[ETH_start]

I respectfully disagree. There are vast opportunities, even on Earth, to expand energy generation without overloading the environment — such as utilizing arid lands for large-scale solar farms and expanding nuclear power, among other solutions.

That said, I believe a robust space economy is imminent, not some distant uncertainty. Starship has already had partially successful test launches, and if it follows the same trajectory as the reusable Falcon 9, we will soon have a fully reusable vehicle capable of delivering 150 tons to low-Earth orbit per launch.

If Musk follows through on his ambition to develop a fleet large enough to transport the materials needed for a self-sustaining Martian civilization, we could see an explosion in lift capacity within the next decade or two, radically transforming the scale of human expansion into space.

[gf000]

Even a post-ww3 nuclear wasteland Earth with climate catastrophe is orderS of more habitable than anything else in the Solar system.

Musk is a scammer and is dumb as a rock on any technological question.

Also, energy is useless if it's not where you actually want to use it, and transporting it is expensive/lossy.

The cheapest energy is one which doesn't have to be used up to begin with, and we could optimize the existing workflow much more, over some child-dream Martian scam.

[ETH_start]

That is simply not true. A post-World War III nuclear wasteland would be subject to attack and pillaging by roving human bands, whereas a deep space colony would not be. And energy transportation being lossy is not a deal breaker when you can generate massive amounts of energy out in space. Even if you lose 90% of it, 10% of an enormous number is still an enormous number.

[gf000]

Did you account for the maintainance of any equipment out in space? Just because we can produce space junk faster doesn't make the rest any cheaper.

Also, getting robbed is a luxury compared to not having air to breathe.

[ETH_start]

It will get more affordable as the amount of infrastructure that is outside of Earth's gravity well — and any other steep gravity well — increases. The thing with the Starship is it allows us to expand that infrastructure rapidly, so we can soon have a sizable industrial base that can access low-gravity resources like asteroids and moon regolith.

[ben_w]

Anywhere we can get to at the scale necessary to make significant power, there's not much stopping humans, or at least automated robots, from also going there to attack and pillage.

--

The most habitable place in the solar system, outside of Earth, is Mars.

Mars has 50% of the sunlight that Earth. Owing to the lower sunlight level, it is colder than Antarctica.

The atmosphere is equivalent to taking ours, then systematically deleting every molecule that isn't carbon dioxide without replacing it with anything else.

Owing to the combination of low partial pressure and low temperature, half the atmosphere condenses into the polar caps each Martian winter.

The ground is more toxic than an actual, literal, superfund cleanup site.

It is drier than the actual, literal Sahara.

The lack of oxygen in the atmosphere means there's no ozone layer.

The lack of ozone layer, the thin remaining atmosphere, and the lack of magnetosphere, means it's a high-radiation environment.

PV there also gets regularly covered in dust.

Our moon is even less hospitable, owing to no atmosphere at all and being tidally locked with Earth.

Venus has an atmosphere so dense that it has gone beyond the critical point where gas and liquid cease to be distinguishable, so you could reasonably also describe it as an ocean. An ocean of 465°C supercritical CO2 in which lead occasionally condenses onto mountaintops.

--

There's three currently achievable ways to transport power through space at scale. Optical, microwave, or kinetic.

Optical is either a bunch of mirrors or a laser on the sending side, with a normal PV system on the receiving side. Usual caveats apply, Earth spins so it has a relative night, doesn't work through clouds, maximum power density before PV systems overheat etc.

All EM systems, microwave and optical, share a constraint about focussing: minimal size of target depends on the size of the antenna and the wavelength used. Because microwaves are so much longer (no much freedom to choose a different wavelength as there's a limited atmospheric window), the normal suggestion for ground stations is a 10 km diameter receiving rectenna — that's contiguous, you don't get PV's advantage of being able to split it up.

Kinetic currently means an RFG — launch it e.g. electromagnetically towards a similar coil on the ground that decelerates it to extract the energy. This is theoretically possible and would totally work, but to be clear: it's shooting a bullet into the barrel of another gun, and this is not something we have a lot of experience doing, certainly not at scale or for the purposes of power generation.

[ETH_start]

There's little advantage in raiding a colony six months away if you then have to spend another six months returning with the stolen goods before you can even use them.

Defending a settlement where the nearest potential aggressor is 50,000,000 km away is also a much easier task than defending one where the closest adversary is 1,000 km away.

