EPISODE 7: MUSHROOMS ON MARS
BIOMASS PRODUCTION SYSTEM(BPS) ON THE ISS
The Biomass Production System (BPS) was an experimental plant growth system developed by NASA in collaboration with private industry partners to study plant growth and biomass production in the unique environment of microgravity. BPS was one of the earlier systems used on the International Space Station (ISS) to explore the potential of space-based agriculture, with the goal of producing sustainable food and oxygen for future long-duration missions to the Moon, Mars, or deep space.
While the Veggie and Advanced Plant Habitat (APH) systems currently represent the forefront of space agriculture, BPS played a key role in advancing our understanding of plant biology in space, especially in the early stages of space farming research. Though BPS is no longer in use, its contribution to space exploration remains important, as it helped lay the foundation for current and future plant growth systems.
Purpose and Goals of the BPS System
The BPS system was primarily designed to:
1. Study Plant Growth in Microgravity: One of the primary goals of BPS was to investigate how microgravity affects plant growth and development. On Earth, gravity plays a significant role in how plants grow, particularly in root development, nutrient uptake, and water distribution. BPS helped researchers understand how plants adapt to the absence of gravity, focusing on how to optimize space farming for long-duration missions.
2. Biomass Production for Food and Oxygen: BPS aimed to study how plants produce biomass (i.e., the organic matter that forms the structure of the plant) in microgravity. Biomass is important for both food production and oxygen generation. By growing plants in space, astronauts can produce their own food and recycle carbon dioxide (CO₂) into oxygen through photosynthesis, contributing to the sustainability of life support systems.
3. Test Closed-Loop Systems: BPS was a key component of NASA’s efforts to develop closed-loop life support systems in space. A closed-loop system is one in which waste products, such as CO₂ and organic waste, are recycled into usable resources like oxygen and food. BPS helped researchers understand how plants could be integrated into these systems to provide essential life support functions for astronauts.
4. Study Environmental Control in Space: The BPS system allowed for the precise control of environmental factors such as light, temperature, humidity, and nutrient delivery, enabling researchers to test how plants respond to different conditions. Understanding how to create an optimal environment for plants in space is crucial for ensuring the success of future space farming efforts.
Key Features of the BPS System
BPS was designed as a compact, modular system that could be easily integrated into the ISS for long-term plant experiments. Although it was retired after completing its mission, the technology and research from BPS have significantly influenced the design of more advanced plant growth systems like Veggie and APH.
1. Modular Growth Chambers
- Four Independent Growth Chambers: BPS consisted of four independent plant growth chambers, each capable of supporting its own experiment. This allowed scientists to conduct multiple experiments simultaneously under different environmental conditions, such as varying light cycles or nutrient levels. The independent chambers provided flexibility for testing a variety of plant species and growth conditions.
- Controlled Atmosphere: Each growth chamber was a sealed unit with its own environmental controls, allowing for the precise regulation of temperature, humidity, and air composition. This control was essential for testing how different environmental factors affected plant growth in microgravity.
2. Hydroponic Growth System
- Soil-Less Growth: The BPS system used a hydroponic growth system, meaning that plants were grown without soil. Instead, the plants were supported by a growth medium and received their nutrients from a nutrient-rich water solution. Hydroponics is ideal for space because it reduces the mass and volume needed to grow plants, while allowing for precise control over nutrient delivery.
- Nutrient Delivery: The hydroponic system allowed researchers to experiment with different nutrient delivery methods in microgravity. In the absence of gravity, water and nutrients do not flow through the growth medium as they do on Earth, so the BPS system was designed to ensure that plants received the right amount of nutrients without causing overwatering or nutrient imbalances.
3. Advanced Lighting System
- LED Lighting: BPS was equipped with LED lights that could be programmed to simulate different light cycles, such as Earth’s day-night cycle or the longer day-night cycles on Mars. The lighting system provided the wavelengths necessary for photosynthesis, ensuring that the plants received enough energy to grow.
- Customizable Light Cycles: Researchers could control the duration and intensity of light exposure to study how different light conditions affected plant growth. This allowed for experimentation with various light cycles to determine which conditions were optimal for biomass production and plant health in space.
4. Environmental Monitoring and Data Collection
- Real-Time Monitoring: BPS was equipped with sensors that monitored environmental conditions such as temperature, humidity, and light intensity. This data was transmitted back to Earth in real-time, allowing researchers to observe how the plants were growing and make adjustments to the experimental conditions if necessary.
- Imaging and Plant Monitoring: Cameras were integrated into the system to capture images of the plants at regular intervals, providing visual data on plant growth and development. This imaging was critical for tracking how microgravity affected plant structure, such as leaf orientation, root growth, and stem elongation.
5. Airflow and Gas Exchange
- Ventilation System: BPS was designed with a ventilation system to ensure proper air circulation within each growth chamber. In microgravity, natural convection does not occur, so air must be actively circulated to prevent the buildup of CO₂ around the plants and ensure that they receive enough oxygen for respiration.
- CO₂ and O₂ Monitoring: The system monitored CO₂ and O₂ levels to ensure that the plants had the right balance of gases for photosynthesis and respiration. Maintaining the proper gas exchange is crucial for plant growth in a closed environment like the ISS.
Crops Grown in BPS
The BPS system supported a variety of plant species, many of which were selected for their potential to provide food or oxygen in space. Some of the key crops grown in BPS included:
1. Wheat (Triticum aestivum):
- Wheat is a staple crop on Earth, providing essential carbohydrates for human nutrition. In space, wheat was studied for its potential to produce food and oxygen through photosynthesis. The BPS system allowed researchers to study how microgravity affected wheat’s growth, grain production, and biomass.
