Space Groceries

 Humans can only explore as far as the food holds out – then things get ugly.  NASA recently confirmed that plants (food) can indeed be grown in lunar regolith.

https://www.nasa.gov/feature/biological-physical/scientists-grow-plants-in-soil-from-the-moon

They grow, but not necessarily thrive. They need nutrients for that because the radiated regolith is pretty much bare. Nutrients can be brought from Earth and organic matter can be added to regolith (for instance, from packing material on the cargo shipments brought from Earth, or the processed waste from humans). 

A pressurized lunar lava tube could be the first space grocery store. Here is an excerpt from my book Tube Town- Frontier where Tubers first encounter the Farm.

The three roommates bolted out the front door and raced toward the airlock to the Farm. The last of their group was already going in. When the airlock opened, they felt a rush of thick, warm air and saw and smelled “green.”  As far as the eye could see, there were hydroponic planting columns arranged in rows down the length of the Tube. Bailey saw something black and white streaking down one of the rows. At an intersection, it nearly collided with another streak that was brown and white.

“Doggies!” she called. “Come here doggies!”

Patches and Rennie bolted to her side and nearly knocked her down as they had trouble stopping in time. She gave them a big petting and they licked her face. The dogs were quickly adjusting to running in the reduced gravity. These border collies were fast runners on Earth. On the Moon – they were jets. 

Next to the airlock were two giant white silos about 6 meters (20 ft) in diameter and 12 meters (40 ft) high.  A short, strangely dressed older man was standing on an overturned box between the two containers. He wore old-fashioned eyeglasses, a Panama hat, and an “enhanced” thinsuit with a t-shirt, shorts, sandals, and a vest with innumerable pockets. He spoke with a distinct Texas accent.

“Welcome omnivores! My name is Harvey Pollan and I am a foodist. Y’all are willing participants in an experiment to see if we can extend the food chain beyond our little planet. All living things that we know must eat, in one way or another. The Earth is an eating planet so why should we presume the universe to be any different? Of course, the nice folks on the blue planet send us frozen and preserved food and we have a large supply of algae food base from which we can manufacture faux food. But what if those shipments should slow or stop, due to natural disasters or war number 15,501? It would behoove us to learn to make our food. Billy has asked me to give y’all a thorough tour of the Farm, so please follow me to the back of the section where our link in the food chain begins.”

Harvey hopped off the box and began loping towards the back of the section. The group followed. There were rows and rows of tables with lights above them. At the beginning of the section, the tables were all empty but as they got closer to the back, they saw rows of tables with trays of growing medium and then tables with growing medium and seedlings.  At the end of the section was a staging area of labeled containers of seeds and thousands of seedlings – fruits vegetables and grains, many still in protective packaging, lining the floor of the Tube. There were also sounds coming from the back – humming, crunching, scraping, and gurgling sounds.

“Light, air, and water, that’s what we need for starters,” said Harvey. “NASA has been experimenting with plant growth in microgravity for over forty years. However, with only limited space at the International Space Station, they couldn’t do much more than grow lettuce in a little box. We, however, have an enormous expanse of room for production and further development of what I call “Low/Highs”. These are crops that can thrive in low gravity, light, water, and temperature, yet yield high nutritional value. These are the best of the Low/Highs,” he said, with a sweeping gesture of his arm.

At the back of the Farm, on the west side near the airlock, were a series of large stainless-steel bins. Inside the bins were large chunks of gray frozen regolith sitting on top of a grate.

“The bots have been harvesting water ice for two years now, so we have a good supply. They come in several times a day and load frozen water in these bins. We can only melt so much of it in a day, so we have stockpiles of ice in the North End. Let me drop the floor down so you can see the subfloor set up.”

Harvey motioned everyone to get inside the yellow square painted on the floor and he hit the red button. The familiar claxon went off and the yellow lights spun. The floor dropped about ten feet where Harvey stopped it and the claxon.

“This is one of ten ASRTGs that we have operational under the subfloor. For you non-mechanical engineers, that is a Large-scale Advanced Stirling Radioisotope Generator which is nerd-speak for a radioactive generator,” he said, pointing to a white metal box the size of a refrigerator.

Metal fins stuck out from the box and radiated heat to the bottom of the stainless-steel bin. They could hear water dripping into the bottom of the bin.

“The water flows south through pipes where it is filtered, purified, and iodized and goes into the potable water line to the two 5,000-gallon (18,927 liters) collection tanks at the beginning of the Farm. These tanks plus the three-degree slope to the south provide all the water pressure we need all the way to the Factory. There are two water lines in this facility folks. The white line is the potable water for drinking, cooking, showering, and laundry. The blue line is gray water. Gray water from showers and laundry is used to flush the toilets. All organic waste and water, gray water, blood, poop, pee, kitchen waste, etc. anywhere in the Tube gets pumped to Organic Recycling over there on the east side of the Farm.

Our mission requirements are a minimum of three gallons of potable water per person per day. With a population of approximately 100 people that is 300 gallons per day and a little over 100,000 gallons per year. But that doesn’t include water for growing our food, and water for Factory production needs. We process regolith at either end of the Tube to produce water for propellant. We are lucky to have found a large quantity of frozen water near the North pole because we don’t have to spend much energy to process it. There are decades of supply, but by recycling all our water, all the time, we are extending this finite resource and reducing our harvesting energy expense.

