Zubrin and McKay plans for terraforming Mars with giant orbital mirrors cited by Elon Musk

by

The McKay-Zubrin plan for terraforming Mars in 50 years was cited by Elon Musk.

Orbital mirrors with 100 km radius are required to vaporize the CO2 in the south polar cap. If manufactured of solar sail like material, such mirrors would have a mass on the order of 200,000 tonnes. If manufactured in space out of asteroidal or Martian moon material, about 120 MWe-years of energy would be needed to produce the required aluminum.

The use of orbiting mirrors is another way for hydrosphere activation. For example, if the 125 km radius reflector discussed earlier for use in vaporizing the pole were to concentrate its power on a smaller region, 27 TW would be available to melt lakes or volatilize nitrate beds. This is triple the power available from the impact of a 10 billion tonne asteroid per year, and in all probability would be far more controllable. A single such mirror could drive vast amounts of water out of the permafrost and into the nascent Martian ecosystem very quickly. Thus while the engineering of such mirrors may be somewhat grandiose, the benefits to terraforming of being able to wield tens of TW of power in a controllable way can hardly be overstated.

Energy for making the aluminum can use near-term multimegawatt nuclear power units, such as the 5 MWe
modules now under consideration for NEP spacecraft.

Los Alamos and NASA are researching a 35-ton two-megawatt Megapower reactor.

Four large nuclear thermal rockets to move four big asterods

Orbital transfer of very massive bodies from the outer solar system can be accomplished using nuclear thermal rocket engines using the asteroid’s volatile material as propellant. Using major planets for gravity assists, the rocket DV required to move an outer solar system asteroid onto a collision trajectory with Mars can be as little as 300 m/s. If the asteroid is made of NH3, specific impulses of about 400 seconds can be attained, and as little as 10% of the asteroid will be required for propellant. Four 5000 MWt NTR engines would require a 10 year burn time to push a 10 billion tonne asteroid through a DV of 300 m/s. About 4 such objects would be sufficient to greenhouse Mars.

An asteroid made of frozen ammonia with a mass of 10 billion tonnes orbiting the sun at a distance of 12 AU. Such an object, if spherical, would have a diameter of about 2.6 km, and changing its orbit to intersect Saturn’s.

Alternative – bacteria to make Ammonia and methane

A possible improvement to the ammonia asteroidal impact method would use bacteria which can metabolize nitrogen and water to produce ammonia. If an initial greenhouse condition were to be created by ammonia object importation, it may be possible that a bacterial ecology could be set up on the planet’s surface that would recycle the nitrogen resulting from ammonia photolysis back into the atmosphere as ammonia, thereby maintaining the system without the need for further impacts. Similar schemes might also be feasible for cycling methane, another short-lived natural greenhouse gas which might be imported to the planet.

Alternative- One gigawatt reactor to make halocarbon – CF4 to trigger warming effect

Greenhousing Mars via the manufacture of halocarbon gases on the planet’s surface may well be the most practical option. Total surface power requirements to drive planetary warming using this method are calculated and found to be on the order of 1000 MWe, and the required times scale for climate and atmosphere modification is on the order of 50 years.

The amount of a greenhouse gas needed to heat a planet is roughly proportional to the square of the temperature change required, driving Mars into a runaway greenhouse with an artificial 4 K temperature rise only requires about 1/200th the engineering effort that would be needed if the entire 55 K rise had to be engineered by brute force.

The dynamics of the regolith gas-release process are only approximately understood, and the total available reserves of CO2 won’t be known until human explorers journey to Mars to make a detailed assessment.

14 thoughts on “Zubrin and McKay plans for terraforming Mars with giant orbital mirrors cited by Elon Musk”

  1. Put the reflective material on phobos. That way it if it ever needs to be repaired or altered it could be done with solar powered rovers. One meteor shower and a 100 km satelite could be destoyed by being hit. Plus it would have to be refueled from time to time and so on and so on.

  2. Put the reflective material on phobos. That way it if it ever needs to be repaired or altered it could be done with solar powered rovers. One meteor shower and a 100 km satelite could be destoyed by being hit. Plus it would have to be refueled from time to time and so on and so on.

  3. Put the reflective material on phobos. That way it if it ever needs to be repaired or altered it could be done with solar powered rovers. One meteor shower and a 100 km satelite could be destoyed by being hit. Plus it would have to be refueled from time to time and so on and so on.

  6. It may be a perfectly worthless investment of time, but I LIKE independently reproducing the calculations whose “results” are bandied about so glibly. Gives me some comfort that the Zubrin team has done its homework without dropping a decimal someplace.

    In this case, I’ve replicated the calculations, and I CONCUR with their basic premise(s). That 20 GW (nuclear, thermal) for 10 years or so, accelerating 12% of the NH₃ mass of a largely NH₃ composed asteroid, out there at 100 AU, with a ΔV expectation of 0.3 km/s … indeed fits almost exactly into their results.

    One certainly hopes that the “firing team” is super-incredibly-protected against hacking. A few extra meters per second, and said Antarctic Ross Shelf scale flying iceberg could be lined up to collide with Earth. Which would definitely change a few Scout outing plans.

    Nice job, Zubrin & Co.
    GoatGuy

  7. Right. No need of terraforming project for using the planet. Nevertheless, once people lives there, they will try some high impact/low cost geoengineering schemes, if they have the means and freedom to do so.

  8. When there’s people over there, they will “terraform” Mars wether we like it or not. Or either intentionally or not.

    That’s what we do, change our environment.

    But terraforming most likely won’t be a single colossal project costing trillions across decades (nobody would pay for that), but a myriad of small scale efforts and changes mostly brought as an offshoot of human presence over time. With a few deliberate high-impact efforts, like releasing super-greenhouse gases, some solar mirrors heating the poles and some seeding of GMO lichens and bacteria.

    More like the organic way countries and cities are made than a big, honking sterile project like Brasilia.

  9. Enough CO2 in the atmosphere to keep your blood from boiling, and O2 *inside your breath mask*. The first stage in terraforming is just getting the pressure up enough that you don’t need to wear a pressure suit. Just an O2 tank and rebreather.

  10. Maybe the terraforming of Mars should be left up to the people who live there to decide if they want it.

    Maybe we should find a massive Nitrogen ice asteroid in the Oort belt and move it. Sure it will take decades longer but Nitrogen is useful stuff in an atmosphere.

    Maybe we should just dome large craters and make large cities. There is no reason to walk around on the surface.

  13. Last I looked into it, there was still some question as to whether there was enough CO2 to get up to an air pressure that was marginally sufficient. High enough that humans could get by on pure oxygen at that pressure, basically. Say, normal Oxygen partial pressure at 10,000 feet altitude, a bit over 2 psi.

    Anything over about 2.2 psi is a bonus, that’s our target. At that pressure people can walk around with oxygen masks and do moderately stressful work, without having special genetic adaptations. At 3 psi, you’re golden, anything above that you start diluting the oxygen anyway.

Comments are closed.