NASA harnesses the power of light for purposes as varied as laser communications, 3D mapping of land surfaces, and spectroscopy to determine the composition of distant stars. The Space Agency has also devoted significant research and development to using the visible spectrum to drive biological processes, and a number of former contractors have made that knowledge available in the commercial marketplace.
The most important light-driven organic process on Earth is photosynthesis, by which plants convert sunlight into chemical energy, driving the entire food chain.
Light also plays a crucial role in biological cycles related to sleeping and waking. In 2001, an advisor to NASA demonstrated the existence of a third type of light receptor in the mammalian eye. In addition to the rods and cones that enable vision, George “Bud” Brainard, Thomas Jefferson University researcher and frequent NASA consultant, showed that another photoreceptor in the retina, now known as the intrinsically photosensitive retinal ganglion cell, is responsible for regulating both pupil constriction and circadian rhythms.
By then, NASA had been experimenting for about a decade with using LED technology to help plants grow. The Agency has also worked with LEDs to help regulate astronauts’ sleep cycles on the International Space Station (ISS), where 16 sunrises and sunsets every 24 hours tend to throw off their internal clocks.
Now, Biological Innovation and Optimization Systems (BIOS) Lighting, a young company in Melbourne, Florida, is leveraging the know-how of two former NASA contractors who helped the Agency pioneer both these LED applications, as the company brings two different product lines to market.
Neil Yorio started working with NASA as a graduate student in 1989, when the Agency’s Life Sciences Support Facility was housed in a converted hangar at Cape Canaveral Air Force Station, adjacent to Kennedy Space Center. There, Yorio and colleagues retrofitted an old pressure chamber from the Gemini missions to create the Biomass Production Chamber for the Controlled Ecological Life Support System (CELSS) project, planned as a test bed to demonstrate and measure the self-regenerating life support system for long-term space exploration missions and even extraterrestrial colonization.
Plants were central to the system. NASA was—and remains—interested in technology for growing plants on long-duration space exploration missions, not just as a food source but also to perform all the roles they carry out on Earth: eliminating carbon dioxide, providing oxygen, purifying water, and processing waste.
At the time, Yorio says, the researchers primarily used high-pressure sodium lamps to provide light, a technology that still dominates indoor agriculture today. After some initial testing at a NASA Research Partnership Center at the University of Wisconsin-Madison, though, the CELSS team started experimenting with LEDs for plant lighting.
It was still a new technology, expensive and not yet efficient. Nonetheless, Yorio says, “there was interest in using them because they’re small, solid-state, lightweight, they had the potential to be energy-efficient, and they had no hazardous materials.” He coauthored some of the first papers published on LED-based grow lights in 1997 and ’98.
When the Space Life Sciences Lab was built next to Kennedy in 2003, he and fellow researchers moved there as part of the Advanced Life Support Program, and he oversaw a number of projects that continued experimenting with LEDs.
The lab is where he met Robert Soler, who Bionetics Corporation hired in 2007 to help finish the first LED module to provide lighting for astronauts on the ISS.
“We’d started seeing some issues with the general luminaire system on the ISS,” says Howard “Bill” Wells, chief engineer at Bionetics. The fluorescent bulbs were frequently failing and had a relatively low light output. “Another problem was that fluorescent lights have mercury and glass, so you have two potential safety hazards you’ve got to deal with.”
One LED replacement went up in 2008 as a demonstration and still helps light the space station’s U.S. National Laboratory.
Not long after, NASA requested an update to replace all the lighting in the U.S. portion of the space station with LED fixtures, this time incorporating the ability to alter their spectra to help manage astronauts’ sleep cycles.
Soler helped write the proposal that won Bionetics the contract to design and build the new LED-based lighting modules for the ISS. By then, both he and Yorio were working for the company Lighting Science, and Soler helped Bionetics build the modules as a part-time consultant.
The resulting lights have three modes of operation: general task lighting, a pre-sleep mode, and a wake-up mode. The wake-up mode imitates broad daylight, suppressing melatonin in the brain to increase alertness. “Melatonin is basically the night-night drug your body uses to sleep,” Wells says. Pre-sleep mode, on the other hand, eliminates blue-green wavelengths to allow melatonin release.
The lighting in all three modes also needed to be energy- efficient, render true colors—meaning it wouldn’t cast its own hue—and be pleasing to the eye, avoiding any harshness. “To bring all those things together, that’s kind of what my area of expertise is,” Soler says.
The work eventually led Lighting Science to release a commercial line of LED bulbs with similar capabilities (Spinoff 2015).
All the while, LEDs have been catching on for more and more applications. “We’ve had the benefit of capitalizing on technological development on the part of a lot of companies, to the point that the consumer market was driving that technology,” Yorio says. This has meant ever-increasing efficiency at lower and lower costs.
LEDs have finally advanced to the point that they can match or surpass the performance of, for example, high-pressure sodium lamps in agricultural applications. “Now we find ourselves with the opportunity to replace high-energy-consuming, hazardous-waste-containing products with more efficient and sustainable alternatives.”
Yorio, Soler, and a handful of others left Lighting Science in 2014 to create BIOS, where they’ve continued to develop LED technology and adapt it to human and agricultural biology.
Photosynthesis requires light in roughly the same wavelengths that enable vision—about 400 to 700 nanometers. But most lamps for indoor agriculture emit radiation well beyond this spectrum, especially in the form of heat. LEDs, on the other hand, produce light only within a narrow spectrum determined by the material they’re made of. Most of the energy put into an LED, therefore, can be used to produce what’s known as photosynthetically active radiation (PAR)—the light that plants use.