Where is my von Braun wheel?
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(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.
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?
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.
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 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.
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.
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.
There have been proposals to use scoopers with structurally integrated electrodynamic propulsion ("tether without the tether"),[0] which would use zero propellant.
[0] https://forum.nasaspaceflight.com/index.php?topic=44542.msg1...
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)
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.
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.
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Request ID: zte7dpy79ryEUqFA5UUBPv4Yl4t6NIL4lyHvs6yqTcdr8wCrXG5xHA==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?
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.
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.
What does this even mean? Transmutation?
What about gravity?
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)
It's not coincidence the first Ceres orbiter was also a flagship prototype for advanced electric propulsion. It's a deceptively remote target.
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.)
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.
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.
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.
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.
You could ship liquid ammonia and then burn it to produce nitrogen and water.
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!
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.
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!
[1] https://www.nasa.gov/mission/station/research-explorer/searc...
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-...
Tiangong [1]
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.
But for the second one, more information on artificial gravity through centripetal force makes a lot of sense.
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.
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.
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 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.
(I assume the astronauts in 2001 A Space Odyssey jogged in the direction that made themselves weigh more, to make their workout more intense.)
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.
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.
> 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 )
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 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.
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.
I wonder if a hypothetical, high-Isp fusion rocket could manage it (incidentally the journey would only take a couple days or so).
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?
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?
I sometimes hear this called a "barbell" design.
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.
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’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).
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.
Until we settle on the moon, our forays into space will always be limited by pesky things such as Earth's gravity and atmosphere.
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 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!
One can add more "spokes" over time to complete the wagon wheel.
Or even just one pod with a cable and a counterweight.
Project Orion had been proposed as early as '46.
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.
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.
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.
Similarly, how is the gravity generated? By grav-plating of course![0]
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."