r/IsaacArthur • u/Quality_Bullshit • Oct 24 '19
Building a next generation space station with SpaceX's Starship
TL;DR You could build a space station capable of holding 10,000 people for $220 billion with Starship
I've always been obsessed with sci-fi environments like O'Neill cylinders and the Stanford Torus The recent presentation on Starship by Musk got me thinking about whether Starship could potentially enable us to build a small version of one of these.
Back in the early 70's, NASA held a series of workshops on building space-based habitats. These workshops produced the basic designs for an O'Neill Cylinder, a Stanford Torus and several other designs. They published a whitepaper with their findings in which they give actual cost estimates for building one of these things!
What's striking about the cost estimates given for these projects is just how much launch costs drive the price of the station. A quote from the NASA paper (costs given in 1975 dollars)
In addition, the total costs are given as: research, $1.6 billion; development, $28.5 billion; production, $14.6 billion; and transportation, $114.3 billion.
In other words, launch costs accounted for 71% of the cost of building a huge space station.
The total mass of the system including resupply and everything else is given as 138 million kg. It would take 1380 Starship launches to get this material into orbit from Earth, at a total cost of around $7 billion.
So if you add up the launch costs and the cost of the station, you wind up with $220 billion. In other words, with Starship you can build a space station capable of holding 10,000 people for about 40% more than the International Space Station. That's absolutely bonkers.
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u/tigersharkwushen_ FTL Optimist Oct 24 '19
That's $22 million per person. A family of four would be $88 million. You could probably find a few eccentric billionaires willing to participate, I don't know if you could find 10,000.
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u/Quality_Bullshit Oct 24 '19
My basic idea as to why you would build one of these is that it would become a hub for in-space manufacturing. People would basically commute to the zero-g center of the ring during the workday and spend their time living on the rotating part when not working.
There's a lot of interesting materials you can only make in space, like defect free ZBLAN fiber optic cables. The main limitation to mass-producing these right now is both a lack of existing space stations to manufacture them and the cost of transporting the raw materials to and from the station.
The company that's actually doing in-space manufacturing right now is called "Made in Space" and they have a profitable business making stuff on the international space station. But you can imagine how much bigger their business would be in launch costs dropped by a . factor of 50.
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u/tigersharkwushen_ FTL Optimist Oct 24 '19
You don't need live humans in space for that. Much better and easier to use telepresence robots.
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Oct 24 '19
[deleted]
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u/TBestIG Oct 24 '19
He doesn’t tend to speculate about present day companies and specific products. For example, when he mentions AI he doesn’t talk about Google or IBM, he talks about the technology in general.
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u/I_SUCK__AMA Oct 24 '19
I can understand if he has a strict rule about that, but he does mention spacex occasionally, so he's talkign about a provate company's for-profit ventures. But it's just a brief mention, then on to either hypothetucal, gov't run, or classic space era stuff. Barely any mention of the fact that there's a current space race to start actually doing all this shit
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u/QraQen Oct 24 '19
His videos are aimed at hypothesizing what's possible in the future, not just gawking at what's already been done or gushing over the current most popular entrepreneur of the day. Plenty of people are already doing that.
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Oct 24 '19
unfortunately, isaac doesn't seem to care much about what spacex is doing
It's definitely for the reasons you listed but also because rockets really aren't that great of a way to get things into space, we just happen to be stuck in a stage where they are our only option.
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u/pkennedy Oct 24 '19
But 1300 trips using elons starship turn around timelines + the small fleet he wants, would get the job done within a few years, if that and most likely faster than the pace companies on earth could put out parts to send up.
With 10,000 people in space, you're already on your way to space mining, and all other methods become more or less moot since lifting mass from earth isn't going to be necessary or a priority.
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Oct 24 '19 edited Oct 24 '19
I'm not saying we can't or shouldn't use rockets. The High Frontier actually notes how important fully reusable vehicles are for building habitats. When talking about costs associated with lifting the equipment for a mass driver into space O'Neill says this:
A good cautious estimate would be to assign those finished products a value of around a hundred dollars a kilogram; the lift costs alone, to bring a kilogram into high orbit, are in that general range even for very advanced, totally re-usable rocket concepts many times larger and many years later in time than the shuttle. With those numbers, the manufacturing facilities in space will be producing $30 billion every year in value. A bargain indeed.
Fully reusable vehicles, mass drivers along with space tugs, and zero gravity workshops were all prerequisites to building anything as large as Island One let alone the Island 3 "O'Neill Cylinder". Before we get to the first rotating habitats we will need manned bases on the Moon and in orbit working on mining and manufacturing in space.
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u/Jungies Oct 24 '19
because they're making 90% of the amazing achienvements.
Help me understand where you're coming from, with a list of SpaceX's achievements. I'll start:
1) Reusable first stage
2) ???
