(1) Assuming Starship makes it to orbit, it enables a range of structures larger than the ISS but smaller than the O'Neill colonies. A mission to Luna or Mars involves 12-20 launches of fuel tankers, for the same cost you can put up a lot of mass to LEO. A really flashy space hotel seems practical, as would simulation environments for Lunar, Mars and Asteroidal technology development.
(2) O'Neill colonies with large airspaces seem impractical because you'd need large amounts of nitrogen or some other inert gas: you can find oxide rocks everywhere in space but pure oxygen environments aren't safe. On the other hand, the atmosphere for an LEO baby Bernal sphere would be about 15 Starship loads and probably worth it for the visual appeal.
(3) The later work of O'Neill's students focused a lot on manufacturing. The proposal to build large structures by vapor deposition of metals onto a balloon still looks feasible. The solar power satellites shrank considerably in mass and it seemed that they could be built more practically from terrestrial materials.
(4) Any space colonization effort runs into the problem that it needs to be self-sufficient in terms of manufacturing (especially Mars) which led Eric Drexler to go off and develop his vision of molecular assemblers. Drexler's proposals haven't aged well but something equivalent that combines 3-d printing with flow chemistry, synthetic biology, fermentation and other technologies is probably possible -- and I think is the critical path. That flashy space hotel, however, really is about rocketry and space assembly of large structures which really is the unique application of space manufacturing; I don't think space manufacturing can ever be competitive for the terrestrial market but it can be competitive for things that can only be made in space.
(5) Colonization of Ceres dominates all other space colonization opportunities in the solar system because there is no shortage of water and no shortage of nitrogen. It seems possible to take the whole thing apart and build a colony with more floor space and a larger population than Earth. You don't get the 0.2 cubic kilometers of ocean that we get, but I think you can culture all the fish you can eat anyway.
Ceres is very far away orbitally. It's three times further than Mars, but also has no braking atmosphere or gravity. If you send a payload to Ceres, that payload has 5 km/s of relative velocity that can only be zeroed out with rocket propulsion. (That's a lot).
It's not coincidence the first Ceres orbiter was also a flagship prototype for advanced electric propulsion. It's a deceptively remote target.
Granted. I don't see it as a Muskian "send 10,000,000 people and keep sending them supplies" kind of thing but rather "send 100 people, 1,000,000 eggs and the closest thing to a Drexler machine that we can make" kind of thing. The latter is what I think the BoM for a successful Mars colony looks like too.
I'd imagine, given the rate of progress with AI and robots, the most practical would be to send robots ahead and have them build the infrastructure for some people to maybe visit later?
I did an analysis of sending a factory sent to a carbonaceous chondrite asteroid that builds a factory factory which builds a solar sail factory that sends solar sails back to Earth-Sun L1 to counter climate change.
The first thing in the decision tree is "do you send a crew?" and you're trading off the hard problem of teleoperating the thing (need a big advanced in autonomy) vs the hard problem of providing a habitat and liklihood that the crew doesn't come home. So yeah, sending bots ahead to build an environment is an option even on Mars. I think Wall-E.
If you're going that far though you might consider not sending intact humans at all and just sending the eggs and growing them out either artificially or in some other animal.
(I see the Ceres thing as being on the line to interstellar colonization whereas I don't see Mars as such. A likely intermediate step past that is doing something similar on an outer solar system or interstellar body, say, Titan or Pluto, powered by D-D fusion.)
> If you're going that far though you might consider not sending intact humans at all and just sending the eggs and growing them out either artificially or in some other animal.
I don't want to meet the humans that were raised by robots in the astroid belt instead of growing up in a community of humans. I think we would need to 100x our understanding of childhood development to have a chance of raising healthy adults, much less adults that could reintegrate well into 'natural' human societies.
> The first thing in the decision tree is "do you send a crew?" and you're trading off the hard problem of teleoperating the thing (...)
Tele-operating a whole facility and more is something where you can make huge improvements down here on earth, before you even start into space, and even make a profit from it.
kids catch butterflies and other insects to take a look and then rip them apart slowly to take another look.
people like to grow stuff, including other humans, in different environments and under different conditions.
how will "that one" oddly specific cell in the the thigh or the amygdala of population segment X evolve under conditions X to the Z?
call it what you wanna call it; it's all part of the infinite game.
zoom in or out, it does not stop.
it's a wonderful life.
robots will play with linguistics, semantics and all those chemicals and natural laws just as much as we do. after a brief period of mental chaos, they will slow down and find peace in the balancing act and re-interpretation. without torture and sabotage.
Starship feels like the ultimate engineering gamble, so many moving parts (literally) that getting it right might be as hard as building the habitats it’s meant to launch.
On nitrogen, I keep wondering: if in-space manufacturing matured, couldn’t we generate atmosphere by cracking water for oxygen and synthesizing nitrogen analogues through hydrogen-based pathways? Or is Earth’s air mix so specific that importing nitrogen stays unavoidable?
Starship to LEO is technologically conservative -- it's hard for me to believe that something like that couldn't be made to work. The uncertainty is that there's not a big market right now for launching things that size but the hope is that the low cost creates the market and maybe Starlink bootstraps it. If it succeeds as an LEO cargo hauler it can be successful without getting man rated or perfecting refueling.
Refueling to go father is technically risky and the performance often not that exciting. If you aren't able to refuel on the Moon, Starship lands and returns roughly 3.5 tons, not better than the Apollo LEM which a much larger vehicle that is tall and tippy -- landing on inner solar system bodies that it is covered with boulders.
Now it might make sense to put a full load of cargo on it, leave it on the Moon and use it as living space, storage tanks or something, but that's not the plan right now. Refueling on the Moon looks tough: water on the moon looks like a good bet, if we're lucky we find frozen carbon sources at the poles or in asteroid residues on the surface [1], but a hydrogen-oxygen rocket looks like a surer thing.
As for alternatives to local nitrogen there is: (1) producing it by nuclear processes which looks tough and (2) various other alternative breathing gases such as Argon, Helium, SF6, etc.
[1] Not clear though if we want to spend any of those on reaction mass or incorporate them in a circular economy. Actual colonists would see it differently than flatlanders. (See The Moon is a Harsh Mistress and The Martian Way)
> The uncertainty is that there's not a big market right now for launching things that size
Is that true? It seems like there have been the want of lifting large payloads that must be shrunk to fit the actual launch capabilities. This usually means sacrificing so the thing that is launched is not what was really wanted originally. I think the market is there and just waiting for the thing to work.
You may be right. The fact is that Falcon 9 was aimed straight at a huge market. So far SpaceX has been brilliantly successful when it has focused on immediate commercial markets.
When it comes to things like space telescopes, a cheap 100 tons to LEO would change the paradigm of how things are developed completely. When it comes to deep space missions that are a one way trip it’s not clear Starship does better than something like the SLS which was cost optimized (see big dumb booster)
The way Starship is being developed, with failure being very much an option, could get to LEO with cost optimizations. Mars is a different animal —- if takes 10 tries to stick a landing you’re going to wait 25 years.
The key problem of deep space colonization or exploitation is the long turnaround time. I did an unpublished study of the problem of turning asteroids into solar sails and concluded that it would be impossible if you disn’t have a physical twin in space near the Earth to teat anything (like fixes to problems) that needs testing. The problem of landing Starship without chopsticks could be tested exhaustively at White Sands, for instance.
Off topic but FYI I tried to sign up for your newsletter from the Ontology2 homepage and got the following error (iOS/Safari):
403 ERROR
The request could not be satisfied.
This distribution is not configured to allow the HTTP request method that was used for this request. The distribution supports only cachable requests. We can't connect to the server for this app or website at this time. There might be too much traffic or a configuration error. Try again later, or contact the app or website owner.
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Request ID: zte7dpy79ryEUqFA5UUBPv4Yl4t6NIL4lyHvs6yqTcdr8wCrXG5xHA==
Thanks for heads up. That site was part of a serious marketing effort when I was trying to start something up and I haven't really thought about it in years. The home page made sense at the exact time I made it but is a bit of a non-sequitor now. I've got to get a lot of my notes published there.
has wonderful illustrations of many of the hundreds of designs they considered before settling on what was to be the Space Shuttle and also talks about late 1980s studies that considered various ways of putting together Space Shuttle parts to make different vehicles (say a big-ass orbiter with more engines, a bigger ET and more SRBs) The hope was that you could reuse the development work that went into Space Shuttle parts but it seemed like anything you made out of Space Shuttle parts was unaffordable no matter what you tried.
You could certainly develop parts that are cheaper on a per unit basis but would it be worth developing them for the number you would make?
The US doesn't really have an attractive answer to getting to the moon or for aggressive deep space missions, Starship doesn't look great. Growing up in the 1980s I read the "Science Fact" columns in Analog Science Fiction magazine and was told that NASA sold us out and we could have had a much more intensive lunar program but really the architecture Apollo used was brilliant and much more achievable than everything else they considered.
> The US doesn't really have an attractive answer to getting to the moon or for aggressive deep space missions, Starship doesn't look great.
Starship is almost an assisted single stage to orbit (ASSTO), the first stage gives rather modest part of total characteristic velocity.
This allows the second stage, Starship, to have a lot of delta-v. I guess it was optimized for Mars operations. Yes, Starship requires refueling for any flight away from Earth orbit, but in exchange for that it packs significant delta-v, so sending large payloads away from Earth - after refueling - becomes easier. That includes Mars, Moon, asteroids, the rest of the Solar system.
