Heating Mars On The Cheap

Mars is fairly attractive as a potential future home for humanity. It’s solid, with firm land underfoot. It’s able to hang on to a little atmosphere, which is more than you can say about the moon. It’s even got a day/night cycle remarkably close to our own. The only problem is it’s too darn cold, and there’s not a lot of oxygen to breathe, either.

Terraforming is the concept of fixing problems like these on a planet-wide scale. Forget living in domes—let’s just make the whole thing habitable!

That’s a huge task, so much current work involves exploring just what we could achieve with today’s technology. In the case of Mars, [Casey Handmer] doesn’t have a plan to terraform the whole planet. But he does suggest we could potentially achieve significant warming of the Red Planet for $10 billion in just 10 years.

Giga-Scale Production

Mars actually looks pretty livable in photos, but you’d die if you were standing there in the open. Credit: NASA, public domain

Handmer doesn’t hope to give Mars a comfortable climate and fully breathable atmosphere in one go. Instead, the idea is first to warm Mars up significantly and release additional carbon dioxide. The hope is that this would help create a warmer blanket around the planet as a starting point for further terraforming works. His plan involves no nuclear reactors, chemical seeding, or big mining operations. Instead, it’s about maximising the amount of heat pumped into Mars for the lowest cost.

The concept is simple. By increasing the amount of sunlight falling on to Mars, its temperature can be increased significantly. That additional warmth would ideally release CO2 from cold storage in carbonate deposits already on  Mars. This would further accelerate warming just as it does on Earth via the Greenhouse effect. Ideally, pump enough heat in initially to get that CO2 into the atmosphere, and our favorite greenhouse gas might just do the rest.

To get more sunlight on Mars, Handmer proposes using solar sails. Not just one, or two, or a hundred, but solar sails in their billions. They would use light from the sun to travel from Earth to Mars on a timescale of months. When arriving at Mars, they would be stationed at the Sun-Mars L2 Lagrange point, where the required orbital corrections would be at a minimum. From that point, the solar cells would position themselves to reflect sunlight on to the Martian surface to provide heating.

The Martian atmosphere is made up of 95.32% carbon dioxide, 2.7% nitrogen, 1.6% argon, and just 0.13% oxygen. Atmospheric pressure is just 6.35 millibar, compared to 1013 millibar on Earth. That very thin atmosphere nonetheless gives Mars a nice tan sky. 

The sun already provides energy on the level of roughly 600 watts per square meter on the Martian surface. That sums up to about 21,600 terawatts across the entire planet. Compare that to the 8 gigawatts or so put out by our largest nuclear reactor, and it’s easy to see the sun is providing a lot more energy than we could hope to achieve with any kind of operation on the Martian surface. Reflect more of that sun, and that number goes up nicely.

Large solar sails placed opposite the Sun and Mars could be used to increase the amount of solar radiation falling on the red planet. Credit: Casey Handmer

Handmer notes that a reflector covering 1,000 square meters would reflect 600 kW of sunlight towards Mars. 1,000 sails of this size would effectively add a square kilometer of surface to Mars’s existing cross-sectional area of 36,000,000 square kilometers. That’s not really a whole lot.

As mentioned above, the key is to scale into the billions. The idea is that these simple solar sails could be manufactured on the cheap. Handmer posits that a 1,000 gram sail craft could cover the aforementioned 1,000 square meters. He estimates a production cost on the order of $100, roughly equivalent to a modern cellphone. For electronics, the sail would need a processor, a telemetry radio, a small solar panel, and a camera to act as a star tracker for navigation. It would then use LCD panels to act as reflectively-variable elements to change its direction under the influence of the sun. At that weight, launch costs would be around $2000. Add that on to the manufacturing cost, and you’ve got 1,000 square meters of Mars reflector for just $2100. Advances could shave manufacturing costs and weight down further, slashing launch costs which are heavily weight dependent.

