Living in space long term will require a sustainable environment. Plants provide fresh food, clean air, and clean water that will assist this effort, but plants need light to grow, and light requires energy. Here on Earth, most plants get this light from the obvious abundant source, the Sun. The Sun’s solar radiation is ideal for growing plants here on Earth, but it presents some problems for plant growth in space. For starters, the lengths of the days are different depending upon the location of the garden. For growing plants on spacecraft, this problem is compounded, as the vehicle position is constantly changing and is usually not positioned for optimal plant growth. Thus, NASA has been developing methods for growing crops in space using artificial light sources.
Lighting plants with electric lamps overcomes several difficulties, but presents an additional problem: It can require a great deal of valuable energy and produce unwanted heating of the plants. The solution appears to be LED lighting, which allows for precision and control, uses less power than traditional lamps, and radiates minimal heat onto the plants. In addition, LED lighting typically lasts much longer than traditional bulbs, is smaller and lighter weight, and does not present the same potential risks of glass breakage as traditional bulbs.
To help develop technologies for growing edible biomass (food crops) in space, NASA partnered with a small business in Wisconsin. Orbital Technologies Corporation (ORBITEC), located in Madison, is one of the state’s leading developers of new and cutting-edge aerospace technologies. The company has been awarded over $125 million in government contract funds over the course of more than 180 contracts, most of which were through commercial contracts that began in the Small Business Innovation Research (SBIR) program. Over the course of its extensive government work, ORBITEC was awarded Wisconsin’s “Professional Service Business of the Year” in 1995 and received the “Tibbets Award” both in 1996 and 1999 from the Small Business Administration. The “Tibbets Award” acknowledges small businesses that have performed exceptionally well within the SBIR program. One of the highlights of ORBITEC’s space-related work includes the 2002 launch of its Biomass Production System aboard STS-110 for a 73-day stay aboard the International Space Station.
One of the recent projects ORBITEC has been working on with Kennedy Space Center is the development of the High Efficiency Lighting with Integrated Adaptive Control (HELIAC) system, which uses targeted solid-state LEDs to efficiently grow plants. One configuration of the HELIAC system consists of a series of LED light panels called light engines. About 4 cm square and arranged in rows called “lightsicles,” these light engines are precision-controlled and allow for maximum efficiency in plant growth. Research for space applications is continuing through a partnership between ORBITEC and Purdue University.
While NASA is keen on this promising technology for future experiments in space, hardware and software protocols developed through the HELIAC program have the potential to save energy in commercial agriculture and in aquarium lighting while providing a host of additional benefits.