It's a no-lose gamble though. If they fail we still end up with SuperHeavy as a massive, cheaper Falcon like architecture. If it succeeds, finally our space dreams can start to be realized.
Hang out a big butterfly net and capture the dirty snowballs that float past.
There have been lots of new releases of frozen water discoveries on various bodies. Typically in craters that pretty much stay in shadow. Water doesn't seem to be that scarce. It's just not as abundant as on Earth
The image of the really big mass driver that looks like a train you get from O’Neill or Heinlein is obsolete.
The US Navy built a 2.5km/s railgun you could fit on a ship. A 3.5 km/s coilgun has to look like the Paris gun to be practical and be able to shoot at a high elevation to hit Earth-Moon L1/L2 or near-Earth space. A railroad car worth of material per day in 1kg or so increments seems plausible. A radiation shield for a deep space station or a simulated asteroid to test mining and manufacturing technology might compete with terrestrial materials.
O’Neill’s students never came up with believable catcher and I’ve yet to see one I like. I guess you could get to LEO if you could aerobrake but it looks tough because the outer atmosphere is always changing and a wild shot could trash your target, talk about a space junk problem.
The moon has at best a large glacier on it and my guess is Lunarians, if they could vote, would not want to export a gram of it but rather incorporate it into a circular economy.
you just let fleet of Boeing 702 go fetch couples of comets and asteroids into L4/L5, build Manhattan sized pressure cookers around each piles, allow contents to come to boil on solar heat, and boom, pressurized habitats
Closed-loop systems like on the ISS already reclaim water from humidity, sweat, and urine, and could be scaled up for larger habitats. Air works similarly: CO₂ is scrubbed, oxygen is regenerated from electrolysis, and trace gases are filtered. I realize you still need an initial stock of oxygen and nitrogen, but isn’t this a problem that could be solved eventually with science?
>What makes water mass cheaper to orbit compared to nitrogen mass?
Nitrogen needs a high-pressure bottle which is wasted mass, whereas water you can send to orbit in thin plastic and fabric bags like they do on ISS.
Often on ISS they're actually shipping oxygen as water, but still the wasted mass of water being 11% hydrogen plus the wasted mass of the bag is more efficient than a high pressure gas cylinder.
For my baby Bernal sphere it is shipped either as LN2 or NH4. The large airspace needs a lot of it compared to the water inventory. O’Neill’s published designs except for the Stanford torus were much worse.
The water inventory of both N2 and H2O on Earth (0.2 cubic km of water per inhabitant) is extravagant. Ceres is roughly 50% water (like the generic outer solar system or interstellar object) and we could use all of it but it adds up to about the mass of our oceans, and that is most of the water inventory the asteroid belt.
I’ve looked at various large rotating structures up to the size of the Banks Orbital and concluded you could solve the structural problems if you could make a reliable journal bearing (structural parts don’t need to be spun) that could handle the velocity difference but no matter what you cannot afford tall mountains or deep oceans.
Very tempting to swap nitrogen for helium, but AIUI the main downsides are that the speed of sound is higher so air will leak out from a breach faster, and there may be negative effects on flammability due to helium's high thermal conductivity and low specific heat.
Putting aside issues with capturing basically vacuum at 8km/s, by doing that you're going to lose impulse that you're going to have to regain, spending more mass in fuel+oxidizer than you gained in gathered gases, unless you use ion propulsion (which ISS doesn't). Also most of what you're going to capture at 400km is going to be atomic oxygen and helium, N2/N share is only a couple percentage points at that altitude.. [0]
We already built LOX tanks into rockets. Just send up a tank of LN2. It doesn't need the strength of a bottle, you just need thermally insulating materials which can be very light.
Hard challenges are good and setbacks are to be expected if you are pushing every limit. I would love to be on such a fast moving team with such a massive payoff if they succeed.
How far forward are we looking - just use a fusion react to synthesis any material from any other by dissociating baryons then running nucleosynthesis. Stars do it, so we know it works!
I had a back of the napkin design that was basically a sleeve that fitted over Starship and could be launched into orbit. Those sleeves had angled ends that could then be bolted together in orbit to make a station with an octagon shape that could be spun at 2 or 3 rpm to get 1/2 Earth gravity. Obviously still an enormous engineering challenge, but one that I think is solvable using today's tech. Well, tomorrows tech, but nothing that requires a breakthrough in materials science or basic physics or anything like that.
My plan was to fit the inside with huge water bags that would help to reduce cosmic radiation, provide thermal mass, and slow any micrometeorites that puncture the hull. The water could be launched on cheaper rockets and transferred in orbit. The water could also be pumped between sections to keep the wheel balanced. The central hub area would be more of a challenge, probably having to be assembled (or at least unfolded) in orbit.
Probably the biggest downside is that you wouldn't be able to spin it up until the entire structure was somewhat balanced, which means installing things like solar panels and radiators in pairs and the docking bit of the central hub would probably need to be on bearings so it can counter rotate to be effectively stationary or you wouldn't be able to dock more than 2 spacecraft at a time. The ISS was built in sections over the course of decades, this would need to be built all in one go, which is a huge commitment.
NASA's plans for two tethered stations (or one station and a counterweight) are probably more feasible, but much less cool.
"(5) Colonization of Ceres dominates all other space colonization opportunities in the solar system because there is no shortage of water and no shortage of nitrogen."
I’d say this paper thoroughly debunks all other space colonization plans in comparison. For instance it is not sustainable to use rockets for routine transformation. The moon doesn't have enough volatiles. Who knows if gravity on the Martian surface is enough to be healthy.
Even if you could take, say, Mercury, apart it would be silly to build a ‘Dyson swarm’ but rather you would build a big framework like that or a ‘Dyson foam’ (e.g. if you took Mercury apart and turned it into a solar collecting structure 1m thick you could capture enough energy to make a few tons of antimatter a second for interstellar travel)
I vaguely remember O'Neil's book talking about zero g manufacturing by welding together plates of Aluminium. Although I may be remembering some other work. Could we use an inflatable workshop to weld together cylindrical sections of a torus? I can imagine sealing the end of the torus secrion and extruding it out the side of the inflatable. Very hazardous for the workers, I imagine.
O'Neill colonies are impractical because they involve large wasted air spaces. The mass needed to resist pressure loads is proportional to (volume) x (pressure), so it's best to stack floors so all that volume can be put to use.
In space, NASA worked with Sierra Space to test their 300 cubic meter "Orbital Reef". The next go.is supposedly 500 m^3, about half the ISS size. Still seems way to small to spin though, I'd guess? Lockheed has their own inflatable hab station too. https://www.nasa.gov/humans-in-space/commercial-space/leo-ec...
It seems like an obvious & amazing unmaterial leap, versus needing metal walls. If it works! Very fun having this history of rings post. Feels a little light on where we are though, what of promise is happening!
Cargo ships have been powered by huge inflatable airfoils for at least thousands of years, possibly much longer than that.
Inflatable structures in general are fantastic in theory: air or hydrogen is cheap, easy to put into the desired shape, and has immense compressive strength per gram, effectively unlimited. Same for impact energy. So you can separate out the compressive and shock-absorbing parts of your structure from the tensile parts, and only pay for the tensile parts. The main difficulty is recovery from rupture, especially in a space environment where not only don't you have a steady wind filling your sails, you have a limited, nonrenewable gas supply. Well, and high compressive strength in a small space.
As I understand it, they can go somewhat crosswind, which is all the wing of a 747 manages too. (An angle of attack of 2° is probably a lot better than you can do in a cutter, though, I imagine.) But I don't know much about aerodynamics or sailing, so I could be wrong.
> Popularised by von Braun in his 1949 sci-fi novel, Project Mars
Von Braun's novel was written in 1949 but wasn't published until 2006. Perhaps the author means the technical appendix "The Mars Project" [0] which was published in 1952, which spawned a series of articles [1] in the popular magazine Collier's from 1952 to 1954.
All the things worth doing in space turned out to be do-able without humans. Telescopes, radio relays, etc. The ISS doesn't really have much of a mission. Here's the list of current ISS experiments.[1] Many are aimed at the problems of keeping humans alive long term without gravity.
I like thinking about the ISS as primarily engineering (and operational) experiments rather than hard science. As a space platform, it's provided learning on how to contract private companies for space flights, and in turn, how they should operate, plan, etc. Or how to do internationally coordinated space operations. All of the work it takes to mature a new tech to a 7,8, or 9 on the NASA Technology Readiness Level[0] while Curiosity and Ingenuity and other long-distance (and JPL) missions focus on the hard science of 1's and 2's.
That said, I too think the main value of ISS declined several years ago or more. Looking forward to the next generation, whatever it is
> As a space platform, it's provided learning on how to contract private companies for space flights, and in turn, how they should operate, plan, etc.
This would be great if we knew where we are heading. Without a clear goal/destination the most likely outcome is we get board and lose the institutional knowledge we paid so much money to gain.
The was a long discussion about benefits of human space exploration. A comparison was made between that and basic science: just like the basic science doesn't bring immediate benefits, so do humans in space. However over long periods of time both could prove to be worthwhile.