2. Arabidopsis thaliana:
- Arabidopsis is a small flowering plant that is widely used as a model organism in plant biology due to its simple genome and short life cycle. It was grown in BPS to study genetic responses to microgravity, as well as how spaceflight affects plant growth at the cellular and molecular levels. While not a food crop, Arabidopsis provides valuable insights into how plants adapt to the stresses of space.
3. Brassica rapa (Mustard Plant):
- Mustard plants were grown in BPS to study their growth and reproductive cycles in microgravity. Like Arabidopsis, mustard is a fast-growing plant that provides valuable data on how plants develop in space.
4. Soybeans (Glycine max):
- Soybeans were also tested in BPS for their potential as a protein-rich food source in space. Soybeans are important in terrestrial agriculture for their ability to fix nitrogen in the soil, and they were studied in space to understand how microgravity affects their nitrogen-fixing abilities.
Experiments Conducted with BPS
BPS enabled a wide range of experiments that provided valuable insights into plant biology in space. Some notable experiments included:
1. Photosynthesis and Biomass Production:
- One of the primary experiments conducted with BPS was focused on understanding how plants conduct photosynthesis in microgravity. Researchers studied how light, CO₂ levels, and other environmental factors influenced biomass production in plants like wheat and soybeans. These experiments helped determine the optimal conditions for growing food and generating oxygen in space.
2. Root and Shoot Development:
- Microgravity significantly affects how plants grow roots and shoots, as gravity plays a key role in directing their development on Earth. BPS experiments investigated how plants orient themselves without gravity and how their roots and shoots develop in space. Understanding these processes is critical for optimizing nutrient uptake and plant stability in microgravity.
3. Nutrient Uptake and Water Delivery:
- Experiments in BPS explored how plants absorb nutrients and water in the absence of gravity. The hydroponic system allowed researchers to test different methods of nutrient delivery and water management to ensure that plants received the right balance of nutrients without waterlogging or underfeeding.
4. Plant Reproduction in Space:
- BPS also supported experiments on plant reproduction in microgravity, studying how plants like mustard and Arabidopsis produced seeds and flowers in space. Reproduction is essential for sustaining long-term food production in space, as astronauts will need to grow multiple generations of crops during long-duration missions.
5. Gravitropism and Light Responses:
- Gravitropism, the process by which plants grow in response to gravity, was a key focus of BPS experiments. Without gravity, plants must rely on other environmental cues, such as light, to guide their growth. Researchers studied how plants adapted to these changes, with a particular focus on light’s role in directing plant growth.
Contributions of BPS to Space Agriculture
While the BPS system is no longer in use, it played an important role in advancing our understanding of plant biology in space. The data and insights gained from BPS have contributed to the development of more advanced plant growth systems, such as Veggie and APH, and have helped NASA and other space agencies move closer to the goal of sustainable space agriculture.
Some of BPS’s key contributions include:
1. Foundation for Future Plant Growth Systems:
- BPS provided essential data on how plants grow and develop in microgravity, laying the foundation for more advanced plant growth systems like Veggie and APH. The lessons learned from BPS have informed the design of these newer systems, particularly in terms of nutrient delivery, water management, and environmental control.
2. Understanding Microgravity Effects on Plant Biology:
- BPS experiments helped scientists understand how microgravity affects plant physiology, from root development to photosynthesis. This knowledge is crucial for optimizing plant growth in space and ensuring that astronauts can produce food and oxygen during long-duration missions.
3. Support for Closed-Loop Life Support Systems:
- The research conducted with BPS contributed to NASA’s efforts to develop closed-loop life support systems that can recycle waste and produce essential resources like food and oxygen. By studying how plants function in a controlled, closed environment, BPS helped pave the way for future life support systems that will be critical for sustaining human life on the Moon, Mars, and beyond.
4. Influence on Current and Future Space Missions:
- BPS played a significant role in shaping current and future space missions that aim to grow food in space. The system’s contributions to our understanding of plant growth in microgravity are still being used today as NASA and other space agencies work to develop sustainable food production systems for deep space exploration.
Challenges and Limitations of BPS
1. Limited Scale:
- BPS was a relatively small system designed for early-stage experiments. While it provided valuable data, its scale was too limited to support large-scale food production. Future systems like APH have been designed to support more complex, larger-scale experiments that are closer to the needs of long-term space missions.
2. Energy and Resource Requirements:
- BPS, like many early space technologies, required a significant amount of energy to maintain the precise environmental conditions needed for plant growth. Future systems must be more energy-efficient, especially for missions to destinations like Mars, where energy resources will be limited.
3. Complexity of Nutrient Delivery in Microgravity:
- While the hydroponic system in BPS provided valuable insights into nutrient delivery in space, the challenge of evenly distributing water and nutrients in microgravity remains. Future systems must continue to refine these methods to ensure that plants receive the right amount of nutrients without the risks of over- or under-watering.
The Legacy of the Biomass Production System
The Biomass Production System (BPS) was an important early step in NASA’s journey toward sustainable space agriculture. By providing a controlled environment for studying plant growth in microgravity, BPS generated valuable data on how plants can produce food and oxygen in space. Although BPS is no longer in use, the knowledge gained from its experiments continues to influence the design of current plant growth systems, such as Veggie and the Advanced Plant Habitat (APH), and supports NASA’s broader efforts to develop closed-loop life support systems for long-duration space missions. As humanity prepares for missions to the Moon, Mars, and beyond, the lessons learned from BPS will play a crucial role in ensuring that astronauts can grow their own food and live sustainably in space.