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Sublake Settlements for Mars

Terraforming a world is a breathtaking task, one often thought about in relation to making Mars into a benign environment for human settlers. But there are less challenging alternatives for providing shelter to sustain a colony. As Robert Zubrin explains in the essay below, ice-covered lakes are an option that can offer needed resources while protecting colonists from radiation. The founder of the Mars Society and author of several books and numerous papers, Zubrin is the originator of the Mars Direct concept, which envisions exploration using current and near-term technologies. We’ve examined many of his ideas on interstellar flight, including magsail braking and the nuclear salt water rocket concept, in these pages. Now president of Pioneer Astronautics, Zubrin’s latest book is The Case for Space: How the Revolution in Spaceflight Opens Up a Future of Limitless Possibility, recently published by Prometheus Books.

by Robert Zubrin

Abstract

This paper examines the possibilities of establishing Martian settlements beneath the surface of ice-covered lakes. It is shown that such settlements offer many advantages, including the ability to rapidly engineer very large volumes of pressurized space, comprehensive radiation protection, highly efficient power generation, temperature regulation, copious resource availability, outdoor recreation, and the creation of a vibrant local biosphere supporting both the nutritional and aesthetic needs of a growing human population.

Introduction

The surface of Mars offers many challenges to human settlement. Atmospheric pressure is only about 1 percent that of Earth, imposing a necessity for pressurized habits, making spacesuits necessary for outdoor activity, and providing less than optimum shielding against cosmic radiation. For these reasons some have proposed creating large subsurface structures, comparable to city subway systems, to provide pressurized well-shielded volumes for human habitation [1]. The civil engineering challenges of constructing such systems, however, are quite formidable. Moreover, food for such settlements would have to be grown in greenhouses, limiting potential acreage, and imposing either huge power requirements if placed underground, or the necessity of building large transparent pressurized structures on the surface. Water is available on the Martian surface as either ice or permafrost. These materials can be mined and the product transported to the base, but the logistics of doing so, while greatly superior to anything possible on the Moon, are considerably less convenient than the direct access to liquid water available to nearly all human settlements on Earth. While daytime temperatures are acceptably close to 0 C, nighttime temperatures drop to -90 C, imposing issues on machinery and surface greenhouses. Yet despite the cold night temperatures, the efficiency of nuclear power is impaired by the necessity of rejecting waste heat to a near-vacuum environment.

All of these difficulties could readily be solved by terraforming the planet [2]. However, that is an enormous project whose vast scale will require an already-existing Martian civilization of considerable size and industrial power to be seriously undertaken. For this reason, some have proposed the idea of “para terraforming,” [3] that is, roofing over a more limited region of the Red Planet, such as the Valles Marineris, and terraforming just that part. But building such a roof would itself be a much larger engineering project than any yet done in human history.

There are, however, locations on Mars that have already been roofed over. These are the planet’s numerous ice-filled craters.

Making Lakes on Mars

Earth’s Arctic and Antarctic regions feature numerous permanently ice covered or “sub glacial” lakes [4]. These lakes have been shown to support active microbial and planktonic ecosystems.

Most sub Arctic and high latitude temperate lakes are ice-covered in winter, but many members of their aquatic communities remain highly active, a fact well-known to ice fishermen.

Could there be comparable ice-covered lakes on Mars?

At the moment, it appears that there are not. The ESA Mars Express orbiter has detected highly-saline liquid water deep underground on Mars using ground penetrating radar, and such environments are of great interest for scientific sampling via drilling. But to be of use for settlement, we need ice-covered lakes that are directly accessible from the surface. There are plenty of ice-filled craters on Mars. These are not lakes, however, as while composed of nearly pure water ice, they are frozen top to bottom. But might this shortcoming be correctable?

I believe so. Let us examine the problem by considering an example.

Korolev is an ice-filled impact crater in the Mare Boreum quadrangle of Mars, located at 73° north latitude and 165° east longitude (Fig. 1). It is 81.4 kilometers in diameter and contains about 2,200 cubic kilometers of water ice, similar in volume to Great Bear Lake in northern Canada. Why not use a nuclear reactor to melt the water under the ice to create a huge ice-covered lake?

Fig. 1. Korolev Crater could provide a home for sublake city on Mars. Photo by ESA/DLR.

Let’s do the math. Melting ice at 0 C requires 334 kJ/kg. We will need to supply this plus another 200 kJ/kg, assuming that the ice’s initial temperature is -100 C, for 534 kJ/kg in all. Ice has a density of 0.92 kg/liter, so melting 1 cubic kilometer of ice would require 4.9 x 1017 J, or 15.6 GW-years of energy. A 1 GWe nuclear power plant on Earth requires about 3 GWt of thermal power generation. This would also be true in the case of a power plant located adjacent to Korolev, since it would be using the ice water it was creating in the crater as an excellent heat rejection medium. With the aid of 5 such installations, using both their waste heat and the dissipation from their electric power systems, we could melt a cubic kilometer of ice every year.

Korolev averages 500 m in depth, which is much deeper than we need. So rather than try to melt it all the way through, an optimized strategy might be to focus on coastal regions with an average depth of perhaps 40 meters. In that case, each cubic kilometer of ice melted would open 25 square kilometers of liquid lake for settlement. Alternatively, we could just choose a smaller crater with less depth, and melt the whole thing, except the ice cover at its top.

Housing in a Martian Lake

On Earth, 10 meters of water creates one atmosphere of pressure. Because Martian gravity is only 38 percent as great as that of Earth, 26 meters of water would be required to create the same pressure. But so much pressure is not necessary. With as little as 10 meters of water above, we would still have 0.38 bar of outside pressure, or 5.6 psi, allowing a 3 psi oxygen/2.6 psi nitrogen atmosphere comparable to that used on the Skylab space station. Reducing nitrogen atmospheric content in this way could also be advantageous because nitrogen is only a small minority constituent of the Martian atmosphere, making it harder to come by on Mars, and limiting the nitrogen fraction of breathing air would also facilitate traveling to lower pressure environments without fear of getting the bends. Ten meters of water above an underwater habitat would also provide shielding against cosmic rays equivalent to that provided by Earth’s atmosphere at sea level.

Construction of the habitats could be done using any the methods employed for underwater habitats on Earth. These include closed pressure vessels, like submarines, or open-bottom systems, like diving bells. The latter offer the advantage of minimizing structural mass since they have an interior pressure nearly equal to that of the surrounding environment, and direct easy access to the sea via their bottom doors, without any need for airlocks. Thus, while closed submarines are probably better for travel, as their occupants do not experience pressure changes with depth, open bottom habitats offer superior options for settlement. We will therefore focus our interest on the latter.

Consider an open-bottom settlement module consisting of a dome 100 m in diameter, whose peak is 4 meters below the surface and whose base in 16 meters below the surface. The dome thus has four decks, with 3 meters of head space for each. The dome is in tension, because all the air in it is all at a pressure of 9 psi, corresponding to the lake water pressure at its base, while the lake water pressure at its top is only about 2.2 psi, for an outward pressure on the dome material near the top of 6.8 psi. The dome has a radius of curvature of 110 m.

The required yield stress of the material composing a pressurized sphere is given by:

σ = xPR/2t (1)

Where σ is the yield stress, P is the pressure, R is the radius, t is the dome thickness, and x is the safety factor. Let’s say the dome is made of steel with a yield stress of 100,000 psi and x=2. In that case, equation (1) says that:

100,000 = (6.8)(110)/t, or t= 0.0075 m = 7.5 mm.

The mass of the steel would be about 600 tons. That’s not to bad, for creating a habitat with about 30,000 square meters of living space.

If instead of using steel, we made a tent dome from spectra fabric, which has 4 times the strength of steel and 1/9th the density, the mass of the dome would only need to be about 17 tons. It would, however, need to be tied down around its circumference. Ballast weights of 90,000 tons of rocks could be used for this purpose. Otherwise the tie down lines could be anchored to stakes driven deep into the frozen ground under the lake.

An attractive alternative to these engineering methods for creating a dome out of manufactured materials could be to simply melt the dome out of the ice covering the lake itself. For example, let’s say the ice cover is 20 m thick, and we melt a dome into it that is 12 m tall, 100 m in diameter, and has a radius of curvature of 110 m. Filling this with an oxygen/nitrogen gas mixture would provide a habitat of equal size to that discussed above. The pressure under 20 m of ice (density = 0.92) is 0.7 bar, or 10.3 psi. The roof of the dome is under 8 m of ice, whose mass exerts of compressive pressure of 0.28 bar, or 4.1 psi, leaving a pressure difference of 6.2 psi to be held by the strength of the ice. The tensile strength of ice is about 150 psi, so sticking these values into equation (1) we find that the safety factor, x, at the dome’s thinnest point would be:

150 = x(6.2)(110)/[(8)(2)], or x = 3.52

This safety factor is more than adequate. Networks of domes of this size could be melted into the ice cover, linked by tunnels through the thick material at their bases. If domes with a much larger radius of curvature were desired, the ice could be greatly strengthened by freezing a spectra net into it.

The mass of ice melted to create each such dome is about 80,000 tons, requiring 1 MWt-year of energy to do the melting. It would also require about 90 tons of oxygen to fill the dome with gas. This could be generated via water electrolysis. Assuming 80% efficient electrolysis units, this would require 1950 GJ, or 62 kWe-year of electric power to produce. Such large habitation domes could therefore be constructed and filled with breathable gas well in advance of the creation of the lake using much more modest power sources.

Compressive habitation structures can be created under ice that are much larger still. This is so because ice has 92 percent the density of water, so that if a 50 meters deep column of ice beneath the lake’s ice surface were melted, it would yield a column of water 42 meters deep and 8 meters of void, which could be filled with air.