With respect to space-based solar power and EM power transmission: my first thought is that a 10-kilometre diameter receiving antenna is totally doable, especially considering how much energy can be sent from space to this one rectenna. Such a rectenna can also double as a PV station.

[ben_w]

> There's little advantage in raiding a colony six months away if you then have to spend another six months returning with the stolen goods before you can even use them.

First: If it otherwise takes a year to build them, no difference.

Second: If they're useful for you in-situ, they're useful for anyone else in-situ. Don't need to move an object to take control of it, for exactly the same reasons that the British didn't want to physically relocate the Suez Canal during the Suez crisis.

> Defending a settlement where the nearest potential aggressor is 50,000,000 km away is also a much easier task than defending one where the closest adversary is 1,000 km away.

False. Whether attacker or defender has advantage is not distance dependent, it's tech-dependent. Absolute stealth in space is only becomes impossible when you've already got something around a K1.5 civilisation in the vicinity, before that you can fairly easily hide passive IR signatures, deflect/absorb/otherwise minimise active EM scans, and the defender doesn't have the resources to saturate volume with gravity sensors to spot attacker's mass. Even with Starship, the current state of the art passive and active scanning of the entire planet Earth still has trouble — most recent news-worthy item is 2024 YR₄ which we know so little about that it could be anywhere from 40 to 90 metres. Even just painting that rock black would have meant it never got spotted because nobody wants to waste effort on active radar — and even if we did all start using active radar that too could be fairly easily defeated until it was too late, using even just the relatively primitive cross-section stealth reduction tech of the 1980s, because the scale of space itself makes radar less effective (radar bounces have a double inverse square).

On the ground, you absolutely can saturate with CCTV even now, sufficient for banditry; military-quality stealth is much harder to defeat at scale. Close-in surveillance still available in space, but then you're back to a few kilometres, no distance advantage. Actually it's worse than that, because outside an atmosphere you can do a hard-gee deceleration in the last few seconds, but also you can just let go of some plastic ball bearings before decelerating and have your approach preceded by a deadly shower of hypervelocity radar-invisible shrapnel hitting whatever bits you didn't want to keep, e.g. the existing defence systems. Heck, if it's a military action, they can perform the attack years in advance and with almost total plausible deniability.

> With respect to space-based solar power and EM power transmission: my first thought is that a 10-kilometre diameter receiving antenna is totally doable, especially considering how much energy can be sent from space to this one rectenna. Such a rectenna can also double as a PV station.

Contiguous. And that's per ground station, not total, you'd need in the order of 250 for the default proposal just to reach current Terran electrical power usage levels, or 2000 if you add in non-electrical power usage levels. Name an existing artificial 10 km diameter contiguous surface. Closest I can think of is "an entire city", but even those are not usually contiguous. Well, touching, but not fully filled in, not fully wired up. Not even the concrete and tarmac, let alone the plumbing or wiring.

If you're building stuff at this scale, the resources requirements for the ground stations alone, let alone the space elements, are enough to seriously consider a low-resistance high-current DC global planetary grid as an alternative, and then you just put PV plants in antipodal deserts and get 24/7 PV from ground mounted PV without storage. And the political problems which prevent that being built starting today and over the next five years, are trivial in comparison to the political issues from any significant space based beamed power system, even one which is sincerely and openly designed in a peaceful fashion (which is hard to prove).

The overall power density isn't even much different than PV for a bunch of reasons, including safety, it just gives the possibility of getting powered in what is to our eyes darkness. If you could see RF, it would be like a time-averaged equivalent of a slightly cloudy day, 24/7 — lower peak, higher average, than PV in the same place.

Consider the converse: if you were to design a system that is capable of having an arbitrarily high power density, it's no longer just a power source, it's a death ray. Other governments take a dim view of such things, and will likely cause aforementioned years-in-advance attacks with almost total plausible deniability.

But even then, this is the wrong usage. Use power locally in space for things, don't beam it.

If/when humanity gets to a full K2, suborning that much power generation capacity and pointing it at Earth doesn't look like a grape in a microwave, it looks like Alderaan every 14 days or so.

We're not even politically ready for this kind of change, in much the same way and for many of the same reasons as ancient Athens would not have been politically ready for the sudden availability of Tsar Bomba during one of their fights with Sparta — but that only makes it fortunate that Starship is orders of magnitude too small to cause such an industrial change.