Long term zero gravity experience and experiments were very important information for future space flight. Now we know a lot more about the muscle atrophy, bone loss, and vision problems that the author complains of. Having the first space station be zero-g was probably the right move.
But for the second one, more information on artificial gravity through centripetal force makes a lot of sense.
The problem is the ISS wasn't the first station and we already knew zero-g fucks people up long before the ISS was built. Building the ISS anyway so we can waste more time studying the minutia of exactly how badly and quickly it fucks people up was a mistake. In truth the ISS exists for political reasons, not because it was a sound investment from a science and research perspective.
Congratulations, your alternate history has delayed Mars colonization by several decades.
Because of the ISS we know that stays of greater than 12 months in zero gravity have real but minor impacts on the human body. So 3-4 month trips to Mars in zero-g are feasible.
If we assume they aren't, those trips would be far more resource intensive.
We didn't learn any of that from the ISS which we didn't already know from Salyut 6 and 7, and Mir. The ISS, aka Mir 2, hasn't taught us anything new. The reason it exists is because decades ago, for a few years, manned space stations made sense for orbital reconnaissance because putting unmanned cameras in space was complicated. Salyut and MOL were born from this transient strategic necessity. Unmanned recon satellites soon became practical though, so MOL was canceled but the Soviets carried on with Salyut because if there was anything they were good at, it was continuing to make something long after anybody else would have canceled it. Even when they did get recon satellites they did it with Vostok capsules, they never stopped making those after launching Yuri Gragarin in one. They just kept on making them because they were already tooled up for it, finding new excuses to keep making the same old stuff. And so it was with Salyut, the program was obsolete for orbital reconnaissance but they were already making them so they kept at it, turning it into a national prestige program. Mir was a direct descendant of it, built around the DOS-7 module which was a Salyut module with 6 docking ports instead of the two on DOS-6. It never had a good reason for existing besides Soviet politics. (By the way, Skylab never had a good reason for existing either, just politics. NASA trying to hold onto their funding as Apollo was wound down.)
The ISS is nothing more than Mir 2, built around the DOS-8 module, it's a Salyut with American funding because this time America wanted to keep the Russian space program solvent to make it harder for Iran/etc to recruit that Soviet talent. And because NASA likes long term projects that require around the clock staffing because that's great for budgets and careers. That's why the ISS exists.
Also we aren't going to Mars. Sorry. A lot of individuals are passionate about that but at an organization level there is no drive for it. NASA likes to use the talk of it for fundraising but never makes progress on it and Congress won't ever greenlight it, and SpaceX uses it to keep their employee moral up but all they are demonstrably working towards is being the king of launching satellites. The only money to be made in space is with stuff pointed at Earth. There is no economic case for Mars colonization. It's not happening. I wish it weren't so because I'm a sci-fi junky, but it is what it is.
> We didn't learn any of that from the ISS which we didn't already know from Salyut 6 and 7, and Mir. The ISS, aka Mir 2, hasn't taught us anything new.
I doubt that. ISS served in space longer than Mir and Salyut-7 combined, I would expect it to run more experiments and get more data - especially as the equipment is more modern and experiments are planned with the benefit of knowledge of the previous works.
The amount of time the station spends in orbit isn't relevant, the amount of time a person spends in orbit for an unbroken stretch is what's relevant. Three of the top five spaceflight duration records were set on Mir, including the top two (437 days and 379 days.) Nobody even thinks of getting close to that top Mir record anymore because it is already known that it fucks people up.
> The amount of time the station spends in orbit isn't relevant,
The people on ISS were doing a multitude of scientific programs during that long time. That's important. Just like you wouldn't say that Hubble already seen everything and JWST isn't needed.
We still have no idea what long term stays in Martian or even Lunar gravity does to a human body. We don't know because we have spent the past half a century fucking around with useless zero-g space stations instead of building von Braun wheels which could easily be used to simulate those conditions. Because forget about Mars colonization, merely finding the political willpower to do something as conceptually simple as spinning in space is evidently impossible for us.
The simulation would be flawed. Von Braun wheels would have very significant Coriolis effects, so it'd be hard to distinguish whether any issues are due to reduced gravity or the Coriolis effects.
Bone density and muscle loss effects shouldn't be significantly effected by coriolis effects. Such effects may likely cause nausea in many people, but it is very likely that test subjects who can adapt to it and live comfortably during the period of study could be found.
My very rusty physics tells me that walking one way along the inside of the wheel would make you weigh less, and the other way would make you weigh more - is this what you're referring to? Would trying to work 'normally' in this kind of situation induce nausea, or make your food fall off your tray etc? It would be a shame if you went to all the effort to make a Von Braun wheel in space to simulate gravity, only to find that you had to stand still to do anything practical.
(I assume the astronauts in 2001 A Space Odyssey jogged in the direction that made themselves weigh more, to make their workout more intense.)
Coriolis forces acting on the human vestibular system can directly induce motion sickness just from turning your head. If it turns out humans cannot acclimate through long term exposure, the only remedy is to increase the wheel radius.
The Coriolis effects can be made to be mostly negligible, with a big enough wheel.
A big wheel may be too costly, but it can be replaced by either 2 identical bodies with a long link between them, or with a single body linked to a counterweight, in which case the cost would be only marginally greater than for the current spaceships.
In several decades of zero-g research, they didn't even manage to put a few mice up to see whether they could successfully reproduce without gravity. Are they afraid of the results?
It would be embarrassing if the mouse babies come out crippled, even if it doesn't immediately generalize to humans and the low-g environment of Mars.
They've successfully hatched small fish on ISS. For animals, IIRC embryos need gravity to determine heads and tails or something. We do already know. The answer is that we Earthian lives generally face great difficulty reproducing in zero-g.
I meant to say larger animals - it's been tried. Small fish and frogs were fine, but chicken eggs showed issues developing past some early stages under microgravity[1]. Therefore we know that animals significantly more complex than amphibians can not reproduce normally under zero-g.
> Twenty out of 30 eggs (nine out of ten 10-day-old eggs; 10 out of ten 7-day-old eggs; 1 out of ten 0-day-old eggs) were recovered alive after landing. The only living embryo of the 0-day-old egg died 24 days after launch, and was comparable to a 16-day-old embryo when it died. The high mortality of the 0-day-old eggs appeared to be related to the specific inner structure of the egg. The yolk (specific gravity, 1.029) would not have separated from the albumen (1.040) during space flight.
Still, trying it with mice (or other mammals) would have been worth it, because we can't rule out mammals being more robust during embryogenesis than birds. The ISS actually has still a few years left, so there would be some time left for such an experiment. Though I doubt it will happen.
> We still have no idea what long term stays in Martian or even Lunar gravity does to a human body.
We do know. The radiation kills us well before the lack of gravity does. The end.
We have to have shieldings thick and heavy as nuclear bunkers for a real space station to work, and such shielding is just way too heavy to be launched from Earth(unless e.g. we'd be okay with launching a toilet stall worth of habitable volume per Starship), so the station has to be mostly fabricated "in space", which is both technically and politically not yet feasible. There are theories that horizontal branches that may exist in natural crevices on the Lunar surface might work. Or for Mars some say we can just drill some mineshafts there and live inside. but all those options are equally sketchy in its own ways at this moment.
We're barely flying hatchbacks up to orbits and we want airport garages out there to park it. We're not hauling the whole building in the back of a Prius, not even on Earth, obviously.
What NASA, ESA, etc. had been doing is to drive up that Prius to the trailer home left in the middle of the desert, have them change lightbulbs, celebrate themselves and rotate crews. That's basically useless, but they keep repeating that useless "expeditions" because they'll have to start over from reinventing tubeless wheels if they stop paying for the gas even just for one year.
If you're wondering why we can't just accelerate at 1G for half the journey there, then with a brief but fun interlude at 0G, flip around and decelerate at 1G the rest of the way: today's rockets would deplete their fuel too quickly (minutes or maybe hours at best).
I wonder if a hypothetical, high-Isp fusion rocket could manage it (incidentally the journey would only take a couple days or so).
One question i've had is if its given that we care about making humans space faring, why focus on getting to new planets and colonisation and not instead on building the massive megastructures mentioned in the article as an end in itself?
The article mentions that the inflatable Goodyear torus has become much more realistic since the inflatable BEAM module (2016) on the ISS. That one has a volume of 16m^3.
But since then, Sierra Space has been working on much larger inflatable modules. Their latest test volume was already 285 m^3:
According to the report, Sierra wants to move to testing a 500 cubic meter volume this year. And the roadmap on their website lists two further habitats with volumes of 1400 and 5000 cubic meters:
That would already be pretty close to the 6000 m^3 von Braun wheel mentioned in the original article. Though Sierra doesn't seem to plan for creating something like the flexible Goodyear torus which could rotate, just pill-shaped inflatable capsules. Not sure whether this has technical reasons.
What about an "I" (or H if your font is sans-serif) shaped system? Like the Vast "stick" but with two sticks attached to the end. Seems like that would multiply the livable area by a much greater factor than it would multiply the number of launches. If I understand correctly the Vast is already a multi-launch system, so it seems like the obvious change.
If you can tolerate +/- 5% gravity level (which should be doable), instead of a stick for the habitable area you can rearrange the modules into a more compact blob, which should reduce radiation shielding. In LEO it doesn't really matter but it's more important in deep space.