So, let’s say we had an ice crater, section of an ice crater, or even a glacier 5 km in radius and 70 meters or more deep. We melt a section of it starting 20 m under the top of the ice and going down 50 m. As noted, this would create a headroom space 4 m thick above the water. The ice above this void would have a weight of 7 psi, so we would fill the void with an oxygen/nitrogen gas mixture with a pressure of 6.999 psi. This would negate almost all the weight to leave the ice roof in an extremely mild state of compression. (Mild compression is preferred to mild tension, because the compressive strength of ice is about 1500 psi – ten times the tensile strength.) Under such circumstances the radius of curvature of the overhanging surface could be unlimited. As a result, a pressurized and amply shielded habitable region of 78 square kilometers would be created. Habitats could be placed on rafts or houseboats on this indoor lake, or an ice shelf formed to provide a solid floor for conventional buildings over much of it.

The total amount of water that would need to be melted to create this indoor lake city would be 4 cubic kilometers. This could be done in about 4 years by our proposed 5 GWe power system. Further heating would continue to expand the habitable region laterally over time. If the lake were deep, so that there was ice beneath the water column, it would gradually melt, increasing the headroom over the settlement as well.

Terraforming the Lake

The living environment of the sublake Mars settlement need not be limited to the interior of the air-filled habitats. By melting the ice, we are creating the potential for a vibrant surrounding aquatic biosphere, which could be readily visited by Mars colonists wearing ordinary wet suits and SCUBA gear.

The lake is being melted using hot water produced by the heat rejection of onshore or floating nuclear reactors. If the heat is rejected near the bottom of the lake, forceful upwelling will occur, powerfully fertilizing the lake water with mineral nutrients.

Assuming that the ice cover is reduced to less than 30 meters, there will be enough natural light during daytime to support phytoplankton growth, as has been observed in the Earth’s Arctic ocean [5]. The lake’s primary biological productivity could be greatly augmented, however, by the addition of artificial light.

The Arctic ocean exhibits high biological activity as far north as 75 N, where the sea receives an average day/night year-round solar illumination of about 50 W/m2. If we take this as our standard, then each GW of our available electric power could be used to illuminate 20 square kilometers of lake. Combined with the mineral-rich water produced by thermal upwelling, and artificial delivery of CO2 from the Martian atmosphere as required, this illumination could serve to create an extremely productive biosphere in the waters surrounding the settlement.

The first organisms to be released into the lake should be photosynthetic phytoplankton and other algae, including macroscopic forms such as kelp. These would serve to oxygenate the water. Once that is done, animals could be released, starting with zooplankton, with a wide range of aquatic macrofauna, potentially including sponges, corals, worms, mollusks, arthropods, and fish coming next. Penguins and sea otters could follow.

As the lake continues to grow, its cities would multiply, giving birth to a new branch of human civilization, supported by and supporting a lively new biosphere on a new world.

Conclusion

We find that the best places to settle Mars could be under water. By creating lakes beneath the surface of ice-covered craters, we can create miniature worlds, providing acceptable pressure, temperature, radiation protection, voluminous living space, and everything else needed for life and civilization. The sublake cities of Mars could serve as bases for the exploration and development of the Red Planet, providing homes within which new nations can be born and grow in size, technological ability, and industrial capacity, until such time as they can wield sufficient power to go forth and take on the challenge of terraforming Mars itself.

References

1. Frank Crossman, editor, Mars Colonies: Plans for Settling the Red Planet, The Mars Society, Polaris Books, 2019

2. Robert Zubrin with Richard Wagner, The Case for Mars: The Planet to Settle the Red Planet and Why We Must, Simon and Schuster, NY, 1996, 2011.

3. Richard S. Taylor, “Paraterraforming: The Worldhouse Concept,” Journal of the British Interplanetary Society, vol. 45, no. 8, Aug. 1992, p. 341-352.

4. Sub Glacial Lake, Wikipedia, https://en.wikipedia.org/wiki/Subglacial_lake#Biology accessed May 15, 2020.

5. Kevin Arrigo, et al, “Massive Phytoplankton Blooms Under Sea Ice,” Science, Vol. 336, page 1408, June 15, 2012 https://www2.whoi.edu/staff/hsosik/wp-content/uploads/sites/11/2017/03/Arrigo_etal_Science2012.pdf. Accessed May 15, 2020.

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{ 104 comments… add one }
  • jonW May 29, 2020, 12:28

    Amazing ideas, and very convincingly explored. It would be so exciting to see this happen and to see humanity branching out like this. But as I contemplate the idea of me, me personally, living deep under a frozen-over lake, no natural light, surrounded by nuclear power plants and separated by a thick layer of ice from a largely airless atmosphere on a lifeless planet, and by comparison I look around my sunny back deck here, on a beautiful breezy May morning surrounding by foliage and gentle voices of kids playing out in the back alley, I think: jeez, no thanks! (even with the possibility of excursions from the base in a wetsuit!)

    I’m glad not everyone is as enamoured of their creature comforts as I am, so we can dare hope that people might undertake something like this one day and the rest of us can be inspired.

    • Antonio May 29, 2020, 17:22

      I, for one, would go, if I had the money for the ticket.

    • Brett May 29, 2020, 17:33

      I’m in the same boat. I’m glad it might be happening, and I’d even be willing to visit at the expense of 2-3 years of my life, but I wouldn’t want to live there.

  • Law Wong May 29, 2020, 13:01

    An intriguing idea, and one that could potentially be adapted to those lens lake thingys on Europa beneath chaos terrain, but rather expensive. You have to ship infrastructure to Mars, build habitats optimized for underwater lakes, and also build surface habitats to support your underwater colony… which raises the question: why not build on the surface with similar materials? Diving bells are heavy, and a few meters of dirt will provide similar radiation protection to ten meters of water. A lake ecology in addition to a surface colony does make sense.

  • Law Wong May 29, 2020, 13:11

    Ah, the pressure equalizes underwater. Interesting similarities might be had with the old Spacecoach concept, the pykrete-water low cost interplanetary spacecraft. Similar equipment might be usable for both spacecoach and sublake colonies, although I think the dust, bleach and brine (???) in the lake might make adapting the equipment somewhat difficult.

  • anon86 May 29, 2020, 13:22

    I read Zubrin’s work as a teenager and it was inspiring.

    That being said, there will not be space colonization in the foreseeable future. It’s hard for people to understand that sending folks to a place does not mean colonizing it. They’re very different. You can send people to Antarctica or Svalbard or on a cruise ship but no one’s ever been born and grown up there. I wish there was some way to communicate this better. Has anyone thought of ways to do that?

    There’s very little interest in reality on this. Check out http://www.reddit.com/r/frontier_colonization to see a dead reddit sub. The technologies you would need to colonize space are not space technologies. I’m not sure what they are. Anyone know? What would need to change for us to build cities in Antarctica? It probably gets boring fast and that’s one reason nobody talks about it.

    I’d say it might be easier to just send humans to all the way to Alpha Centauri than to colonize Mars.

    Other links, for the uninitiated:
    https://splinternews.com/the-tech-billionaires-are-wrong-we-are-never-going-to-1793851545
    https://slatestarcodex.com/2014/07/21/promising-the-moon/
    http://www.overcomingbias.com/2008/05/empty-space.html

    • Thomas W. Hair May 29, 2020, 15:04

      I promise I am not picking at your fleas, but interestingly eleven people have been born in Antarctica and the eighth, José Manuel Valladares Solís (1980), is a personal friend here in Cape Coral, Florida. Here is a youtube video that explains how this happened:

      https://www.youtube.com/watch?v=avwC-ZCYLI4

      • Robin Datta May 30, 2020, 5:22

        The eleven seemed to be pawns in the old game of colonialism, just a day late and a dollar short.

      • anon86 May 30, 2020, 13:02

        Cool video. I would like to see more space enthusiasts going to Antarctica. That seems to me like a kind of personal space pilgrimage! It would be a symbolism or signal that we hope to expand humanity’s frontier.

        • Alex Tolley May 30, 2020, 13:38

          There are so many tours and cruises to Antarctica that the local environment is being damaged. :(

    • Antonio May 29, 2020, 16:50

      “I wish there was some way to communicate this better. Has anyone thought of ways to do that?”

      Maybe it’s you who don’t get other people’s communication. To begin with, Svalbard and similar places on Earth are not much inhabited not only due to their intrinsic difficulty to be colonized but because people have better places to live in (why to live in Svalbard when you can live in Oslo or near it?). They aren’t comparable to Mars colonies, because those would be set in the best places of Mars.

      Of course, living in most towns of Earth will be far easier than living on Mars, but there are things than can’t be done on Earth and will attract people to Mars, like trying to find out whether is non-terrestrial life in the universe or settling and exploring a completely new frontier.

    • Antonio May 29, 2020, 17:06

      “Other links, for the uninitiated:”

      https://splinternews.com/the-tech-billionaires-are-wrong-we-are-never-going-to-1793851545

      If it where true that cities can only be created when connetecd to pre-existing cities, then the Americas or Australia would never have had cities.

      Contradicting himself, he then says that American colonies where possible due to “fertile and plentiful hinterland”. And continues wrongly stating that such fertile land can’t exist on Mars.

    • Robin Datta May 30, 2020, 5:38

      Tom Murphy is an astrophysicist and a professor on the faculty at the University of California, San Diego; his NASA job is to monitor the movement of and distance to the moon to centimeter precision by laser interferometry to mirrors left by the Apollo missions.

      He has a rather jaundiced view of human prospects in space.

      • Antonio May 30, 2020, 9:33

        I find his arguments very weak, and some of them based on false data (like travel time to Mars).

      • Alex Tolley May 30, 2020, 13:33

        Murphy’s post seems like a good argument in favor of intelligent robots doing the colonizing, rather than biological humans. They don’t need to construct ecological colonies or even O’Neills. They can live unprotected in space and power themselves with abundant solar energy. Was it Stross or Varley who had beings encased in bodysuits with huge diaphenous solar collectors living in orbit around Saturn? So much easier if you are a machine instead, as the Cassini probe demonstrated. Machine intelligences will prove to be the analogous space-living descendants of humans, just as reptiles proved the true land-living descendants of fishes.

