When people live in space for long periods of time, they need to be as self-sufficient as possible. The same applies to settlements on the moon, on Mars and other bodies in the solar system. In order not to be completely dependent on Earth replenishment missions (which is expensive and time consuming), residents must harvest resources locally – also known as. In-Situ Resource Use (ISRU).
This means they have to source their own water sources and building materials, and grow their own food. While the ISS has allowed all kinds of hydroponic experiments in space, little has been done to determine how the ground behaves in zero gravity (or lower gravity). To remedy this, Morgan Irons – Chief Science Officer of Virginia-based startup Deep Space Ecology (DSE) – recently sent their "Soil Health in Space" experiment to the ISS.
The experiment, Determining the Effects of Gravity on Soil Stability for Controlled Environmental Agriculture, was sponsored by Morgan's fellowship with the Norfolk Institute, which provided grants from numerous companies (including DSE). An agreement between the Norfolk Institute and Rhodium Scientific, LLC (an official space implementation partner of the USS National Laboratory of the ISS) provided access to NASA and ISS launch facilities.
The experiment was launched for the ISS on October 2, 2020 by NASA's Wallops Flight Facility near Wattsville, Virginia. As one of several scientific payloads and technology demonstrators, this one has the honor of being the first of its kind to be sent to the ISS. While seeds and plants have been sent into space since the beginning of the space age, no soil has ever come into being.
In fact, all previous attempts to study whether earth plants can grow in non-terrestrial environments have centered on obtaining regolith samples such as the moon, Mars, asteroids, and other locations in the solar system to see if they can be used as soil. In most of the experiments, the experiments were simulants rather than reality (given the cost of obtaining regolith samples).
This experiment, which examines the effects of space travel and microgravity on soil aggregates formed by fungi and bacteria, is the culmination of years of work and studies by father-daughter duo Lee and Morgan Irons, who jointly founded Deep Space Ecology. As Lee shared Universe Today via email:
“Space ecology is all about food security. Since Mars is the biggest food security problem, if we can solve the problem for Mars, we can solve food security problems anywhere on earth, from sub-sea salt marshes to the high Himalayas, from the Sahara to the Arctic. from the most remote places on earth to the densest urban centers. "
Dwarf wheat grows in the ISS Advanced Plant Habitat. Photo credit: NASA
The right stuff
DSE's story began in 2016 shortly after Morgan and Lee attended the Humans to Mars Summit (H2M) in Washington DC. This annual event, hosted by Explore Mars, brings together researchers from diverse fields of study with industry experts and people from around the world to discuss the latest Mars research news and the necessities for humans to eventually live on Mars.
While attending the conference, Morgan and Lee became concerned that the focus of this and other conferences like this one was still on the history of Mars exploration and the technology needed to make the trip. What was missing was what people will do when they get to Mars. Because how are they going to grow their own food in a sustainable way? As Lee related:
“When I saw that young people were still being encouraged to apply to be astronauts if they wanted to work in the space industry, I knew that the space industry as it existed wasn't going to do the job. And we're not just the ones who saw this. We know many who started their New Space business around the same time. "
While numerous studies have been aimed at determining whether earth cultures can grow in the Mars regolith, virtually nothing has been done to study how to keep this soil rich in organic molecules and minerals (i.e. fertile) over time. Morgan was both intrigued and excellently qualified to answer this question as she was about to complete a double thesis in environmental science and biology at Duke University in North Carolina.
Morgan does research on soil health and biochemistry. Photo credit: Morgan Irons
Since January 2015, Morgan has been researching a CES (Closed Ecological System) model that enables the sustainable colonization of space. In the school year leading up to her trip to the H2M conference, she developed an experimental method for testing pre-treatments in Mars regoliths to aid in plant growth. While she was at the conference, the Duke University greenhouse received her shipment of the Mars regolith simulan.
One of the fruits of this work is a patented CES model that uses three zones to ensure sustainable agricultural practices and food security for habitats outside the world. The simple arrangement of the three zones forms concentric circles and consists of an ecological buffer zone (outer circle), an agricultural zone (second circle) and human habitation (inner circle).
According to the patent (tentatively filed in July 2016 and granted in May 2018), this model "mimics the self-sufficient and resilient capacity of the earth" and would enable the creation of "self-supporting and resilient human habitation on earth" for the Moon and Mars as well as for food security and climate protection all over the world. "
Morgan is currently working on her PhD. at Cornell University's Lehmann Lab, where she investigates bacterial organic adhesion mechanisms in soil aggregates and their effects on the persistence of organic carbon in soil. Her ultimate research interest is to understand how biogeochemical cycles are established in soils here on Earth and on other astronomical bodies.
