Monday July 2, 2012 0 comments
Future astronauts will reap benefits of what robots sow
By Betsy Lynch
BOULDER -- The maxim, "Eat Fresh, Eat Local," is taking on an interplanetary dimension as University of Colorado-Boulder students and faculty work with NASA scientists to develop gardens designed to flourish in deep space.
Being able to grow food remotely is considered essential to supporting extended manned space missions.
Depending on the constellation of the planets, a round trip to Mars will take 400-450 days, according to CU-Boulder Professor Nikolaus Correll. Add time to the itinerary for scientific exploration, and that's a lot of days between bites if what you're really craving is fresh greens.
Thanks to a $40,000 grant from NASA and the National Space Grant Foundation, a graduate-level, interdisciplinary project will focus on developing a robot-tended garden. The goal is to design a bioregenerative system that can produce a variety of edibles while revitalizing the atmosphere, purifying water and recycling plant residues. The plan is to deliver an operating system to NASA by next summer.
Professors Joe Tanner, Nikolaus Correll and Dave Klaus will be leading the program. Tanner is an aerospace engineer and former Space Shuttle astronaut. Correll is a computer science professor who spent two years working on robotic gardening systems at MIT. Klaus is also an aerospace engineer and associate director of BioServe Space Technologies, with expertise in space habitat design and space life sciences.
Aerospace engineering graduate student Christine Fanchiang is managing early project development along with fellow grad students Daniel Zukowski and Heather Hava. Colorado State University Soil and Crop instructor Adriane Elliott will also collaborate.
The team already has something of a head-start. Over the last two years, Zukowski, a computer scientist with a love of plants in CU's Computer Science Department -- along with other imaginative thinkers -- have been tinkering at Solid State Depot (Boulder's hackerspace) to put together a prototype growing environment for space gardening.
Zukowski dubs the bookshelf-like 'hybrid aeroponic' system "autoponics," because -- with the help of automation -- it is designed to be self-tending.
"It is unclear whether the final system will be hydro- or aeroponic," said Prof. Correll. "Concerns with aeroponics are that a) the total mass of water needs to be roughly the same in both systems; and b) pumps/nozzles required for aeroponics might be additional points of failures."
Space gardening has unique set of challenges
Mechanization, of course, is not new to the greenhouse industry. Many earthbound growers use automated systems for planting, watering, lighting, fertilization and inventory management. But growing plants in outer space presents its own set of challenges, including maximizing production in a very small footprint.
Gardening in space will also require a delicate touch. Robots will perform functions such as seeding, monitoring, pollinating, pruning, harvesting and composting. The system must be versatile enough to handle all these tasks, and in the event some part fails, it needs to have the capability to remotely make repairs.
That's a lot to engineer into a vertical garden roughly the size of a large refrigerator.
"One of the challenges of remote operation is giving the robot's operator the right kind of visual and tactile feedback, so that manipulating the remote environment feels as natural as possible," explained Zukowski. "Much research has been done in this area as related to remotely operated surgical devices.
"Another big challenge is dealing with the time it takes for signals to travel back and forth between a remote location like Mars," he noted. "Depending on the orbital position of Earth and Mars, the round-trip for electromagnetic signals is somewhere between 9 and 42 minutes. At that point, it becomes impractical for a human operator to be guiding the robot's every move, making autonomous operation of the system extremely important."
And let's not forget the botanical complexities. Researchers know that plants respond to gravity during the germination cycle, signaling where roots should grow. Additionally, gravity may play a role in strengthening plant stems and stalks. Plants grown in microgravity may be more fragile and easy to break, Fanchiang noted.
From the engineering side, microgravity -- or even reduced gravity -- presents challenges regarding delivery of nutrients and their containment so as not to have them float around the living quarters, she said.
"Containing and delivering liquids is a challenge," agrees Carroll.
Other engineering challenges include finding lightweight, highly-efficient ways to heat, light and power the entire system.
Growing food only makes sense for missions exceeding 2.2 years in time," said Correll. "Otherwise, weight required for the growing experiment is better used for food storage itself.
Gardening requires many steps. But how much of the process should be the purview of robots? Tending plants provides psychological benefits for people, as avid gardeners can attest. Space travelers may adapt better to their interplanetary journeys if given a chance to sow, nurture and harvest some of their own crops.
"Psychology is a major driver of how well people can survive in isolated, confined environments," said Fanchiang. "Picking the tasks to automate, and determining if there is a way to mix automation with some manual tasks -- like picking the fruit -- are part of the project," she said.
Biology, psychology and botany will all play roles in what plants are grown in space. How do the aromatics and visual appeal of the plant benefit the physical and psychological health of the habitat's occupants? How difficult is the plant to maintain and harvest robotically? What are the nutrient profiles, pH levels, lighting and temperature needs, germination and maturity rates, nutrient uptake, transpiration, oxygen production, CO2 consumption?
And so on...
There's a slew of choices when it comes to crop selection for a bio-regenerative food system," Fanchiang said. Yes, nutrition is a factor, but so is preventing "menu fatigue."
Though leafy greens are much easier to grow and tend robotically than fruit-bearing plants, there are a lot of psychological benefits to watching an tending to a brightly-colored strawberry growing than a piece of kale. There is also research that points to familiar foods in space to reduce homesickness, even if they don't provide as much nutrition as, say, spirulina," Fanchiang noted.
The CU-Boulder team will design, manufacture, assemble and test its systems and concepts in cooperation with the NASA Advanced Exploration Systems (AES) Program's Habitation Systems Project team. CU-Boulder is one of five schools in the nation to receive an award as part of the Exploration Habitat (X-Hab) Academic Innovation Challenge.
"NASA benefits from the fresh and innovative perspective of these university teams," said Jason Crusan, NASA's AES program manager, "while they learn about deep space human exploration and the systems engineering approach from an experienced NASA team."
The cross-disciplinary nature of the project is what makes it fascinating and fun, say those involved. Biology, botany, engineering, robotics, computer science, psychology -- all are considerations in the continuing effort to send humans into space with a fresh taste of home.