        • Antonio May 30, 2020, 14:19

          Curiosity rover costs $ 2.5 billion and takes a day to travel the same distance an astronaut can walk in a minute. Ponder that for a moment.

    • Robin Datta May 30, 2020, 5:54

      John Michael Greer’s article, referenced by Tom Murphy.

      • James Jason Wentworth May 31, 2020, 11:40

        Having corresponded with the former Grand Archdruid John Michael Greer regarding improving our lot via space technology, including asteroid mining and creating off-Earth settlements (no, he did not insist on being called by his title; he said, “John will be fine, thanks” :-) ), I found it troubling that not only was he certain that a Dark Age is coming, but that he seemed to welcome it. That’s his right, of course, but just thinking about the *veterinary* medical technology of the Middle Ages (where horses who contracted mange had their feet bled, and treated with pork fat) makes me shudder! I would not care to live in a world that had back-slid so far. Now:

        Maybe he (and the other doubters) is right, and we won’t ever really fulfill Tsiolkovsky’s, Goddard’s, and Oberth’s shared vision. But I would rather see humanity try mightily and fail at it, than simply give up, and:

        If nothing else, Robert Zubrin has to be *THE* most persistent and tireless promoter of what most people (outside our relatively small “enclave”) consider the most unpromising, unattractive real estate to be had anywhere! Although living under a Martian version of Lake Vostok doesn’t tickle my fancy (Arthur C. Clarke’s [non-fictional] proposed pressure-supported, domed-over towns are a different story…), I admire Dr. Zubrin’s tenacity in working to make his dream a reality; that kind of intestinal fortitude is inspiring and infectious, and we need more of it.

      • anon86 May 31, 2020, 16:21

        Greer’s discussion of sci-fi was good in his article on the Monofuture, which I read yesterday. That being said, I don’t agree with him philosophically. All the folks who wrote the three articles I linked to are pro-growth.

      • Alex Tolley June 1, 2020, 14:33

        Is it time to reread J G Ballard’s stories of the post space age?

        If John Greer was an intelligent Devonian Age fish, he would be arguing that the attempts to fin up onto dry land marks the end of fish civilization that is exhausting its oceanic environment. The land will forever be out of reach. And the sky? Don’t even think about it.

        Humans may not be more than a blip of intelligent carbon off planet, but our robots have a potentially glorious future. Today they struggle with even teh simplest things, but eventually, we will hit upon the technology whereby they can truly live on their own. They will colonize the system and build economies that work for them. If anything reaches the stars, it will be their descendants. We humans will remain on Earth, just as our fish ancestors remained in the seas. Perhaps some of us will colonize teh Moon and Mars, as some fish evolved to live in freshwater. But no fish adapted to living on land, they had to evolve into new types such as the reptiles.

    • Brett Bellmore May 31, 2020, 8:45

      “What would need to change for us to build cities in Antarctica?”

      Well, for starters you’d need to repeal the Antarctic Treaty. Antarctica would likely have been colonized by now, (It’s quite rich in natural resources.) if doing so weren’t illegal.

    • Bounty June 5, 2020, 1:39

      I think it just takes money and time. Were I live it used to be fairly dead useless desert. Then people spent money to irrigate it and now it’s the San Joaquin Valley of California. Bread basket to the universe. When the first European person visited here, it was Antarctica to them in 1772. Antarctica was discovered roughly 50 years later. Imagine what might be there in another 200 years?

      • Alex Tolley June 5, 2020, 13:55

        If the use of irrigation water isn’t rationalized, the San Joaquin valley will not be the agricultural powerhouse it is today. Over irrigation with unsustainable use of aquifer water, farming for profits with water-intensive nut orchards for foreign export, and other water demanding crops will eventually force a reduction in farming and the land will return to its semi-desert state. If it can be rewilded, that would be a good thing,

  • Brett May 29, 2020, 14:02

    That really is a great idea. I’d thought about having rotating habitats that were submerged in water for shielding/heat, but not about having underwater habitats on Mars. And the idea of accompanying that with photosynthetic plants, aquatic life . . . great stuff. Pretty cool imagery too.

    So if 10 meters of water overhead creates the equivalent of 0.38 bar of atmospheric pressure on the habitat, and you match that with the same pressure inside, does your habitat have to be built like a pressure vessel?

  • Gary Wilson May 29, 2020, 14:43

    I assume you would have to insulate the inner surface of each ice dome Dr. Zubrin to prevent continuous melting and reduction of the structural strength of the dome(s)? Also do you have any estimate of how long it would take, and the cost of building 1 dome of roughly the size you are discussing? I’m wondering about how many supply trips to Mars would be required with existing technology assuming we use SLS or the Falcon Ultra Heavy rockets for example or are you assuming this project is still many decades in the future? It’s an incredibly useful idea for human habitation of Mars and clearly the details could be expanded on until we have a full plan. Thank you for your continued efforts to promote human exploration of Mars.

    • Brett May 30, 2020, 13:49

      You would have to insulate the ice.

      The cost is impossible to guess, especially since this would not be a “first wave” project given the need for a 1 GWe nuclear power plant. It might be be built out of local resources for all we know rather than being shipped in pieces from Earth.

  • Alex Tolley May 29, 2020, 14:58

    Some thoughts:

    1. This idea was effectively what I was suggesting in te fictional interludes in my post on Europa: https://www.centauri-dreams.org/2019/05/10/europas-oxygen-and-aerobic-life/

    2. It appears Zubrin might be finally backing off from his insistence that the radiation level on the surface of Mars has low risk. He is now saying it is “sub-optimal”. I hope his more fervent followers at the Mars Society take note.

    3. The structural strength of the ice “roof” could be enhanced by refreezing a layer of pulp to make pycrete. This was suggested as a means to harden the hull of the “Spacecoach” concept by my colleague Brian McConnell and myself. The only downside is the reduced illumination for crop growth. However artificial light will be needed for the human residents, so why not also use it for the terrestrial plants/crops?

    4. Once the air bubble is created under the ice cover from electrolyzed/photosynthesis, wouldn’t it be better to add an insulating layer between the ice surface and the liquid and the air bubble? This might be made of almost anything available and need not be structural.
    The habitat then becomes less like living in an ice cabin or igloo, and more like a conventional habitat. Ray Bradbury suggested that the colonists would want “sun domes” in his fictional very wet and steamy Venus in his short story “The Long Rain”. A personal anecdote. Having lived in Bermuda, it was a monthly treat to stay for a week in Manhattan and enjoy dry bed linen. But perhaps I would never have made a good Mars colonist if I had to live in cold, but likely highly humid, ice cavern.

    5. I am not clear why open bottom domes are better than closed domes. The water temperature is unsuited for travel without a vehicle for most people. Rather than having an exposed pool of icy water cooling the space above it, why not just make it an insulated chamber which allows a vehicle to dock with it instead. Everyone stays dry and warm. If the ice becomes the main structural element of the roof, only the insulated skin of the “floor” on the lake water need be manufactured. Unlike a pressure dome, it needn’t be structural, over even fully waterproof. It could be largely made of floating rafts (inflated materials) linked together as a fray floor or even supporting a floor. The floating rafts could be made of metals, concrete, hollowed rocks or ice, or organic polymers – whatever resources are most economic and available.

    6. Why even create a lake at all? Living and farming space could just be hollows melted out if the ice, with tunnels connecting each habitat. The meltwater would be immediately electrolyzed for O2 and the hydrogen stored or vented. The slow trickly of meltwater would be collected in a cistern and electrolyzed to keep the volume manageable. Some would always be retained for ECLSS and irrigation. Because ice is easier to bore through and can be used for the colonists, it might well make a better underground habitat than drilling underground or finding a lava tube and sealing it. Ice is perfect for remolding and resealing, maintaining pressure without leaks.

    • Antonio May 29, 2020, 17:49

      “2. It appears Zubrin might be finally backing off from his insistence that the radiation level on the surface of Mars has low risk. He is now saying it is “sub-optimal”. I hope his more fervent followers at the Mars Society take note.”

      Take note of what? Radiation levels on Mars haven’t changed. Radiation levels measured by Curiosity are roughly the same than those measured by Mars Odyssey, which where also similar to those computed by Viking scientists. Effects of radiation on the human body haven’t changed either. Do you think that Mars Society is some kind of cult or what? That people there will follow their messiah’s change of opinion even when the data don’t change at all?

      • Alex Tolley May 30, 2020, 11:55

        Have you read any of Zubrin’s books? Zubrin has made light of the risks of radiation on the surface of Mars. It has been claimed that humans live in more radiation bathed areas on Earth and are OK, so so should humans living on Mars. I think that when Zubrin uses teh term “sub-optimal” he is acknowledging that just maybe the risk of radiation damage causing cancers is perhaps worth avoiding by using shielding. As I have sparred with Mars Society folks over this, perhaps they will also change their minds about the risks.

        • Brett May 30, 2020, 13:53

          Zubrin is mostly dismissive of radiation concerns on Mars missions that return the crew in several years a la Mars Direct. I don’t recall him being dismissive of radiation issues for people living permanently on Mars.

        • Antonio May 30, 2020, 13:57

          Yes, I have read some of them.

          “Zubrin has made light of the risks of radiation on the surface of Mars. It has been claimed that humans live in more radiation bathed areas on Earth and are OK, so so should humans living on Mars. I think that when Zubrin uses teh term “sub-optimal” he is acknowledging that just maybe the risk of radiation damage causing cancers is perhaps worth avoiding by using shielding.”

          Nowhere in The Case for Mars or other books it’s written that radiation levels on Mars are comparable to Earth nor that shielding is not needed. Just the opposite. The needed amount of shielding is computed and clearly stated, both on Mars’ surface and during interplanetary travel.

