Astronaut Scott Kelly tweeted from the International Space State on Dec. 27, 2015, “Our plants aren’t looking too good.”
The station’s garden was struggling to recover from a mold problem. This issue is familiar to terrestrial gardens. On Earth, the issue simply requires a trip to the nursery for replacement plants, however, this is not an option in space.
The brightly colored zinnias were part of the Veggie experiment, which was designed to provide crews on the ISS with a long-term source of food.
In prior tests, astronauts were able to successfully harvest lettuce. The zinnias needed longer to grow – 60 to 80 days. Once they bloomed, they would produce neon-hued blossoms that looked like part of a psychedelic corsage. They were practice for a tastier alternative to lettuce: tomatoes. One of the things the station crews would have to learn how to deal with included mold among other things.
Veggie was designed to be an uncomplicated way for astronauts to grow plants. Gioia Massa, one of the project’s lead scientists, said “It’s a very simple system. It doesn’t control much at all, instead the humans do.”
Someday, space gardening will be essential if astronauts are to go beyond the moon. Space travelers cannot carry all the food they need, and the rations they bring lose nutrients. Therefore, astronauts need to replenish rations with extra vitamins. They will also need effective ways to generate more oxygen, recycle waste, and help them not be as homesick. Theoretically, space gardens can provide all of these things.
Veggie is helping researchers learn how the lack of gravity and radiation affects plants. How much water is necessary, and how to handle deplorables, such as mold. Additionally, scientists are learning how much work the astronauts have to put into the plants and how the plants nourish the brains and bodies of the astronauts.
Veggie is not a very large piece of equipment. It weighs 41 pounds, which is a little less than the 44-pound coffeemaker on the ISS. The top is an off-white box that houses the grow lights. It resembles a VCR. A curtain of clear plastic encases the 1.7 square-foot planting surface.
The lights are pre-set by the astronauts each day; how long they are on; how bright the light emitted; they emit a red light to optimize photosynthesis, a blue light to control the function and formation of the plants. Astronauts can also control humidity by activating a built-in fan.
The most important part of Veggie is the bounty it is meant to cultivate. The bounty begins as seeds that are encased in small Teflon-coated Kevlar pouches. Scientists call them “plant pillows.” Massa thinks of them as grow bags filled with seeds, water wicks, fertilizer, and soil.
History of Space Gardening
People have been anticipating vegetables growing in space for over a century. In the 1950s, NASA and the U.S. Air Force began growing algae to see if it would help with life support. However, the algae tasted bad, was full of indigestible cell walls, and contained too much protein.
Soviet scientists experimented with ecosystems that were almost self-sufficient. Humans survived on water, oxygen, and nutrition produced predominately within the enclosed habitat. The longest run was a 180-day trial inside the BIOS-3, an earthbound crew was able to receive 80 percent of their food from the habitat’s own wheat and vegetables.
In 1982, Soviet cosmonauts grew Arabidopsis thaliana. It is a flowering plant related to cabbage and mustard. However, the yield was too small to provide food.
In the mid-‘80s, Veggie’s creator was in middle school. Her seventh-grade teacher returned from an astro-agriculture workshop at the Kennedy Space Center with “reams of information on the topic.” Massa was inspired by the information and continued to take classes on the subject through high school. She later teamed up with her middle-school teacher for a hydroponic project.
While Massa was continuing her studies and self-guided experimentation, NASA was building an orbital plant-growing apparatus. It was called the Biomass Production System, created for space station experiments. It was a rectangle with sides the length of an arm. There were four cube-shaped growth chambers inside. It was designed by scientists at a Wisconsin-based company called Orbitec. The Biomass Production System was placed on the ISS in 2001. There, the Brassica rapa filed mustard sprouted tall and was illuminated by white fluorescent light.
Researchers compared the mustard harvest to a control plant on Earth and discovered the space mustard contained more fungus and bacteria. NASA’s conclusion was that the significance in the difference was uncertain. NASA was not sure why the microbes proliferated, not that their presence was not important. In fact, Veggie’s mold proved it was critically important.
In 2002, NASA retired the Biomass Production System. However, Russian cosmonauts picked up where the United States left off. In the last decade, cosmonauts successfully grew leafy mizuna, dwarf wheat, and dwarf peas. They have grown four successive generations of space dwarf peas without genetic messiness.
