Question What would industrialised cis-lunar space actually look like?

[jedidia]

I am wondering a bit about how an "industrialised earth orbit" is sometimes portrayed, and I thought it would be cool to have a discussion about it here.

What I don't want to discuss is how we get there. There's plenty of models around, all with their own issues, but for this I really want to get a better idea of what it might look like.
For that purpose, I'm going to outline some assumptions without going into any nitty-gritty details about how they came to be:

• costs of Launch to LEO is much cheaper, but still significant, let's say 0.5 million dollars per ton (not quite a factor of 10 more expensive than current-day international airfreight)
• There is a sizable population (100'000+) living on the moon.
• There is a growing outpost on Mars with some light traffic (mostly supply runs scheduled on launch windows).
• Mining NEOs is a thing, and mining in the belt is starting to pick up.
• There are regular unmanned scientific missions to the outer planets and preparations for establishing a permanent base on ganymede
• Earth is, obviously, still the major industrial and economic centre.
• Some reliable solution for long-term zero-g effects has been found, be that medical or engineered (e.g. rotating habitats).

Also, when thinking "industry", don't think "metal and machines", just think "manufacturing stuff, any kind of stuff".
Things I am interested in:

• Most prominently, the shape of the whole thing. Earth has radiation belts, and they're not healthy places to be in for longer times. In fact, the GEO-band lies inside a radiation belt. So do you think that bands with higher radiation would just simply be avoided and filled with satelites, or do you consider it likely that a simple and good enough solution would be found to make this only a minor setback?
• What industries would make sense to have in earth or lunar orbit that could produce things from lunar materials for off-earth use (cutting the launch costs)
• What industries would make sense for producing goods for earth?
• Tourism from earth would be present but limited from earth, but what potential is there for tourism from the moon or from other habitats in orbit themselves?
• Is it even remotely imaginable that there would be something akin to cities, where people live in orbit permanently and found families, or do you think the orbital population would always be cycling?
• What science would be done in orbit?
• Where would most of the food consumed in orbit come from? Earth, Lunar farms, or specialised habitats in orbit?
• Who would organise and regulate the entire thing? Do you consider it likely that a central authority would start to charge "rent" for orbital spots as things start to get crowded? Who makes traffic regulations and keeps the place cleaned up? Who enforces law?

 

[4throck]

Short answer: The Expanse

Seems like a realistic extrapolation based on current trends and tech.
Off Earth you have large scale mining and building, taking advantage of low gravity and no environmental concerns.
Earth is pretty much limited to services and food/organics production.

 

[jedidia]

Seems like a realistic extrapolation based on current trends and tech.

Unfortunately, the expanse universe does not give a lot of details about its cislunar infrastructure and organisation specifically.

 

[Urwumpe]

Short answer: The Expanse

Seems like a realistic extrapolation based on current trends and tech.
Off Earth you have large scale mining and building, taking advantage of low gravity and no environmental concerns.
Earth is pretty much limited to services and food/organics production.

Except if you care about physics. Then it is pretty unrealistic.

 

[jedidia]

Except if you care about physics. Then it is pretty unrealistic.

Well, at least if you care about thermodynamics...

 

[Urwumpe]

Well, at least if you care about thermodynamics...

Not just that - the idea of rotating asteroid bases is also pretty far off. Or how they depict the impact of a railgun projectile. Sorry, if that happens in your room, you are dead. Even just stopping 100g of the projectile during passage would be equivalent to a naval artillery shell exploding.

 

[jedidia]

Sorry, if that happens in your room, you are dead.

Ah yes, that one. From what I heard, the initial story setup was actually adapted from a P&P campaign the authors were playing. One player left the group and the GM had to kill off the character. It's not surprising that he didn't consider the dynamics of expanding plasma at that point...

In any case, unless someone brings examples for how the expanse organises its cislunar space, I think that's about enough on the expanse for this thread.

 

[Urwumpe]

Ah yes, that one. From what I heard, the initial story setup was actually adapted from a P&P campaign the authors were playing. One player left the group and the GM had to kill off the character. It's not surprising that he didn't consider the dynamics of expanding plasma at that point...

In any case, unless someone brings examples for how the expanse organises its cislunar space, I think that's about enough on the expanse for this thread.

In that case, did you read about stuff like LUNOX or the Stanford Torus?

 

[jedidia]

I know about stanford toruses, yes. I've never heard of LUNOX, and googling it gives me a lamp manufacturer, something to do with aluminium profiles, and apparently it's a leage of legends character or something?

 

[Urwumpe]

I know about stanford toruses, yes. I've never heard of LUNOX, and googling it gives me a lamp manufacturer, something to do with aluminium profiles, and apparently it's a leage of legends character or something?

Lunox

Lunox

www.astronautix.com

This one.