After launching cheap solar sails high enough into Earth orbit, they would use light pressure from the sun to make their way to the Sun-Mars L2 point. Handmer believes such craft could be built as cheaply as $100 in grand numbers. Credit: Casey Handmer

If these solar sails could be manufactured with the same efficiency we churn out smartphones, we could churn out hundreds of millions of these craft in a few years. Handmer suggests a decade of launches could net 1.5 billion sails in position around Mars, which would be good enough for increasing energy input to the planet by 4%. In turn, Mars’ thermal radiation would have to increase by 4% to balance this extra energy input, which suggests its basic temperature would rise from 210 K to 212 K—or roughly -61.15 Celsius.  He costs all this out at around $10 billion, which sounds awfully cheap in the grand scheme of things.

Worth It?

Okay, so that still sounds terribly cold. And it is! But that rise of two degrees isn’t to be sniffed at. As Handmer points out, that’s more than we’ve achieved here on Earth in 250 years of rampant fossil fuel use.  He also notes that the shining solar sails would make for a brilliant view from Mars’s surface, though it’s perhaps unlikely many humans would be there to see it, at such cold temperatures.

Further gains could be made with some strategy. If cold deposits of stored carbon dioxide were spotted on the surface, the sail network could ideally be aimed to some degree to prioritize warming of those areas first. Done right, this could speed temperature rises on Mars quite significantly.

Reality Check

The higher escape velocity of heavier planets allows them to hold on to an atmosphere more easily. Lower temperatures are a boost, too. If we warmed Mars to Earth’s temperature, it’s atmosphere would lose oxygen and nitrogen more quickly than it already does.  We could end up giving Mars an atmosphere only to lose it in short order. Credit: Cmglee, CC BY-SA 3.0

It’s a brilliant idea, and one we’d like to see explored further. At the same time, it’s unlikely to get real legs any time soon. There’s little will to terraform Mars right now, given we haven’t even sent a human over for look just yet.

Furthermore, even if Mars was warmed significantly, there’s still the question of whether the atmosphere and environment could be made livable. Humans need oxygen, and we like a certain atmospheric pressure and lots of water. Getting Mars into the right ball park on all these measures would be tough, and maintaining it would involve countering the effects of the solar wind, which has stripped the planet’s atmosphere in the past.

The plan also glosses over some finer points of the engineering required. It’s one thing to build 1.5 billion solar sails, and another thing entirely to launch them all and get them to Mars. Once there, they’d need to be very well organized to avoid crashing into each other and turning into one big tangled blob in orbit.

Handmer has put together a very compelling plan to warm Mars, and to do it on the cheap. Whether it would work is an open question, but this is the kind of wide-ranged blue-sky thinking that’s required to solve the space-based problems of tomorrow. Terraforming an entire planet isn’t something you do on the small scale; it’s something that requires the massed industrial outputs of entire societies. That’s a lesson we must learn, not just on Mars, but on Earth.  

78 thoughts on “Heating Mars On The Cheap

    1. Heating Mars is a fool’s errand. There is no protection from solar radiation. Temperatures of -80 – 120 are common. We are ruining our own planet with selfishness, but Mars is uninhabitable, period. One mishap and it’s over. Zero oxygen and 8 milli-bar pressure, only people eith a death wish would attempt it.

        1. Yeah, and planet is our common good. Selfishness is for one person gain and against common good. You get big gains but everyone else is poisoned a little (including you, but you still get more good than poison).

          1. Some utilitarians evaluate the moral choice by looking at which option returns the most utility to society.

            I’m like that, except it’s utility to me.

            Most places ‘free roads’ were paid for with gas tax. Along with lots of useless pork. The cost isn’t obvious, but is there.

        2. “Our” (collective) self interest is different from some BP or Exxon Mobil exec’s self interest.

          They’re perfectly happy to make several billion dollars if it means runining the planet.

    1. Earth will be fine, it has suffered orders of magnitude worse climate shifts. Homo sapiens will probably be fine. Our current mode of existence will perish. But yes, the idea that we will claim another world is outrageously remote

      1. True, but people tend to overlook the fact that if we could do it then we would have developed the technologies needed to not need to do it, because we could build permanent space habitats, even mobile ones. No need for deep gravity well dwelling at all. The protection offered by the atmosphere is the same as only a couple meters of ice, and we can already make magnetic fields far more powerful than those which protect Earth. Using spin to get 1g is trivial too.

      2. “Earth will be fine, it has suffered orders of magnitude worse climate shifts.”

