HN Reader

(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.

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...

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).

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!

> 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!

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.

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?

> 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?

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.

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.

I propose we swing around a module by a teather suspended from Kamoʻoalewa. No need for the contraption to be circular?

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 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.

> 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!

Quick OT question to any treckies out here: how is artificial gravity generated on Starfleet vessels?

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?

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.

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.

> 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."