Biomass Production System (BPS) - 01.09.14
Science Objectives for Everyone The Biomass Production System (BPS) environmental control subsystems provides a complete growing environment for plants in microgravity. Results can lead to the development of regenerative life support systems on future exploration missions to the Moon or Mars.
Science Results for Everyone
Imagine fresh bread in spaceflight. Studies of the effects of microgravity on wheat photosynthesis and metabolism may make it possible to use plants as regenerative life support systems on long missions. This investigation revealed differences between immature seeds from International Space Station and on the ground that could affect flavor and nutritional quality of the plant, but analysis of germination rates and leaf growth suggest that microgravity is not a significant environmental stress for the plants. The 73-day experiment produced a total of eight harvests and a plant tissue archive of more than 300 plants and 3,000 images.
NASA Ames Research Center, Moffett Field, CA, United States
Dynamac Corporation, Cape Canaveral, FL, United States
Orbital Technologies Corporation, Madison, WI, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Human Exploration and Operations Mission Directorate (HEOMD)
ISS Expedition Duration
December 2001 - June 2002
Previous ISS Missions
ISS Expedition 4 was the first mission for the BPS hardware.
- The Biomass Production System (BPS) environmental control subsystems were tested as potential hardware for regenerative life support system investigations.
- The BPS was delivered to ISS and activated. The technology verification test (TVT) conducted in the BPS used one of four plant growth chambers (PGCs) to grow Brassica rapa (field mustard plant) in microgravity. Triticum aestivum (common bread wheat plant) was grown in the remaining PGCs for the Photosynthesis Experiment and System Testing and Operation (PESTO) investigation.
- Plants grown inside the BPS were compared to plants grown in an Earth based BPS. The data obtained will increase the understanding of the use of plants in regenerative life support systems.
The Biomass Production System (BPS) was developed as a precursor to systems capable of maintaining plant growth in microgravity for more than 90 days (e.g., planetary missions). The BPS objective was to validate plant growth system hardware functionality and performance, plant productivity and health, information acquisition, and experiment operations and support in microgravity. The BPS housed two experiments: the Technology Verification experiment and the Photosynthesis Experiment and System Testing and Operation (PESTO) experiment.
Brassica rapa (field mustard) was the test species for the BPS. The BPS plant growth chambers (PGCs) contained plants that were started on the ground and that had already developed their photosynthetic apparatus, such as stoma, guard cells, and other structures found in the leaves. Samples taken from the plants were compared to data taken from previous ground-based experiments conducted using BPS. Over the course of the 73-day test, additional sets of plants were germinated and grown in microgravity conditions. In-flight progress of plant growth was monitored through image collection; harvested plants were frozen or fixed for later analysis on the ground.
BPS tested the hypothesis that environmental control subsystems would provide a stress-free growing environment in microgravity. These technology validation studies provide a foundation on which to base the design of future plant growth units for station or future Exploration missions. These results can lead to the development of regenerative life support systems on future missions to the moon or Mars. While creating useful technology and science, BPS allowed students in grades Kindergarten through twelve to work as co-investigators on real space research. This research, known as "Farming in Space", examined the basic principles and concepts related to plant biology, agricultural production, ecology, and the space environment. Activities associated with this research encouraged curiosity in the sciences while teaching good scientific methodology.
The amount of food necessary to sustain a crew during a long duration mission to Mars would prohibitively increase the mass of spacecraft and the overall cost of the mission. Some of the crew's food would need to come from a selection of renewable crops grown in biomass production systems. The biomass production systems may also be used as a filtration system for water and atmospheric gases. Plant growth chambers would also offer a comforting, green reminder of Earth to a crew a long way from home.
As less fertile land becomes available to grow food, alternative agricultural systems that efficiently produce greater quantities of high-quality crops will be increasingly important. Data from the operation of the BPS will advance greenhouse and controlled-environment agricultural systems and will help farmers produce better, healthier crops in a small space using the optimum amount of nutrients.
BPS consists of four plant growth chambers. The TVT for BPS operations grew Brassica rapa in one of the four BPS chambers. Each chamber has 264 cm square growth area, while the roots of the plants were placed 3 cm below the growth area. A total of 32 plants were grown for 73 days on ISS. The plants were exposed to 20 hours of light and 4 hours of dark daily at 24 degrees C and 78 percent relative humidity. A control group of plants were treated exactly as the experimental group on ISS. Although BPS is fully automated, the crew conducted periodic system checks and some support tasks.
Following the transfer of the BPS to EXpedite the PRocessing of Experiments to Space Station (EXPRESS) Rack, the crew refilled the water reservoirs as needed and periodically changed carbon dioxide canisters. Gas and liquid samples using ports in the growth chambers were taken weekly.
During operations on Expedition 4, plant samples were taken for harvesting and fixation 21 days following BPS activation on ISS. The fixed samples were stowed in the ARCTIC freezer. The crew hand-pollinated blooms on the plants during flowering to ensure seed set. BPS was returned to Earth on STS-110/8A while the plants continued to grow.
Data and near real-time video from inside the growth chambers were transmitted from BPS to the investigators via the Telescience Resource Kit (TReK) system. Student and teacher participants in the ISS Challenge: Farming in Space program were also able to view the real-time video from BPS. The participants conducted their own in-class plant growth experiments and were encouraged to share questions and data with other participants and members of the ISS Challenge support team.
The Biomass Production System (BPS) was flown aboard the Space Shuttle and International Space Station for 73 days. The BPS contained two plant related experiments, the Technology Verification Test (TVT) which was done to test and validate several hardware systems and protocols for growing plants in microgravity, and the Photosynthesis Experiment and System Testing and Operation ( PESTO) which studied the effects of microgravity on wheat photosynthesis and metabolism.