For all the reasons I gave in the previous comment, if you consider Apollo to be analogous to a Kon-Tiki raft, Starship is a carrack, an orbital ring is a highway network, and even if we had one of those we're still orders of magnitude short of K1.

[ETH_start]

>First: If it otherwise takes a year to build them, no difference.

This overlooks a couple factors. First, a raid requires building and launching a fleet of vehicles — a massive investment in logistics and capital. Second, most materials targeted for raiding take less than a year to produce. Spending enormous resources to steal something that can be manufactured more cheaply on Earth or in situ is economically unsound. In nearly all practical scenarios, the costs and risks associated with long-distance raids vastly outweigh any marginal benefits. So yes, and colony on Mars would be safer from raids than one on Earth.

>Second: If they're useful for you in-situ, they're useful for anyone else in-situ.

This is totally different than the Suez Canal, because it would require the raiding party to want to completely relocate for those resources to be useful. There's no meaningful trade between Mars and Earth due to logistics, so they cannot economically utilize those resources of Mars on Earth.

> False. Whether attacker or defender has advantage is not distance dependent, it's tech-dependent. Absolute stealth in space only becomes impossible when you've already got something around a K1.5 civilization in the vicinity, before that you can fairly easily hide passive IR signatures, deflect/absorb/otherwise minimize active EM scans, and the defender doesn't have the resources to saturate volume with gravity sensors to spot attacker's mass.

Irrespective of the level of technology available, distance imposes inherent logistical constraints. A nearby attacker can maintain sustained pressure, rapid resupply, and repeated engagements at lower cost, while a distant force must overcome long transit times and a vulnerable supply chain.

As for stealth, sven assuming near-future stealth and tracking advancements, proximity still affords defenders longer reaction times and more thorough surveillance.

>Contiguous. And that's per ground station, not total, you'd need in the order of 250 for the default proposal just to reach current Terran electrical power usage levels, or 2000 if you add in non-electrical power usage levels. Name an existing artificial 10 km diameter contiguous surface.

2,000 city-sized rectennas to power all of Earth seems like a great deal.

This 2002 study models a 5 GW SBSP system with a 12-km rectenna that is transparent enough to allow vegetation to grow underneath. This mitigates land-use concerns while allowing high efficiency for power collection:

https://www.researchgate.net/publication/3427153_How_Safe_Ar...

[ben_w]

Starship is only a breakthrough compared to the status quo; compared to the scale needed to unlock even a full K1 power consumption it's about as close as the 25m swimming certificate I got as a kid is to swimming across the Atlantic from Lisbon to Miami… 276,400 times.

K2 is 10 orders of magnitude harder than K1.

Using rockets at all for K2 is a terrible idea, as you are forced to start treating oxygen as a mineral to be extracted from rocks, because there isn't enough in Earth's atmosphere… by 8 orders of magnitude.

[ETH_start]

It's clearly a stepping stone. If we can transport 15,000 tons of mass to low earth orbit per day, we can set up an extraterrestrial industrial infrastructure for harvesting and refining building materials, so that we don't need to overcome Earth's gravity well to acquire material for space-based construction.

[ben_w]

A stepping stone in the way that the Pesse canoe was the stepping stone to the creation of the modern USA.

Actually, not even that.

15,000 tons of mass to low earth orbit per day isn't nothing, but at the same time, rockets cannot ever scale to K2. Can barely scale to K1, but only if you don't mind catastrophic climate change from burning order-of one percent of Earth's atmospheric oxygen.

K2 requires a VN replicator. If you have one of those, you only need one successful rocket launch. Not one per day, one total. Just so long as the rocket is big enough to fit the replicator, that's it.

Hmm. 15000 tons, so 100 Block 2 Starship+Booster, per day. Accounting for fuel-rich engines and methane's greenhouse factor, launching that with rockets is ~150 million tons of CO₂-equivalent per year.

Seems small, but even all by itself that's 3x the maximum sustainable level of emissions — even if absolutely everything else, everywhere in the planet, was completely and perfectly greenhouse-neutral, it's too much.

Shame, really. Mars missions only work if SpaceX gets a Sabatier plant that fits in a Starship, masses less than 150 tons including power systems (or 200 tons on Block 3), and can produce 330 tons (for Block 2) in two years while on Mars, yet no talk from them about work on this because Musk is too busy Muntzing his government.

