In an effort to solve the problem of what to feed astronauts with on long-term, deep space missions, a team of plant biologists working on NASA's Advanced Exploration Systems (AES) Habitation Projects at the Space Life Sciences Laboratory at the Kennedy Space Centre are looking at ways to successfully grow plant life in space. According to Gioia Massa, NASA Postdoctoral Fellow and one of the scientists working on the AES Habitation-related Project, she and her team are looking at the behaviour of a certain type/s of red leaf lettuce and radish plants to varying sources of light, from fluorescent lighting, classic incandescent lights, and red and blue light-emitting diode (LED) lighting. Massa notes that their experiments have shown that LED lights stand out for being incredibly energy-efficient and flexible for different applications. She added that LEDs are highly suitable for space missions without a constant flow of supplies due to their solid-state durability and long lifespan (some consumer-grade LED lights are rated at 50,000 hours).
LEDs as Grow Lights Dr. Ray Wheeler, who heads life support activities under NASA’s Engineering Directorate, notes that the use of light-emitting diodes as grow lights isn’t a new idea—in fact, it was considered as early as the late 80s to early 90s. At the time, NASA funded experiments by the University of Wisconsin and at Kennedy using red-light LEDs and wheat. Test results, however, failed to meet expectations, with the wheat plants coming out bleached and leggy, forcing scientists to look at the next best alternative—fluorescents. Needless to say, LEDs have improved greatly during the past few years alone, now capable of generating a blue light that’s optimal for plant growth and being incredibly efficient.
Results Experiments by Dr. Matthew Mickens, a NASA Predoctoral Fellow, show that plants illuminated by LEDs had better shoot length and diameter, and had a better total fresh weight at the time of harvest when compared to plants lit by fluorescent lamps. Moreover, plants lit under LEDs showed higher levels of anthocyanin, a powerful antioxidant. NASA’s experiments on LEDs for grow lighting are still ongoing, but based on these early results, LEDs are poised to play a crucial role in deep space exploration.