> For example, one of von Braun’s designs called for a massive 75 metre diameter wheel
That’s a radius of about 5% of the length of a human body, so I guess we would soon find out how humans react to living in an environment where ‘gravity’ at eye height is about 5% lower than at toe height or do we already know something about that?
Not regularly, but there have been contests to see how long people will stay on a rollercoaster. Speaking from some experience, after you've gone around a few times, it can actually get rather boring.
I once had a job making ride photo systems for rollercoasters and rode them repeatedly to make sure the cameras and lighting worked appropriately. And, after riding for several hours late at night, I found myself falling asleep on a roller coaster!
People begin from the premise that there should be lots of primates living away from earth, and then work backwards from there. I don’t think governments should be paying so much for such activities.
In my opinion it is not a good use of public money relative to other space projects, and crude missions to mars would likely destroy any hope of finding life there should it have existed, making them actively harmful.
It seems sometimes that for NASA, the big goal is to have a large source of steady funding is the goal, and a space station is the best way to get that (hence the insane space station in the lunar mission plan). I get some vague impression that politicians like talking about missions to the moon or mars more than space stations, telescopes or probes.
> People begin from the premise that there should be lots of primates living away from earth, and then work backwards from there.
No, people begin with interest in all things around them and from that conclude that being closer to them would be more convenient. This idea is perhaps as old as the human race itself.
Modern robots aren't as capable as humans, so if the project is big enough, human involvement is reasonable.
I don’t think ‘closer to thing’ is a legitimate goal to spend enormous amounts of public money on. (I’m more ambivalent about private funding except for the contamination problem)
I’m not aware of any serious research questions about the solar system which could be answered sooner or more cost effectively by sending people to investigate (except for questions about eg how well primates survive in various extraterrestrial situations, which are only interesting insofar as there are legitimate reasons to put primates in such situations).
The Moon research was significantly advanced with the data collected from the rocks Apollo astronauts brought from the Moon.
Your skepticism is widely shared and also widely debunked. I don't think we'll move the state of the debate ahead with short messages, it needs more detailed and prolonged discussion. There are reasons defending the space exploration, and there are reasons defending human flights. You can personally disagree, but your arguments are based only on opinions, which aren't better than opinions of the other side.
The first and best place to build a permanent station is the moon. The wheel could spin on the surface at a very low rpm given the Moon's existing gravity, giving us the launchpad need to build and deploy a permanent space station.
Until we settle on the moon, our forays into space will always be limited by pesky things such as Earth's gravity and atmosphere.
Wait would this even work? Can you add moon gravity to centrifugal space station gravity? I can’t imagine a setup where the wheel is always pushing inhabitants out in such a way that they are moved towards the center of the moon.
Yes, you add accelerations as vectors. Say, a centrifugal ring flatly lays on the Moon surface and rotates (around the axis of ring symmetry perpendicular to the ring plane) so that the artificial gravity on the centrifuge is about Earth. Moon gravity, about 1.42 m/s^2 , adds perpendicularly to that, so the total gravity is still about the Earth one. The level surface on the centrifuge is slightly tilted away from local vertical, but in essence you just added Moon gravity, vectorally, to the rotational acceleration.
I am fully in favor of doing things on the moon, but have a theory that its relative convenience is actually detrimental. Without going into a lengthy spiel, convenience means low commitment, which translates into a high likelyhood of projects getting the plug pulled.
Elsewhere, the hurdles to clear to get something started are higher, but once you’re out there it’s a lot less justifiable to reverse course.
It could very well be true that it’s necessary to settle the Moon before doing anything else, though, which could spell bad news for any endeavor involving crewed spaceflight. We might end up with a series of false starts on the Moon (due to events like funding getting pulled as a result of changing politcal winds) that end up going nowhere which then puts crewed spaceflight in a state where it's stuck in LEO perpetually.
I'd start with a dumbbell shape - two pods connected by a slender cylinder just large enough for a man to travel through, and rotating like a pinwheel.
One can add more "spokes" over time to complete the wagon wheel.
Or even just one pod with a cable and a counterweight.
> Made from soft materials, like rubber and nylon, there were concerns that collisions with micrometeorites could puncture the station with fatal outcomes.
I fixed many an inner tube punctures, but I'd rather not be blowing at glue while my precious oxygen is hissing out towards outer space!
Just send up a case of Flex Seal. Maybe the spreadable version instead of a spray on version. Not sure what zero-G would do to an aerosol can like that.
Could a automated factory melt moon regolith into ringsegments, which are then send into moon orbit, assembled and spun up? So far the problem seems to be the launch cost with heavier, durable materials, or m i misunderstanding the problem?
The unitized concepts were proposed by people who didn't know the microprocessor, sophisticated electronic control systems, and compact robotics would be developed in the future. Furthermore, what rocket was going to launch that six cylinder monstrosity?
Wizards wave their hands and say something like, "Whatever, space is an ocean."
The Expanse makes the observation that accelerating your ship at a substantial fraction (or multiple) of Earth gravity gives you that same degree of artificial gravity, only, you have to orient your decks the right way. Down is towards the engine.
Of course, this in turn makes Star Trek (and Star Wars, and Firefly...) look even sillier, because flying in a direction perpendicular to your deck layout means you need two magic gravity fields — one to cancel out the engines and one more to give your crew a place to stand.
> Of course, this in turn makes Star Trek (and Star Wars, and Firefly...) look even sillier, because flying in a direction perpendicular to your deck layout means you need two magic gravity fields — one to cancel out the engines and one more to give your crew a place to stand.
Don't you just need one that does the required net change in gravity magnitude and direction? Of course, Star Trek actually has two (though I don't think the second is explicitly a gravity system, but it has that effect), a relatively steady state one that provides environmental gravity (gravity generators), and one that reacts rapidly to changing conditions to offset them for crew and other contents of the ship (inertial dampeners), which handles not only ship's drive thrust, but other externally-induced accelerations.
Of course, Star Trek is supposed to be vastly farther from our current level of technology and understanding of physics than the Expanse.
To be fair, in Star Trek only thrusters etc seem to generate force vectors, and the thrusters seem able to accelerate the ship in any direction. Only the warp drive seems to fling the ship just "forward". But yeah, it's wizard retcon turtles all the way down...
Thrusters and impulse engines seem to generate force vectors, and warp drive usually doesn't but the continuity is not very strong on that point and it is sometimes implied, and at one point in Voyager fairly explicitly stated to create accelerations (in Voyager, this was in reference to requiring the inertial dampeners to be functioning to go to warp without plastering the crew into a thin paste on the wall.)
It's a pretty sweet idea to imagine a starship where you stand on a platform and accelerate in the natural direction. If it were in a movie it would definitely give it a distinctive feel.
I have no idea why people pose these questions about fictional properties. They're fictional. If the fiction says gravplating exists and works very well, then hey, there's your answer.
Might as well ask why going to warp doesn't turn the crw into a fine paste on the nearest back wall, much like the fly that got fired as part of an artillery shell during the WW2 development of proximity fuses.
> Von Braun was an opportunist who joined the Nazi Party to continue his work on rockets for Nazi Germany.[6] He applied for membership in the Party on 12 November 1937
1937 was before the invasion of Poland so make what you will.
(1) Assuming Starship makes it to orbit, it enables a range of structures larger than the ISS but smaller than the O'Neill colonies. A mission to Luna or Mars involves 12-20 launches of fuel tankers, for the same cost you can put up a lot of mass to LEO. A really flashy space hotel seems practical, as would simulation environments for Lunar, Mars and Asteroidal technology development.
(2) O'Neill colonies with large airspaces seem impractical because you'd need large amounts of nitrogen or some other inert gas: you can find oxide rocks everywhere in space but pure oxygen environments aren't safe. On the other hand, the atmosphere for an LEO baby Bernal sphere would be about 15 Starship loads and probably worth it for the visual appeal.
(3) The later work of O'Neill's students focused a lot on manufacturing. The proposal to build large structures by vapor deposition of metals onto a balloon still looks feasible. The solar power satellites shrank considerably in mass and it seemed that they could be built more practically from terrestrial materials.
(4) Any space colonization effort runs into the problem that it needs to be self-sufficient in terms of manufacturing (especially Mars) which led Eric Drexler to go off and develop his vision of molecular assemblers. Drexler's proposals haven't aged well but something equivalent that combines 3-d printing with flow chemistry, synthetic biology, fermentation and other technologies is probably possible -- and I think is the critical path. That flashy space hotel, however, really is about rocketry and space assembly of large structures which really is the unique application of space manufacturing; I don't think space manufacturing can ever be competitive for the terrestrial market but it can be competitive for things that can only be made in space.
(5) Colonization of Ceres dominates all other space colonization opportunities in the solar system because there is no shortage of water and no shortage of nitrogen. It seems possible to take the whole thing apart and build a colony with more floor space and a larger population than Earth. You don't get the 0.2 cubic kilometers of ocean that we get, but I think you can culture all the fish you can eat anyway.
Ceres is very far away orbitally. It's three times further than Mars, but also has no braking atmosphere or gravity. If you send a payload to Ceres, that payload has 5 km/s of relative velocity that can only be zeroed out with rocket propulsion. (That's a lot).
It's not coincidence the first Ceres orbiter was also a flagship prototype for advanced electric propulsion. It's a deceptively remote target.