Orbitec, in consultation with NASA, created another instrument for growing plants. In 2012, NASA awarded a grant for a new space garden. Veggie, unlike its predecessor, was meant to produce edible food. By this time, Massa was a postdoc, who had tested a multitude of media and crops for the plant pillows. She had prepared for this type of “tinkering” since she was 12 years old. The first real space garden, created by the U.S., was launched in 2014. By this time, Massa had become a Veggie project scientist at NASA.
Until the flower flop, things with Veggie were going well. A variety of lettuce called Outredgeous sprouted as expected, in 2014, and was sent to Earth for testing. According to Massa, scientists are still working on the analyses. So far, the lettuce seems to be similar to the ground samples. When the analyses are finished, scientists will know about the chemical contents, such as antioxidants, phenolics, and anthocyanin. Phenolics protect plants and anthocyanin are the pigments in the plants. However, the short-term priority was if the lettuce was safe to eat. Yes, it was microbially safe to eat.
In 2015, astronauts planted a second set of seeds. Massa discovered a new challenge: NASA did not have a protocol to approve the crew eating the leaves of their labor. They only had 28 days and then the astronauts were going to eat the harvest. Management found a way to officially include the lettuce into the astronauts’ diet.
On Aug. 9, Kelly took a picture with the growing greens. “Tomorrow we’ll eat the anticipated veggie harvest on @space_station! But first, lettuce take a #selfie.”
It may not seem like a big deal, but that single leaf can make a big difference to astronauts who have been ingesting rehydrated food for months. During a later harvest, Peggy Whitson would use the leafy lettuce to wrap a reconstituted lobster salad.
Massa says, “Even with a really good diet with hundreds of items, there’s a dietary fatigue. People get bored. Adding a new flavor or texture – like something crisp and juicy – could spice up your regular meal.”
Every 90 minutes, astronauts can look out at Earth and see all of its most beautiful spots. However, all of those places are out of reach, and they are a reminder of how far away sea level actually is. Having something close that photosynthesizes can cheer up the crew. “It’s the psychological aspect of something green and growing when you’re far away from home.”
In the next growing cycle, the astronauts added the ill-fated zinnias. Two weeks into the grow cycle, Kjell Lindgren saw the warning signs from the plants. First, water leaked from the wicks that held the seeds. Then, moisture started to seep from the baby leaves, and they started to curl on themselves.
Veggie staff on the ground turned the airflow fan from low to high. However, an impromptu spacewalk to fix a broken arm delayed the change. The zinnia leaves started to die. Dying vegetation is a breeding ground for mold, which arrived in space with the astronauts and their cargo. Soon, white fuzzy mold started killing the plants.
By the time the mold had overtaken the zinnia’s, Lindgren had returned to Earth and Kelly was overseeing the garden. On Dec. 22, with instructions from ground control, Kelly cut away the moldy parts and swabbed the zinnias and equipment with disposable cleaning wipes. The fans were left on high to dehydrate the area. The dehydration came with a cost: it made the plants thirsty. Ground control told Kelly it was not time to water the zinnias yet. He needed to wait until Dec. 27. According to the write-up of the event by NASA, Kelly stated, “You know, I think if we’re going to Mars, and we were growing stuff, we would be responsible for deciding when the stuff needed water.”
Ground control did give autonomy to the person who was taking care of the actual plants, along with a page of instructions called, “The Zinnia Care Guide for the On-Orbit Gardner.”
Under the thumb on the On-Orbit Gardner, half of the zinnias were revived. NASA took the entire ordeal as a positive: They now knew that crops could survive drought, floods, and disease. They could excise the plants that were sick and clean the healthy plants to keep the fungus from taking over all the plants.
Kelly enjoyed the flourishing flowers and carried them in a container all over the space station for photo shoots. Kelly asked if he could harvest the zinnias on Valentine’s Day. He had been in space with his smelly crew mates for over 300 days, according to Massa. NASA approved the bouquet.
Massa said, it was one of her favorite moments “We had been a part of something that gave him pleasure.”
The Advanced Plant Habitat Space Garden
Space gardens will be essential someday if astronauts are to go beyond low-earth orbit or make more than a quick trip to the moon. They can’t carry all the food they need. https://t.co/MMyWCfBfsP https://t.co/kKKfMuDoPd
— Mark Kovarski (@mkovarski) June 23, 2018
In future Veggie experiments, scientists will learn more about the mental part of gardening. They have heard some things anecdotally, but they have not been able to collect data, according to Massa. She says they will also learn how much gardening the crew members would actually like to do: How much is fun, versus how much is a chore. They will learn how the sense of taste changes in orbit and which plants can survive human error.