    • Law Wong May 29, 2020, 20:01

      As project iceworm and camp century on the Greenland ice sheet found out, ice can be rather unstable, shifting constantly and closing tunnels. While (dusty?) ice in a martian crater will certainly be different from Greenland, this may also be the case on Mars and Europa

      • Jens Knudsen May 30, 2020, 7:35

        I don’t have the whole picture, but the structural strength of water ice improve when the temperature drops. This part of it might be easier on Mars or a Jovian moon than on Earth. And what a solution, to use water ice, both as a building material and shielding for anything in the radiation field in the Jupiter system! Good stuff! But maybe we should do Mars first :)

      • Antonio May 30, 2020, 9:39

        Greenland ice is constantly moving, spreading out from the center of the island to the coast, slipping from high ground to sea level, being continually replaced by falling snow. That doesn’t happen in a Mars crater.

    • Antonio May 30, 2020, 14:12

      “3. […] However artificial light will be needed for the human residents, so why not also use it for the terrestrial plants/crops?”

      Because the amount of energy needed would be prohibitive.

      “5. […] Rather than having an exposed pool of icy water cooling the space above it, why not just make it an insulated chamber […]”

      I think the option explained in the article doesn’t imply that a big area of water is exposed to the air above. It can be as small as the inhabitants wish. For example, almost all the available area could be covered by floating buildings/streets and only one of the buildings would have a hole to access the water below.

      • Alex Tolley May 30, 2020, 22:25

        “Because the amount of energy [for lighting] needed would be prohibitive.

        Not at all. LED lighting is not only efficient, it can be tailored to the wavelengths needed for plant growth. You have probably seen them in indoor vertical farms. While white light LEDs would be more energy intensive, humans do not need anything close to teh intensity of full sunlight whether on Earth or Mars. Our indoor lighting is quite low intensity. Therefore creating illumination is likely to be quite efficient.

        “I think the option explained in the article doesn’t imply that a big area of water is exposed to the air above.”

        Perhaps I was not clear. The model is an ice roof that provides the mass to maintain the needed air pressure for the habitat while not incurring tension loads. Underneath that ice is air. Below that air is water in the lake. That water will be icy cold and cooling the air above it. The ice roof will also be cooling the air as well as being warmed by the warmer habitat air. Insulating the roof from teh habitat air will prevent the heat loss and warming of the icy roof. Separating the lake from teh habitat air will prevent the lake from cooling the habitat air. All this avoids heat losses, living is very cold conditions, (even if there are insulated tents as local “indoors” living spaces), and requiring energy to maintain conditions. The trick is to minimize resources to achieve this. For example, inflated plastic rafts provide a nice floor that also insulates the living space from the lake below – a low-mass solution.

        Zubrin wants to keep things “open” to try to build an ecology with humans as part of it. Whatever the merits of teh idea, it is clearly a FU to anyone who argues we should reduce contamination to a minimum until we have attempted to determine if Mars is either sterile or already just contaminated with life from Earth (c.f. his panspermia argument for Mars).

        Should this lake habitat be built in the southern hemisphere of Mars, it would likely contaminate the [frozen] aquifers with any liquid water slowly migrating to the north polar region. Best to locate this in the Boreal region to prevent this.

        • Brett Bellmore May 31, 2020, 9:02

          I doubt that we can use incident sunlight for growing crops on Mars. Not that it’s insufficient, (Less than idea, maybe, for some crops.) but rather, unreliable. You really don’t want to plant a crop that you’re relying on for both food and air, and then have one of those months long dust storms interrupt sunlight and coat your greenhouse with dust.

          The same reasoning applies to ground level solar power, obviously.

          I’d say you’d want to use a mix of ground level nuclear power, and solar power satellites. Mars is ideal for SPS’s, as synchronous orbit is much lower. And dust storms won’t disrupt the operation of rectennas.

          Then you’d use those frequency tailored LEDs to illuminate the crops. You need the waste heat for heating anyway.

          I have a Mars colony idea I call the “dirt bag”; Use a secondary system attached to the fuel generation plant to transform Methane into long chain polyethylene. (Which is “spectra” once oriented by stretching.) Then manufacture balloons on site using internal stays to contain the air pressure without forcing a spherical shape.

          You can gradually inflate them while stacking sandbags also made of polyethylene, filled with screened dirt, on top to counter some of the internal pressure. For stability reasons you’d want the network of stays to handle some of it.

          Where you want stable compressive strength, you could mix dirt screened for a good packing fraction and baked dry, mixed with polyethylene powder, and then heated and compressed to form bricks. These could be used to build domes and arches to cover the entrances to the balloon.

          The key advantage of this over Zubrin’s proposal is a much greater freedom of where you locate the colonies.

          • Antonio May 31, 2020, 11:49

            @Brett Bellmore:

            “You really don’t want to plant a crop that you’re relying on for both food and air, and then have one of those months long dust storms interrupt sunlight and coat your greenhouse with dust.”

            You are grossly overestimating the effects of dust storms on Mars. Since the air is quite thin, the wind is quite weak, and there is not that much dust in suspension during even the strongest storms. If you were inside a dust storm on Mars, it would feel like a overcast day on Earth, not a sand storm on Sahara. Also, deposited dust on the greenhouse is not that much of a problem, even if you don’t clean it daily, as Spirit and Opportuny showed (they simply accummulated dust and continued working, until a dust devil cleaned it).

            “Then you’d use those frequency tailored LEDs to illuminate the crops. You need the waste heat for heating anyway.”

            As I explained above, artificial light for a meaningful amount of cropland is simply out of the question. For a little garden? Yes. For feeding the colonists? Nope. Also, the heating is provided by the greenhouse itself, like on Earth.

        • Antonio May 31, 2020, 11:31

          “While white light LEDs would be more energy intensive, humans do not need anything close to teh intensity of full sunlight whether on Earth or Mars. Our indoor lighting is quite low intensity.”

          Huh? I thought we were talking about light for crops. From The Case for Mars:

          “Plants require an enormous amount of energy which can only come from sunlight. For example, a single square kilometer of cropland on Earth is illuminated with about 1,000 MW of sunlight at noon, a power load equal to an American city of one million people. Put another way, the amount of power required to generate the sunlight responsible for the crop output of the tiny country of El Salvador exceeds the combined capacity of every powerplant on Earth. Plants can stand a drop of perhaps a factor of five in their light intake compared to terrestrial norms and still grow, but the fact remains: The energetics of plant growth make it inconceivable to raise crops on any kind of meaningful scale with artificially generated light.”

          Next you say:

          “Zubrin wants to keep things “open” to try to build an ecology with humans as part of it.”

          Nope. The reasons are clearly stated in the article:

          “Construction of the habitats could be done using any the methods employed for underwater habitats on Earth. These include closed pressure vessels, like submarines, or open-bottom systems, like diving bells. The latter offer the advantage of minimizing structural mass since they have an interior pressure nearly equal to that of the surrounding environment, and direct easy access to the sea via their bottom doors, without any need for airlocks. Thus, while closed submarines are probably better for travel, as their occupants do not experience pressure changes with depth, open bottom habitats offer superior options for settlement.”

          • Alex Tolley May 31, 2020, 14:19

            LED lighting with tailored wavelengths is far more efficient even for crops grown in full sunlight. 30W/sqft (300W/m^2).
            There are many plants that grow at far lower illuminations, and or course algae can grow at depths that are very dim. (Red algae are found near the bottom of the euphotic zone)

  • Antonio May 29, 2020, 16:36

    A very interesting idea, and one that could be tested on Earth. From a biological point of view of the test (i.e. whether such closed ecosystem could work and how it should be created and managed) it probably could be more easily tested than a surface habitat.

    PS: Please, don’t mix unit systems. It’s quite annoying.

  • Geoffrey Hillend May 29, 2020, 17:00

    The colonization of Mars is Passe and obsolete due to the effects of Mars lower gravity on the growth of human bones, organs etc. A permanent base on Mars is more realistic. I like the idea of an underground base and digging underground on Mars to look for life and study soil chemistry and geology. I like the grand scale of the project, but there are some ethics involved here comparable to terraforming. What if microbial life is found on Mars? Should we change the landscape on the large scales?

    • Antonio May 29, 2020, 17:28

      “The colonization of Mars is Passe and obsolete due to the effects of Mars lower gravity on the growth of human bones, organs etc.”

      Nobody knows those effects, you included.

      • Abelard Lindsey June 2, 2020, 18:10

        We have two data points with regards to gravitational effects on physiology. We know one-g is good and that zero-g quite bad for you. Anything else, like Moon or Mars gravity, is based on guesses. We don’t know. If you assume a linear progression, the moon is probably out and Mars is an outpost. Since nature usually doesn’t do linear progressions, Mars will either be not so bad, or it will be nearly as bad as the Moon and zero-g.

        I believe the latter. My reasoning is based on body building, which has been very good for me over the past 30 plus years. In terms of physiology, long term natural (no steroids or other compounds) body building is essentially simulated higher gravity envirionment, perhaps 1.1 or 1.2 g. Thus a gravity lower than Earth will not be good. Say, we had a planet with 0.7 g gravity, and you lived there and worked out all the time, then you might get the same health benefits as living on Earth (but without the body building work outs).

      • Matt Williams June 2, 2020, 18:13

        Indeed we don’t. And chances are, we won’t know that until long after we establish a human presence on the Moon and Mars. But it’s not like there aren’t countermeasures. For instance, a Von Braun Wheel (Standford Torus) in orbit of either body that are spun up to 1 g. People on the surface go there to get therapy periodically. Only time will tell if this is enough.

  • Robin Datta May 29, 2020, 23:12

    Leaving Africa in the great diaspora of Homo sapiens, at each step along the way adaptation for self-sustainability in each new environment was a sine qua non for the next step. Supply from elsewhere makes life possible where it is not locally sustained, as in the Antarctic, the International Space Station and nuclear submarines, penguins, extremophiles and cetaceans notwithstanding.

    If we should have the extreme degree of foresight into deep time to the red giant phase of the sun, the basic biologic imperatives need be projected to other planets as a first step beyond the solar system.

    Those environments are so inimical that the adaptations will be so much more demanding in terms both human and matériel that the Earth base will need substantial disposable resources. For this it becomes imperative that the Earth base get its house in order before the depletion of non-renewable resources.

