Author Topic: Asteroid Mining Architectures  (Read 17410 times)

Online DanClemmensen

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Re: Asteroid Mining Architectures
« Reply #40 on: 03/12/2022 04:18 pm »
Fun fact: if we brought 16 Psyche's infamous "100 quadrillion dollars worth of metals" back to Earth, that'd be enough iron to completely consume all the free oxygen in Earth's atmosphere. :D :D

Fun Fact? Somebody don't do something!

No $100,000,000,000,000,000 payday huh? Sounds like somebody hates growth and jobs. Gettim boys!

;D
Sigh. The iron is not very valuable on Earth, not worth sending down to the surface. Keep it in space and use it to build rockets, spacecraft, structures, etc. Separate out the stuff that is valuable on Earth and send it down, completely destroying nearly the entire mining industry and the financial structure instead of destroying life by consuming the oxygen.

The price calculation is based on the spot metal value on Earth.

Point being, it's an absurd calculation on a number of levels.

"Keep it in space" is a good quip, but it's begging the biggest unsolved question in spaceflight economics. It's still an open question whether it can ever be economical to live your entire life in space.



All you've done is replace one hard problem (asteroid mining economics) with an even harder problem (space habitation economics).
I guess you missed the implicit tags, so here:
<sardonic>
    Separate out the stuff that is valuable on Earth and send it down, completely destroying nearly the entire mining industry and the financial structure instead of destroying life by consuming the oxygen.
</sardonic>

Offline Twark_Main

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Re: Asteroid Mining Architectures
« Reply #41 on: 03/28/2022 03:21 am »
Fun fact: if we brought 16 Psyche's infamous "100 quadrillion dollars worth of metals" back to Earth, that'd be enough iron to completely consume all the free oxygen in Earth's atmosphere. :D :D

Fun Fact? Somebody don't do something!

No $100,000,000,000,000,000 payday huh? Sounds like somebody hates growth and jobs. Gettim boys!

;D
Sigh. The iron is not very valuable on Earth, not worth sending down to the surface. Keep it in space and use it to build rockets, spacecraft, structures, etc. Separate out the stuff that is valuable on Earth and send it down, completely destroying nearly the entire mining industry and the financial structure instead of destroying life by consuming the oxygen.

The price calculation is based on the spot metal value on Earth.

Point being, it's an absurd calculation on a number of levels.

"Keep it in space" is a good quip, but it's begging the biggest unsolved question in spaceflight economics. It's still an open question whether it can ever be economical to live your entire life in space.



All you've done is replace one hard problem (asteroid mining economics) with an even harder problem (space habitation economics).
I guess you missed the implicit tags, so here:
<sardonic>
    Separate out the stuff that is valuable on Earth and send it down, completely destroying nearly the entire mining industry and the financial structure instead of destroying life by consuming the oxygen.
</sardonic>

The part you missed is that, in that calculation, "the stuff that is valuable on Earth" is the iron.

For obvious reasons, you can't separate the iron from the iron.  ;)
« Last Edit: 03/28/2022 03:22 am by Twark_Main »
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Online meekGee

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Re: Asteroid Mining Architectures
« Reply #42 on: 04/18/2022 01:32 am »
Fun fact: if we brought 16 Psyche's infamous "100 quadrillion dollars worth of metals" back to Earth, that'd be enough iron to completely consume all the free oxygen in Earth's atmosphere. :D :D

Fun Fact? Somebody don't do something!

No $100,000,000,000,000,000 payday huh? Sounds like somebody hates growth and jobs. Gettim boys!

;D
Sigh. The iron is not very valuable on Earth, not worth sending down to the surface. Keep it in space and use it to build rockets, spacecraft, structures, etc. Separate out the stuff that is valuable on Earth and send it down, completely destroying nearly the entire mining industry and the financial structure instead of destroying life by consuming the oxygen.

The price calculation is based on the spot metal value on Earth.

Point being, it's an absurd calculation on a number of levels.

"Keep it in space" is a good quip, but it's begging the biggest unsolved question in spaceflight economics. It's still an open question whether it can ever be economical to live your entire life in space.