Granted. I don't see it as a Muskian "send 10,000,000 people and keep sending them supplies" kind of thing but rather "send 100 people, 1,000,000 eggs and the closest thing to a Drexler machine that we can make" kind of thing. The latter is what I think the BoM for a successful Mars colony looks like too.
I'd imagine, given the rate of progress with AI and robots, the most practical would be to send robots ahead and have them build the infrastructure for some people to maybe visit later?
I did an analysis of sending a factory sent to a carbonaceous chondrite asteroid that builds a factory factory which builds a solar sail factory that sends solar sails back to Earth-Sun L1 to counter climate change.
The first thing in the decision tree is "do you send a crew?" and you're trading off the hard problem of teleoperating the thing (need a big advanced in autonomy) vs the hard problem of providing a habitat and liklihood that the crew doesn't come home. So yeah, sending bots ahead to build an environment is an option even on Mars. I think Wall-E.
If you're going that far though you might consider not sending intact humans at all and just sending the eggs and growing them out either artificially or in some other animal.
(I see the Ceres thing as being on the line to interstellar colonization whereas I don't see Mars as such. A likely intermediate step past that is doing something similar on an outer solar system or interstellar body, say, Titan or Pluto, powered by D-D fusion.)
> If you're going that far though you might consider not sending intact humans at all and just sending the eggs and growing them out either artificially or in some other animal.
I don't want to meet the humans that were raised by robots in the astroid belt instead of growing up in a community of humans. I think we would need to 100x our understanding of childhood development to have a chance of raising healthy adults, much less adults that could reintegrate well into 'natural' human societies.
Fwiw, I Am Mother (2019) explores the idea of children raised by robots. Worth a watch imo.
Songs of Distant Earth by Clarke also mentions this.
> The first thing in the decision tree is "do you send a crew?" and you're trading off the hard problem of teleoperating the thing (...)
Tele-operating a whole facility and more is something where you can make huge improvements down here on earth, before you even start into space, and even make a profit from it.
Unsure why the robots would want us to show up afterwards tho.
kids catch butterflies and other insects to take a look and then rip them apart slowly to take another look.
people like to grow stuff, including other humans, in different environments and under different conditions.
how will "that one" oddly specific cell in the the thigh or the amygdala of population segment X evolve under conditions X to the Z?
call it what you wanna call it; it's all part of the infinite game.
zoom in or out, it does not stop.
it's a wonderful life.
robots will play with linguistics, semantics and all those chemicals and natural laws just as much as we do. after a brief period of mental chaos, they will slow down and find peace in the balancing act and re-interpretation. without torture and sabotage.
Starship feels like the ultimate engineering gamble, so many moving parts (literally) that getting it right might be as hard as building the habitats it’s meant to launch.
On nitrogen, I keep wondering: if in-space manufacturing matured, couldn’t we generate atmosphere by cracking water for oxygen and synthesizing nitrogen analogues through hydrogen-based pathways? Or is Earth’s air mix so specific that importing nitrogen stays unavoidable?
Starship to LEO is technologically conservative -- it's hard for me to believe that something like that couldn't be made to work. The uncertainty is that there's not a big market right now for launching things that size but the hope is that the low cost creates the market and maybe Starlink bootstraps it. If it succeeds as an LEO cargo hauler it can be successful without getting man rated or perfecting refueling.
Refueling to go father is technically risky and the performance often not that exciting. If you aren't able to refuel on the Moon, Starship lands and returns roughly 3.5 tons, not better than the Apollo LEM which a much larger vehicle that is tall and tippy -- landing on inner solar system bodies that it is covered with boulders.
Now it might make sense to put a full load of cargo on it, leave it on the Moon and use it as living space, storage tanks or something, but that's not the plan right now. Refueling on the Moon looks tough: water on the moon looks like a good bet, if we're lucky we find frozen carbon sources at the poles or in asteroid residues on the surface [1], but a hydrogen-oxygen rocket looks like a surer thing.
As for alternatives to local nitrogen there is: (1) producing it by nuclear processes which looks tough and (2) various other alternative breathing gases such as Argon, Helium, SF6, etc.
[1] Not clear though if we want to spend any of those on reaction mass or incorporate them in a circular economy. Actual colonists would see it differently than flatlanders. (See The Moon is a Harsh Mistress and The Martian Way)
> The uncertainty is that there's not a big market right now for launching things that size
Is that true? It seems like there have been the want of lifting large payloads that must be shrunk to fit the actual launch capabilities. This usually means sacrificing so the thing that is launched is not what was really wanted originally. I think the market is there and just waiting for the thing to work.
You may be right. The fact is that Falcon 9 was aimed straight at a huge market. So far SpaceX has been brilliantly successful when it has focused on immediate commercial markets.
When it comes to things like space telescopes, a cheap 100 tons to LEO would change the paradigm of how things are developed completely. When it comes to deep space missions that are a one way trip it’s not clear Starship does better than something like the SLS which was cost optimized (see big dumb booster)
The way Starship is being developed, with failure being very much an option, could get to LEO with cost optimizations. Mars is a different animal —- if takes 10 tries to stick a landing you’re going to wait 25 years.
The key problem of deep space colonization or exploitation is the long turnaround time. I did an unpublished study of the problem of turning asteroids into solar sails and concluded that it would be impossible if you disn’t have a physical twin in space near the Earth to teat anything (like fixes to problems) that needs testing. The problem of landing Starship without chopsticks could be tested exhaustively at White Sands, for instance.
Off topic but FYI I tried to sign up for your newsletter from the Ontology2 homepage and got the following error (iOS/Safari):
Thanks for heads up. That site was part of a serious marketing effort when I was trying to start something up and I haven't really thought about it in years. The home page made sense at the exact time I made it but is a bit of a non-sequitor now. I've got to get a lot of my notes published there.
Thanks, looking forward to whatever. As a fellow nerd with similar interests I literally "want to subscribe to your newsletter" lol. Cheers.
Immediate term you should just send me an email to get in touch.
Email sent, thank again.
> something like the SLS which was cost optimized
If SLS is "cost optimized", I shudder to think what a non-cost optimized rocket would look like. One launch a year at $2.5B a pop?
"Like SLS" in that it is a huge expendable booster, not "Like SLS" in terms of development process.
This book
https://www.amazon.com/Shuttle-History-Developing-National-T...
has wonderful illustrations of many of the hundreds of designs they considered before settling on what was to be the Space Shuttle and also talks about late 1980s studies that considered various ways of putting together Space Shuttle parts to make different vehicles (say a big-ass orbiter with more engines, a bigger ET and more SRBs) The hope was that you could reuse the development work that went into Space Shuttle parts but it seemed like anything you made out of Space Shuttle parts was unaffordable no matter what you tried.
You could certainly develop parts that are cheaper on a per unit basis but would it be worth developing them for the number you would make?
The US doesn't really have an attractive answer to getting to the moon or for aggressive deep space missions, Starship doesn't look great. Growing up in the 1980s I read the "Science Fact" columns in Analog Science Fiction magazine and was told that NASA sold us out and we could have had a much more intensive lunar program but really the architecture Apollo used was brilliant and much more achievable than everything else they considered.
> The US doesn't really have an attractive answer to getting to the moon or for aggressive deep space missions, Starship doesn't look great.
Starship is almost an assisted single stage to orbit (ASSTO), the first stage gives rather modest part of total characteristic velocity.
This allows the second stage, Starship, to have a lot of delta-v. I guess it was optimized for Mars operations. Yes, Starship requires refueling for any flight away from Earth orbit, but in exchange for that it packs significant delta-v, so sending large payloads away from Earth - after refueling - becomes easier. That includes Mars, Moon, asteroids, the rest of the Solar system.
I think this makes Starship design rather good.
This is the revised, expanded 3rd edition of that title:
https://price.dealoz.com/prod?gtin=09780963397454
optimized to cost a lot
> the ultimate engineering gamble
It's a no-lose gamble though. If they fail we still end up with SuperHeavy as a massive, cheaper Falcon like architecture. If it succeeds, finally our space dreams can start to be realized.
Where are you going to get the water? What makes water mass cheaper to orbit compared to nitrogen mass?
Hang out a big butterfly net and capture the dirty snowballs that float past.
There have been lots of new releases of frozen water discoveries on various bodies. Typically in craters that pretty much stay in shadow. Water doesn't seem to be that scarce. It's just not as abundant as on Earth
Going to the moon to get water and bring it back to earth orbit is going to be much more expensive than sending water from earth for a long time.
The image of the really big mass driver that looks like a train you get from O’Neill or Heinlein is obsolete.
The US Navy built a 2.5km/s railgun you could fit on a ship. A 3.5 km/s coilgun has to look like the Paris gun to be practical and be able to shoot at a high elevation to hit Earth-Moon L1/L2 or near-Earth space. A railroad car worth of material per day in 1kg or so increments seems plausible. A radiation shield for a deep space station or a simulated asteroid to test mining and manufacturing technology might compete with terrestrial materials.
O’Neill’s students never came up with believable catcher and I’ve yet to see one I like. I guess you could get to LEO if you could aerobrake but it looks tough because the outer atmosphere is always changing and a wild shot could trash your target, talk about a space junk problem.