    A prosperous Earth can more easily be the starting point for adventures beyond.

    • Antonio May 30, 2020, 9:47

      “Those environments are so inimical that the adaptations will be so much more demanding in terms both human and matériel that the Earth base will need substantial disposable resources. For this it becomes imperative that the Earth base get its house in order before the depletion of non-renewable resources.”

      Non sense. We no longer need adaptations to live in new places anymore, from long long ago. We use technology for that. Also, no need to transport a substantial ammount of resources from Earth to Mars. Contrary to the Moon, Mars is rich, having fertile soil, ocean-sized reservoirs of easily accesible frozen water, even more easily accesible oxygen (as CO2), and geological processes that have accumulated as much mineral ores as we could wish for.

      • Alex Tolley May 30, 2020, 12:06

        Mars is rich, having fertile soil,

        You certainly have an interesting dictionary for the term “fertile”.

        From Wikipedia entry on Martian Soil:

        Martian soil is the fine regolith found on the surface of Mars. Its properties can differ significantly from those of terrestrial soil, including its toxicity due to the presence of perchlorates. The term Martian soil typically refers to the finer fraction of regolith.

        And:

        Martian soil is toxic, due to relatively high concentrations of perchlorate compounds containing chlorine. Elemental chlorine was first discovered during localised investigations by Mars rover Sojourner, and has been confirmed by Spirit, Opportunity and Curiosity. The Mars Odyssey orbiter has also detected perchlorates across the surface of the planet.

        Perhaps you can share your references for claiming Martian soil is fertile?

        • Antonio May 30, 2020, 14:47
          • Alex Tolley May 31, 2020, 14:03

            You still do not seem to understand what “fertile” means. That you even suggest hydroponics shows that quite clearly. There is a reason that farmers use chemicals called “fertilizer” because they help make the impoverished soils fertile.

            As the perchlorate article states, Mars soil is like a Superfund site.

            We would need to have ways to clean it up while astronauts are there. … It is essentially a giant Superfund site.

            The soil has to be dug out and the perchlorate removed. You may recall that when Rome sacked Carthage, they salted the soils so that the Carthaginians could never recover as they would have no food.
            Note that the article also states that perchlorates were only discovered by teh P{hoenix lander is 2008. The Case for Mars was published in 1996, before this was known. This finding put an end to the idea that you could grow plants in Martian soil. (Mark Watney could not use Martian regolith and his feces to grow his spuds. However, he might have dug down to get water rather than nearly killing himself burning hydrazine!)

            The Google books reference is for Zubrin’s “The Case for Mars”. (Circular reference?) I think you have extracted the wrong citation, as the relevant one is Stoker et al. Zubrin’s claim that Martian soil is even more fertile than Earth is laughable and based on data that did not include the later discovery of toxic perchlorates. His own table shows no data for nitrogen which the text suggests he hopes to amend by converting N2 in the atmosphere to fertilizer if necessary. IOW, the soil was not known to be fertile and would likely require amendments. Zubrin was hyping Mars colonization like land speculators selling Florida swampland in the 1920s. If the soil was ready for plants but just nitrogen-poor, the obvious solution is to allowing nitrogen-fixing plants to grown and supply the needed accessible nitrogen and do this with a crop rotation basis to maintain fertility. However, the perchlorate problem remains and cannot be solved without removal. For a flavor of real information use scholar.goole.com and search for “growing plants in Mars soil”. If Martian soil is to be used, it is probably best sourced where perchlorates are unable to form or be mixed in due to impact gardening. It is almost certainly not the case that erecting a greenhouse with air over a patch of Mars will allow crops to be grown in that soil.

      • Gary Wilson May 30, 2020, 13:34

        I think you may be overstating the livability of Mars by a huge amount Antonio. “No need to transport a substantial ammount (sp) of resources from Earth to Mars.”? That is completely untrue. If you re-read Dr. Zubrin’s article and many others on the exploration and possible colonization of Mars you will see what types of materials would need to be brought along. And no, Martian “soil” is not fertile as Alex says. It is full of perchlorates which are extremely oxidizing. If you look at the composition of soil (which is not what the surface of Mars is covered with) it contains many organic components which would have to be supplied. Yes, there is frozen water available for use by colonists or explorers but many other resources would have to be brought along. Please refrain from using terms like nonsense when commenting as it adds nothing to the discussion.

        • Antonio May 30, 2020, 15:38

          I call something nonsense when I think it’s nonsense, and I already explained why it’s nonsense. There’s no point in calling it something different. Simply saying “nonsense” and nothing more certainly wouldn’t add much to the discussion, but I didn’t do that and I see no reason to hide my assessment of the argument I’m replying to. When it’s right, I say “it’s right”, when it’s false, I say “it’s false”, when I agree, I say “I agree”, when it’s nonsense, I say “it’s nonsense”.

          “If you re-read Dr. Zubrin’s article and many others on the exploration and possible colonization of Mars you will see what types of materials would need to be brought along”

          It seems that you didn’t read Dr. Zubrin’s articles or books. In them he explains what could be produced on Mars and what not. Apart from the very first missions, only a small amount of materials and products will need to be transported from Earth compared to what will be produced on Mars, mostly high technology products, like microchips, turbines, etc. Around 1/3 or 1/4 of The Case for Mars is devoted to explain how to manufacture the rest, so I will not develop it further here.

          “If you look at the composition of soil (which is not what the surface of Mars is covered with) it contains many organic components which would have to be supplied”

          Again, nonsense.

          – Plants feed on inorganic salts and produce organic compounds from them and sunlight. It’s animals (and fungi, etc.) who feed on organic matter. Plants can perfectly grow in soils with no organic compounds at all.

          – The organisms that use the organic compounds are fungi, bacteria, etc. They recycle dead plant matter, decomposing it into elements and salts that the plants can use.

          – So the organic compounds in the soil are part of the recycling process, not something the crops need. The elements and salts lacking in the soil and needed for the first seeds in a new greenhouse can be supplied by artificial fertilizers (that can be produced on Mars) or from the colonists feces.

          • Gary Wilson May 30, 2020, 22:10

            “In general, soil contains 40-45% inorganic matter, 5% organic matter, 25% water, and 25% air. In order to sustain plant life, the proper mix of air, water, minerals, and organic material is required.” The source is “The Soil, Boundless Biology.” If you read the second sentence above Antonio you might learn something. I only pointed out your unnecessary use of the word nonsense because it implies you know what are are talking about whereas many others on here don’t, which seems unlikely based on the responses you get on here. I learn something on here every day. Do you? Or do you already know everything? You rarely cite the sources of your information and opinions even when requested to do so. This is my last comment to you. You even imply in your comment that plants do need organic material ala “can be supplied by artificial fertilizers (that can be produced on Mars) or from the colonists feces.” “Feces are composed of water, protein, undigested fats, polysaccharides, bacterial biomass, ash, and undigested food residues.”

            • Brett Bellmore May 31, 2020, 16:04

              Look, if you were right, hydroponics would simply be impossible. The truth is, plants do just fine on simple inorganic compounds.

              They tend to do better than fine if you have the right organics present, due to symbiotic relationships with fungi, and because organic materials can improve water retention. But you can grow plants quite easily using nothing but simple chemicals available in a lab.

              People do it all the time.

  • Joel Schoenberg May 29, 2020, 23:17

    I wonder if organisms have already figured out the Mars life dynamics described in this article. For instance, is it possible there are lots of life organisms that have figured out that closer to the center of Mars there will be sufficient pressure to be more habitable. And maybe over eons those organisms have figured out nutrient cycles that work in that environment and allow it to flourish. Then, when humans get there and start digging they expose and find some of these organisms. Sounds like a great science fiction story!!

    • Alex Tolley May 30, 2020, 12:18

      There is certainly a lot of astrobiology interest in teh idea of subsurface organisms. They may be living in caves largely sealed off from teh surface. They may be pockets of water deep below the surface that temperature and pressure ensure remain liquid. They may be lithophiles living in the crustal rocks where liquid water can seep slowly between the grains in the rocks. All of these locations are hard to reach, except possibly near-surface caves or lava tubes. Drilling kilometers down into the regolith will require substantial drilling equipment and probably won’t happen until there is a need for local water supplies. That scenario was tangentially depicted in the National Geographic series “Mars”.

      If Mars has life, samples would be so valuable because they would uncover differences between Martian biology and our own. Is it a 2nd genesis or a common one with Earth?

      I can’t help visualizing the Apollo 15 discovery of the “genesis rock” on the Moon that was also dramatized in teh tv series “From the Earth to the Moon” (ep. “Galileo was Right”). If there is life on Mars, a future scientist might have just such a moment if the analysis indicates it was definitely from a 2nd genesis.

    • Antonio May 30, 2020, 15:50

      There is active volcanism in Mars (according to Mars Express, as recently as two million years ago), so certainly there is subsurface liquid water relatively near the surface, where ancient life from the surface when Mars was wet and warm could have survived and continued evolving.

      https://www.space.com/198-mars-volcanoes-possibly-active-pictures-show.html

  • ole burde May 30, 2020, 2:27

    Generally ,Martian water is likely to contain high concentrations of poisonous chemicals , and this wil probably include frozen crater-lakes .
    This is a serious problem for all utilisation of martian resources .Any water to be used , will probably need to de-salted using tecnology similar but not identical to existing desalination plants on earth……so if we want to calculate the launch-weight requirements for a martian base , add a few tons !

  • Mike Serfas May 30, 2020, 16:57

    This is an ingenious essay which may reshape how we imagine a Mars environment. However, I was thinking the same as Alex Tolley – why use liquid water?

    For all its advantages to life, liquid water has a tendency to get into trouble – leaking into the living space, or flowing outward and dissipating, or dissolving toxins, or even serving as the environment for unwanted terrestrial or martian microorganisms whose biochemical activities could be harmful.