All you've done is replace one hard problem (asteroid mining economics) with an even harder problem (space habitation economics).
Not sure which is harder... 

I think both are interdependent, so the iron will stay in space.  How to bootstrap this in-space economic cycle is currently unsolved, but I don't think it'll be by shipping iron down to Earth.
ABCD - Always Be Counting Down

Offline mikelepage

Re: Asteroid Mining Architectures
« Reply #43 on: 07/05/2022 09:26 am »
While the Moon and Mars dominate, and likely will continue to dominate, spaceflight plans, the asteroids in general may hold a place still.

Creating this thread so people can discuss asteroid mining and what routes companies, SpaceX or otherwise, could take to obtain materials for Earthly and extraterrestrial use.
(snip)
Add your own thoughts to the above and anything regarding mining strategies.

I never know quite how to answer these questions simply. My thinking below has evolved over a number of years, with more owed to conversations on the NSF forum than could ever be reflected in citations. It's about time I wrote it down. My preferred "asteroid mining architecture" is intrinsic to, but inseparable from what I see as a broader space settlement strategy.

I would argue - for reasons beyond the scope of this thread - that it's a mistake to conceive of technology growth as inevitably exponential: I think it's more realistic to see the progress of the last two centuries, and this one, as representing more of a sigmoid step function, driven by the excess energy of the fossil fuel boom and hopefully landing on a high technology, sustainable/low growth society. For my purposes here, my aim is for anything that I'd propose to be possible with today's technology, or at least that which is conceivable in the next couple of decades or so, and feasibly built by limited, vertically integrated organisations of (say <10k) people. So Starship? yes. Small space based nuclear power? yes. Autonomous robot swarms? yes. Fusion and antimatter drives? no. Space elevators? no.   

Context:
The Earth-Moon system will remain the centre of activity, and Mars is clearly the destination with the most momentum at the moment. Any conversation about asteroid mining has to take place in that context, but orbital mechanics sets the rules. Will mined materials be returned to Earth or sent to Mars? Not unless they're very low mass and/or precious, or unless the delta V to move the materials is otherwise small. These conditions create a strong preference for choosing asteroids that can be maneuvered onto regular close approaches with Earth or Mars.

First takeaway: The mining architecture should have as its bi-product a way to maneuver the host asteroid - doesn't have to be by much, relatively speaking, we're talking "station-keeping" delta V for small mountains. There will be an incentive to select asteroids which are in orbits that are close to a regular ratio with Earth or Mars (say 2:3, 3:4, 3:5, 2:7, etc) so that they can be maneuvered to an orbit such close approaches occur regularly. This probably puts a reasonably small upper-size-limit on the asteroids that can be viably mined for profit on Earth-based or Mars-based markets.

My second takeaway is something you really can't escape after playing with the NASA trajectory browser for any length of time, is just how long it takes to get most places.  The radiation issue from GCRs and CMEs is not going to go away, and we can't have people maxing out their lifetime radiation exposures after just 3-5 years in space if we're serious about settling the solar system. While Starship looks like it will be a great vehicle for moving cargo to Mars and elsewhere, and for moving humans up and out of/down and into a gravity well/atmosphere, the realities of interplanetary passenger transport on Starship (needing fast transits) is incredibly limiting to where you can go. Something much bigger, and with much better passive shielding will be preferred to do the transporting of significant numbers of "settlers" to Mars or anywhere else.

I think the plan for at least some of the asteroids being mined - particularly those that are both Earth and Mars crossers and could be maneuvered into Mars-cycler trajectories - should be to become something like tourist towns: mostly unoccupied for large stretches of time (likely years at a time), followed by periods of intense activity during key transit windows.

Spin gravity is also something I think is fairly obvious to integrate into such a scenario - to make it worth the delta V to rendezvous with the cycler asteroid. More on how that fits in below

Notional Plan:
So, what architecture can we use to mine asteroids which also has asteroid redirection as a bi-product? We will eventually use solar sails and mag sails, but for even moderate sized asteroids these sails will have to be huge. What's the first step? Asteroids already alter their trajectories out of strictly Keplerian orbits through the Yarkovsky effect as they spin. If we could modify the spin rate of these asteroids even slightly, we could change the average direction of this existing propulsive effect, and start to actively steer the asteroid towards the desired orbits where we can deliver the materials that are mined.