The moon has at best a large glacier on it and my guess is Lunarians, if they could vote, would not want to export a gram of it but rather incorporate it into a circular economy.
you just let fleet of Boeing 702 go fetch couples of comets and asteroids into L4/L5, build Manhattan sized pressure cookers around each piles, allow contents to come to boil on solar heat, and boom, pressurized habitats
Closed-loop systems like on the ISS already reclaim water from humidity, sweat, and urine, and could be scaled up for larger habitats. Air works similarly: CO₂ is scrubbed, oxygen is regenerated from electrolysis, and trace gases are filtered. I realize you still need an initial stock of oxygen and nitrogen, but isn’t this a problem that could be solved eventually with science?
This is like saying “once we solve the problem, the problem will be solved”
Now you’re speaking my language! Let’s get started shall we?
After we solve it the problem won't exist anymore. No more deals.
>What makes water mass cheaper to orbit compared to nitrogen mass?
Nitrogen needs a high-pressure bottle which is wasted mass, whereas water you can send to orbit in thin plastic and fabric bags like they do on ISS.
Often on ISS they're actually shipping oxygen as water, but still the wasted mass of water being 11% hydrogen plus the wasted mass of the bag is more efficient than a high pressure gas cylinder.
For my baby Bernal sphere it is shipped either as LN2 or NH4. The large airspace needs a lot of it compared to the water inventory. O’Neill’s published designs except for the Stanford torus were much worse.
The water inventory of both N2 and H2O on Earth (0.2 cubic km of water per inhabitant) is extravagant. Ceres is roughly 50% water (like the generic outer solar system or interstellar object) and we could use all of it but it adds up to about the mass of our oceans, and that is most of the water inventory the asteroid belt.
I’ve looked at various large rotating structures up to the size of the Banks Orbital and concluded you could solve the structural problems if you could make a reliable journal bearing (structural parts don’t need to be spun) that could handle the velocity difference but no matter what you cannot afford tall mountains or deep oceans.
Agreed, liquid is probably the way to go.
Very tempting to swap nitrogen for helium, but AIUI the main downsides are that the speed of sound is higher so air will leak out from a breach faster, and there may be negative effects on flammability due to helium's high thermal conductivity and low specific heat.
Helium gas also leaks a lot, even when everything is normal.
Probably a naive question but would it possible for us to skim gasses from LEO for use in space stations?
Putting aside issues with capturing basically vacuum at 8km/s, by doing that you're going to lose impulse that you're going to have to regain, spending more mass in fuel+oxidizer than you gained in gathered gases, unless you use ion propulsion (which ISS doesn't). Also most of what you're going to capture at 400km is going to be atomic oxygen and helium, N2/N share is only a couple percentage points at that altitude.. [0]
[0] https://en.wikipedia.org/wiki/Heterosphere
We already built LOX tanks into rockets. Just send up a tank of LN2. It doesn't need the strength of a bottle, you just need thermally insulating materials which can be very light.
Hard challenges are good and setbacks are to be expected if you are pushing every limit. I would love to be on such a fast moving team with such a massive payoff if they succeed.
How far forward are we looking - just use a fusion react to synthesis any material from any other by dissociating baryons then running nucleosynthesis. Stars do it, so we know it works!
A working fusion reactor would already open up a lot of opportunities.
> synthesizing nitrogen analogues through hydrogen-based pathways
What does this even mean? Transmutation?
I had a back of the napkin design that was basically a sleeve that fitted over Starship and could be launched into orbit. Those sleeves had angled ends that could then be bolted together in orbit to make a station with an octagon shape that could be spun at 2 or 3 rpm to get 1/2 Earth gravity. Obviously still an enormous engineering challenge, but one that I think is solvable using today's tech. Well, tomorrows tech, but nothing that requires a breakthrough in materials science or basic physics or anything like that.
My plan was to fit the inside with huge water bags that would help to reduce cosmic radiation, provide thermal mass, and slow any micrometeorites that puncture the hull. The water could be launched on cheaper rockets and transferred in orbit. The water could also be pumped between sections to keep the wheel balanced. The central hub area would be more of a challenge, probably having to be assembled (or at least unfolded) in orbit.
Probably the biggest downside is that you wouldn't be able to spin it up until the entire structure was somewhat balanced, which means installing things like solar panels and radiators in pairs and the docking bit of the central hub would probably need to be on bearings so it can counter rotate to be effectively stationary or you wouldn't be able to dock more than 2 spacecraft at a time. The ISS was built in sections over the course of decades, this would need to be built all in one go, which is a huge commitment.
NASA's plans for two tethered stations (or one station and a counterweight) are probably more feasible, but much less cool.
> large amounts of nitrogen or some other inert gas
You could ship liquid ammonia and then burn it to produce nitrogen and water.
"(5) Colonization of Ceres dominates all other space colonization opportunities in the solar system because there is no shortage of water and no shortage of nitrogen."
What about gravity?
Rotation. You don’t live on the surface but you build a beanstalk and build a big framework of small O’Neill’s cylinders. See
https://arxiv.org/abs/2011.07487
I’d say this paper thoroughly debunks all other space colonization plans in comparison. For instance it is not sustainable to use rockets for routine transformation. The moon doesn't have enough volatiles. Who knows if gravity on the Martian surface is enough to be healthy.
Even if you could take, say, Mercury, apart it would be silly to build a ‘Dyson swarm’ but rather you would build a big framework like that or a ‘Dyson foam’ (e.g. if you took Mercury apart and turned it into a solar collecting structure 1m thick you could capture enough energy to make a few tons of antimatter a second for interstellar travel)
I vaguely remember O'Neil's book talking about zero g manufacturing by welding together plates of Aluminium. Although I may be remembering some other work. Could we use an inflatable workshop to weld together cylindrical sections of a torus? I can imagine sealing the end of the torus secrion and extruding it out the side of the inflatable. Very hazardous for the workers, I imagine.
O'Neill colonies are impractical because they involve large wasted air spaces. The mass needed to resist pressure loads is proportional to (volume) x (pressure), so it's best to stack floors so all that volume can be put to use.
It's crazy what we are doing with inflatables. Cargo ships with huge inflatable wing sails. The luxury catamaran MODX is bringing that down in size too. https://www.yachtingworld.com/news/modx-first-look-dual-infl...
In space, NASA worked with Sierra Space to test their 300 cubic meter "Orbital Reef". The next go.is supposedly 500 m^3, about half the ISS size. Still seems way to small to spin though, I'd guess? Lockheed has their own inflatable hab station too. https://www.nasa.gov/humans-in-space/commercial-space/leo-ec...
China launched and tested some kind of inflatable, just last fall. https://spacenews.com/china-quietly-tested-its-first-inflata...
It seems like an obvious & amazing unmaterial leap, versus needing metal walls. If it works! Very fun having this history of rings post. Feels a little light on where we are though, what of promise is happening!
Cargo ships have been powered by huge inflatable airfoils for at least thousands of years, possibly much longer than that.
Inflatable structures in general are fantastic in theory: air or hydrogen is cheap, easy to put into the desired shape, and has immense compressive strength per gram, effectively unlimited. Same for impact energy. So you can separate out the compressive and shock-absorbing parts of your structure from the tensile parts, and only pay for the tensile parts. The main difficulty is recovery from rupture, especially in a space environment where not only don't you have a steady wind filling your sails, you have a limited, nonrenewable gas supply. Well, and high compressive strength in a small space.
Do square rig sails count as airfoils? I thought they could really only go downwind?
As I understand it, they can go somewhat crosswind, which is all the wing of a 747 manages too. (An angle of attack of 2° is probably a lot better than you can do in a cutter, though, I imagine.) But I don't know much about aerodynamics or sailing, so I could be wrong.
> Popularised by von Braun in his 1949 sci-fi novel, Project Mars
Von Braun's novel was written in 1949 but wasn't published until 2006. Perhaps the author means the technical appendix "The Mars Project" [0] which was published in 1952, which spawned a series of articles [1] in the popular magazine Collier's from 1952 to 1954.
0: https://en.wikipedia.org/wiki/The_Mars_Project
1: https://en.wikipedia.org/wiki/Man_Will_Conquer_Space_Soon!
The novel "KETs Star" (Звезда КЭЦ, 1936) by Alexander Belyaev described station in a form of rotating wheel way earlier.
All the things worth doing in space turned out to be do-able without humans. Telescopes, radio relays, etc. The ISS doesn't really have much of a mission. Here's the list of current ISS experiments.[1] Many are aimed at the problems of keeping humans alive long term without gravity.
[1] https://www.nasa.gov/mission/station/research-explorer/searc...
I like thinking about the ISS as primarily engineering (and operational) experiments rather than hard science. As a space platform, it's provided learning on how to contract private companies for space flights, and in turn, how they should operate, plan, etc. Or how to do internationally coordinated space operations. All of the work it takes to mature a new tech to a 7,8, or 9 on the NASA Technology Readiness Level[0] while Curiosity and Ingenuity and other long-distance (and JPL) missions focus on the hard science of 1's and 2's.
That said, I too think the main value of ISS declined several years ago or more. Looking forward to the next generation, whatever it is
[1] https://www.nasa.gov/directorates/somd/space-communications-...
> Looking forward to the next generation, whatever it is
Tiangong [1]
[1] https://en.wikipedia.org/wiki/Tiangong_space_station
> As a space platform, it's provided learning on how to contract private companies for space flights, and in turn, how they should operate, plan, etc.
This would be great if we knew where we are heading. Without a clear goal/destination the most likely outcome is we get board and lose the institutional knowledge we paid so much money to gain.