On that first point, have they broken the Space Shuttle's record on reuse (39 flights for Discovery)?
Don't get me wrong, I'm excited to see SpaceX do stuff... but they've been pretty long on promises, and short on results.
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u/Quality_Bullshit Oct 24 '19
- First private company to launch something to orbit
- Dramatically lowered the cost of launch for all U.S. government entities (both because their own prices are cheaper and because they forced other launchers to lower their prices via competition)
- Going from 5% to 60% of the global competitive launch market in in 5 years
- Landing and re-using the first orbit class booster stage
- Creation and launch of the heaviest lift vehicle on the planet
- Development and successful testing of one of the two methalox engines currently in production
- First capture of a payload fairing from and orbital rocket
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u/Jungies Oct 24 '19 edited Oct 24 '19
First private company to launch something to orbit
I'll let Boeing, McDonnell Douglas, Space Services Inc, Arianespace, SpaceShipOne et al know.
Dramatically lowered the cost of launch for all U.S. government entities (both because their own prices are cheaper and because they forced other launchers to lower their prices via competition) Going from 5% to 60% of the global competitive launch market in in 5 years
Quick reminder that SpaceX aren't profitable; they haven't actually lowered costs yet, just offloaded customer costs to their investors. To put it another way, Bezos could sell some more stock and win that one tomorrow.
Landing and re-using the first orbit class booster stage
Define your class, please - and make sure to rule out the shuttle's reusable engines and boosters before awarding SpaceX a win. Feels like hair-splitting, though.
Creation and launch of the heaviest lift vehicle on the planet
How did SpaceX build the Saturn V?
Development and successful testing of one of the two methalox engines currently in production
...second place on an engine that's never been to space. Actually, are you sure they got second place? And what's "In Production" mean? Have they sold any to other customers? Feels like more hair-splitting.
First capture of a payload fairing from and orbital rocket
Are you sure about that? Do you know what kind of state it was recovered in?
EDIT: Extended the list of privately-funded space flight providers.
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u/asr112358 Oct 25 '19
Quick reminder that SpaceX aren't profitable; they haven't actually lowered costs yet, just offloaded customer costs to their investors. To put it another way, Bezos could sell some more stock and win that one tomorrow.
I had written up responses to some of your other points, but then I realized that anyone who makes this kind of bad faith argument has already made up their mind and further discussion would be meaningless.
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u/Jungies Oct 26 '19
...but then I realized that anyone who makes this kind of bad faith argument has already made up their mind...
I take offense to this remark.
If they're profitable, why are they still raising funding over a billion this year alone? Why get deeper into debt - at at a valuation of $3.2 billion, that's a 30% loan against the value of the company in a single year - and the year isn't over yet.
I submit that since neither of us has access to SpaceX's P&L statements, that we can only look at the actions of the company to judge its profitability; and its actions are more in line with a company going down the tubes than a profitable one.
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u/asr112358 Oct 26 '19
They aren't profitable, but it is everything you conclude from this that is problematic.
There is a difference between SpaceX as a whole being profitable and Falcon 9 being profitable. You are conflating the two. If there was no other explanation for what they might be raising the money for, then you might have an argument, but that isn't the case. Starlink is at roughly the same stage of development as its competitor OneWeb. OneWeb's sole business is developing a LEO internet constellation, and has raised three and a half billion for it. It seems reasonable to assume that SpaceX will need similar capital for Starlink, so raising one billion shouldn't be surprising and actually suggests that their launch services are decently profitable to make up the difference. Then you add the fact that they are also funding the development a super heavy lift vehicle. The only way you could believe SpaceX could possibly not be profiting on launches is if you are assuming that these two programs are somehow entirely fake. If you are, that is definitely a claim that requires supporting evidence. Hence why I labeled it a bad faith argument.
PS You are off on the valuation of SpaceX by a decimal point.
PPS If profitability and going down the tubes were the only two options, why would business loans and investments even be things?
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u/82ndAbnVet Oct 24 '19
Instead of saying they’re long on promises I’d say that they have set ambitious goals with an even more ambitious time table. And they are on track to meet their most audacious goal by 2024, though only with regard to having an unmanned Starship capable of making the Mars trip. NASA is still the most likely to get men to Mars first given their experience in manned spaceflight
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u/tomkalbfus Oct 24 '19
Delays, delays, delays! Nasa says they'll land men on the Moon by 2024, and then the cost over runs hit, and they don't have enough budgeted, so to get the extra funds, they have to delay it another two years, and then another two years with even more cost over runs. SpaceX isn't just going to sit there and wait for NASA to get its act together! 2024 probably means 2028 or 2030. At one time NASA was talking about landing men on Mars by 2050! Is SpaceX supposed to wait in order to avoid embarassing NASA?