[ETH_start]

Your argument is short-sighted. It assumes that success must be measured by immediate scalability to a K2 civilization. The Pesse canoe wasn’t the final product — it was an early, rudimentary tool that eventually enabled modern seafaring and global commerce. Similarly, Starship and current rocketry aren’t expected to instantly create a K2 civilization; they are necessary stepping stones that lay the foundation for future, transformative technologies.

Even if rockets can barely scale to a K1 civilization without severe environmental consequences, that doesn’t diminish their value. Affordable, frequent access to space is exactly what we need to build the infrastructure for later breakthroughs — such as Von Neumann replicators — which could then accelerate the expansion of space-based industry exponentially. Without the ability to reliably launch materials into orbit, we wouldn’t even get close to the point where self-replication becomes feasible.

Regarding environmental concerns, while launching 15,000 tons per day might sound like a lot, the estimated 150 million tons of CO2-equivalent per year is only about 0.3% of current global emissions. Moreover, if we shift industry into space, Earth’s overall emissions could eventually drop, making the trade-off much more acceptable. And that's completely putting aside the potential to synthesize rocket fuel using carbon sequestration, which would make the launches carbon neutral.

And on Mars: criticizing SpaceX for not yet having a Sabatier plant misses the point. SpaceX is trying to solve the biggest pain point of Mars colonization: the immense cost of launching mass to orbit. They can solve the other pain points later or leave it to others to do that.

[henearkr]

I agree on rockets.

I'm more hopeful about centripetal launchers (can run on electricity). The first prototypes seem promising.

[ben_w]

I think they'd be very helpful for anything involving an airless body, e.g the moon. At least as a bootstrap — when we get going, we might want to do megastructure-scale electromagnets so humans can survive the gee-forces.

(We can't do megastructure-scale electromagnets right now: while they would work and China has a big enough industrial base, nobody on Earth is in the mood for anyone talking about building a 1000km diameter electromagnet significantly stronger than Earth's magnetic field).

[henearkr]

Yes, and also there is a limit to what we accelerate within Earth's atmosphere, as it tends to burn up from friction.

So yes, the simpler machines on Earth are mainly useful at first as a bootstrap, and after that it would rather be from the Moon or Mars as a hub, with huge electromagnetic railguns.

Between Earth and low orbit, maybe some version of a space elevator could finally see the light?

If we follow this kind of blueprints, prioritizing electromagnetic tech instead of fossil fuels, we can successfully bootstrap some amount of space-based industry without trashing too much Earth's liveability.

[henearkr]

Oops, I mean centrifuge, not centripete.

I think the main company operating such tech is SpinLaunch.

[throwawayqqq11]

I think you are very delusional.

1) "Opportunities on earth" will always be more efficient in many aspects. Cost, waste, energy demand, reliability, throughput to provide for the 99% remaining on earth, the ones we actually try to solve problems for. You are ignoring cost-benefit analysis, scaling factors and side effects.

2) You are betting on space industries to compete and replace earth bound processes but only give launch capabilities as an argument. I think there are vast uncertainties and unknowns to overcome. Even if it plays out as you imagine, it will probably neither happen in your lifetime nor in next generations. All the while we continue to damage your foundation because we chase a pie in the sky.

3) Shooting for mars is idiotic. Going for the moon yields similar results and is much "easier". From there the rest of the solar system gets closer to us but please keep in mind, I am still not talking about self sustaining colonies or industries. Given that our earth still provides plenty, shooting for space in general is idiotic imo. If I had to bet on a technical long shot solution, I would go for nuclear fusion instead of bezos/musk, who I suspect to be equally delusional.

Please read closely. Id like to tell you something about population dynamics.

Maybe you have heard about the malthusian point of crisis, where food demand overshoots supply and a population starts to decline/collapse. This picture is incomplete.

Every species faces 3 categories of destabilizing threats: resources/nutriment, waste products and selective factors (a general term for internal/external stressors like predators, war, diseases, catastrophes, etc). All of our man made problems fit into one of these categories! In the long run, every species has to solve these problems!

Pointing at the potential resources and space for landfills beyond earth will not free you from these constraints, it just extend your grace period and enables you to pretend to have solved anything. An actual self sustaining colony means producing _and recycling_ everything, from the vital technology stack down to every day products. If any tech billionaire ever reaches that awareness of the problem and a solution for it, then why build it in space?!