        There are 2 claims you’re making simultaneously – one, that Earth can survive our current trend. That part is probably true.

        The second claim you’re making is that we won’t make it any worse. I don’t know about that. I think humans are totally *capable* of completely effing the planet, I just don’t think we’re quite that dumb. Close, sure, but not quite dumb enough.

  1. Great idea… but utterly useless until you fix the lack of a usable magnetosphere. Otherwise the solar wind will just slowly blow the new atmosphere away like it’s been doing for the last several hundred million years. Slowly but surely the atmosphere will return to near its current state. Fix the magnetosphere, increase the atmospheric pressure/volume, then you can work on making it breathable and warmer, and that’ll probably involve transforming the surface so it can support flora and fauna.

    1. And if you warm it.. All that Valuable Water will get blown away as well.. Then it will have less CO2 and H2O than it does now..

      Them Solar Winds.. That is what we need to Stop, and this Project would work..

      1. The trick there is to dig down to the core, which we shall presume is mostly iron, and wrap a few turns of wire around it. Then boom, giant electromagnet and field problem solved.

        After that, sprinkle the surface with Acme dehydrated water and add a single drop to get it all started.

    2. Yip… magnetosphere is a point… but for me that points more at the need to block radiation… the new martians will live in lava tubes.
      And then they will evolve to fit the different gravity.
      And colonies like to turn into enemies.

      And after all how shall we reach Mars if … eeeeh … when the Kessler syndrome locks us in on earth? Elon saves Mars from Elon! ⠀ \o/

      Let’s trigger it now and clean up Planet-A.

    3. The only (relatively) feasible way to get an atmosphere going on Mars is to kickstart the planet’s plate tectonics. The only way I can think of to do that is to either find a way to move one of Mars’s moons into either a lower or more elliptical orbit, or tow in an asteroid with a large enough mass to do the same thing. Stronger gravitational forces over a long period of time should help get the plate tectonics going and possibly even volcanic activity, which would put more greenhouse gases in the atmosphere than we could ever hope for.

      Theoretically, you could restore the magnetosphere by drilling all the way into the core of the planet and adding enough refined Uranium or Plutonium to create a natural nuclear reactor that would reheat the core, but the amount of fissionable material needed for such an adventure would likely far exceed the amount available to us. Not to mention the number of holes needed across the planet.

      1. I quite like the idea of moving enough rocks into orbit to make a significant tidal effect. Mars’s current moons are way too teeny weeny for that though, they’re already in pretty low orbits and they don’t have enough mass to circularise themselves. If you want to move that much rock that precisely you’d need a lot of power and reaction mass from somewhere.

      2. Just look at the Moon. Does it have plate tectonics? No. And it’s experiencing internal tidal stresses from Earth that are nearly *100x higher* than the reverse. It’s also *smaller* than Mars, so the net effect for Mars would be *lower*.

        In other words, if you took *the Moon* and put it *5 times closer* to Mars… it still wouldn’t be big enough. Heck, if you take Ceres and put it at Phobos’s orbit (which is too close to be stable!) it’d only be around ~700x the Moon’s tides or so.

        I seriously can’t wrap my head around the idea of trying to “kickstart plate tectonics” using tides. Do you know what “liquifying the interior of a planet due to tidal interactions” is called?

        It’s called “destroying the planet.”

    4. “Great idea… but utterly useless until you fix the lack of a usable magnetosphere. Otherwise the solar wind will just slowly blow the new atmosphere away”

      oh, no, the atmosphere we’re talking about establishing in hundreds of years might only last 10,000 times as long as it took to make it, whatever will we do

  2. There are so many things wrong with this idea. First the photon pressure on the sails of the lightweight aircraft will shift it out of its instable Lagrange point almost in a few days. The Lagrange point is also a virtual and small space. You can’t fit billions of km² of ships in such a small space without a propulsion and collision avoidance system.

    The only way to resist the photonic pressure is to have sails in the back of your first sail to reflect photons. But that sail will support the pressure itself and be ejected from its orbit too.

