| Aerospace | Lighting

LED Lighting Enables Better Sleep and Wake Cycles

LED technology helps astronauts sleep and keeps gardens growing.

Because NASA is planning for future visits to distant locations like Mars, the agency is researching how to grow plants in space. Live plants on space missions provide a nutritious food source and contribute to cleaning air in a spacecraft. When looking at how to best grow plants on space missions, NASA looked at high-intensity halogen lights, special UV bulbs, and light-emitting diodes (LEDs). By incorporating different LEDs on a single circuit board, the light can be changed and controlled to include or omit specific wavelengths of light, and at different times.

The newest plant-growing experiment on the International Space Station, called Veggie, went live in May of 2014. Veggie uses LED lighting to stimulate plant growth, and provides fresh lettuce and produce to astronauts.
NASA is interested in using LEDs not only for plants, but for general lighting needs in spacecraft. LEDs require little power, last a long time, can function in extreme temperatures, are lightweight and shatterproof, don’t give off heat at the light source, and are able to produce specific colors of light.

The NASA-funded National Space Biomedical Research Program (NSBRI) studied how light affects the human body. Kennedy Space Center built a prototype LED light for the research and found that different colors of light help people stay awake and go to sleep. Blue light at a particular spectrum could reduce melatonin production, which helps maintain the body’s natural body clock. More melatonin helps people sleep; less disturbs the circadian rhythm. For NASA, this meant lighting could possibly assist in helping astronauts avoid sleep deprivation. Because astronauts see more than a dozen sunrises and sunsets every 24 hours, their circadian rhythms are disturbed.

In addition to building the LED lighting used in the NSBRI research, the Kennedy team also started developing the first prototype LED system for the ISS. They worked with a NASA contractor, Bionetics, and by 2008, the system was installed in the station, where it continues to function successfully.

After installation, Bionetics started working with Lighting Science of Satellite Beach, FL, to help bring the developments of LED lighting for space back down to Earth. Several other scientists and engineers involved with the LED work at Kennedy also brought their expertise to the Florida company; their aim was to develop and commercialize new LED products to benefit people, plants, animals, and the environment.

By late 2013, Lighting Science launched a new line of lighting called DefinityDigital. The family of products includes four LED lights: Awake & Alert, Goodnight, MyNature Grow, and MyNature Coastal. Awake & Alert is programmed to produce wavelengths of blue light to suppress the production of melatonin. According to the company, the Awake & Alert light promotes natural energy, alertness, focus, and overall performance. Some of the places where it could have the biggest benefits include gyms, schools, libraries, hospitals, in common spaces in senior centers, and in homes and offices. Recommended for everyday use, it can also be particularly beneficial during times of the year when people experience seasonal affective disorder, as well as for people who experience delayed sleep phase disorder. The 9-Watt bulb is meant to replace a 65-Watt bulb, and it uses a patented spectrum filter with blue-enriched white light.

In contrast, the Goodnight LED bulb emits significantly less blue light than regular light bulbs, with the intention of supporting natural melatonin production. The Goodnight light does not affect sleep as much as regular lights. The 12-Watt LED Goodnight light is meant to replace 60-Watt bulbs in private homes, university dorms, senior living centers, healthcare settings, spas, and throughout the hospitality industry.

The third DefinityDigital product — MyNature Grow — was designed to deliver more blue and red light per Watt than typical gardening lights. This LED can be used with any plant species, and because it does not radiate heat, the plant can be situated closer to the lighting source. These LEDs last an average of 50,000 hours, resulting in energy and maintenance cost savings. Applications include urban farming, propagation research, indoor hobby gardening, agrotech research, hydroculture farming, and floriculture.

A similar DefinityDigital product, MyNature Coastal, was designed to deliver lighting that does not attract sea turtles. When sea turtle eggs hatch on the shore, the hatchlings are attracted inland by regular white lights, and instead of going to the ocean, they move toward the buildings and roads. MyNature Coastal LED is in the amber spectrum and does not attract turtles. During hatching season, regular light bulbs can be replaced with the MyNature Coastal light at resorts, residences, municipalities, parks, restaurants, and marinas.

Visit http://spinoff.nasa.gov/Spinoff2015/cg_6.html.