And if you take these search results,there are quite many economic studies among it:

Search - NASA Technical Reports Server (NTRS)

ntrs.nasa.gov

 

[Urwumpe]

BTW, who looks for the NASA report of the Stanford Torus, SP-413 is located here:

http://large.stanford.edu/courses/2016/ph240/martelaro2/docs/nasa-sp-413.pdf

Having some more economics in a Stanford Torus mod might get interesting for Orbiter, the distances and travel times are rather short, the technology in the report not too wild.

 

[cannon_gray]

Hope it could look like in Interstellar

 

[jedidia]

I don't have that much time to really give this thread the proper care it needs, I was kind of hoping that some discussion would get going, but it looks like I have to move things on a bit.

So, the first thing I want to tackle is the shape of a hypothetical populated and heavily trafficked earth orbit, extending from LEO to GEO and potentially a bit beyond.

The main issue I always have with this when looking at hard-ish science fiction settings that actually provide some details on this topic (as rare as they are. The RPG setting Orbital 2100 being the most detailed around, the GURPS- Transhuman space setting to a lesser extent - if anyone knows of similar stuff, please let me know) is that everybody completely forgets about the van allen belts. Yet they are pretty much a geographic feature of our orbital space, and I think they would have quite some influence on what the whole thing would look like.

To quickly summarize, there are two main belts:
Inner belt: 1000 km - 2000km
Outer belt: 13000 km - 60000 km

The radiation in these belts is not evenly distributed. This explanation by Nasa for why the Apollo astronauts weren't fried by the radiation has a nice image of the distribution:

https://www.nasa.gov/sites/default/files/files/SMIII_Problem7.pdf

A lesser known feature of the van allen belts is that they're actually quite variable. When solar activity picks up, they swell. In fact, the ISS (at roughly 400 km) seems to have been enveloped by the inner belt a couple of times, meaning that the thing can essentially swallow the entire LEO band at times.

There also seems to be a third, temporary belt further out that only forms in times of very high solar activities. I haven't had the time to find reliable data on that one, unfortunately.

Orbits are also coarsly classified into three "distance bands" (numbers may vary a bit depending on who you ask):
LEO: 400-2000 km
MEO: 2000-35786km
GEO: 35786
HEO: anything between GEO and L1

We can see that the inner belt blankets most of LEO permanently, and the outer belt cuts out a god deal of MEO and HEO. And GEO, unfortunately, sits right smack in the most radiation intense zones of the outer belt.

The radiation in those most intense zones, according to the NASA document linked above, is about 0.05 Rads/second, or about 180 rads an hour. This is more than half of what is considered a lethal dose (300 rads an hour), which is pretty hefty. In the zones that make up the largest part of the belts (orange in the document), there's still a dose of 36 rads per hour.
This adds up to 1'555'200 rem resp. 311'040 rem per year (assuming there's no alpha radiation, which, quite frankly, I have no idea whether it's the case). The current radiation dose considered safe by work regulations is 5000 rem / year. So yeah... protracted residence in these zones would be rather unhealthy.

Radiation can be shielded against, obviously, especially on orbital infrastructure that doesn't need to be as concerned with mass as something that has to move around. The trouble is, you probably still need to get outside every now and then, and there's traffic... We can assume that nobody would like to spend the hours of docking in an orange zone, and nobody would be keen to park for prolonged time because their crafts interior might be a bit radioactive for a while after doing that.

I don't know much about radiation, and even less about radiation shielding, but to me this seems like any of the orange zones in that document (which, as you can see, is most of the belts) would just not be populated by anything that has to accommodate people. There will probably be a decent amount of satellites, but nothing where a craft transporting people ever has to dock to.

Unfortunately, GEO is right smack in the worst of it. So... there's definitely not going to be a large GEO space port as depicted in Orbital 2100 (and other, less detialed settings which always seem mention some traffic node in GEO, and if it's the only thing they mention about earth orbit infrastructure). Also, certainly no hotels...

I do see highly paid jobs for satellite repairs within the radiation belts for those who have the necessary equipment, or are just plain desperate. That's a nice bit of flavour for a setting, I guess.

So... Any thoughts from you lot? What do you think about this?

 

[Urwumpe]

Don't fall prone to the same scientific blunder as people who estimate the number of Chernobyl deaths from the radiation: You can't simply integrate radiation doses to estimate the damage. Weak radiation damage does get repaired faster, than you get it. Obviously: Spending a day in the Van Allen belt will be bad for your health. That is why Space Elevators are a rather poor idea for human transportation.

Also the vector is important - ingesting an alpha emitter is always a rather poor idea, while having a beta emitter on your clothes does not harm you.

The relevant xkcd chart can be found here: https://xkcd.com/radiation/

I think repairs in the Van Allen belts will be really desperate out of many reasons, since there will also not be many satellites there. If you have to put your satellite there, it is because all other orbits are taken.

 

[Urwumpe]

Lets approach this from the eyes of an economist. (I hate it, when I have to do this.) What products and services will exist? What is the value chain? What will be needed, to make production of those products and services optimal in space, instead of staying on terra firma?