    Melting large areas for habitation requires the construction of an impressive reactor. By comparison, there is no obvious physical limit to the efficiency with which clever new inventions could cut into ice and remove pieces. Chunks of ice might be purified as a source of some elements and refrozen in a countercurrent arrangement that recycles much of the spent energy, leaving habitable real estate plus an intensely valuable resource for human habitation and propulsion in a safe, pure form for later use. Caverns cut from the ice can be sealed up with layers of applied water. If an internal liquid water lake is truly desired, a sturdy impermeable polymer wrapping can be laid down inside first.

    The technology for these things should not be left for Martians to figure out. Our own Earth is provided with a continent ripe for colonization beneath the ice, at least for a little while, which in time might be the best place on the planet for humans to cling to life.

    Other cavernous features of Mars might come with enough water, or have it brought in on trucks, to permit shells of ice to be constructed for similar use. If plants can be designed capable of surviving local conditions (Mars has about 600 pascals of CO2 versus only 40 pascals partial pressure on Earth) you could even make Pykrete. :) I daydream of caverns leading deep into the old subduction zones of Mars – and unexpected wonders.

    • anon86 May 30, 2020, 22:23

      Maybe we can find some places with shallow ice in Antarctica to test out this proposal. Sounds like a hell of an aquarium.

    • Antonio May 31, 2020, 12:22

      There have been some studies about constructing with Mars ice[1]. This is simply another alternative.

      [1] An example, but there are others: https://www.youtube.com/watch?v=kgIEyKtQlTc

  • Geoffrey Hillend May 30, 2020, 18:01

    Antonio, I am making an extrapolation based on the harmful effects of long term zero gravity spaceflight. I did not make up this idea myself, but read it from various sources, books and internet articles. There is bone loss and muscle atrophy. Cosmonauts first discovered this when they spend a long time in space. After their capsule landed, they couldn’t walk because of muscle atrophy which is why now long term space flight requires continuous exercise in orbit. Older people need to walk and get some foot impact with the ground, the stress on the bones keeps them strong.

    The gravity on Mars is 38 percent that of Earth, so 100 pounds only weights thirty eight pounds on Mars. On the Moon, one weighs on 17 percent of being on the Earth. The surface gravity is based on planetary mass, the smaller the mass, the weaker the gravity.

    The problem is that if an astronaut spends a long time on the on a Moon base there will be some problems with bone and muscle loss due to the less gravity. Bones and muscles need the right amount of stress. The same it true on Mars. If a baby is born on Mars or the Moon and grows up only in a lower gravity environment, there will be changes in bone growth and muscle mass that will deviate from normal. These physical problems will be permanent like bone fragility, longer thinner bones, etc. The human body and bone morphology is designed for a human one G environment. https://en.wikipedia.org/wiki/Effect_of_spaceflight_on_the_human_body https://en.wikipedia.org/wiki/Effect_of_spaceflight_on_the_human_body

    Also the colonization of our solar system was science fiction at one time and not a lot was known about the effects of long term living zero gravity and low gravity environments, so these were not in the collective imagination. There are limitations of physical and reality that have become known to me much later in my life. I read Arthur C. Clarke’s book Imperial Earth as a junior in high school. It was very inspiring science fiction because I thought it could happen in our future that we will colonize Saturn’s Moon Titan like in the Clarke’s book. There is a glamour to it, the Red clouds and seeing Earth as a distant star from Titan, a time before we knew that Titan’s sky was completely cloudy with no openings to see Earth. I still like the book since it was inspiring, but I think the colonies will remain science fiction. A base is still possible.

    • James Jason Wentworth May 30, 2020, 23:10

      On the Moon or Mercury (especially in lava tubes, shielded from radiation), Mars, other planetary moons, and even asteroids, combination centrifugal “gravity”/natural gravity habitats could provide a 1 g environment. The rooms’ floors–in rooms inside rotating multi-story cylindrical buildings supported on electromagnetic bearings–would be tilted at an appropriate angle to the local vertical (with the floors’ outer edges angled upward with respect to the horizon, with this angle depending on the local fractional-g gravitational acceleration), such that the vector sum of the centrifugal and natural gravity would produce 1 g, perpendicular to the tilted floor, and:

      On very low-gravity objects, such as small moonlets (like Phobos and Deimos), asteroids, and comets, the centrifugal “gravity” would provide virtually all of the 1 g acceleration, so their floors would be very nearly parallel to the local vertical. Such habitats, which could look like the early “wheel” space station designs, could straddle craters, held in a frame of girders that span the lip of the crater, with the habitat’s central shaft supported in electromagnetic bearings. Entry and exit would be via a walkway across the frame from the crater lip, leading to a central airlock/elevator (which needn’t be prevented from rotating, since it would rotate quite slowly, being at the center of the toroid).

    • Antonio May 31, 2020, 12:37

      @Geoffrey Hillend:

      We simply don’t have enough information to extrapolate. We only have examples at 100% and 0% g. There have not been any experiments in betweeen, even for animals. We simply can’t predict the lifelong effect of 40% g. IIRC, the Mars Society and the Planetary Society (or maybe only one of them) tried to launch such an experiment to LEO with mice, but eventually couldn’t get enough money. There was also a similar soviet experiment but the rocket exploded and the project was discontinued, I think. If I can remember the names I will post them.

  • Alex Tolley May 30, 2020, 18:25

    Zubrin being dismissive of radiation on Mars:

    From “How to Live on Mars” ppbk (2008)
    Chap. 6 How to Save Money on radiation Protection

    Cosmic Rays:

    Let me walk you through the math. Let’s ay you are a 40-year-old woman. At 10 Rem per year, it will take you 60 years to accumulate enough radiation to give you a 10 percent chance of getting cancer within the next 30 years, i.e., by the time you are 130 years old, and almost certainly dead. If you are a man, and thus a bit less vulnerable, you won’t have to face the same modest level of risk until you are 150.

    Solar Flares

    On Mars, however, we don’t need solar flare shelters, because the atmosphere, thin as it is, [provides about 21 grams per square centimeters of carbon dioxide mass shielding looking straight up towards the zenith, and an average of 65 grams per square centimeter if you average all the potential paths for radiation coming in slantwise from all directions. This is significantly more shielding than that offered by even the best onboard shelters used by first-class passengers on the fanciest spaceships, so it’s certainly good enough for you.

    If he believed this, then why build habitats 10 meters below the ice surface? Of course, if you want an ecosystem to develop and last, that might be prudent. However, of the many difficulties creating such an ecology, radiation is going to the least of your problems.

    O’Neill wanted such ecosystems to develop inside his space habitat with separate farming areas. If a disease broke out in the farms, he just suggested exposing the habitat to vacuum and solar heating. No mention of the solution if disease reached the main habitat area. We have some idea of the difficulties of creating ecosystems, enclosed and otherwise. Probably better to manage such living systems like farms or gardens, constantly keeping them under control rather than letting them develop on their own.

    As for disease outbreaks, one can only hope that a Mars colony responds better than the US or the UK to the Covid-19 outbreak. It would be irony indeed if Heinleinian libertarian ideas of “freedom” meant that a number of people had to be summarily thrown out of the airlock with a suit if they failed to comply with struck public health orders. ;)

    • Brett Bellmore May 31, 2020, 10:12

      “If he believed this, then why build habitats 10 meters below the ice surface?”

      I thought that was clear: The weight of the ice counters internal pressure. Radiation shielding is just a bonus.

      • Alex Tolley May 31, 2020, 14:26

        Fair point. The main reason is to use the mass of the ice to counteract the pressure needed to live in teh air bubble. But also let’s be clear that this can be done on the surface, using rock and gravel. What Zubrin wants is an ecosystem to develop in the lake water. However, the depth of the ice roof will largely preclude the light needed to reach the photosynthetic plants in the lake or the habitats, which largely undermines the rationale.

    • Antonio May 31, 2020, 12:54

      I didn’t read that book, but the first quote seems to be about the Earth-Mars cruise, not life on Mars. According to Curiosity data, radiation during cruise (with only the protection of the fairing) was around 66 rem/year, which is not that far from the 10 rem/year you wrote, probably obtained when the crew is surrounded by the water and rations inside a Mars Direct type spacecraft.

      On the second quotes, I read something similar in other books. This obviously doesn’t imply the use of a thick ice cover for radiation shielding. Shielding (whether ice or sand) would be used for “normal” cosmic rays.

      As for the 10 meters of ice, I agree with Brett Bellmore, it’s needed to support the air pressure and for structural stability of big domes.

  • Patrick Underwood May 30, 2020, 18:34

    All y’all’s objections have been duly noted by Elon Musk. :)

  • Geoffrey Hillend May 30, 2020, 18:41

    The idea of creating lakes under craters on Mars is not supported by scientific principles. The problem is the thin Martian atmosphere which is less than one percent as dense as Earth’s or six or seven millibars. Earth’s one bar equals one thousand millibars. Mars thin air is below the water vapor pressure melting point which means that large bodies of water like lakes can’t remain liquid. If the surface temperature is too hot, the water immediately turns into a vapor. If it is too cold it immediately freezes so below the vapor pressure melting point, there is no temperature that water can exist as a liquid, but only frozen or a gas. If we heat the underside of the water in the crater, it might turn to a liquid but only for a short time, since the weight of thin ice on top might not be enough weight, or even if it was enough, the heat of the water through convection, conduction and even radiation, infra red would cause the ice on top the crater to quickly evaporate. The ice would turn directly into a vapor and the so would all the ice in the crater over a long time. The ice would leave the crater and become clouds and not remain in the crater long term. https://en.wikipedia.org/wiki/Water_on_Mars

    The only way to correct this problem would be to increase the amount the mass of the atmosphere of Mars by adding more gas into the air. This would be on the scale of terraforming. There are various ideas to do that like mirrors in space reflecting light on the north and south poles of Mars. Changing the surface reflectivity of the ice with a dark power or dark material. These would be the easiest to accomplish. I question the ethics of it though, since healthy colonists are out of the question, so why would we need to terraform Mars. A permanent, self supporting base might be more practicable to start. Hopefully, a base that has larger living quarters than some proposed barrels and canisters. Larger buildings could be built with more machinery and supplies.