Morgan Irons scoops earth for the experiment's journey into space. Photo credit: Morgan Irons
The soil health experiment in space is part of her doctorate. Research primarily focused on determining what role (if any) gravity plays in microbial soil aggregation and how this affects overall soil health. The results of this experiment will apply to future space missions, but also here at home, where soil degradation is taking place due to unsustainable, intensive agriculture and climate change.
Morgan is also a Graduate Research Fellow of the National Science Foundation (NSF) 2020, Fellow of the Norfolk Institute 2019, and recipient of the Ken Souza Memorial Spaceflight Award 2019 from the American Society for Gravitational and Space Research (ASGSR). Her father, Lee Irons, is also a scientist, engineer and entrepreneur.
His previous work includes research on space plasma physics, power generation, decontamination and remediation of hazardous environments, as well as major engineering and construction projects that he has invested in creating solutions for life outside the world.
This purpose motivated Lee and Dan Lopez (entrepreneurs, technologists and member of the Advisory Board of the SETI Institute) to found the Norfolk Institute. Like DSE, this nonprofit is dedicated to creating food security systems that ensure human resilience in space and on earth. Lee said:
“There is a certain amount of research and development that is best done with charitable funds through for-profit interests to help entire industries. We founded the Norfolk Institute to do this type of work in support of the missions of companies like Deep Space Ecology that are trying to help the human species survive and flourish on our earth and in our universe. "
The three soil types that make up the experiments (from left to right): fibrous, organically rich, silty-clayey. Photo credit: Morgan Irons
Gravity and soil
The soils are far from dead or inert. They live and breathe beings that are filled with microorganisms, soil fauna, nutrients, organic matter and minerals. Its ability to form clumps (aggregates) is central to ensuring that its structure and quality is maintained over time, as aggregates play a huge role in regulating the important biogeochemical processes that make the soil fertile. As Morgan Irons explained to Universe Today about Zoom:
“Aggregates are part of the structure of the soil and, depending on the size of the aggregate, affect the porosity of your floor. Porosity, as it sounds, is the pores that are in your soil structure. Pores are so important because they allow water to penetrate the column of soil, (they) allow air to penetrate and exchange, and allow plant roots to penetrate easily. Aggregates create this porosity structure in your soil that makes these things possible."
However, as Morgan added, the role of aggregates goes beyond the mere maintenance of soil structure. According to several lines of evidence, it is assumed that they also protect organic substances in the long term. This is due to the fact that not all of the organic matter added to the soil is automatically broken down by microorganisms into its chemical components, which are immediately consumed by plants or leached into the soil columns.
In some cases, organic molecules can contain soil minerals, creating a protective shell that the bacteria cannot penetrate. Morgan said:
“In these soil aggregates, organic material can be protected, resulting in long-term sequestration or long-term persistence of organic soil material. Soil organic matter or organic carbon persistence is very important to soil fertility as you don't want your source of nutrients to flow directly through the column of soil or to decompose quickly. If you don't keep the ingress rate for the uptake rate, your soil will be pretty poor in nutrients. Organic substances that are secreted can therefore contribute to the long-term fertility of your soil. "
Artist's impression of the Mars epoch X1 by DSE with a residential zone. Credit: DSE
The purpose of their soil health experiment in space is to find out what (if any) impact microgravity has on the ability of a soil sample to form Microaggregates or Macro aggregates that will bind nutrients. Macro aggregates Are large clumps of dirt that you would find if you dig your hands into a pile of earth, micro-aggregates are much finer.
Because the soil comes in many different varieties, which affects the plants' ability to grow plants, Morgan and her colleagues selected three soil samples for their experiments. These samples fall into three different categories: fibrous, organic, and clayey (muddy) and were chosen for their particular compositions and textures.
The fibrous sample was provided by Bio365, a commercial manufacturer of nutrient-rich soils for commercial agriculture based in Ithaca, NY. This soil has been specially processed and enriched with biochar (natural charcoal made from decomposed biomass) to ensure that it is loaded with nutrients and organic matter.
The organic sampleIt is now a mineral floor that was developed by Dr. Matthias Rillig (Professor of Biology) at the Free University of Berlin was made available. This soil consists mainly of concentrated sand, is highly porous and consists of larger sand particles. It is also high in organic material and has a high density, which makes it "hydrophobic" (which means it does not absorb water well).