    That’s probably a lot easier to terraform Venus than it is to Mars, because, at least they are places on Venus where the environment is habitable for humans (with a breathing appertus and a thin protection against acid). See this paper from Paul Birch for an orbital mirror to *cool* Venus: https://www.orionsarm.com/fm_store/TerraformingVenusQuickly.pdf

        1. Horny women of the moon will kick their butts for us.

          Like your sister had to beat-up girls that hit you after grade school…’I’m not allowed to hit you back, guess who’s behind you.’

    1. How much sodium hydroxide would it take to convert the sulphuric acid rain clouds on Venus to be normal rain clouds. And can sodium hydroxide be sourced from the asteroid belt between mars and jupiter?

      Ok the pressure and temperature at sea level on Venus would still kill but it would be one step closer to being habitable. And the same trick could reduce the carbon dioxide levels since carbonic acid would form and it could react with sodium hydroxide to form water and sodium carbonate. In theory keep on adding more sodium hydroxide until the temperature was low enough.

  3. Kim Stanley Robinson had a similar idea in the Mars books, a solar sail of sorts was put at the Lagrange point between the sun and Mars which redirected light towards Mars, it basically just made the sun brighter.
    Looking at the graph above, would it be more worthwhile to try to cool Venus than warm Mars? It’s closer, it just might take a few generations before you can set foot on it.

  4. No magnetic field. Any atmosphere you could get to adhere to that blasted rock would be blown away by solar wind within a generation or two. Terraforming Mars is a non-starter. Also if you think this would fit in a budget of ten billion you’re wayyyy too optimistic for space. Some optimism is good, but not that much

        1. just launch $10 billion dollars in sailsats… oh wait.

          terraforming is going to be a freakishly complex problem to solve, atmosphere and heat are small potatoes (well not that small given the scale involved). we could throw the entire world’s nuclear arsenal at it and not make a dent (and thats after retrofitting additional fusion stages).

          an artificial magnetic field is going to be a mega project, and one you have to do remotely due to the lack of humans on mars. one mega project among many. also giga/tera may be a more appropriate prefix.

    1. “Any atmosphere you could get to adhere to that blasted rock would be blown away by solar wind within a generation or two.”

      What the heck have *you* been reading?

      Timescales for atmospheric stripping on Mars are hundreds of thousands of years, not “a generation or two.” It can’t possibly be that fast – magnetospheres cannot deflect neutral particles, and a non-zero fraction of the solar wind is neutral anyway, so if you blew away Mars’s atmosphere in “a generation or two,” Earth would still be barren rock – 10,000 generations is still nothing.

      It’s only losing about 1E-16/s right now, or about 0.3% per million years, and the rate wouldn’t increase much more than that.

    1. Yes. That’s because of global warning of the planet reduce the exponential cost of the sail. The first 1 billion sails are offered if you pay for the last 500 million. And the currency is in martian dollars, which is 100 marsian$ = 1 USD$

  5. terrafotmong. good idea. lest try this on the Sahara. it already has a breathable atmosphere, is not far away and has a little water. It’s also quite cheap to travel to. if that succeeds, try Antarctica anb maybe next, maybe then, mars.

    1. Picture the ice at the poles as a moderator (like in a nuclear reactor), with the general hot air flow pattern from the equator towards the poles. The ice prevent the temperature from rising too high and keeps the planet in a mostly stable, predictable, habitable state. What happens if all the ice is gone, there is no safety buffer that can sustain the mostly stable air currents all year round. If that ever happens the equator is going to be extra toasty, more often it higher high temperatures for longer, and the land available for humans to live and grow food would probably be a lot less than it is today. That will lead to more wars. So lets leave the poles alone.

  6. I assume Mars is right now at equilibrium wrt it’s atmosphere, which is already overwhelmingly CO2. Wouldn’t adding more heat to the planet just increase the loss rate to space?

  7. How about a big, solar powered, magnetic “Solar Wind” break in between Mars and the Sun, produce a large enough magnetic field to warp the solar wind around Mars like our magnetosphere does, just artificially and in orbit.