Thirty-two germinating Brassica rapa plants were launched inside the BPS for the TVT. The Brassica rapa plants were grown over two growth cycles on the ISS. Brassica rapa tissue from BPS was analyzed for general morphology, seed anatomy and storage reserves, foliar carbohydrates, and chlorophyll and root zone hypoxia analysis (Morrow 2004). Gross measure of growth, leaf chlorophyll, starch and soluble carbohydrates confirmed comparable performance by the plants on the station and ground controls. Of particular interest were the differences between the immature seeds. Immature seeds from the station had higher concentrations of chlorophyll, starch and soluble carbohydrates than the ground controls. Seed protein was significantly lower in the ISS material. Also, microscopy of immature seeds fixed on the ISS showed embryos to be at a range of developmental stages, while ground control embryos has all reached the same stage of development. These differences could be attributable to differences in water delivery or reduced gas exchange due to lack of convection. These results suggest that the microgravity environment may affect the flavor and nutritional quality of potential space produce (Musgrave 2005). An ancillary component of the TVT tested for bacterial and fungal communities in the BPS chambers and root modules, and these cultures were compared to ground control bacterial and fungal growth. Analysis indicated more species of both bacteria and fungus were identified in the flight samples than the ground samples. The populations were common airborne species found on Earth. The significance of the difference is uncertain (Frazier 2003).
Triticum aesativum plants were also launched inside the BPS for the 73-day PESTO experiment to examine germination, growth, photosynthesis, chloroplast development (organelle where photosynthesis takes place), carbohydrate metabolism and gene expression (Stutte 2003). Analysis demonstrated the ability to obtain high germination rates of Triticum aesativum and also revealed the initial leaf growth was the same in both flight and ground controls (Stutte 2003). The data suggests microgravity is not a significant environmental stress affecting canopy photosynthesis and consequent dry mass buildup (Stutte 2005). On a morphological level, there was little difference in the development of cells under microgravity conditions however the leaves developed in microgravity had a thinner cross-sectional area. Structurally, the chloroplasts of microgravity plants were more oval shaped than those developed on Earth, and the thylakoid membranes exhibited a greater packing density. No differences were observed in starch, soluble sugar, or lignin content of the leaves along with no change in gene expression (Stutte 2006).
By the end of the 73-day experiment, the BPS hardware produced a total of eight harvests, seven root module primings, and a plant tissue archive of more than 300 plants along with over 3000 plant images and an extensive set of hardware system performance data.
Iverson JT, Crabb TM, Morrow RC, Lee MC. Biomass Production System Hardware Performance. SAE Technical Paper. 2003; 2003-01-2484.
Frazier CM, Simpson JB, Roberts MS, Stutte GW, Fields ND, Melendez-Andrade J, Morrow RC. Bacterial and fungal communities in BPS chambers and root modules. SAE Technical Paper. 2003; 2003-01-2528. DOI: 10.4271/2003-01-2528.
Morrow RC, Iverson JT, Richter RC, Stadler JJ. Biomass Production System (BPS) Technology Validation Test Results. International Conference on Environmental Systems, Colorado Springs, CO; 2004 Jul 19 1061-1070.
Musgrave ME, Kuang A, Tuominen LK, Levine LH, Morrow RC. Seed Storage Reserves and Glucosinolates in Brassica rapa L. Grown on the International Space Station. Journal of the American Society for Horticultural Science. 2005; 130(6): 848-856.
Monje O, Stutte GW, Chapman DK. Microgravity does not alter plant stand gas exchange of wheat at moderate light levels and saturating CO2 concentration. Planta. 2005; 222(2): 336-345. DOI: 10.1007/s00425-005-1529-1.
Stutte GW, Monje O, Goins GD, Tripathy BC. Microgravity effects on thylakoid, single leaf, and whole canopy photosynthesis on dwarf wheat. Planta. 2005: 1-11. DOI: 10.1007/s00425-005-0066-2.
Ground Based Results Publications
Allen J, Bisbee PA, Darnell RL, Kuang A, Levine LH, Musgrave ME, van Loon JJ, van Loon JJ. Gravity control of growth form in Brassica rapa and Arabidopsis thaliana (Brassicaceae): Consequences for secondary metabolism. American Journal of Botany. 2009; 96(3): 652-660.
Morrow RC, Crabbe TM. Biomass Production System (BPS) plant growth unit. Advances in Space Research. 2000; 26(2): 289-298.
Morrow RC, Stadler JJ. Analysis of Crew Interaction with Long-Duration Plant Growth Experiment. SAE Technical Paper. 2003; 2003-01-2482. DOI: 4271/2003-01-2482.
NASA Image: ISS004E11725 - Expedition Four Flight Engineer Daniel Bursch, in the Destiny U.S. Laboratory, harvests Brassica plants from plant growth chamber 2 as part of the Biomass Production System.
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Video screen shot of Brassica rapa, 36 days after planting on ISS during Increment 4.
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NASA Image: ISS004E11712 - View of Brassica plants in plant growth chamber 2 grown as a part of the technical validation test in the Biomass Production System conducted onboard the International Space Station during Expedition 4.
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NASA Image: ISS004E11721 - View of Brassica plants from plant growth chamber 2 being harvested as part of the technical validation test of the Biomass Production System conducted during ISS Expedition 4.
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NASA Image: STS111E5026 - Astronaut Daniel W. Bursch, aboard the ISS is pictured at the Biomass Production System (BPS) on Endeavour's middeck.
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