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Want Fresh Food in Space? NASA Turns to LEDs

Plants in space may seem a bit far-fetched, but NASA considers this a serious subject, as do astronauts. While the famous dehydrated astronaut “food-in-a-tube” will be with us for some time, it’s not the same food astronauts had in the 60s when they journeyed to the Moon, but a much-improved version that emphasizes nutrition (Figure 1). I hope it tastes good too because it may well be the main source of nourishment in space, maybe even for the journey to Mars, which is expected to be in the 2030’s. By that time, however, there will be lots of improvements and possible alternatives.

Figure 1: Traditional dehydrated astronaut “food-in-a-tube” has improved since the 60s, but research into the use of LEDs to grow fresh vegetables in space holds promise. (Image source: NASA)

To get a glimpse of the future of space food, I visited the “VEGGIE” lab at NASA’s Kennedy Space Center in Florida to see the latest developments in Cosmic Cuisine. There I was greeted by Dr. Gioia Massa, a life science project scientist for NASA’s VEGGIE program, a vegetable growing project on the International Space Station (ISS) (Figure 2).

Figure 2: NASA has a “VEGGIE” program at Kennedy Space Center (KSC) led by Dr. Gioia Massa (right). This program is an ongoing vegetable growing program on the (ISS). (Image source: Loretta Taranovich)

Why and how to grow vegetables in space

As I mentioned, astronauts will still eat their meals from a tube. However, they may soon also have something fresh and familiar like a freshly grown piece of lettuce. This is important: astronauts have commented to me that this small luxury of something fresh brings a look, feel, and fragrance of a familiar meal that greatly enhances their eating experience.

To grow fresh vegetables in space, NASA has turned to the humble LED (Figure 3). LEDs are useful in this context because they can provide concentrated energy at the various wavelengths of the spectrum that are conducive to plant growth. LEDs also produce very little heat, allowing them to be located close to the vegetable plants in a small space.

Figure 3: NASA research has determined that LED lighting is an optimum light source for vigorous plant growth in space. (Image source: Loretta Taranovich)

While artificial lighting has been used for plant growth on Earth for some time, plant growth in space is far more challenging. In space, artificial lighting and fans must be rigged “just right” to replicate the sun and wind. Also, reliability and durability are crucial for space travel, making LEDs ideal for long space missions, like going to Mars.

The role of different LED wavelengths

LEDs of specific wavelengths offer their own benefits:

Red (630 to 660 nanometers (nm)): Essential for the growth of stems, as well as the expansion of leaves. This wavelength also regulates flowering, dormancy periods, and seed germination.

Blue (400 to 520 nm): This needs to be carefully mixed with light in other spectra since overexposure to light in this wavelength may stunt the growth of certain plant species. Light in the blue range also affects the chlorophyll content present in the plant, as well as leaf thickness.

Green (500 to 600 nm): This was once thought not to be necessary for plants, but recent studies show this wavelength penetrates through thick top canopies to support the leaves beneath.

Far-Red (720 to 740 nm): This also passes through dense upper canopies to support the growth of plants lower down. In addition, exposure to IR light reduces the time a plant needs to flower. Another benefit of far-red light is that plants exposed to this wavelength tend to produce larger leaves than those not exposed to light in this spectrum.

NASA scientists have also found that including white LED light within LED arrays serves to ensure plants cultivated indoors receive all the photosynthetically active radiation they need to optimize their health, growth, and yield in space.

OSRAM is already working closely with NASA on the concept of growing plants in space. Its Phytofy LED lighting system is a unique, tunable LED horticultural lighting system that ranges from UV to far-red with real-time control and scheduling features for each individual channel (Figure 4). This calibrated system is designed for delivering light treatments with varying spectra, wavelength, and intensity for horticulture research. Phytofy is the perfect choice for the research and development of plant-specific light recipes. Light control is available through a graphical user interface. The system helps NASA fine-tune its LED characteristics for space with the optimum color, duration, and intensity of LED lighting for maximum plant growth and health.

Figure 4: OSRAM is working with NASA on its Phytofy system to determine the optimum LED color, duration, and intensity for plant growth. (Image source: NASA)

Although much of NASA’s research is being done here on Earth, LEDs have been sent to the ISS for final testing. Commercial grade LEDs can ultimately be qualified for use in space by a wide variety of companies.

Space watering

Of course, plants need water. For this, each plant seed sits in an individual “root mat” or “pillow” and water is applied individually (Figure 5). Inside each pillow is arcillite, a solid growth substrate that has been shown to be best for growing plants in space. There is a foam pad used to help retain the arcillite rooting medium that also helps to keep the roots from inadvertently growing into the LED lights.

Figure 5: Dr. Massa setting up the water feed system for the plants. (Image source: Loretta Taranovich)

Water and growth height are monitored all through the growth cycle, after which the vegetables are harvested and another growth cycle is started.

Conclusion

Space is a tough environment at the best of times, so anything NASA can do to make it more comfortable would clearly be appreciated by the next generation of astronauts as they venture ever further from Earth. Working with companies like OSRAM, it seems likely NASA’s plant scientists will be able to grow plants in space. It seems like a small matter in the overall scheme things, but this will provide much-needed nourishment, flavor, and a sense of home to the brave explorers of this final frontier.

Personally, I can’t wait to see the next steps in food for space. Maybe pizza?

About this author

Image of Steve Taranovich

Steve Taranovich is a freelance technical writer with 47 years of experience in the electronics industry. He received an MSEE from Polytechnic University, Brooklyn, New York, and his BEEE from New York University, Bronx, New York. He was also chairman of the Educational Activities Committee for IEEE Long Island. Presently an Eta Kappa Nu Member and an IEEE Life Senior Member. His expertise is in analog, RF and power management with a diverse embedded processing education as it relates to analog design from his years at Burr-Brown and Texas Instruments.

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