Besides melting ice, the ASRTGs are, of course, producing electricity that is fed through the spine into our electrical grid. Fans blow the residual heat through tubing which is routed into the hollow legs of every growing column in the Farm. As you may know, heat rises, so a series of fans circulate the warmest air which collects at the ceiling back down the walls through mylar ducts to the subfloor below. Let’s go see Organic Recycling.”

Harvey raised the elevator and the group loped over to the east side of the Tube. There was a bit of a barnyard odor. A large cylindrical green metal vessel sat on the floor. A large diameter pipe rose from the subfloor and entered one end, at the other end was a large valve and a slough that was full of plants.

“The International Space Station tried to create a sterile environment aboard that tiny habitat. But you can’t get around the fact that each human is host to an entire ecosystem of bacteria and microbes. Here at Moon Base Three, we embrace our tiny ecosystems and even feel that a good inventory of beneficial microbes can be an asset to us in space.  This baby is chock full of our hungriest beneficial microbes brought up from Mother Earth. They go to work on this tankful of organic waste for two weeks. We vent the methane gas out the top of the tank and collect and store it with the other volatile gasses. After week two, Com2 opens a valve and the compost slurry flows slowly into our natural purification bed. I’d like to have limestone, but regolith is a pretty good substitute. The regolith starts out very coarse and gets finer as we go downstream. As the water filters through the regolith, it is also filtered through a nice crop of what the people of Southeast Asia call Khai-Nam and the western world calls duckweed. The duckweed root system contains beneficial microbes that like to snack on any volatile organic compounds that may have survived the other predators in the big green tank. In addition, this duckweed is edible and contains a large amount of high-quality protein with an even better composition of essential amino acids than other plant-based proteins. Our talented cooks spice this up and use it in our ‘meat’ dishes.  

“I also have some fabulous little friends here growing on the perimeter. Behold – the fungus among us!”

 All along the edges of the fine gray regolith were scores of mushrooms of all shapes and colors. Some of them were unnaturally tall extending over twelve inches high on incredibly skinny stalks.

“Neither plant nor animal, this creature’s forte is breaking down complex organic molecules. All varieties here are also very good to eat. It is fitting that mushrooms are growing on the moon. Ancient folklore says that mushrooms derive their energy from the Moon, not the Sun, if so, they should do really well here.

“At the end of the purification zone, the water is tested. When it tests good, Com2 pumps it to the growing columns where we use it for plant irrigation and the compost goes into the growing medium for the tables. Most of the growing medium comes from grinding up the organic packaging from our supply shipments – plant fiber like corn and wheat stalks glued together by mycelium from fungi and pressed into molds. The Mission Control logistics folks assure me that organic packaging is used whenever possible in our supply shipments. We are using organic medium and our organic fertilizer for the table crops, but the column crops are all aeroponically grown – no soil. Aboard spaceships, the food will need to be grown aeroponically. On the Martian surface, however, an advanced organic method may be better. NASA has never had the chance to test large-scale crop production in low gravity, so we are it!” 

“This is fabulous Harvey, what about non-organic recycling?” asked Bailey.

“Good question – even better segue,” replied Harvey.

He moved onto the yellow square on the east side. This time he took the group all the way down to the bottom of the tube.

“Here is our non-organic recycling. We have a shredder and sorter. Glass here, urethanes and plastics here, and metals here,” he said pointing to large bins. “And this,” he said with a sweeping gesture of his arm, “is our raw material.”

As far as the eye could see were semi-sorted stacks of used materials of all sizes shapes and colors – wrapping material, containers, shipping boxes, etc. Nearly everything in the Tube was shipped in payloads from Earth. These payloads were carefully packed to get maximum volume with minimum cargo shifting and damage.

“The Mission Control logistics folks assure me that organic packaging is used whenever possible in our supply shipments,” repeated Harvey with a sarcastic look on his face.  “Our supply exceeds demand,” said Harvey in the understatement of the day. 

Harvey brought the group back to floor level. “Okay, I’ve got five minutes for questions before the next group. What you got?”

“Harvey, do the mature plants need to stay on the Farm, or can some go to the other sections?” asked Sung.

“They can and should,” replied Harvey. “They can go as far south as the Commons. We are, of course, working on developing plant varieties that can withstand colder temperatures and low light, but only controlled experiments can go in the Factory. My team will identify and mark a group of plants that are available for re-location to other sections. Most of the food crops should stay in the Farm but some can go near the kitchen in the Commons and the oxygenators can go wherever.”

“Harvey, how will you grow fruits and vegetables without pollinators?” asked Michael Berlinovic.

“You mean we, right?” replied Harvey. “The question is how will we grow fruits and vegetables without pollinators. Since we don’t have bees – yet, we will have to rely on manual and airborne pollination. Billy will talk about this ‘we’ concept at dinner tonight. Alright, get out of our Farm. I got the next group coming through the airlock.”