    1. big deflector at l1, except then you eclipse the sun unless its transparent. a large superconducting solenoid does this. but charged particles like to follow flux lines in corkscrew fashion. so you have a small protected bubble on the inside and a lens on the outside. the flux lines must enclose mars. you could do an electrostatic shield but it will be mostly opaque. orbital mirror spam required.

      a couple of huge superconducting halbach arrays at the poles might do the trick, but i loathe to think of the power requirements. big solar arrays may do the trick, but i think id use a cluster of fission power plants, the ice caps can be used as a cold source and running the reactors has the side effect of melting the ice caps with the waste heat. they need to run for a long time so make them breeders.

      in the time it takes to build a thick co2 atmosphere (let alone convert it to an o2 atmo with bioreactors) you will probably burn through all the fissile materials on the planet. replacing with fusion reactors, once they are workable, will be a good idea.

      would be more feasible to dome the mariner valley imho. city sized domes are easier to build than city size magnets.

  8. Since Mars have no magnetic field, the solar wind will strip away any extra admosphere we might create. So it is useless. Mars core lost heat, stopped turning, magnetic shielding gone.
    You may try lower Mars orbit close to Earth _but_ you risk a collision or gravitational chaos interaction sooner or later.
    Also Earth’s core is cooling down (all vulcanic activity, gheisers, hidrothermals – Iceland I’m fingerpointing you). We’ll need a solution sooner than the 5 billion years till the Sun goes boom or Andromeda crashes into Milky Way. And not with nukes detonated in the core.

    1. Why is this idea so prevalent? I don’t get it. Yes, the solar wind contributes to atmospheric loss at Mars, but it’s not a “bye bye in a generation” thing – it’s an O(million-year) timescale, which is just not that big a deal in terms of maintenance compared to doing it in the first place on timescales much less than that.

      “Also Earth’s core is cooling down (all vulcanic activity, gheisers, hidrothermals – Iceland I’m fingerpointing you). We’ll need a solution sooner than the 5 billion years”

      Earth’s cooldown time is comparable to the Sun’s lifetime, and that’s *not* the timescale to be concerned about – that’s in under a billion years due to water loss.

        1. All terraforming projects would need maintenance. The other planets in the Solar System became barren for a reason, not just random chance.

          If you found a way to practically give Mars an Earth-scale atmosphere (which is already a massive challenge!) maintaining it against the minor loss due to the solar wind is of negligible additional difficulty.

          To me the frustrating thing about this blog post is that it’s, to be frank, half-assed. It’s clearly insane – I mean, sure, it’s a blog post, rather than even one of the goofy proposals that people submit to papers and we all chuckle about. But building and launching billions of ultralight spacecraft is actually the *easy* part! He then says “oh, we’ll park them at L2.”

          L2, like all Lagrange points regardless of stability, is surrounded by heavily chaotic orbits. You can’t simulate or predict things because the delta-V to shift between *massively* different orbits is tiny. This is the entire basis of the interplanetary superhighway orbital system.

          Sticking billions of objects there is just not a practical solution, period. You definitely can’t do it with only solar sail propulsion, because you don’t have *anywhere near* the control mechanisms to deal with it.

          It’s about a 5-second thought process to realize that you can’t do what he’s trying to do. All of the mirrors would need to be in a significant halo orbit around L2 (since the Sun is occulted at L2) and would need to be continually changing the angle of the mirror in order to keep Mars in focus. Which means you have zero ability to maintain the orbit since you have no other means of stationkeeping.

          Except 1.5 million km^2 of objects *wouldn’t even be able to fit* in the halo orbits around L2.

  9. This article contains nonsense. CO2 is not a proven contributor to heat retention on even remotely relevant scales. Even though Mars’ atmosphere is 1% of Earth’s it is still around 96% CO2 meaning that even in absolute terms there are orders of magnitude more CO2 on Mars already. Earth is a bit warmer because of its position and the amount of nuclear decay in its core. So the real task is to restart or replace Mars’ core to get a magnetosphere. BTW a jungle absorbs more heat than a barren desert does, so surface albedo will have a big impact too. Once water can exist on Mars in all 3 phases the massive convection driven heat engines we call thunderheads will start up and moderate the day|night temperature swings.

