The desert moss that could help terraform Mars

AI generated image of Mars in the process of being terraformed. Credit: Image Creator

Mars is currently not very hospitable to life, although it may have been billions of years ago. Many Mars settlement advocates and science fiction writers dream of the turning the Red Planet green by terraforming its atmosphere to make it more Earth-like. Even partially changing smaller regions, i.e. para-terraforming, would be a good first step.

To get things started it would be helpful if there were organisms that could survive the frigid temperatures, low ambient pressure and harsh radiation on Mars while helping to boost the oxygen levels in the atmosphere and assisting with soil fertility. Fortunately, there is a desert moss called Syntrichia caninervis that fits the bill. In a report in the journal The Innovation a team* of Chinese researchers present results of a study that demonstrate the extremotolerance of this plant to conditions on the Red Planet. This hardy organism can withstand temperatures down to a frosty -197°C, has extreme desiccation tolerance recovering within seconds after losing 97% of its water content and is super resistant to gamma radiation.

S. canivervis is a pioneering organism that has wide distribution in extreme biomes on Earth, from the Gurbantunggut Desert in China to the Mojave Desert in the California . It plays a key role in development of biological soil crust, a type of widespread ground cover which is the precursor of fertile soil. A major source of carbon and nitrogen in arid regions, these so called “living skins of the Earth” are responsible for a quarter of the total nitrogen fixation of terrestrial ecosystems. As stated in the paper, this resilient moss “…has evolved several morphological mechanisms to adapt to extreme environments, including overlapping leaves that conserve water and shield the plant from intense sunlight and white awns at the tops of leaves that reflect strong solar radiation and enhance water utilization efficiency.”

To test the desiccation tolerance of S. caninervis the researchers subjected the organism to air-drying treatment followed by measurements of plant phenotypes, water content, photochemical efficiency and changes in leaf angle. The mosses exhibited an exceptional ability to recover rapidly after being dehydrated. Incredibly, the plants were observed to be green when hydrated, turned black as water was gradually extracted, then returned to green only after 2 seconds upon rehydration.

Extended low temperature tolerance was tested by placing two samples of the plants in a freezer set at -80o C for 3 and 5 years, respectively. Short duration extreme cold was studied by subjecting the samples to -196o C in a liquid nitrogen tank for 15 and 30 days. The plants were then cultivated normally to determine their ability to regenerate. Remarkably, in the 3 and 5 year long duration freezer cohorts, both sample branch regeneration rates recovered to approximately 90% of that observed in the control group after 30 days of growth. Similar results were noted for the plants subjected to the 15 and 30 day -196o C treatment with 95% regeneration rate when compared to the controls.

For radiation resistance, samples of S. caninervis were subjected to gradually increasing levels of gamma radiation from 500 Gy up to 16000 Gy. At the upper end of the range the plants died. However, the organism survived exposures up to 2000 Gy with regeneration of branches slightly delayed when compared to controls with no radiation exposure (most plants can’t tolerate more than 1000Gy). A surprising result was noted when exposure to 500 Gy actually increased the regeneration of branches vs no exposure. Humans are sickened by exposure to 2.5 Gy and die upon exposure to 50 Gy. These results demonstrate that S. caninervis has exceptional radiation tolerance.

Finally, simulated Mars conditions were tested by placing S. caninervis in an environmental chamber called the Planetary Atmospheres Simulation Facility operated by the Chinese Academy of Sciences. Parameters were set in the chamber to mimic Mars conditions in mid-latitude regions with temperatures dipping down to −60oC at night and rising to +20oC during the day; atmospheric pressure pegged at 650 Pascals ( 0.09 PSI); Martian atmospheric gasses set to match Martian conditions ( 95% CO2, 3% N2, 1.5% Ar, 0.5% O2); and the expected ultraviolet radiation flux tuned across the UVA, UVB, and UVC wavelength bands. The treatments were applied for 1, 2, 3, and 7 days and then regeneration of branches was measured and compared to control samples. The results showed that S. caninervis can survive in a simulated Mars environment regenerating branches after 15 days of recovery. This hardy moss, having evolved to colonize extremely dry, cold environments on Earth make it ideally suited as a pioneer species to start the process of greening Mars, helping to establish an ecosystem through oxygen production, carbon sequestration, and generation of fertile soil.