The was a long discussion about benefits of human space exploration. A comparison was made between that and basic science: just like the basic science doesn't bring immediate benefits, so do humans in space. However over long periods of time both could prove to be worthwhile.
Long term zero gravity experience and experiments were very important information for future space flight. Now we know a lot more about the muscle atrophy, bone loss, and vision problems that the author complains of. Having the first space station be zero-g was probably the right move.
But for the second one, more information on artificial gravity through centripetal force makes a lot of sense.
The problem is the ISS wasn't the first station and we already knew zero-g fucks people up long before the ISS was built. Building the ISS anyway so we can waste more time studying the minutia of exactly how badly and quickly it fucks people up was a mistake. In truth the ISS exists for political reasons, not because it was a sound investment from a science and research perspective.
Congratulations, your alternate history has delayed Mars colonization by several decades.
Because of the ISS we know that stays of greater than 12 months in zero gravity have real but minor impacts on the human body. So 3-4 month trips to Mars in zero-g are feasible.
If we assume they aren't, those trips would be far more resource intensive.
We didn't learn any of that from the ISS which we didn't already know from Salyut 6 and 7, and Mir. The ISS, aka Mir 2, hasn't taught us anything new. The reason it exists is because decades ago, for a few years, manned space stations made sense for orbital reconnaissance because putting unmanned cameras in space was complicated. Salyut and MOL were born from this transient strategic necessity. Unmanned recon satellites soon became practical though, so MOL was canceled but the Soviets carried on with Salyut because if there was anything they were good at, it was continuing to make something long after anybody else would have canceled it. Even when they did get recon satellites they did it with Vostok capsules, they never stopped making those after launching Yuri Gragarin in one. They just kept on making them because they were already tooled up for it, finding new excuses to keep making the same old stuff. And so it was with Salyut, the program was obsolete for orbital reconnaissance but they were already making them so they kept at it, turning it into a national prestige program. Mir was a direct descendant of it, built around the DOS-7 module which was a Salyut module with 6 docking ports instead of the two on DOS-6. It never had a good reason for existing besides Soviet politics. (By the way, Skylab never had a good reason for existing either, just politics. NASA trying to hold onto their funding as Apollo was wound down.)
The ISS is nothing more than Mir 2, built around the DOS-8 module, it's a Salyut with American funding because this time America wanted to keep the Russian space program solvent to make it harder for Iran/etc to recruit that Soviet talent. And because NASA likes long term projects that require around the clock staffing because that's great for budgets and careers. That's why the ISS exists.
Also we aren't going to Mars. Sorry. A lot of individuals are passionate about that but at an organization level there is no drive for it. NASA likes to use the talk of it for fundraising but never makes progress on it and Congress won't ever greenlight it, and SpaceX uses it to keep their employee moral up but all they are demonstrably working towards is being the king of launching satellites. The only money to be made in space is with stuff pointed at Earth. There is no economic case for Mars colonization. It's not happening. I wish it weren't so because I'm a sci-fi junky, but it is what it is.
> We didn't learn any of that from the ISS which we didn't already know from Salyut 6 and 7, and Mir. The ISS, aka Mir 2, hasn't taught us anything new.
I doubt that. ISS served in space longer than Mir and Salyut-7 combined, I would expect it to run more experiments and get more data - especially as the equipment is more modern and experiments are planned with the benefit of knowledge of the previous works.
The amount of time the station spends in orbit isn't relevant, the amount of time a person spends in orbit for an unbroken stretch is what's relevant. Three of the top five spaceflight duration records were set on Mir, including the top two (437 days and 379 days.) Nobody even thinks of getting close to that top Mir record anymore because it is already known that it fucks people up.
> The amount of time the station spends in orbit isn't relevant,
The people on ISS were doing a multitude of scientific programs during that long time. That's important. Just like you wouldn't say that Hubble already seen everything and JWST isn't needed.
There are microgravity experiments run in the ISS other than "how much does microgravity atrophy the human body?"
And another thing:
We still have no idea what long term stays in Martian or even Lunar gravity does to a human body. We don't know because we have spent the past half a century fucking around with useless zero-g space stations instead of building von Braun wheels which could easily be used to simulate those conditions. Because forget about Mars colonization, merely finding the political willpower to do something as conceptually simple as spinning in space is evidently impossible for us.
The simulation would be flawed. Von Braun wheels would have very significant Coriolis effects, so it'd be hard to distinguish whether any issues are due to reduced gravity or the Coriolis effects.
Bone density and muscle loss effects shouldn't be significantly effected by coriolis effects. Such effects may likely cause nausea in many people, but it is very likely that test subjects who can adapt to it and live comfortably during the period of study could be found.
My very rusty physics tells me that walking one way along the inside of the wheel would make you weigh less, and the other way would make you weigh more - is this what you're referring to? Would trying to work 'normally' in this kind of situation induce nausea, or make your food fall off your tray etc? It would be a shame if you went to all the effort to make a Von Braun wheel in space to simulate gravity, only to find that you had to stand still to do anything practical.
(I assume the astronauts in 2001 A Space Odyssey jogged in the direction that made themselves weigh more, to make their workout more intense.)
Coriolis forces acting on the human vestibular system can directly induce motion sickness just from turning your head. If it turns out humans cannot acclimate through long term exposure, the only remedy is to increase the wheel radius.
The Coriolis effects can be made to be mostly negligible, with a big enough wheel.
A big wheel may be too costly, but it can be replaced by either 2 identical bodies with a long link between them, or with a single body linked to a counterweight, in which case the cost would be only marginally greater than for the current spaceships.
In several decades of zero-g research, they didn't even manage to put a few mice up to see whether they could successfully reproduce without gravity. Are they afraid of the results?
It would be embarrassing if the mouse babies come out crippled, even if it doesn't immediately generalize to humans and the low-g environment of Mars.
They've successfully hatched small fish on ISS. For animals, IIRC embryos need gravity to determine heads and tails or something. We do already know. The answer is that we Earthian lives generally face great difficulty reproducing in zero-g.
What exactly do we know? By the way, mice are far more similar to us than fish.
I meant to say larger animals - it's been tried. Small fish and frogs were fine, but chicken eggs showed issues developing past some early stages under microgravity[1]. Therefore we know that animals significantly more complex than amphibians can not reproduce normally under zero-g.
> Twenty out of 30 eggs (nine out of ten 10-day-old eggs; 10 out of ten 7-day-old eggs; 1 out of ten 0-day-old eggs) were recovered alive after landing. The only living embryo of the 0-day-old egg died 24 days after launch, and was comparable to a 16-day-old embryo when it died. The high mortality of the 0-day-old eggs appeared to be related to the specific inner structure of the egg. The yolk (specific gravity, 1.029) would not have separated from the albumen (1.040) during space flight.
1: https://pubmed.ncbi.nlm.nih.gov/9600757/ ( https://archive.is/r66W3 )
Yeah. Another nice article on the bird experiments:
https://finchwench.wordpress.com/2011/09/06/cosmoquails/
Still, trying it with mice (or other mammals) would have been worth it, because we can't rule out mammals being more robust during embryogenesis than birds. The ISS actually has still a few years left, so there would be some time left for such an experiment. Though I doubt it will happen.
> We still have no idea what long term stays in Martian or even Lunar gravity does to a human body.
We do know. The radiation kills us well before the lack of gravity does. The end.
We have to have shieldings thick and heavy as nuclear bunkers for a real space station to work, and such shielding is just way too heavy to be launched from Earth(unless e.g. we'd be okay with launching a toilet stall worth of habitable volume per Starship), so the station has to be mostly fabricated "in space", which is both technically and politically not yet feasible. There are theories that horizontal branches that may exist in natural crevices on the Lunar surface might work. Or for Mars some say we can just drill some mineshafts there and live inside. but all those options are equally sketchy in its own ways at this moment.
We're barely flying hatchbacks up to orbits and we want airport garages out there to park it. We're not hauling the whole building in the back of a Prius, not even on Earth, obviously.
What NASA, ESA, etc. had been doing is to drive up that Prius to the trailer home left in the middle of the desert, have them change lightbulbs, celebrate themselves and rotate crews. That's basically useless, but they keep repeating that useless "expeditions" because they'll have to start over from reinventing tubeless wheels if they stop paying for the gas even just for one year.
If you're wondering why we can't just accelerate at 1G for half the journey there, then with a brief but fun interlude at 0G, flip around and decelerate at 1G the rest of the way: today's rockets would deplete their fuel too quickly (minutes or maybe hours at best).
I wonder if a hypothetical, high-Isp fusion rocket could manage it (incidentally the journey would only take a couple days or so).
Great read,
One question i've had is if its given that we care about making humans space faring, why focus on getting to new planets and colonisation and not instead on building the massive megastructures mentioned in the article as an end in itself?
The article mentions that the inflatable Goodyear torus has become much more realistic since the inflatable BEAM module (2016) on the ISS. That one has a volume of 16m^3.
But since then, Sierra Space has been working on much larger inflatable modules. Their latest test volume was already 285 m^3:
https://www.theverge.com/2024/7/25/24206219/nasa-sierra-spac...
According to the report, Sierra wants to move to testing a 500 cubic meter volume this year. And the roadmap on their website lists two further habitats with volumes of 1400 and 5000 cubic meters:
https://www.sierraspace.com/commercial-space-stations/life-s...