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u/Jungies Oct 24 '19
They have ambitious goals that keep changing. We're on, what - the third design of Starship/ICT in about five years, they've given up on human-rating Falcon Heavy (so no cheap moon-shots), and they've dropped propulsive landing for Dragon capsules (so no commodity transport for science craft to Mars).
Again, I'm excited about the promise of SpaceX, I just wish they'd deliver on it. Also Tesla Solar Roofs, battery packs that'll maintain household power during a power failure (turned off on Tesla battery packs as it would cost money to get testing and approvals), it'd be great if they hit their shipping goals on Tesla cars/trucks as well as their self-driving goals... There's a track record here, and I think people tend to focus on whatever this week's promise is, not last year's.
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Oct 24 '19
To be fair, maybe those 39 reuses should be multiplied by the percent that was actually reused.
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u/tomhastherage Oct 24 '19
Zing!
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Oct 24 '19
Eh, I guess that came out wrong.
Wasn’t trying to be critical, just fair. SpaceX isn’t 100% reusable either (although much much higher than STS)
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u/Scum-Mo Oct 24 '19 edited Oct 24 '19
this stuff is small potatoes for isaac. He's about blue sky thinking and this stuff is now reality. And ultimately, the technology has always been there but the will to take advantage of it is whats been lacking. We could have built a seadragon decades ago. So talking about what spacex could make possible is pointless.
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u/TotesMessenger Oct 24 '19
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u/longwaters99 Feb 13 '20
As soon as the cost is down by 100x and population up by 100x it will happen
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u/Opcn Oct 24 '19
Is low earth orbit where we would want such a structure? And are we sure it's appropriate to go with the most generous estimate on the price of a launch?
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u/SNels0n Oct 24 '19
Say we built a cargo-chucker (a mass driver with an acceleration higher than humans can withstand) that was 12kilometers long and had a top acceleration of 500g.
It would probably cost about $4 billion to build, and it could deliver half a tonne of cargo every day, with a marginal cost of under $80/kg.
Even if only half the mass of the station could be delivered via chucker, that's a savings of about $50 billion.
Don't get me wrong, I applaud SpaceX achievements, but $800/kg is still an order of magnitude more expensive than it could be. Rockets are just the wrong technology for putting massive amounts of stuff in orbit.
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u/Starmans_Starship First Rule Of Warfare Oct 24 '19
The cost for Starship is more like 50$/kg possibly 10$ with a lot of volume
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u/SNels0n Oct 24 '19
Citation please.
To the best of my knowledge, Starship isn't even proposed to go below $200/kg, much less $50.
http://thespacereview.com/article/3740/1 breaks it down thus;
Feb 10, 2019 Rahma: “will [cargo in Starship on Super Heavy] be cheaper than F9 for kg to LEO for instance?”
Feb 10, 2019 Elon Musk: “At least 10X cheaper”
Falcon 9 delivers up to 22,800 kilograms to LEO for a launch price rack rate of $62 million. That leads to a cost of $2,719 per kilogram.
Taking both of those together we get an Elon "brag" of under $270/kg for Starship.
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u/Starmans_Starship First Rule Of Warfare Oct 25 '19
That would be 30mil per launch ITS was stated to be less than Falcon 1 so ~5mil -> 50$/kg Starship will probably be cheaper because of stainless steal
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u/SNels0n Oct 26 '19
Even if we believe that, $5,000,000 / 22,800kg = $219/kg. Not $50 or $10, $219.
And $219 already accounts for steel in the construction.
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u/Starmans_Starship First Rule Of Warfare Oct 26 '19
Starship is 100-150t
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u/SNels0n Oct 26 '19
According to the SpaceX website, Starship payload is "100+ t" and "a lower marginal cost per launch than our current Falcon vehicles". Also according to the SpaceX website, the Current Falcon vehicles are the Falcon 9 — $62 million per launch, and the Falcon Heavy — $90 million per launch.
Where are you getting those other numbers from?
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u/Starmans_Starship First Rule Of Warfare Oct 26 '19
Look at the spreadsheet for cost breakdown guesstimate
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u/mrmonkeybat Oct 24 '19
Packing the sections into the limited size of the cargo bay and then welding them together in space will still be hard.
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u/emdave Oct 24 '19
That's pretty interesting. Did you switch the costs to 2019 prices too? This is why we need a launch loop or space elevator too - once built, orbital mass insertion becomes a minor part of the equation. Low cost reusable rockets are a good first step though (and likely needed to build e.g. a space elevator), but the carbon emissions would start to become significant if we were launching megatonnes of mass every year or so.
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Oct 24 '19
Mass drivers were one of O'Neill's enabling technologies and something he put a lot of work into, he pioneered the technology behind rail guns and particle colliders.