Graphical illustration depicting extremotolerant properties of the moss Syntrichia caninervis showing superior desiccation and freezing tolerance, radiation resistance and pioneering benefits for terraforming Mars (slight modifications made to text of Public Summary). Credits: Xiaoshuang Li et al., under creative commons license CC BY-NC-ND 4.0

Of course terraforming Mars may take many years, perhaps centuries. In the near term, an ancient farming method called intercropping could help boost the yields of vegetables grown on Mars to sustain a healthy settler’s diet. The technique coordinates the cultivation of two or more crops simultaneously in close proximity. In a research article in PLOS ONE scientists at the Wageningen University & Research in the Netherlands describe the method of soil based food production using Martian regolith simulate. The researchers acknowledge that some processing of Martian regolith will be required to remove toxic components such as perchlorates. Research on these techniques is already underway. The study found that intercropping “…shows promise as a method for optimizing food production in Martian colonies.”


* Authors of the Report The extremotolerant desert moss Syntrichia caninervis is a promising pioneer plant for colonizing extraterrestrial environments:

Xiaoshuang Li 1, Wenwan Bai 1 2, Qilin Yang 1 2, Benfeng Yin 1, Zhenlong Zhang 3, Banchi Zhao 3, Tingyun Kuang 4, Yuanming Zhang 1, aoyuan Zhang 1
1 – State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
2 – University of Chinese Academy of Sciences, Beijing 100049, China
3 – National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China
4 – Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China

Mars as breadbasket for the outer solar system

Artist’s rendering of a farming settlement on Mars. Credits: HP Mars Home Planet Rendering Challenge via International Business Times.

Space settlement will eventually require space farming to feed colonists and to provide life support. It’s clear that we will replicate our biosphere wherever we go. In that spirit, Bryce L. Meyer envisions Mars as the breadbasket of the outer solar system. In a presentation at Archon 45, a science fiction and fantasy convention held annually by St. Louis area fans, he makes the case for why the fourth planet would be the ideal spot to grow crops and feed an expanding population as part of the roadmap to agriculture in space.

Carbon dioxide and subsurface water ice are plentiful on Mars, critical inputs for crop photosynthesis. There is also evidence of lava tubes there which could provide an ideal growing environment protected from radiation, micrometeorite bombardment and temperature extremes. The regolith should provide good nutrients and there is already research on methods to filter out perchlorates, a toxic chemical compound in the Martian soil.

Image of Lava tubes on the surface of Mars as photographed by ESA’s Mars Express spacecraft. Credits: ESA/DLR/FU Berlin/G Neukum / NewScientist

Another advantage that Mars holds as a food production hub for the asteroids and beyond is its placement further out in the solar system. Since it is higher up in the sun’s gravity well, Meyer calculates that it would take less than 43% of the fuel needed to transport goods from Mars outward than from Earth. He even suggests that with its lower gravity and recent advancements in materials research, a space elevator at Mars could be economically feasible to cheaply and reliably transport foodstuff off the planet.

Meyer keeps a webpage featuring space agriculture, terraforming, and closed cycle microgravity farming where he poses the question “Why settle space?” I like his answer: “Trillions of Happy Smiling Babies!!!”

Basic input/output diagram of an environmental control and life support system like what would be expected in a space farm. Credits: Bryce L. Meyer

Meyer is the founder and CEO of Cyan React, LLC, a startup that designs compact photobioreactors and provides expertise in closed-cycle farming and life support especially for space settlement and space habitats. He is also a National Space Society Space Ambassador doing his part to educate the public about the potential benefits to humanity through the use of the bountiful resources in space. In a presentation at this year’s International Space Development Conference, he describes his research on bioreactors explaining how settlers will grow food and recycle waste sustainably on the high frontier.

Diagram depicting the flow of materials in a closed space farm habitat utilizing bioreactors. Credits: Bryce L. Meyer

Complete closure and stability of an environmental control and life support system (ECLSS) is challenging and not without limitations. As launch and space transportation costs come down in the near future and off-Earth supply chains become more reliable, complete closure will not be required at least initially. In situ resource utilization will provide replacement of some ECLSS consumables where available for colonists to live off the land. As missions go deeper into space reaching the limits of supply chain infrastructure and even out to the stars, closure of habitat ECLSS and resource planning will become more important. Meyer has done the math for farms in space to provide food and air for trillions of smiling babies…and their families as they move out into the solar system.