That would already be pretty close to the 6000 m^3 von Braun wheel mentioned in the original article. Though Sierra doesn't seem to plan for creating something like the flexible Goodyear torus which could rotate, just pill-shaped inflatable capsules. Not sure whether this has technical reasons.
What about an "I" (or H if your font is sans-serif) shaped system? Like the Vast "stick" but with two sticks attached to the end. Seems like that would multiply the livable area by a much greater factor than it would multiply the number of launches. If I understand correctly the Vast is already a multi-launch system, so it seems like the obvious change.
If you can tolerate +/- 5% gravity level (which should be doable), instead of a stick for the habitable area you can rearrange the modules into a more compact blob, which should reduce radiation shielding. In LEO it doesn't really matter but it's more important in deep space.
I sometimes hear this called a "barbell" design.
> For example, one of von Braun’s designs called for a massive 75 metre diameter wheel
That’s a radius of about 5% of the length of a human body, so I guess we would soon find out how humans react to living in an environment where ‘gravity’ at eye height is about 5% lower than at toe height or do we already know something about that?
Some people would lose their lunch, but that's nothing new for space flight. It's just a much more mellow version of classic carnival rides.
I know it’s nothing vs a rollercoaster, but people don’t regularly spend 24 × 7 in rollercoasters.
Not regularly, but there have been contests to see how long people will stay on a rollercoaster. Speaking from some experience, after you've gone around a few times, it can actually get rather boring.
I once had a job making ride photo systems for rollercoasters and rode them repeatedly to make sure the cameras and lighting worked appropriately. And, after riding for several hours late at night, I found myself falling asleep on a roller coaster!
People begin from the premise that there should be lots of primates living away from earth, and then work backwards from there. I don’t think governments should be paying so much for such activities.
In my opinion it is not a good use of public money relative to other space projects, and crude missions to mars would likely destroy any hope of finding life there should it have existed, making them actively harmful.
It seems sometimes that for NASA, the big goal is to have a large source of steady funding is the goal, and a space station is the best way to get that (hence the insane space station in the lunar mission plan). I get some vague impression that politicians like talking about missions to the moon or mars more than space stations, telescopes or probes.
> People begin from the premise that there should be lots of primates living away from earth, and then work backwards from there.
No, people begin with interest in all things around them and from that conclude that being closer to them would be more convenient. This idea is perhaps as old as the human race itself.
Modern robots aren't as capable as humans, so if the project is big enough, human involvement is reasonable.
I don’t think ‘closer to thing’ is a legitimate goal to spend enormous amounts of public money on. (I’m more ambivalent about private funding except for the contamination problem)
I’m not aware of any serious research questions about the solar system which could be answered sooner or more cost effectively by sending people to investigate (except for questions about eg how well primates survive in various extraterrestrial situations, which are only interesting insofar as there are legitimate reasons to put primates in such situations).
The Moon research was significantly advanced with the data collected from the rocks Apollo astronauts brought from the Moon.
Your skepticism is widely shared and also widely debunked. I don't think we'll move the state of the debate ahead with short messages, it needs more detailed and prolonged discussion. There are reasons defending the space exploration, and there are reasons defending human flights. You can personally disagree, but your arguments are based only on opinions, which aren't better than opinions of the other side.
I propose we swing around a module by a teather suspended from Kamoʻoalewa. No need for the contraption to be circular?
The first and best place to build a permanent station is the moon. The wheel could spin on the surface at a very low rpm given the Moon's existing gravity, giving us the launchpad need to build and deploy a permanent space station.
Until we settle on the moon, our forays into space will always be limited by pesky things such as Earth's gravity and atmosphere.
Wait would this even work? Can you add moon gravity to centrifugal space station gravity? I can’t imagine a setup where the wheel is always pushing inhabitants out in such a way that they are moved towards the center of the moon.
Yes, you add accelerations as vectors. Say, a centrifugal ring flatly lays on the Moon surface and rotates (around the axis of ring symmetry perpendicular to the ring plane) so that the artificial gravity on the centrifuge is about Earth. Moon gravity, about 1.42 m/s^2 , adds perpendicularly to that, so the total gravity is still about the Earth one. The level surface on the centrifuge is slightly tilted away from local vertical, but in essence you just added Moon gravity, vectorally, to the rotational acceleration.
I am fully in favor of doing things on the moon, but have a theory that its relative convenience is actually detrimental. Without going into a lengthy spiel, convenience means low commitment, which translates into a high likelyhood of projects getting the plug pulled.
Elsewhere, the hurdles to clear to get something started are higher, but once you’re out there it’s a lot less justifiable to reverse course.
It could very well be true that it’s necessary to settle the Moon before doing anything else, though, which could spell bad news for any endeavor involving crewed spaceflight. We might end up with a series of false starts on the Moon (due to events like funding getting pulled as a result of changing politcal winds) that end up going nowhere which then puts crewed spaceflight in a state where it's stuck in LEO perpetually.
I'd start with a dumbbell shape - two pods connected by a slender cylinder just large enough for a man to travel through, and rotating like a pinwheel.
One can add more "spokes" over time to complete the wagon wheel.
Or even just one pod with a cable and a counterweight.
> Made from soft materials, like rubber and nylon, there were concerns that collisions with micrometeorites could puncture the station with fatal outcomes.
I fixed many an inner tube punctures, but I'd rather not be blowing at glue while my precious oxygen is hissing out towards outer space!
I bet something like tubeless sealant could be utilized for automatic sealing.
Just send up a case of Flex Seal. Maybe the spreadable version instead of a spray on version. Not sure what zero-G would do to an aerosol can like that.
Even better: Make the entire structure out of Flex Seal.
I mean, tapered rubber bung stoppers are a commonly used technology in day to day life...
Could a automated factory melt moon regolith into ringsegments, which are then send into moon orbit, assembled and spun up? So far the problem seems to be the launch cost with heavier, durable materials, or m i misunderstanding the problem?
The unitized concepts were proposed by people who didn't know the microprocessor, sophisticated electronic control systems, and compact robotics would be developed in the future. Furthermore, what rocket was going to launch that six cylinder monstrosity?
https://en.wikipedia.org/wiki/NERVA had already been in development for several years by 1961.
Project Orion had been proposed as early as '46.
Quick OT question to any treckies out here: how is artificial gravity generated on Starfleet vessels?
Wizards wave their hands and say something like, "Whatever, space is an ocean."
The Expanse makes the observation that accelerating your ship at a substantial fraction (or multiple) of Earth gravity gives you that same degree of artificial gravity, only, you have to orient your decks the right way. Down is towards the engine.
Of course, this in turn makes Star Trek (and Star Wars, and Firefly...) look even sillier, because flying in a direction perpendicular to your deck layout means you need two magic gravity fields — one to cancel out the engines and one more to give your crew a place to stand.
> Of course, this in turn makes Star Trek (and Star Wars, and Firefly...) look even sillier, because flying in a direction perpendicular to your deck layout means you need two magic gravity fields — one to cancel out the engines and one more to give your crew a place to stand.
Don't you just need one that does the required net change in gravity magnitude and direction? Of course, Star Trek actually has two (though I don't think the second is explicitly a gravity system, but it has that effect), a relatively steady state one that provides environmental gravity (gravity generators), and one that reacts rapidly to changing conditions to offset them for crew and other contents of the ship (inertial dampeners), which handles not only ship's drive thrust, but other externally-induced accelerations.
Of course, Star Trek is supposed to be vastly farther from our current level of technology and understanding of physics than the Expanse.
To be fair, in Star Trek only thrusters etc seem to generate force vectors, and the thrusters seem able to accelerate the ship in any direction. Only the warp drive seems to fling the ship just "forward". But yeah, it's wizard retcon turtles all the way down...
Thrusters and impulse engines seem to generate force vectors, and warp drive usually doesn't but the continuity is not very strong on that point and it is sometimes implied, and at one point in Voyager fairly explicitly stated to create accelerations (in Voyager, this was in reference to requiring the inertial dampeners to be functioning to go to warp without plastering the crew into a thin paste on the wall.)
It's a pretty sweet idea to imagine a starship where you stand on a platform and accelerate in the natural direction. If it were in a movie it would definitely give it a distinctive feel.
They wouldn’t need to stand if they had chairs with belts.
I have no idea why people pose these questions about fictional properties. They're fictional. If the fiction says gravplating exists and works very well, then hey, there's your answer.
Might as well ask why going to warp doesn't turn the crw into a fine paste on the nearest back wall, much like the fly that got fired as part of an artillery shell during the WW2 development of proximity fuses.
Compact gyroscopes under the floor everywhere generating mass thus gravity. It's one of sketchiest parts of Trek science.
By magical techno-babble.
> Early space visionaries, such as Werner von Braun
I mean, space visionary? Sure, yes. Nazi? Also yes. Just want to keep the record straight.
https://en.wikipedia.org/wiki/Wernher_von_Braun#Membership_i...
> Von Braun was an opportunist who joined the Nazi Party to continue his work on rockets for Nazi Germany.[6] He applied for membership in the Party on 12 November 1937
1937 was before the invasion of Poland so make what you will.
> In 1940, von Braun joined the SS
1940, after Nazi Germany invaded Poland.
What do they call apolitical Nazis? "Nazis."
There is a wonderful novel focusing on that point: Moonglow by Michael Chabon.
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