  10. we cant even set up a moon base and we want to start terraforming. you have to walk before you can run and were still crawling. though were not far from standing up for the first time.

    still not convinced this is the best use of 10 billion dollars. especially with all the question marks. the big one being mars weak magnetic field. even if you up the tempurature and atmospheric pressure, what keeps the sun from striping it all away again? you would probably need to install gargantuan superconducting solenoids at the poles and good luck powering them. and possibly drilling down several kilometers at both ends to install a flux conduit of sorts so that your solenoids stand a snowflake’s chance in hell and connecting their flux lines.

    doing the same with a satellite constellation might be possible, but these are not going to be $ 2100 a pop. since they need superconductors, and coolant, and a substantial power supply and a lot of fuel for station keeping, given the instability of large magnetic systems. a single ginormous solenoid at mars l1 might cut the mustard. but its going to be so big you might as well have an attached space colony there.

  11. Okay, let’s leave out the possibility of launch disasters and think about the greenhouse gasses we know about already. If someone is going to warm up Mars wouldn’t it be cheaper to produce or ship the worst ones we have for heating and just dump them in the atmosphere? I’ve read proposals for decades on slamming a comet into Mars but we don’t have that tech yet. We absolutely do know how to warm up an atmosphere though. Tons (literally) of stuff would be required to do it, but it’s within our knowledge.

  12. Mars barely holds an atmosphere, its thin layer wouldnt support algae let alone humans.
    Hiding in your muskhole is your only safety from radiation,
    BUT even that wont help with the greatest shortcoming of the red planet…..

    Mars has 38% of earths gravity.
    Boots on mars, probably before I die at the rate we are going.
    Living on (under the surface of) Mars, not in any capacity greater than the ISS counts as us LIVING in space.
    Living on mars long term will require genetic modification, cybernetic augmentation, or at the very least hours a day under centrifugal pseudogravity stimulation.

    A few centuries of Catalytic Bombardment of Venus with magnesium and calcium is humanities only hope of a second planet to call home.
    A storm of Stanford Tori or Oneil Cylinders are our best hope to actually offworld anytime in the foreseeable future

  13. How did the cost of building and launching them go from $2100 to $6?

    Or did you typo the total cost from trillions to billions. I can’t really call any program that costs $10 trillion dollars “cheap”

  14. The expanding sun will do it for free during the time when it WILL be necessary to move outward in the solar system. In the mean time, invest more in planetary defense to prevent the highly unlikely total extinction of humanity as Elon fears.

  15. With limitless free or nearly free energy all things are possible. Until then we won’t be terraforming Mars. And why would we want to is the real question. Room, space for more people, isn’t an issue. We have plenty of room here on earth if you want to live in a dry desert underground, and we have air unlike Mars. There are so many problems around humans living on Mars that it seems nearly impossible unless we have free energy and a reason to go there. Is there any research that can’t be done by robots or drones? Don’t get me wrong, I think we will send Scientists to Mars, but even that will be extremely difficult and dangerous.

  16. Lemme get this straight. $10B. To launch O(1E9) kilograms. To increase the heat to Mars by 2 degrees.

    And this is better than the greenhouse gas plan because we would… need to build self-replicating thingies or something and that would take trillions of dollars…?

    except – and follow me on this one… the total amount of gas needed is O(1E10 kg) which we could just… send there

  17. Maybe we should just move Mars closer to the sun.
    Send a space craft into the asteroid belt, knock one off course, that creates a chain reaction, knocking a large asteroid into Mars, slowing it down, so it falls closer to the sun.

  18. A much cheaper way would be to park a solar-powered 4 Tesla MRI at the L2 LaGrange point. This would create a shield and raise temps immediately as Mars would no longer lose its atmosphere from solar winds and protect the planet from solar radiation.

  19. seems like the kind of thing that would be better to manufacture there on Mars and launched “locally”. Long after a settlement is established, and they start talking about setting up small scale manufacturing, along with their own space port to return items to orbit. Ship components there such as the PCBs / batteries in a supply trip. Manufacture the sail material on Mars as well as assemble and pack the satellites for launch there.

    1. His entire argument for this is really that Martian manufacturing of any kind would take too long. If you’ve got a manufacturing environment on Mars just start churning out specialized greenhouse gases, you can spike the temperature easily. Mass-wise it’s not actually even that much more to get equivalent temperature increases if you just launch the stuff from Earth.

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