Duckweed, a rich, edible source of protein, may soon grow in space, providing essential nutrients to astronauts.
NASA certainly sees duckweed’s potential. It awarded Thomas Liu’s team 10K to design a machine capable of growing duckweed for consumption in microgravity. Liu, an EE freshman, led 13 engineering students through NPWEE’s remote workforce development program this fall, beating over two dozen other submissions. Liu’s team now has a year to put its pitch into practice.
When implemented, the duckweed would grow inside the confines of a small machine within the ship. To thrive, the duckweed would require water, a full spectrum of lights, including reddish, pinkish lights, as well additional nitrogen. “It would be growing inside the machine automatically, so it would harvest automatically as well,” Liu noted.
Of course, the proposal doesn’t come without its obstacles to overcome. “In microgravity, there are difficulties growing plants. They have some trouble absorbing nutrients in microgravity. So, we have to figure out a way to fix that as well,” Liu said. “One possible solution is to spin the machine like a centrifuge which can help the plants absorb nutrients as if they were experiencing gravity on Earth,” Liu explained.
“Our goal is to use it as a supplement in space for astronauts,” Liu said. “Right now, they’re getting a lot of protein from pills.”
When it comes to taste, “it depends on the species,” Liu said. “Some don’t taste like anything. Others taste like grass,” Liu said. Since it’s a small plant, astronauts could easily use it as a garnish. One of the astronauts interviewed by Liu “said he would really like this added to a smoothie”
Throughout the proposal process, Liu managed a mix of undergraduate, masters, and doctoral students from all over the country. Given his age, and the fact that he was not only the youngest person on the team, but the project’s principal investigator (PI), “I was worried,” Liu said. “But everyone was willing to do their parts. It was good working with adults,” Liu stressed. “They really get their stuff done.”
Winning the 10K speaks volumes. Though so does the overall NPWEE workforce development experience. For Liu, the program provided a substantial background in entrepreneurship and product design. “At Penn, I feel like everyone has an interest in business,” Liu said, “even the engineering students.”
The project also connects to Liu’s broader concerns with environmental sustainability. “If you could grow this food in space, you could also grow it on earth,” Liu said. Of course, duckweed does grow–in abundance– across earthly ponds. Rather, Liu’s comments refer to an easy to access “protein supplement that you could continuously grow by itself.”