals and Challenges:
1. Fully Autonomous System: The ultimate goal of the MELiSSA project is to create a fully autonomous life support system that can operate without human intervention, even in extreme environments like space. This requires further research into automation, self-regulation, and long-term reliability.
2. Scaling Up: While MELiSSA has demonstrated success in small-scale experiments, scaling the system up to support a larger crew on a long-duration mission is one of the project’s key challenges. Researchers are working to ensure that the system can handle the needs of a larger population and produce enough food, oxygen, and water over the long term.
3. Space-Based Testing: Ongoing tests on the ISS and other space platforms will be crucial for understanding how the system functions in microgravity and how to adapt it for use on the Moon, Mars, or other destinations.
The MELiSSA project is a pioneering effort by ESA to develop a closed-loop life support system that could enable humans to live and work in space for extended periods. By recycling waste into essential resources like oxygen, water, and food, MELiSSA offers a sustainable solution for long-duration space missions and future space habitats. The project’s technologies have the potential to revolutionize not only space exploration but also resource management on Earth, contributing to more sustainable practices in agriculture, water purification, and waste management.