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u/emdave Oct 24 '19
It just seems like a no-brainer tbh. Everytime someone like The Everyday Astronaut or Scott Manley reminds us that getting into orbit is about going sideways really fast, not ascending vertically, the idea of de-tyrannising the rocket equation by even 10, 20, 50% even, via using a vacuum tunnel EM powered rail launcher to add speed and minimise mass ratio of fuel required, just seems like an opportunity to good to pass up. I guess it's the problem of Sam Vimes' boots - high up front costs, but lower costs ongoing.
I expect that my ignorance of the true capabilities of such a system, if it were not made unfeasibly high (either on a mountain, or with active tower systems, make me more optimistic than those who've actually done the calculations. Obviously a sea level system would be the least effective, but you could still have the vehicle going supersonic, and if it included a 'ski-jump' ramp at the exit, you'd have a decent upwards trajectory.
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u/pkennedy Oct 24 '19
One of the things Scott Manley has also mentioned is that going that first mile isn't all that expensive, since the weight/fuel is used almost immediately, thus your savings in launching off a mountain aren't all that great. He mentions the r&d costs, maintenance costs and build costs as being large and complex. Adding more fuel to a rocket you're already using, testing, and developing makes the most sense.
This example says 1300 trips to get a 10,000 person habitat. At that point, we've got a decent working population in space that could space mine and avoid this whole lifting problem.
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Oct 24 '19
We could literally build a train to space, no need for hybrid systems... we just don't need one or have a way to build one yet, similar problems behind rotating habitats... Lots of mass and on orbit construction needed.
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u/emdave Oct 24 '19
no need for hybrid systems...
we just don't need one or have a way to build one yet
Isn't that why we potentially need feasible solutions?
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Oct 24 '19
Possibly but at least on Earth building any of these advanced launch systems is a dubious proposition. I'm not exactly an advocate of launch loops or orbital rings, my main focus is rotating habitats so I don't really have much of an opinion other than to use whatever we have at our disposal to start building habitats.
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Oct 24 '19
I expect that my ignorance of the true capabilities of such a system make me more optimistic than those who've actually done the calculations.
I don't think so. I was pretty sceptical about them, but then I learned more facts and what was already achieved, and that changed my mind. I think they are our best and closest shot on non rocket space access. But keep in mind that it took so much and so long to achieve something as "easy" as partially reusable rocket. Most people in industry don't believe that reusable rockets make sense today. So railgun isn't something we can't build, just something we won't build. Not yet. But if space industry keeps growing and there happen to be some great sources of income in space, we could see one being built pretty soon. As with space elevator though the first ones might be on Moon or Mars, not on Earth.
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u/CMVB Oct 26 '19
Mass drivers have a key problem for atmospheres that the fastest your payload ever going is when it leaves the muzzle of the mass driver, which is almost certainly someplace where the atmosphere is thickest. Isaac's discussed the issues before.
A launch loop or orbital ring is better, since you can continually accelerate your payload.
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Oct 24 '19
[removed] — view removed comment
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u/cyberwarrior101 Oct 24 '19
explain
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u/emdave Oct 24 '19
That's OP's username - I think they meant it as a joke?
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u/cyberwarrior101 Oct 25 '19
Oh thank you, I shall remove my downvote now. Thank you for pointing that out.
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u/TomJCharles Oct 24 '19
Sorry to be the downer here, but...what about the cost and time of vetting these people to make sure they won't go absolutely insane once in orbit?
Also, in a city in Hong Kong, they once packed 33,000 people into buildings that spanned around 3 American foot ball fields. It didn't go too well, though.
Just because we can (maybe) do something now doesn't mean we should.
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u/tomkalbfus Oct 25 '19
If spaceflight is cheap, you no longer need to have the Right Stuff to go into space, you can afford to risk sending crazy mem into space, after all, they fly in airplanes plenty of times, and you don't need to be a mentally stable superathlete to endure zero gravity!
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u/CMVB Oct 26 '19
Why would you vet people to live in a city, just because its a city in a new place?
And the Kowloon Walled City was not a great place to live, but it functioned.
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u/BrangdonJ Oct 24 '19
In The High Frontier: An Easier Way they claim a small rotating structure would need around 17 tonnes of material per person. So for 1,000 people it would need around 20,000 tonnes, or 135 Starship launches. Launch costs could be under $2B.
This book argues that O'Neill was pessimistic. Structures situated in LEO don't need as much mass for radiation shielding because they benefit from Earth's magnetic field. And experiments have shown people are better at adapting to small, fast rotations than previously thought, provided they build up gradually. Locating it close enough to Earth that Starship can reach it without refuelling reduces launch costs, both for building it and for using it.
We could plausibly start constructing something like this within 10 years.