For example: There could be huge solarthermal stations at the Earth-Sun L4 and L5 points, that use the abundant solar power for melting ore into metals or use the heat and microgravity for producing really pure silicium wafers for microelectronics. But getting the ore there would be overly expensive and something would have to be done with the slag. Just dumping it into space would be bad idea, what goes around the sun, comes around the sun.

So, maybe placing them on the moon, despite the two weeks of lunar night could be more effective - but likely still less effective as putting them on Earth, unless the available surface area on Earth has to be used for something else....

 

[jedidia]

But getting the ore there would be overly expensive

Unless the ore does not come from earth... That's why I wrote that NEO-mining is a thing in the assumptions. As long as you have to get everything up from earth, there's not going to be much of an industry. You need to be able to cover at least most of your on-orbit propellant requirements from sources of earth, otherwise the money sink is too huge.

However, I didn't even seriously consider heavy industries like ore refining... That's kind of a new thought. If anywhere off-earth, I would intuitively have placed it on the moon. But the problem is that it is a lot easier to get the ore down to earth (aerobraking) than it is to get it down to the moon. The drawback being, obviously, that it's very expencive to get the products back up if you need them off-earth.

So in my opinion, having something like an actual metal industry off-earth would presuppose that there is also enough demand for it off-earth for the launch costs to offset the investment required for the infrastructure...
Now I'm wondering what could possibly generate enough off-earth demand for metals, and the only thing I can think of would be to build big dumb objects like Oneil Cylinders. Which would be awesome of course, but ultimately pose the question why there would be high enough demand for orbital living space unless there is a significant export market to give the economy a drastic growth spurt.

So far, the value chain seems to be kind of circular.

 

[Sbb1413]

This is somewhat similar to the nuclear fusion paradox. Nuclear fusion generates a lot of energy. But fusion requires very high temperature, and reaching to that temperature would require a lot of energy. Therefore, the fusion energy may seem useless, contrary to what the Sun is doing.
But still, I don't believe that we are in a simulation. You can't programme an irrational number in your computer.

 

[Urwumpe]

Well - there is a problem with aerobraking large amounts of ore: It is expensive as well. You need heat shields and containers. And you need MASSIVE heatshields, since any significant amount of ore has a high density and thus, a rather bad ballistic coefficient for reentry.

So, refining metals from NEOs in space makes sense, since it reduces the mass that needs to be downloaded to Earth massively. But I think, this would not take place on L4 or L5 initially then, because of the problem what to do with the slag. The metal would be just one product out of many that gets created that way and has to be processed or paid for disposing it safely.

For NEOs, it would even make sense to place the refinery close to the object that gets mined, so that any waste product can be simply cemented in place of the old asteroid or merging the waste of multiple asteroids in a family (trojans, which are at L4 and L5....) together. Which would be another plus for a refinery at L4 and L5. And possibly a large habitat near it, instead of putting a habitat to a highly automated factory, that could be build cheaper and more efficient without permanent human presence on board.

So, with this kind of assumption, we would have tests of the technology near the moon, but then move it towards L4 and L5.

 

[Urwumpe]

I would have to ask my universities library if they have this book available, it could be interesting for adding some more constraints to the model:

Electromagnetic Levitation Refining of Silicon–Iron Alloys for Generation of Solar Grade Silicon

At present, expensive semiconductor grade silicon (SEG-Si) is used for the manufacture of cells to convert solar energy into electricity. This results in a high cost for photovoltaic electricity compared to electricity derived from conventional …

www.springerprofessional.de

 

[jedidia]

Well - there is a problem with aerobraking large amounts of ore: It is expensive as well. You need heat shields and containers. And you need MASSIVE heatshields, since any significant amount of ore has a high density and thus, a rather bad ballistic coefficient for reentry.

I'm not sure how bad it really is... If you brake them down on shallow trajectories, skipping a couple of times, I guess you could do by ablating some cheap mass. Don't have any math for that though, and not the time and skill to do any, so I might be hilariously wrong.

Suppose there would be some on-orbit refining. There would certainly be demand for it, just probably not enough to justify the infrastructure expense. But in that case, this could beat multiple birds with one stone. Enough infrastructure to refine some of it, which could be consumed on-orbit, while the waste products of the process might be used as ablation mass for heat shields to get the rest unrefined down to earth. That sounds like a point where something like this might start, and the exports to earth might be enough to pay for the initial facility (since it couldn't pay for itself just by selling its meager production to other orbital facilities).
It's an inefficient process, since a lot of the mass sent down to earth is just garbage. But now there's an on-orbit source of materials, making it cheaper to build additional facilites. Basically, the more you can reduce the waste mass being sent down to earth, the more efficient the process gets, and the more production capabilities you have on orbit the cheaper it gets to build more of that to make the export more efficient. That sounds like a potential bootstrap...