The ecological buffer zone within Mars epoch X1. Credit: DSE
The clay-rich sample also came from Ithaca, specifically from an organic farm on the Cornell University campus. This type of soil is common in New York State and dates back to the last Ice Age (about 115,000-11,700 years ago). Its material origin (starting material) is "Glaciolacustrin", as it comes from the retreating ice sheets that scraped material from the Great Lakes region and deposited elsewhere as soil.
Compared to the other samples, this soil has smaller pore sizes and a better aggregation probability than the sandy soil (the Berlin sample). In between these samples, Morgan studies the effects of gravity (or its lack of it) on fungal mycelial production and bacterial organic glue (adhesive strength) production in the soil, the resulting effects on the stability of soil aggregates and the occlusion of organic carbon in those aggregates.
Understanding the effects of gravity on the functional and ecological dynamics of soil microorganisms and thus on soil biogeochemistry would enable agriculture in space. This supports the goals of Deep Space Ecology. As Morgan put it:
“The different textures between these mineral soils allow us to study the possible formation of microaggregates versus macroaggregates to see if they can actually form in a microgravity environment. And when they form in a microgravity environment, we ask the question: "Is it because of the microorganisms that produce organic adhesives in the soil that create the necessary organic-mineral interactions?" If these aggregates are still forming, it likely means that the microbial mechanism that makes this possible is not necessarily gravity-dependent. "
The agricultural zone within Mars epoch X1. Credit: DSE
In short, the experiment seeks to investigate whether gravity is part of the mechanism that enables microorganisms to perform the function of aggregating. Given that these microorganisms evolved in soils here on Earth, it is widely believed that once they are removed from Earth's gravity, they may not function right away. But as Morgan has suggested, plant studies on board the ISS have already shown that this is not always the case.
"Sometimes gravity, which is this huge force vector, has this masking effect where it covers or hides what is actually happening at this fundamental mechanistic level," she said. "So if you take that huge force vector out of this equation and everything still works the same, you have to ask yourself what actually drives this facility, this system, to work this way."
The Soil Health in Space experiment consists of three soil samples, each split and placed in 12 4 ml (0.135 fluid ounces) vials. Each set of 12 was then divided into two groups of six, which Morgan referred to as the "free-floating" and "restricted movement groups". In the first case, the floor can float freely in weightlessness, while the second was equipped with mesh plugs that hold the floor in place but let water and air through.
As Morgan said, the aim is to study the impact of free floating versus being closely cohesive on the soil's microbiome. And they assume the results will be a bit mixed:
“If we allow free-floating or restricted movements, we can test the abiotic effect of the soil structure on the soil microbiome. This goes into one of our hypotheses in which we believe that the mushrooms will not necessarily work if the ground is allowed to float freely. So we could see a shift in the population where the fungal populations could decrease while the bacterial populations either stay the same or increase.
“Bacteria have a tendency to tell where they are – they stick to a mineral, they stick to organic matter, and they're good to go. While with mushrooms, they rely on their mycelial network in the soil sample. And if you break up this structure where it is now just floating free, the mushrooms may not be that good. This, of course, affects the frequency and stability of the aggregates that we may or may not find in the samples. "
The Antares missile in the Wallops Flight Facility on September 28, 2020 is preparing for launch. Photo credit: Morgan Irons
But it doesn't end there. For the next trial treatment, the samples with restricted movement and free-floating samples were each divided into two groups of three, which were then given water at 60% and 30% of their respective holding capacity. As Morgan explained, all samples had to be air-dried beforehand and could only be watered just before the jump at the launch site (which she had done herself):
“Just before the start, just before I gave them up, I gave them water to activate them. Because as soon as water hits them and is allowed to get into this environment, the microorganisms intensify their microbial processes. Using 30% versus 60% water holding capacity allows us to test the biotic effect of microbial activity on the soil – 30% are drought-like conditions while 60% are optimal water conditions. Microorganisms in the 30% tubes may not perform as well as the microorganisms in the 60% tubes. "
On October 15, NASA announced via the ISS On-Orbit Status Report that the crew had removed the five chambers of the experiment aboard the Cygnus spacecraft from their hiding place and placed the samples in a cold store.
Solve for the earth
To the famous science communicator Dr. To quote Sian Proctor: "Solving for space solves solving for earth." This is especially true for the description of space ecology and its experiments, which focus on the development of systems, modern science and biology with ancient knowledge and " Use best practices ”that enable people to work in extreme environments.
