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Filling an 18-foot long cylindrical chamber are hearty crops of tomatoes, strawberries and sweet potatoes. They grew to a profuse jungle of sustaining edibles in less than a month under quartz-encased lights, surrounded by darkness. They are green and tangible testament to how a lunar greenhouse could sustain long-term human presence on the moon.

Built in a laboratory surrounded by the dusty farmland of the University of Arizona’s agricultural center, the lunar greenhouse prototype is designed for three purposes – water recycling, air revitalization, and food production – that would enable the next great leap in space exploration, a scientific base on the moon.

A collaboration between scientists at the UA-College of Life Science’s Controlled Environment Agriculture Center [UA-CALS-CEAC] and Phil Sadler, a Tempe-based engineer and manufacturer who specializes in extreme environments, the lunar greenhouse is designed as an expandable hydroponic chamber, pre-loaded with seeds and nutrient solution, that could be deployed on the moon robotically.

Taking concepts honed at the team’s experimental greenhouse at the South Pole, the lunar greenhouse is designed to provide half of the food for a lunar crew and accomplish 100 percent of the necessary air, water and waste recycling.

“Food is a byproduct,” Sadler says. “We’re trying to revitalize air and recycle water.”

The researchers took “seven years of small steps to get to this point,” says the CEAC’s director Gene Giacomelli, with a shoestring budget of less than $50,000. Now the team is pushing for a NASA grant to continue the research. Without funding the project will be shut down.

“We’ve gotten this far on Phil’s back basically and the center here just to demonstrate a biological principle, but it’s a significant one,” Giacomelli says. “Nobody else is doing it and it needs to be done.”

Though it funded such research in the past, NASA is the only one of the world’s space agencies without an ongoing Bioregenerative Life Support System program. But without such a life support system, a new era of manned spaceflight to the moon isn’t possible.

The European Space Agency just embarked on a similar concept in Spain with its MELiSSA project, an acronym for Micro-Ecological Life Support System Alternative.

Giacomelli says NASA’s focus on developing the Ares rocket and Orion crew vehicle has been too narrow, at the expense of other crucial research.

“My complaint is this: NASA is dismantling and taking away all that has been built for the previous 30 years. All of those students, faculty and researchers are going to do other things. Then when NASA comes back and says ‘Let’s get started,’ there is going to be a slow learning curve, just like there was in the 1960s and 1970s,” Giacomelli says. “The interest is there, but the money to do the research just isn’t.”

The current success of robotic space exploration – like NASA’s twin Mars rovers and the UA-led Mars Phoenix mission – could be feeding reluctance on NASA’s part to work on manned spaceflight, Giacomelli says.

“We feel we have a dart on the wall,” Giacomelli says. “We have data that’s positive to show we should keep it going.”

Graduate student Lane Patterson has worked at the South Pole and handles much of the day-to-day work on the lunar greenhouse, monitoring the plants and the oxygen and carbon dioxide levels via a camera and myriad sensors.

“We can walk away from the chamber for days and days at a time. Tele-presence allows that,” he says.

The UA’s Peter Smith – who headed the water-finding Mars Phoenix Mission – sees the convergence of robotic missions and the promise of future manned space exploration in the greenhouse.

“The lunar greenhouse experiments at CEAC bring us closer to the day when space travelers can truly become part of a full service artificial ecosystem that purifies their water, oxygenates the air, and provides healthy fresh food,” Smith says.

Touring the greenhouse facility, Smith hits on the key question: “What makes it an extraterrestrial system rather than something you put in your yard?”

Sadler describes how the greenhouse is designed to compress to just 4 feet in length for launch, then inflate to its full length once it lands on the moon.

The team imagines a structure of four greenhouses branching out in separate directions around a central core that houses four 16-foot solar collectors that funnel the necessary light to the crops through a fiber optical system. “It’s impossible to design a lunar greenhouse unless you design the habitat it goes in,” Sadler says.

The greenhouses would be encased in multi-layered sheaths, similar to the materials used for astronauts’ space suits. Once the greenhouses are inflated on the moon, a lunar tractor launched on the same craft would bury the greenhouses, protecting the chambers from the micrometeorites constantly pummeling the moon.

“We bury it as fast as we can get it on the ground,” Sadler says. “Then within 10 minutes we can have lights on and nutrients flowing. We could have this thing deployed on the moon without people being there.”

Once astronauts land on the moon, their urine would be fed into a compost unit and the condensation collected for gray water that is mixed with nutrients and used to grow the plants. The plants then transpire the water into the greenhouse atmosphere, where it is condensed and collected to provide clean water for the crew. Patterson says the lunar greenhouse could generate 47 liters of water a day.

The mass of the hydroponic salts used to grow plants and subsequently revitalize the air will actually provide five times more oxygen by weight than launching oxygen tanks.

The greenhouse prototype features specially designed water-cooled lamps, similar to the ones the researchers have installed in the South Pole greenhouse. Each plant’s root system is fed by a separate nutritional solution, allowing several crops to be grown at once.

“Part of the challenge is keeping all three in the right environment so they can all be in production at the same time,” Giacomelli says.

The team credits their experience growing crops at the South Pole as necessary preparation for creating a lunar greenhouse.

“There are so many analogs there,” Sadler says, which allow for a “high degree of mission fidelity.”

Not only is it an isolated, extreme environment, but the temperature one meter below the surface is essentially the same temperature as one meter below the surface of the moon. Also, the South Pole snow and lunar soil are similar in weight and density.

“Most of our colleagues the past 30 years have been in little chambers or capsules. We’re trying to bring it to the scale it would look like in reality,” Giacomelli says.

The research team’s design for the overall structure is just a concept, one they know isn’t likely once NASA begins its own work on the project. But whatever structure a moon base ultimately takes, they are confident the specific design of the greenhouse can be incorporated.

“Regardless what form it takes, the certainty that we can nail down is the biological system,” Patterson says.

Published July 9, 2009 in Tech News Arizona.

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Eric Swedlund is a writer, photographer and editor living in Tucson, Arizona. His music writing has appeared regularly in the Tucson Weekly, Phoenix New Times, East Bay Express, The Rumpus and Souciant Magazine.

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