Highlights from the International Space Development Conference

Conceptual illustration of Mag Mell, a rotating space settlement in the asteroid belt in orbit around Ceres – grand prize winner of the NSS Student Space Settlement Design Contest. Credits: St. Flannan’s College Space Settlement design team*

In this post I summarize a few selected presentations that stood out for me at the National Space Society’s International Space Development Conference 2022 held in Arlington, Virginia May 27-29.

First up is Mag Mel, the grand prize winner of the NSS Student Space Settlement design contest, awarded to a team* of students from St. Flannan’s College in Ireland. This concept caught my eye because it was in part inspired by Pekka Janhunen’s Ceres Megasatellite Space Settlement and leverages Bruce Damer’s SHEPHERD asteroid capture and retrieval system for harvesting building materials.

The title Mag Mell comes from Irish mythology translating to “A delightful or pleasant plain.” These young, bright space enthusiasts designed their space settlement as a pleasant place to live for up to 10,000 people. Each took turns presenting a different aspect of their design to ISDC attendees during the dinner talks on Saturday. I was struck by their optimism for the future and hopeful that they will be representing the next generation of space settlers.

Robotically 3D printed in-situ, Mag Mell would be placed in Ceres equatorial orbit and built using materials mined from that world and other bodies in the Asteroid Belt. The settlement was designed as a rotating half-cut torus with different angular rotation rates for the central hub and outer rim, featuring artificial 1G gravity and an Earth-like atmosphere. Access to the surface of the asteroid would be provided by a space elevator over 1000 km in length.


* St. Flannan’s College Space Settlement design team: Cian Pyne, Jack O’Connor, Adam Downes, Garbhán Monahan, and Naem Haq


Conceptual illustration of a habitat on Mars constructed from self-replicating greenhouses. Credits: GrowMars / Daniel Tompkins

Daniel Tompkins, an agricultural scientist and founder of GrowMars, presented his Expanding Loop concept of self replicating greenhouses which would be 3D printed in situ on the Moon or Mars (or in LEO). The process works by utilizing sunlight and local resources like water and waste CO2 from human respiration to grow algae for food with byproducts of bio-polymers as binders for 3D printing blocks from composite concretes. Tompkins has a plan for a LEO demonstration next year and envisions a facility eventually attached to the International Space Station. He calculates that a 4000kg greenhouse could be fabricated from 1 year of waste CO2 generated by four astronauts. An added bonus is that as the greenhouse expands, an excess of bioplastic output would be produced, enabling additional in-space manufacturing.

Diagram depicting GrowMars Expanding Loop algae growing process to create greenhouse blocks and byproducts such as proteins and fertilizer. Credits: GrowMars / Daniel Tompkins.

Illustration of a portion of the Spacescraper tethered ring from the Atlantis Project. Credits: Phil Swan

Phil Swan introduced the Atlantis Project, an effort to create a permanent tethered ring habitat at the limit of the Earth’s atmosphere, which he calls a Spacescraper.  The structure would be placed on a stayed bearing consisting of two concentric rings magnetically attached and levitated up to 80 km in the air.  In a white paper available on the project’s website, details of the force vectors for levitation of the device, the value proposition and the economic feasibility are described. As discussed during the talk at ISDC, potential applications include:

  • Electromagnetic launch to space
  • Carbon neutral international travel
  • Evacuated tube transit system
  • Astronomical observatories
  • Communication and internet
  • Solar energy collection for electrical power
  • Space tourism
  • High rise real estate

Phil Swan will be coming on The Space Show June 21 to provide more details.


Conceptual illustration of a Mars city design with dual centrifuges for artificial gravity. Credits: Kent Nebergall

Finally, the Chair of the Mars Society Steering committee and founder of MacroInvent Kent Nebergall, gave a presentation on Creating a Space Settlement Cambrian Explosion. That period, 540 million years ago when fossil evidence goes from just multicellular organisms to most of the phyla that exist today in only 10 million years, could be a metaphor for space settlement in our times going from extremely slow progress to a quick expansion via every possible solution. Nebergall suggests that we may be on the verge of a similar growth spurt in space settlement and proposes a roadmap to make it happen this century.

He envisions three settlement eras beginning with development of SpaceX Starship transportation infrastructure transitioning to robust cities on Mars with eventual para-terraforming of that planet. He also has plans for how to overcome some of the most challenging barriers – momentum and money. Stay tuned for more as Kent has agreed to an exclusive interview on this topic in a subsequent post on SSP as well as an appearance on The Space Show July 10th.