An interesting Twitter thread by Phil Metzger, who’s been working the issue for a while. I haven’t reviewed it in any detail.
15 thoughts on “The Economics Of Space Resources”
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An interesting Twitter thread by Phil Metzger, who’s been working the issue for a while. I haven’t reviewed it in any detail.
Comments are closed.
If memory serves the moon doesn’t have a lot of carbon, so how is methane produced on the moon? What am I missing?
Presumably it would have to be imported.
The Moon is not utterly lacking carbon, but there is not very much. This dearth might just make the capture and rendering of carbonaceous chondrite NEOs an economically justifiable pursuit. Anything beyond carbon found in such bodies would just be gravy.
I don’t think it would be sensible to try landing carbon on the Moon using landers that, themselves, require propellant. Getting carbon from lunar orbit down to the surface might just be the justification for building large magnetic decelerators – sort of reverse mass drivers.
Mass of any suitable kind – not just carbon – thus landed would be packed in metal cans that could be reused indefinitely by re-lofting them to lunar orbit, either empty or packed with some suitable commodity made on the lunar surface. That might be metal, water or even propellant.
The lofting of such payloads could be done with either mass drivers or centrifuges of the SpinLaunch type. Centrifuges would require much less initial capital investment and real estate, but there might be a case later that would favor mass drivers capable of continuous flow operation to loft much larger total daily mass.
These sorts of propellantless lofting of payload from lunar surface to lunar orbit would also improve the economics laid out by Mr. Metzger in the linked article.
Well it depends upon how much water is on the Moon.
But Mars could have cheaper water than Earth.
Other than amount water on Moon, the limiting factor is how much rocket fuel can you sell.
This has always been problem with to Moon, but it using Lunar rocket fuel to go to Mars- one has a lot of immediate demand for lunar rocket fuel.
I don’t think we know whether there mineable lunar water, but if moon has more water than ice rinks- sheets of ice hundreds of meter thick below the surface, then lots of water, and it can send million people to Mars. Of course one might want invest in mass driver and get lunar water to lunar orbit for near zero costs.
Or lunar rocket fuel starts it, but the end point is not using chemical rocket fuel to get stuff off the Moon.
But we need lunar exploration of lunar polar regions.
And if there also mineable frozen CO2- it fits well with methane engines of the starship.
If there is ice below the surface at the poles there will be carbon. Remember the black tarry stuff on comets?
The biggest “resource” in space is location (same as any real estate). A sovereign private colony established on Mars could declare its independence of all Earth governments. It would then be free to accept “donations” (deposits) in support of the colony (bank of Mars). Like any bank said deposits would be loaned/invested back on Earth generating revenue supporting the colony. The donors (depositors) would be paid interest, tax free. Tax free because the mars colony wouldn’t have to follow IRS rules about disclosing interest payments made to depositors. Think the ultimate Cayman Islands like tax haven. The colonist would have renounced their citizenship of whatever country they were born in outside of any country legal jurisdiction therefore they would be independent agents not guilty of “tax evasion/fraud”. The 1967 Outer Space Treaty forbids any country on Earth from claiming sovereignty over space or any heavenly body (like Mars).
This is something I think doesn’t get enough attention when debating the economics of space colonization. It’s entirely possible that some early colonies will be the result of some religious or political groups taking to other worlds to build their own societies. Just look at all the American colonies that were built by what were regarded as fringe religious groups back home.
Yes.
What other purpose to go to Mars, other than change the world [or change the Universe].
And why great religions seem uninterested in Heaven is something I don’t understand.
He makes a great case and there are obviously a lot of uncertainties. The specific methods are untried and space is a different place than Earth, so the models might not play out the same but it is reassuring.
It seems that Elon would need someone with drive like him to take on this task in order to realize the models potential.
“He makes a great case and there are obviously a lot of uncertainties.”
I think my suggestion would address allot of those “uncertainties”; you need something (if possible) that would immediately generate revenue for the colony. Something of an easy to understand recognizable “business plan” nature. This would attract investment capital; people know what a tax shelter is they don’t know whether you generate a profit in a reasonable time frame by mining on another planet. Mining/resource exploitation would likely only come into its own much later. They could setup a “Bank of Mars” open for business the 2nd practically from the moment they landed with their initial core group on Mars. You could have fiduciary backer(s) pledged back on Earth to invest in their group the 2nd they are broadcasting live from Mars.
Years ago, I published a story in Asimov’s called “The Rocket into Planetary Space” in which I asserted CHON==Oil. A lot of readers immediatly jumped on the “space resources can’t be imported to Earth” bandwagon, even though I pointed out in the story (a point so obvious it counted as a sharp stick in the eye) that the main utilization would be in cislunar space (to begin with). Part of my point was, we already have a well develeloped oil-based technology. Why give it up when there’s oil in them-thar asteroids?
Another point that seems to be being missed nowadays (in a forest/tree sense) is methane engines can burn hydrogen and vice versa with little modification. And Metzger makes the point, as have others, that 80% by mass of what your “burning” is liquid oxygen. Whence the value of lunox alone. The final point is, there’s not that much carbon in CH4. So if you get the H2 and O2 from the Moon, you’ve got most of what you need anyway.
It takes a fair amount of energy to make LH2, and as far as we know, there could be as much frozen CO2 as there is frozen H20 in the lunar polar region.
But if make Raptor burn H2, it seems they would less powerful- but more efficient.
So, does anyone know how much less powerful?
Or can you replace the second stage Starship with LOX/LH2?
I would guess if used LH2 an Raptor would have to burn 3 times longer. Or they get 1/3 the thrust, because Liquid Methane denser fuel and need more tankage volume for LH2.
So with liquid methane, and you take off from Moon at 1 Gee, with LH2, it would 1/3 gee acceleration.
Based on:
https://everydayastronaut.com/raptor-engine/
Who does not directly say this, but it’s my rough guess from his comparison numbers. Of course if had 18 rather than 6 raptors, it’s roughly the same.
Well-I’m not an aeronautical engineer-but hydrogen is a lot less dense than methane. So imagine the real problem would be that if a raptor engine is still on a Starship now the fuel tanks are much too small. So overall it might lose delta-v capability even if the engines were more efficient.
Both issues are overstated:
1. Starship only uses two of its six methane fueled engines to land on the Moon. If fueled with hydrogen, the six engines are already there. So no problem.
2. The Starship tanks are sized to provide delta-V from LEO to lunar surface and back to NRHO (not LEO). That amounts to 1200 tons of liquid oxygen and methane. If fueled with hydrogen, that would get Starship back to Earth landing from the lunar surface, or LEO with aerobraking.
The main thing about ISRU on the Moon is, returning Starship to LEO (in the case of HSL) or to Earth landing if Standard Starship. The whole point of lunox is, it gets you 80% of the way there. So with the other 20% being CH4, you can get the molecules of hydrogen on the Moon, and you’re only looking for the molecules of carbon to finish the job. No one actually knows if there’s carbon on the Moon. Even if it has to be imported, you only need enough to reach a top-off tanker in LLO. Of course, not only is the economics of this open to question, so is the utility of the Moon for any purpose other than more or less trivial (recreation, science, national security). Not that I’d mind going to the Moon just to gawp around…