For this project, an aeroponic small plant growth chamber was designed, constructed and demonstrated that incorporated a new type of illumination panel that integrates multi-color Light Emitting Diode (LED) clusters with small imaging cameras. Engineering design trades were conducted to optimize illumination quality and uniformity prior to fabricating this portable growth unit.
The LED nodes within the illumination panel consist of small clusters of multi-color red, green, and blue (RGB) LEDs. The LED nodes were designed so that a single cluster could be replaced if required, significantly reducing the time and expense currently required to replace LEDs on commercially available LED panels. For this growth chamber, a single panel housing twelve LED nodes was constructed. The panel was designed to provide two levels of illumination: (1) for small plants just germinated, lower intensity light and (2) for maturing plants, brighter light. Additionally, to observe plant growth and enable unobstructed viewing and time lapse photography, two small imaging cameras were integrated into the array of LED clusters. The imaging camera can also provide a means to measure illumination levels so that individual colored LEDs can be modulated to provide the correct illumination spectra and intensity.
The LED nodes and imaging camera were designed to be powered with low voltage DC power. Low voltage DC power is safer, cleaner and less susceptible to power surges. For safety purposes, the AC powered DC power supplies were placed above all potential wet areas within the growth unit.
LED light sources are ideal for plant growth systems. However, commercially available multi-color LED illumination panels are designed and manufactured to produce a single particular illumination. These panels have very specific LED colors arranged in a very specific fashion. This limits the amount of color mixing, intensity variation, and spatial arrangement that is possible, precluding passive precision illumination. There is no feedback mechanism to detect spectral shifts caused by LED aging and additionally, there is no mechanism to modulate LEDs. It is also not possible to integrate an imaging system into these panels. Furthermore, these panels are commonly operated using high voltage AC power sources, which is not ideal in a potentially wet environment. Therefore, to address these issues, custom LED illumination panels were designed and developed for this project’s plant growth chamber.
A systematic approach was taken to determine the general size, specifications, and shape of a portable plant growth unit. Once the general size and shape were finalized, the detailed design of the support structure, aeroponics, and lighting subsystems were developed. Particular attention was given to heat transfer and the expected LED thermal environment. Additionally, a computational analysis was performed to determine optimal LED nodes placement so that two different uniform illumination fields could be yielded: (1) for germinating plants, lower intensity light, and (2) for larger maturing plants, a brighter one. Also, aeroponic studies were reviewed to identify an efficient and user-friendly system that would require minimal user involvement.More »
Benefits to NASA funded missions include the fact that Crew members aboard the International Space Station (ISS) have been growing plants and vegetables for years in their "space garden." A space station study is helping investigators develop procedures and methods that allow astronauts to grow and safely eat space-grown vegetables. These experiments also investigate another benefit of growing plants in space: the non-nutritional value of providing comfort and relaxation. Data from these investigations help advance Earth-based greenhouses and controlled-environment agricultural systems which can in turn, help farmers produce better, healthier crops in small spaces using the optimum amount of water and nutrients. Illumination panels designed from this project could be infused into these studies.
NASA's research with plants in space is dedicated to systematic studies that explore the role gravity plays at all stages in the life of higher plants. Research includes answering scientific questions focused on determining the effects of the interactions between gravity and other environmental factors on plant systems, and on using hypergravity, simulated hypogravity, and microgravity as tools to advance fundamental knowledge of plant biology. Plant research results contribute to NASA's goals of furthering human exploration of space and improving the quality of life on Earth through applications in medicine, agriculture, biotechnology, and environmental management. Any studies that apply to these areas of research could advance the future ability to successfully grow plants in space.
Benefits to NASA unfunded missions and planned missions include the fact that successful plant growth in space will be an important part of space exploration in the future as NASA plans for long-duration missions to Mars, and beyond. NASA scientists anticipate that astronauts will need to be able to grow plants that could be used to provide for, and supplement meals.
Benefits to the commercial space industry would be similar to those that would benefit NASA.
For example, when the private spaceflight company SpaceX launched the Dragon cargo mission, on Falcon 9, to the International Space Station (ISS), for the fourth attempt on July 14, 2014, the capsule was carrying a small plant growth chamber built to let astronauts grow Outredgeous lettuce in orbit. The goal of the Veg-01 experiment, nicknamed "Veggie", is to see how well plants grow in orbit. If these early tests go well and the food proves safe, scientists hope to expand this capability to grow other vegetables and/or other large plants on the ISS. Demonstration and outcomes related to the viability of this small plant growth chamber, the lighting, the imaging system, and the control system could benefit similar future commercial space industry activities.
Benefits to other government agencies would be similar to those that would benefit NASA. Agencies like the US Department of Agriculture, who provide leadership on food, agriculture, natural resources, conservation, nutrition, and related issues could benefit by understanding means for improved Earth-based greenhouses and controlled-environment agricultural systems.More »
|Organizations Performing Work||Role||Type||Location|
|Stennis Space Center (SSC)||Lead Organization||NASA Center||Stennis Space Center, Mississippi|
|Innovative Imaging and Research Corporation||Supporting Organization||Industry||Stennis Space Center, Mississippi|