In a previous thread on spin-gravity, it was proposed that human habitat modules - exactly like train cars - could run inside a circular (toroidal) tunnel, on tracks that curve over on themselves, all shielded from radiation within the asteroid. This habitat tunnel torus is oriented on the same axis as the spin axis of the asteroid and uses the asteroid itself as the reaction mass. The habitat train could be built up over time as more modules are delivered, eventually connecting the train nose to tail - with that connection providing tensile strength sufficient to allow the train to climb to full speed (for 1xG or as high as possible). 

So to repeat: the idea here is to mine the asteroid in such a way that digging the tunnel creates space for the habitat, which itself becomes the momentum wheel for the asteroid. Digging the tunnel is how the mined materials are acquired, and digging it as a torus is what allows the asteroid to be steered into a more desirable orbit over time, so that those materials can be sold to Earth/Mars markets.

The tunnel itself would be the most complex part of the construction, since most asteroids are rubble piles and the tunnel has to have both strength and rigidity for this to work, but there's upside if you combine this tunnel construction effort with asteroid mining: Most of the mined material is not going to be of value - there will be plenty of waste regolith that you're spending energy to move anyway - so combine the regolith with a polymer substrate to make bricks of a substance very similar to concrete (has already been done with Lunar regolith).

Step 1) An autonomous tunnelling machine + solar array/power craft to arrive at the asteroid. I envisage this as a pair of craft, connected by a detachable power umbilical.
Step 2) After the asteroid has been characterised, the pair take a circuit around the outside of the asteroid, where the tunnelling machine makes a number of radial bore holes down to the planned tunnel "depth".
Step 3) The tunnelling machine then creates the toroidal tunnel itself, harvesting water and other elements of value, reinforcing the walls of the tunnel with "regocrete" bricks, all while detaching and reattaching the power umbilical as necessary.
Step 4) Humans arrive with extra equipment to add value to the mined materials and reinforce the tunnels, since the "regocrete" would need bolstering by steel cables. Effectively the entire structure is a suspension bridge wrapped over on itself, so you would have some cables going through the centre of the asteroid too.
Step 5) Human habitat modules - hosting the crew doing the work - are moved into the tunnel itself.
Step 6) Train tests, at low speed, for low G. The habitat modules are probably already part of a spin-G habitat, so they are already designed to be part of a spin G station.
Step 7) Even whilst all this is going on, the tunnelling machine can be starting on the second tunnel and continuing to mine out more materials. Eventually you've mined out a substantial part of the core of an asteroid, and replaced it with multiple "train-car" habitat rings.

One of the interesting things about this concept I think, is that - if you pick an asteroid spinning slowly enough to start with - you eventually reach a point where you have full pointing control of the entire asteroid. At that point you really can start erecting megastructures like telescopes, solar sails, or mag sails.

Takeaway 3: There is an incentive to harvest asteroids with low spin rates.

Takeaway 4: We already know how to build high-speed trains, and train tunnels. If you suppose that the train cars are eventually able to move at fast-train speeds to produce 1xG, you end up at ~50m/s or around 180 kph, for a toroidal habitat 500m in diameter. (NB: there are a bit over 300 NEO asteroids with diameters 500m-1km)

Takeaway 5: If you suppose the modules have internal diameters of 6m (for transport in Starship), this 1570m circumference gives you at least one hectare of farmable area on a single habitat ring. A rule of thumb I learnt a while back is that one hectare, farmed with high productivity aquaponics/permaculture gives you about enough food to feed 60 people on an ongoing basis.

Takeaway 6: The end-state of this asteroid "mining" project, lets say with a dozen habitat rings, is that you've created a more-or-less self-sufficient settlement for 720 people, which is capable of self-pointing and hosting large megastructures on its surface. If, in centuries to come, fusion reactors and large-scale mag-sails like Wind Rider become feasible... it becomes a ready-made generation ship capable of interstellar travel.