    • Robin Datta May 30, 2020, 22:23

      For a liquid state, the surface has to be in contact with a gas of sufficient pressure to keep the molecules of the liquid from escaping. The warmer the liquid, the faster its molecules move, and the greater the pressure needed to keep them from escaping. This is known as the vapor pressure of the liquid at that temperature.

      The Martian atmosphere has a pressure of 610 Pascals at the surface. Water has a vapor pressure of 652 Pascals at 0°C. Water molecules will escape: the water will boil away. If below-freezing ice were heated to the melting point, it would not melt; it would directly become water vapor. The process of turning from solid directly to gas is sublimation.

      • Antonio May 31, 2020, 13:15

        Nope. The pressure below the melting ice is not the same as the pressure in the surface.

    • Antonio May 31, 2020, 13:13

      Huh? Nobody is talking about making an open air lake, nor a lake under a thin layer of ice. It’s below at least 10 meters of ice.

  • Gary Wilson May 30, 2020, 19:34

    This is off topic but it was wonderful to watch the SpaceX launch today. A beautiful site to see, including the landing of the first stage. Looking forward to many further manned missions. Well done Elon and team!

  • Emil Mihaylov May 31, 2020, 5:37

    Why should we terraform Mars ?
    Venus is 10 million kilometers closer, with the best conditions for humans to live at 50km altitude in the Venus’s Stratosphere where temperature is 27deg.C, pressure is 1bar , gravity is 0.9g, CO2-atmosphere, moderate radiation.
    Same like on the beach in Miami.
    You can go out the Airship Station just in your jeans and t-shirt, with a small O2-mask on your face.
    No need of pressurized suit as on Mars ( not the funny fancy one as in the “Martian” movie) and everywhere in the Solar System .
    Also, times more windows for launching spaceships to Venus than to Mars.
    We can build gigantic Colonies on Venus, using low-cost Basalt-Fiber Composite assembly-modular panels, produced on the Moon, starting to terraform the Venusian hellish surface down there, step by step – it’ll take maybe 1,000 years.

    • James Jason Wentworth May 31, 2020, 13:04

      I’ll get to Mars below, but first:

      There have indeed been studies of near-term Venus atmosphere expeditions (NASA has done this recently), and even projected future colonies floating that high in the Cytherean atmosphere, supported by balloons containing ordinary Earth-type, breathable air (they would be buoyant in Venus’ carbon dioxide atmosphere).

      The NASA study, called HAVOC (High Altitude Venus Operational Concept, see: https://phys.org/news/2018-10-nasa-humans-venus-brilliant-idea.html and https://sacd.larc.nasa.gov/smab/havoc/ [and *this* https://www.youtube.com/watch?v=0az7DEwG68A&feature=emb_logo video shows the mission operations well]) envisions two ships, one of which would enter the atmosphere (the other, Earth-return ship would enter Venus orbit) and deploy a folded solar-electric powered blimp, carrying a crew of two, and:

      The blimp would also have a two-stage, winged liquid propellant rocket (resembling a very short and fat Pegasus launch vehicle) at the rear of the blimp’s pressurized control car, to carry the blimp’s crew back into orbit. The airship would drop instrument packages onto the surface, deploy weather balloons, and might even collect Venus surface samples using a cable winch/scoop system.

      The return to Venus orbit would be very dangerous–once the winged rocket dropped free, if its engine failed to fire, or shut down early, the results would be dire indeed–death by Cytherean atmospheric sulfuric and hydrochloric acid, heat, and pressure (no doubt augmented by the ultimate explosion of the rocket)! The same hazards would apply to people traveling to and from balloon-supported atmospheric colonies, and for both arrivals *and* departures–but it could be done. Terraforming the planet, while it would take longer, would be safer, since colonists could land and live on the surface. Also:

      While Venus’ slow–and backward, to us–rotation doesn’t generate a protective magnetic field (and the long days would perhaps make only the polar regions comfortably habitable; at least the surface gravity would be fine), Venus–with some DIY “sweat equity” invested in terraforming it–may ultimately make a better second home than Mars, but that doesn’t necessarily mean that Mars would be of no use to us:

      Instead of trying to settle the planet itself, given its 0.38 Earth-surface gravity and thin atmosphere (which, even if oxygenated, would leak away into space, and faster than the heavier carbon dioxide), it might prove better to use Mars as a metals/minerals/volatiles mining site…for O’Neill, Kalpana, and perhaps other types of space colonies, which could be built in orbits in the Mars system (a Mars space elevator could be built using existing materials). Rotating-staff Mars surface bases (and bases on its two moons) could be more easily supplied with food grown in the colonies, and the planet itself would become a prime tourist attraction, for the locals as well as visitors from Earth.

  • Harold Shaw May 31, 2020, 9:10

    The habitats wouldn’t survive terraforming Mars. That doesn’t make them a bad idea but it does effect their long term return on investment. They would either have to be abandoned or modified to survive the transition. The ice could become unstable well before terraforming makes the surface habitable.

    The meltwater wouldn’t have to be kept within the habitat. It could be transported outside the habitat and used to build additional structures. If the ice filled crater is adjacent to other craters, the meltwater could be used to fill them. It would likely be easier to slowly fill the crater and repeat the process of opening a cavern than to build a scaffold to support the dome as it freezes.

    • Antonio May 31, 2020, 13:22

      “The habitats wouldn’t survive terraforming Mars.”

      Yep, that’s a big point for inflatable surface habitats. OTOH, they are a good test bed for the colonization of Ganymede, Enceladus and the like.

      • Law Wong May 31, 2020, 23:28

        TBH, a part of me relishes the effects of terraforming on the subsurface and surface habitats as the permafrost turns to mush and the bleachy dust mixes in with the mud.
        Domes, surface structures of all sorts (bridges, railway lines, pipelines), subsurface tunnels… a lot of those might destabilize, and badly, depending on how things go.
        Planetary construction sites are not good places to live.

    • Mike Serfas June 2, 2020, 16:31

      I would like to imagine that if you have the wherewithal to change a whole planet, the loss of a few localized habitats would seem very minor to you. But then again, our terraforming of Earth promises to wipe out habitats like Venice and New York City, and admittedly the inconvenience seems noticeable.

    • Wojciech J June 2, 2020, 19:31

      Terraforming is a very romantic idea, but will be eventually abandoned when more efficient, quicker to build and less costly artificial space habitats will become available.
      I can imagine Mars eventually terraformed as it is a cultural vision many people are attached to, but I don’t believe we will see many planets treated this way.

  • Geoffrey Hillend May 31, 2020, 14:18

    If one melts the ice in a crater beneath the surface, the heat will be transferred through the water through conduction and convention to the surface ice and melt it.

    I’ll agree that nobody has tested living in a low gravity environment, but the idea that is that scientists can predict the outcome based on simple physics There are always human volunteers to try it. Don’t count me in.

  • Dave Moore May 31, 2020, 15:18

    Regardless of the exact merits of Zubrin’s scheme, I think he’s on to something here. Compare tunneling through ice for your first base on Mars to the current ideas of bringing modules from Earth and burying them.

    Cutting tunnels through ice or and ice/soil mixture is easier than digging up rock/soil regolith. (You would have to bring some sort of digger to Mars.)

    Ice has enough structure strength so the tunnels, if deep enough, would hold their shape and can be pressurized. The air in the tunnels would be kept refrigerated. Individual living units could be placed in excavated caves. They would have an inflatable skeleton and an insulating layer so the temperature inside is comfortable. (So, no bringing modules all the way from Earth.) Cold air would be circulated around them to prevent the ice around them from melting. Basically, you have a sub-surface Antarctic base. In fact, you could build an entire replica of this in the Antarctic as a test run.

    And finally, the base is at a site where you can electrolyze ice for rocket fuel.

  • Thomas W. Hair June 1, 2020, 9:50

    I see a lot of talk about soils, perchlorates, and growing stuff. Knowing very little about the subject, but being a keen observer I recall floating in a barge at EPCOT on a ride simply called “The Land” where I witnessed enormous plants growing out of pure white quartz sand and more importantly with no soil whatsoever. It was impressive.

    • Alex Tolley June 1, 2020, 14:06

      Hydroponics and their ilk use non-reacting materials as a substrate. Think of pure silica sand as an extreme version. Then the pH-balanced appropriate nutrients are introduced and sensors control the rate of nutrient addition. But allow toxic contaminants to get into the system and the plants die. Try adding dilute bleach to a pot plant and see what happens. ;)

      To use Martian solid will require removing toxic compounds one way or another. That may be physical or chemical washing many tons of material, or perhaps using microbes to detoxify the solid first. The main thing is that we cannot grow plants in perchlorate soils as presumably, Watney did in the “The Martian”. And he was a botanist!

      • Brett P Bellmore June 1, 2020, 20:22

        The soil would have to be extensively baked and rinsed before use in any agricultural application, not just to deal with percolates, but also salts. In fact, I suspect salt will be a major byproduct of water processing on Mars. I wonder if it would be feasible to use it as a construction material?

        Colonizing Mars has been a regular bedtime story topic for my son, and a minor plot point has been the use of slabs of rock salt as a building material.

      • Thomas W. Hair June 1, 2020, 21:06

        So how does your response or the one that follows dispute the simple fact that hydroponics works. You don’t need soil to grow food. And I know I changed the discussion from soil to hydroponics because as Paul’s rules say “stay on topic”. The topic is Zubrin’s vision for settling Mars and detailed soil analysis is not.

        As someone in the “Treasure of the Sierra Madre” might say if they were an early Martian colonist:

        Soil with perchlorates? We don’t need no stinking soil with perchlorates.

        • Harold Shaw June 2, 2020, 8:47

          Obviously hydroponics and aquaponics work and the argument that Martian soil isn’t fit for growing plants without extensive conditioning shouldn’t be taken to mean that growing food on Mars is impossible.