Perspective view of the habitat DSE Mars Epoch X2. Credit: DSE
After all, agriculture is the oldest science known to mankind, having been around for over 11,500 years. And as Morgan put it, our ancient ancestors who practiced it were scientists themselves – in a way:
"We have indigenous groups of people farming for thousands of years, and they have been able to do so sustainably because they (learned) through trial and error. They (were) scientists themselves, learning what worked and what didn't , and they understood how to handle their environment in a sustainable way, taking into account how ecosystems work and how they can be preserved for generations. "
A good example Morgan cites is the Nabataean civilization, which dates from the 4th century BC. Until 106 AD. Lived in the Negev desert between today's Jordan, Egypt and Saudi Arabia and revolved around the ancient city of Petra. At its peak, this civilization was able to feed a population of 30,000 in the desert thanks to its system of agriculture and water transport.
The engineering achievements that, according to Morgan, led to it amaze archaeologists to this day:
“When modern scientists and archaeologists began researching this area and the city of Petra, they found the water collection system, water storage cisterns (and) the plumbing irrigation systems they used in the 4th century BCE to 106 CE were all" best practice ".
In other words, engineers couldn't do better than trying to recreate it in this day and age using the same materials, and that's because the Nabataeans wanted to understand their landscape (and) how water naturally moves moving through their landscape to develop the most efficient and sustainable technology. "
The entrance to Al Khazneh Temple in the ancient city of Petra, Jordan. Photo credit: Graham Racher / Wikipedia Commons
Agriculture today is very different due to a combination of factors. On the one hand, the European colonization of America, Africa and Asia (16th to early 20th century) led to the destruction and forcible removal of indigenous communities. It also resulted in knowledge and local practices related to living sustainably, with the land being replaced with European agricultural practices (with the focus on yield).
Another important factor was the industrial revolution (around the middle of the 18th to the beginning of the 20th century), which led to the introduction of agricultural machinery that could support larger farms. This trend intensified with the “Green Revolution” of the 1950s and 1960s, which introduced more chemical fertilizers, insecticides and herbicides, as well as intensive land management and the introduction of genetically modified crops.
These practices are unsustainable and lead to land degradation and the disappearance of farmland around the world. This happens at a time when the world population continues to grow and more and more land is being reserved for urban infrastructure. It also contributes to the growing problem of climate change. As Morgan summarizes, soil degradation means that less carbon is removed from our atmosphere over time:
“Our landscape is the largest organic carbon sink on earth. Soil contains a large part of this carbon in organic form and therefore has a soil structure that allows organic matter to be protected, persisted or bound in a pool and not decomposed and released back into the atmosphere as CO2, also very good for climate change important. "
Artist's impression of Mars epoch X2, top view. Credit: DSE
In short, developing methods for sustainable agriculture will not only ensure that people traveling in space or live on other planets have enough to eat, it will also enable soil rejuvenation here at home. One of the first steps is to determine if soil health and soil plants need gravity to grow and thrive.
The answer to this question will have a dramatic impact on food production in space, on the moon, on Mars and elsewhere in the solar system. Humanity wants to build a permanent presence. Morgan and her colleagues suggest that the presence of earth's gravity (1 g) is not always a significant factor, meaning that plants could grow in space or on other earth bodies using real soil (rather than just hydroponics).
However, if Earth's gravity is essential, it means that all future space facilities will rely on artificial gravity to grow their food. For places like the Moon and Mars where gravity is lower, more experimentation is needed to determine how lower gravity affects our ability to grow crops.
DSE has currently developed concepts for three generations of the quasi-closed agro-ecological Mars system – also known as. Mars epochs X1 to X3 – that would enable a gradual adaptation and settlement of Mars. As you can see from the images posted above (and the video below), these designs require the creation of closed ecological systems in sealed and transparent domes and come in many shapes and sizes.
In business terms, Lee Irons stated that DSE will introduce a customer interface in 2021 that allows customers to answer specific questions about what they are looking for. This will be combined with a catalog of products and services that DSE will offer to potential customers. This interface will contain a soon-to-be-announced line of Earth products and services.
"We have shown that we are thinking in the right direction," said Lee. “Our Chief Science Officer, Morgan Irons, is a patent holder, a National Science Foundation graduate and a PhD student at Cornell University, the world's best agricultural university, and is currently doing an experiment on the International Space Station. We have planned earth market solutions and related initiatives for which we are seeking investment finance. "
For more information on research, services, and long-term vision, visit the Deep Space Ecology and Norfolk Institute websites.
Further reading: Deep Space Ecology, Norfolk Institute