Just to finish off this line of thinking, it should be clear that what I'm aiming for here is a program of a similar magnitude to Elon's Musk's city of 1 million people on Mars, except in this case it's tens of thousands of small asteroids being settled, each with several dozen people operating the machines that are building these habitat rings, and the "trains" that run within them. I personally think it's actually a better outcome, because these habitats provide Earth surface-level radiation shielding, they provide a healthy 1xG, and the people working on them also get the chance to work on the asteroid constructs that could eventually go to the stars. I'd like to see a program where the tunnel-building robots, and their human crews, are leaving the Earth-Moon system by the dozen, every week in the 2040's for a tour of a decade or two, before returning home to retire. I hope you found this vision compelling, and cheers for reading to the end.

Offline LMT

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Re: Asteroid Mining Architectures
« Reply #44 on: 07/06/2022 03:00 pm »
The Earth-Moon system will remain the centre of activity, and Mars is clearly the destination with the most momentum at the moment. Any conversation about asteroid mining has to take place in that context, but orbital mechanics sets the rules. Will mined materials be returned to Earth or sent to Mars? Not unless they're very low mass and/or precious, or unless the delta V to move the materials is otherwise small. These conditions create a strong preference for choosing asteroids that can be maneuvered onto regular close approaches with Earth or Mars.

First takeaway: The mining architecture should have as its bi-product a way to maneuver the host asteroid - doesn't have to be by much, relatively speaking, we're talking "station-keeping" delta V for small mountains. There will be an incentive to select asteroids which are in orbits that are close to a regular ratio with Earth or Mars (say 2:3, 3:4, 3:5, 2:7, etc) so that they can be maneuvered to an orbit such close approaches occur regularly. This probably puts a reasonably small upper-size-limit on the asteroids that can be viably mined for profit on Earth-based or Mars-based markets.

What's a "close approach" here, and what's "small delta-v" here?
« Last Edit: 07/06/2022 06:51 pm by LMT »

Online TrevorMonty

Re: Asteroid Mining Architectures
« Reply #45 on: 07/07/2022 01:39 am »



What's a "close approach" here, and what's "small delta-v" here?

Most of bulk ISRU metals and water would end up in CIS lunar space which means round trip from eg EML1 for closer ones is 2-4km/s.
In most cases the return trip should be fuelled from Asteriod water so only 1-2km/s to transport bulk materials to CIS lunar space.

At these low DV ranges simple low ISP water fuelled thrusters become viable.
« Last Edit: 07/21/2022 01:41 am by zubenelgenubi »

Offline LMT

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Re: Asteroid Mining Architectures
« Reply #46 on: 07/07/2022 06:01 am »
What's a "close approach" here, and what's "small delta-v" here?

Most of bulk ISRU metals and water would end up in CIS lunar space which means round trip from eg EML1 for closer ones is 2-4km/s.
In most cases the return trip should be fuelled from Asteriod water so only 1-2km/s to transport bulk materials to CIS lunar space.

At these low DV ranges simple low ISP water fuelled thrusters become viable.

Delta-v from a given metal NEA orbit to EML1 would almost certainly be far greater.  Likewise, outbound.  Metal NEA choices are few:  two are noted below, with orbits shown.  Ballpark relative speeds at closest possible approach.

Metal NEAs seem rather dry thus far.  See 6178 (1986 DA) and 2016 ED85.  Even a carbonaceous NEA, Ryugu, proved dry.  Water is more abundant out in the asteroid belt.
« Last Edit: 07/07/2022 06:18 am by LMT »

Offline libra

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Re: Asteroid Mining Architectures
« Reply #47 on: 07/07/2022 05:20 pm »
It is still there and running, and watching it is kind of hypnotic.

https://www.asterank.com/

I LOVE playing and toying with that thing.

Mandatory soundtrack:

 

Offline floss

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Re: Asteroid Mining Architectures
« Reply #48 on: 08/11/2022 12:49 pm »
First decent design for asteroid mining.

 

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