          • Thomas W. Hair June 2, 2020, 22:30

            Thank you Harold, you say it best. I also have a small hydroponics garden in my sunny south Florida backyard that runs on nothing but tap water and a pinch of Miracle-Gro.

          • Alex Tolley June 3, 2020, 12:26

            The argument stemmed from Antonio’s claim, sourced from Zubrin’s 1996 book “The Case for Mars”, that Martian soil (ie fine regolith) was fertile (possibly even more so than Earth soils). The subsequent discovery of perchlorates in the Martian regolith effectively invalidated that claim. At best perchlorates are like salting perfectly good soil and making it unusable for crops. Poor irrigation techniques that add salts from evaporating water destroy the fertility of soils too. Of course, you can grow crops anywhere where the required nutrients and light are available. Indoor vertical farms and experiments in space have proven that.

    • Harold Shaw June 1, 2020, 15:01

      I am a aquaponics hobbyist and certainly no expert on soil-less growing. The discussion above isn’t about whether plants can be grown without a soil medium but whether plants could be grown directly in Martian soil in a surface greenhouse. Martian soil is not fit for growing plants but there are several ways to remove perchlorates including the use of microbes.

  • ljk June 1, 2020, 12:09

    Biological humans might have a chance to live in all sorts of environments throughout the Sol system and beyond if they were genetically engineered to do so. Perhaps throw in some necessary cybernetics for good measure.

    Of course the ethical issues will probably be more difficult to surmount than the technical/scientific ones, although it would be ironic that some may be upset over genetically changing a human being to live in the oceans of, say, Europa or those Martian crater lakes, yet humans are constantly doing everything they can to change themselves both physically and mentally in the massive and lucrative quest for self-improvement.

    How bad would it really be if changing a human to be able to survive and thrive in all sorts of environments in order to preserve our species and get at least a bunch of our eggs (us) out of that one cradle (Earth)?

    We have evolved over 7 million years from apelike creatures to modern humans. How many are really upset at what nature did for us without our asking? How many want to go back to be Homo habilis?

    Do not be surprised if the organic aliens we may encounter one day are not the original base species but the genetically modified versions designed to survive long space journeys and other worlds. Will they have issues with genetic transformations, or is it just us because we have such a parochial view of existence?

    I still think full-on artificial beings, or Artilects, are how things will go at least with us, but that is for another discussion.

    • Alex Tolley June 1, 2020, 13:59

      If the genetic change was voluntary, as in the movie, “The Titan“, then that is OK. What is not OK is to force people to make the change, i.e. be born changed, which is the only way we can do that now. Humans do evolve, but evolution is slow and incremental. Makin a radical change that isolates the involuntary modified from the rest of humanity is immoral. [I seem to have read several SF short stories about this in recent years].

      The only moral approach is offering choice to those wanting change, and that is most likely to be hardware rather than software. While we do not have teh technology, I always liked John Varley’s solution – a force field skin and implanted O2 device in one lung, allowing unprotected surface living on a range of worlds.

      • Robin Datta June 2, 2020, 0:54

        Human evolution is proceeding faster than ever before; this is a recent acceleration attributed to cultural and ecological influences driving adaptive change. Racial variations at their extremes have already been mistaken for species differences. Rather rapid speciation at the fringes could yet be a possibility, and greater variations in the milieu from residence away from the home planet could further expedite the process.

        • Alex Tolley June 2, 2020, 10:28

          There is a qualitative difference between human evolution and genetically altering humans to teh extent needed for living on other planets. AFAIK, no current evolutionary change makes any human a separate species, isolated from the rest of humanity. Current evolutionary changes are detected at the DNA level and in rare differential physiological responses.

          The changes needed to live on other planets would need to be more extreme, making those individuals very different from Earthlings and possibly a completely separate species. Allowing that to happen slowly over many millennia is one thing, creating such change in the lab another. I think it is morally no different than resurrecting a few Neanderthals now that their species has become extinct, and Neanderthals are likely far closer to us genetically than the gene engineered beings who are designed to be pre-adapted to other planets. There are good reasons why germline gene editing other than for correcting genetic diseases is unacceptable today. Radical germline gene engineering is beyond the pale. The only way for gene engineering to be acceptable would be for voluntary or elective somatic engineering. However, unlike the movies, this cannot change the individual much compared to the base state.

    • anon86 June 1, 2020, 19:46

      The problem with the singularity concept is there’s nothing we can do about it, so it’s better to forget it.

      This blog is more on target. Interstellar probes, finding habitable exoplanets, even communicating with aliens are all goals that might pan out.

    • Harold Shaw June 2, 2020, 12:22

      Since others shoveled coal into this thread derailment I may as well pitch in.

      Transhumanism, or whatever we want to call the model for species transforming themselves, offers the most efficient way for a people to become space faring. We also can’t stop the process. The desire to grow new limbs and organs, transition gender and live longer will take us there. Transhumanism also shows how the trope that colonizing Mars or expanding into space increases the the survival chance of humanity, is over simplified. In the short term colonizing Mars and the solar system could dramatically increase the risk to humanity. The rate at which we will be able to speciate will exceed our ability to embrace diversity. The same tools that protect planets from asteroids can be used to threaten. I don’t think we can learn to embrace diversity without the examples provided by transhuman colonization of space. I also think transhumanism is more vital to the future of Life than humanism. We can’t be blind to the short term increase in risk without increasing the risk.

  • Geoffrey Hillend June 1, 2020, 15:23

    I like the idea underground living quarters for solar radiation protection and geological study, but that capability does not come without establishing some type of permanent base. Some kind of electric digging machines would be needed since the human energy needed to dig tunnels and caves could be used more efficiently to build prefabricated, computer designed shelters. Underground living quarters on Mars is still quite some time in the future.

    We don’t have to learn to live permanently on less habitable, small, cold worlds with little atmosphere and low gravity. We can learn to take care of our own planet and become in harmony with nature and the biosphere. Also with technological innovation we will eventually have interstellar travel and settling on Earth twin exoplanets if we want to. With advanced enough technology, no settling will be necessary maybe until 150 million years in the future when we can move to another star system.

  • Andrei June 1, 2020, 15:31

    Hello Mr Zubrin, it was an interesting read.
    Being a biologist with an interest for life in extreme environments I am far from qualified to comment on several aspects of this presentation.
    But having a lake placed over a colony would indeed work as a shield against the radiation.
    The idea of bioforming Mars is also feasible, meaning that the planet can be changed so that some organisms can live on the surface.
    But I am sorry, a bioformed Mars does not mean that it would be possible to introduce penguins or sea otters.
    We envision the introduction of lichen and algae on a bioformed Mars and if the planet can be managed correctly it might also become home to invertebrates. But such a goal is far off in time, probably several millennia. And such a timespan is needed build up biomass and topsoil so that future colonists can grow crops on the surface.
    Yes several crops that humans can use and digest might be possible to grown on such a world, but the atmosphere will never be suitable for mammals or birds. If geneered species of coldblooded anura or caudata will be added to such an environment – perhaps to keep the number of pesky slug or for aesthetic reasons – is an open question.

  • Abelard Lindsey June 2, 2020, 18:13

    A sober video on what we need to do to go to Mars. Its quite entertaining as well: https://www.youtube.com/watch?v=14_V4nbI8xA&list=WL&index=3&t=5s

    The low gravity is the biggest deal here.

  • Douglas Muir June 4, 2020, 11:40

    This is a fun idea, but I don’t think the math works. The attenuation length of photosynthetically active radiation (PAR) in clear ice is actually pretty short. The reason you see photosynthesis under Arctic ice is because (1) it’s uneven with lots of thinner patches, and (2) in summer, you get very long exposure times. Mars is starting with less than half as much PAR to begin with, so you can’t let the ice be too thick if you want to use natural illumination.

    But if the ice is thin, then you’re going to have a problem with sublimation. Heat conduction from the bubble of warm water will warm the ice — not necessarily up to 0 Celsius, but enough so that sublimation from the upper surface will become an issue.

    Also, Zubrin is ignoring the pretty strong possibility that ice on Mars will not be simple water ice. We already know about the presence of perchlorates. Current thinking is that the Martian surface is generally enriched in heavy volatiles – chlorine, phosphorus, sulfur. All of those form a wide range of salts and other water-soluble compounds. So, it’s strongly suspected that most water on Mars will be in the form of brines, whether liquid or frozen.

    The good news is, those brines will be a lot easier to melt. The bad news is, when melted they’ll probably be something like bleach or diluted battery acid.

    Doug M.

  • charlie June 8, 2020, 15:32

    “If we take this as our standard, then each GW of our available electric power could be used to illuminate 20 square kilometers of lake.
    The first organisms to be released into the lake should be photosynthetic phytoplankton and other algae, including macroscopic forms such as kelp. These would serve to oxygenate the water. Once that is done, animals could be released, starting with zooplankton, with a wide range of aquatic macrofauna, potentially including sponges, corals, worms, mollusks, arthropods, and fish coming next. Penguins and sea otters could follow.”

    All these creatures would live under a cap of ice ??? Seems strange.

  • Richard June 15, 2020, 20:13

    I don’t have too much to add to Mr Zubrin, but I think he was a delusional dreamer, if he wanted to get anybody to mars, he should of built an engine to get there and back within a year, and work out the problem with radiation.

    He claims that NASA’s Gateway is nonsense, but the truth is, it is apart of what Apollo never got to. Testing people in the environment. Who’s been there? Recently?

    And to make matters worse, Dennis Hope continues to sell plots of the Moon. How will anybody get to the star trek future, that Mr Zubrin deluding continues to go on about. The man needs to be serious about space flight, build a hotel in low earth orbit, build a station around the moon that is beefed up for action from radiation and the sun.

    Dreaming is great, but when it concerns space flight, nothing happens. Living on Mars, terra form, seriously.

    Space exploration technologies may get people to the Moon or Mars, but they need to make money first. And then if so, then the legal battles will commence, everything William Anders probably thought of, and warned against going to Mars as a competing, and hating species.

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