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.Principal Investigator(s)
NASA Ames Research Center, Moffett Field, CA, United States
Dynamac Corporation, Cape Canaveral, FL, United States
Orbital Technologies Corporation, Madison, WI, United States
National Aeronautics and Space Administration (NASA)Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)Research Benefits
Information PendingISS Expedition Duration
December 2001 - June 2002Expeditions Assigned
4Previous ISS Missions
ISS Expedition 4 was the first mission for the BPS hardware.
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.Earth Applications
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.Operational Protocols
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.
Thirty-two germinating Brassica rapa plants were launched inside the BPS for the TVT of the hardware. The
Brassica rapa plants were grown over two growth cycles on 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. Some of the wheat plantings were evaluated for growth, germination, weight, chlorophyll concentration and root appearance (Morrow et al. 2004). By the end of the 73-day experiment, BPS TVT produced a total of eight harvests, seven primings, and a plant tissue archive of more than 300 plants.
Gross measure of growth, leaf chlorophyll, starch, and soluble carbohydrates confirmed comparable performance by the plants on the station with ground controls. Of particular interest were the differences between the immature seedlings. Immature seeds from 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 ISS showed embryos to be at a range of developmental stages, while ground control embryos had 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 flavor and nutritional quality on potential space produce (Musgrave et al. 2005).
An ancillary study 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 et al. 2003). (Evans et al. 2009)
Frazier CM, Simpson JB, Stutte GW, Fields ND, Roberts MS, 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.
Iverson JT, Crabb TM, Lee MC, Morrow RC. Biomass Production System Hardware Performance. SAE Technical Paper. 2003; 2003-01-2484. DOI: 10.4271/2003-01-2484.
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.
Iverson JT, Stadler JJ, Richter RC, Morrow RC. Biomass Production System (BPS) Technology Validation Test Results. International Conference on Environmental Systems, Colorado Springs, CO; 2004 Jul 19 1061-1070.
Allen J, Bisbee PA, Darnell RL, Kuang A, Levine LH, Musgrave ME, 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.
Stadler JJ, Morrow RC. Analysis of Crew Interaction with Long-Duration Plant Growth Experiment. SAE Technical Paper. 2003; 2003-01-2482. DOI: 4271/2003-01-2482.
Crabbe TM, Morrow RC. Biomass Production System (BPS) plant growth unit. Advances in Space Research. 2000; 26(2): 289-298.