In the summer of 2014, a SpaceX Dragon capsule on a resupply mission bound for the International Space Station carried precious cargo. The innocuously named Veggie, no larger than a couple of sneaker boxes bound together, would let astronauts cultivate plants in space in the hopes of discerning which varieties of the countless millions found on Earth would work best in orbit and, eventually, beyond.
“Veggie will provide a new resource for U.S. astronauts and researchers as we begin to develop the capabilities of growing fresh produce and other large plants on the space station,” Gioia Massa, a NASA payload scientist for Veggie, said at the time.
Yet the idea was also to devise a way for future space travelers to satisfy their nutritional needs on long voyages like the eventual one to Mars, which takes about a year.
The limited space in the grow box inside the International Space Station meant testing any portion of Earth's fauna would take an immeasurable amount of time. Not long after Veggie was launched into orbit, NASA scientists received an offer from colleagues from Fairchild Tropical Botanic Garden to let some of the thousands of students in South Florida do the heavy lifting.
"We knew we were experts in plants, and we have this hugely engaged group of students who could do the replication base on NASA's criteria," Fairchild director Carl Lewis says.
Since then, the program, funded $300,000 annually by NASA through 2019, has grown to include 150 schools in Miami-Dade and Broward, as well as a handful in Palm Beach County, seven in Ohio, and two in Puerto Rico. The partnership adds about 5,000 additional research staff to NASA's ranks. Perks for the students include a chance to speak live with astronauts in orbit, which a handful of Miami-Dade high schoolers were able to do last month.
The criteria for what makes a good crop in space are as stringent as one might expect. The plants need to thrive in a growing space no larger than 11.5 inches wide by 14.5 inches deep. They must produce a generous yield high in nutrients, particularly vitamin K, which is destroyed by the freeze-drying process that preserves most astronauts' food. Finally, the plants must have a robust flavor, because zero gravity tends to dull the taste buds, possibly subjecting astronauts to a gulag-like dining experience while careening through the void.
"When you're in zero gravity, it's like having a cold," says Amy Padolf, Fairchild's education director. "So when we were starting out, we asked our horticulturists and botanists for the strongest-tasting plants they had."
To date, more than 7,000 species of plants in the garden's catalogue have been assessed for viability in the schools' replica Veggie systems. Of those, 106 have actually been tested. In that time, students and scientists discovered a few trends.
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"Some garden plants from the northern latitudes don't perform that well in constant temperatures, and some of the salad greens have been struggling," Padolf says.
Among the varieties that produce the most edible mass laden with the all-important vitamin K are Chinese cabbage, mizuna, and several types of bok choy.
The experiment has produced a couple of happy accidents that could also save, or vastly improve, space travelers' lives if a larger-scale version of Veggie is installed on future craft.
"The students have been stress-testing these plants, and what I mean is there aren't uniform conditions in the classrooms. Some kids are good about watering, some are not, sometimes the power goes out and there’s no school for a week," Lewis says. "In all the different conditions in the classrooms, we're finding that some plants perform more consistently, like bok choy."