The experiments with Veggie will continue in tandem with those of a new Type-A companion, the Advanced Plant Habitat (APH). It is an 18-inch-square self-sufficient laboratory that contains over 180 sensors and automated watering. Through the new piece of equipment, scientists can establish variables and know the specific conditions needed to cultivate plants – and how those plants cultivate humans. A temperature-control system will keep the air within 0.5°C of the setting on the thermostat.
Sensors relay data about air temperature, moisture, light, and oxygen levels back to ground control. The APH will determine the circumstances necessary for successful gardening on the ISS. Veggie will help quantify how – and why – astronauts can grow their own food supply easier. The habitat will determine which plants will grow the best. These parameters will be used to set up a system like Veggie for astronauts to interact with.
In October 2017, the habitat was assembled by astronauts in over six hours after it arrived in space in two shipments. The automated piece of equipment looks like a microwave. Wires stream from it on a control panel. There are red indicator lights that blink next to toggle switches. Inside the plant chamber, LEDs beam from the ceiling to illuminate the plants with a concert-stage color combinations. Its lights are green, red, blue lights, plus white near-, and far-infrared lights.
Director of environmental systems at Sierra Nevada Corporation, Robert Richter, monitored the progress of the Advanced Habitat from the earthbound Space Station Processing Facility. He helped to create and build Veggie, Biomass, and the new lab. Twenty years ago, when he started in the lab he admits he was naïve. “I thought, How hard is it to grow plants?”
Now, he knows that trying to maintain the humidity levels within three percent of a specific number, making and measuring light and moisture, and maintaining the temperature to a fraction of a degree, “there’s a long row to hoe between growing some basil in a cup and farming lettuce in space.”
The habitat was powered up on the ISS in November 2017. In February 2018, test crops of Arabidopsis thaliana and dwarf wheat sprouted. Soon, experiments, such as investigating the DNA of plants and the physiological changes will be underway. Up until now, the plant research focused on whether plants would grow, according to Sierra Nevada Corporation’s principal scientists, Robert Marrow. Scientists wanted to know if the plants would reproduce from generation to generation and are the plants as productive in space and they are on Earth. The answer to these questions is yes.
Future Space Garden Experiments
— Popular Science (@PopSci) June 6, 2018
Now, it is time to dig into the details and more-complicated ecosystems. For instance, astronauts exhale carbon dioxide that plants inhale. The plants exhale oxygen the astronauts inhale. Human waste can be used as plant hydration and fertilizer. Nothing is wasted in this relationship and everything is gained.
Marrow believes that a deep-space garden will look more like Veggie and less like the APH. “It’s really not practical to put all the stuff you have in APH in a system like that.” There are many tubes and sensors, too much can go wrong mechanically. Veggie is easier to repair.
Scientists are using APH to determine the optimal guidelines for plant growth and to understand how leaving Earth changes the plants, so scientists can instruct astronauts how to manage Veggie-like systems.
Massa is interested in studying the interactions between the instruments and the astronauts. “Do you always want to pick your ripe tomatoes, but maybe you don’t want to have to water them every other day?” Veggie will grow Red Robin dwarf tomatoes early in 2019. Massa will be able to get her answers.
Other Space Gardens
Other nations are continuing their experiments with space gardening too. China intends to send silkworms and potato seeds to the moon aboard the Chang’e-4 spacecraft. Once the silkworms hatch, they will create carbon dioxide, which the potato plants will take in and turn into oxygen, which the silkworms will take in.
This research does not just help the astronauts. Creating self-contained growth systems can help the farmers on Earth grow crops year-round or plants with more protein and a higher yield. Eventually, the experiments will lead to substantial and stable gardening systems that can support space travel. Then, those travelers will be able to wrap whatever the want in lettuce and enjoy the crunch through the cosmos.
By Jeanette Smith
Popular Science: NASA is learning the best way to grow food in space
Featured Image Courtesy of NASA’s Marshall Space Flight Center’s Flickr Page – Creative Commons License
Top Image Courtesy of NASA’s Marshall Space Flight Center’s Flickr Page – Creative Commons License
First Inline Image Courtesy of NASA’s Marshall Space Flight Center’s Flickr Page – Creative Commons License
Second Inline Image Courtesy of NASA Johnson’s Flickr Page – Creative Commons License