What we need is a circular, sustainable econmy, which is also a big moonshot, unfortunately. But either way, the realization of the problems we face is the first step. CO2 is just one our urgent waste products. Can you name a second one with global implications?

[henearkr]

Yeah. water.

I agree with your points, which I could summarize as "my 1) is very difficult".

May it be more accessible with mechanical systems instead of humans working outside of Earth?

Anyway, I hope you understand and agree with my main point: to continue economic growth in our biosphere will just destroy this biosphere, quicker than we realize.

[throwawayqqq11]

Well, its difficult to break our entire civilisation down into a binary destructive: yes/no. On the one side you have the majority not caring to actually solve problems and on the other you have small genetics research teams maybe revolutionizing our waste management.

Going fully sustainable / having recycling rates of 100% / having zero impact on our environment ... is impossible I think. But I absolutely dont need to measure against that hard goal to conclude how much we are f'ing things up. So yea, I generally agree with you, even though i wouldnt put it on economic growth alone.

[ETH_start]

I agree that Earth’s problems should always be a priority, but I think there’s a tendency — especially in today’s political climate — to be overly skeptical of space exploration, particularly when the private sector is involved. It’s worth asking whether that skepticism comes purely from a neutral assessment of the facts or if it’s influenced by a broader narrative that frames space expansion as a distraction rather than an investment in the future.

The thing is, we already have a real-world example of how a large space program benefited Earth: the Apollo program. It wasn’t just about getting to the Moon — it led to a wave of new technologies that had nothing to do with space travel but ended up shaping industries back on Earth. That’s what happens when you push engineering and science to their limits. Space missions are, by their nature, some of the most ambitious and disciplined blue sky projects we undertake. They force researchers and engineers to tackle extreme challenges, and in doing so, they produce breakthroughs that spill over into everyday life. That kind of well-funded, high-stakes R&D has historically driven progress in ways that aren’t always obvious at first but turn out to be game-changers.

Now, when people talk about space expansion as unrealistic or too difficult, what they’re often really saying is that it’s too expensive. And historically, they’ve been right — cost has always been the biggest obstacle. But that’s exactly what’s changing. Before SpaceX, launching anything into orbit cost around $15,000 per kilogram. That meant sending a single astronaut into space could cost nearly a billion dollars. At those prices, space wasn’t an option for anything beyond government-funded prestige projects.

But we’re already past that era. Falcon 9 proved that launch costs can be dramatically reduced, and we’ve seen the direct impact of that—Starlink is a perfect example of a space-based system that’s already providing real-world benefits. With Starship, the cost of going to orbit could drop by another order of magnitude. If that happens, access to space will go from being a rare, ultra-expensive event to something routine. That completely changes what’s possible.

I think it’s shortsighted to assume space won’t provide massive benefits to Earth. Just like how early computing looked niche and impractical until it took over everything, space development is on that same trajectory. The same people who dismissed reusable rockets a decade ago are now watching them land on drone ships in the ocean.

I just think it’s worth taking a step back and asking: is this skepticism really coming from a place of objective analysis? Or is it just part of the broader push to downplay space exploration, especially when it’s coming from the private sector? Because if history has shown us anything, it’s that ambitious, long-term projects often look like distractions — right up until they change the world.

[throwawayqqq11]

> It’s worth asking whether that skepticism comes purely from a neutral assessment

My point of view comes from the other side. I am asking how species/societies fail and land on the 3 categories of failure, call it the great filter if you like. I should have pointed them out more clearly, that resources, waste products and selective factors are what we need to solve in the long term. CO2 is just one waste products of the many, that is in public awareness.

I am not downplaying the advances in space flight. I am also not ignoring, that there are limited benefits along the road for the general population. I strongly do object to the hype, framing it as a solution to societal problems though. I hope I made my self clear now.

Calling me shortsighted is the wrong word, I am pessimistic. Shortsightedness would imply that there are actual things to see. I am pessimistic about the competitiveness of orbital solar energy and about the cost-benefit of bulk deorbiting of resources – which still would be unsustainable. I am also pessimistic about upper atmospherical pollution, space debris and even more detached/delusional and politically way overrepresented billionaires on an ideological doomed mission to mars, while earth burns out.

Besides that, there are military, astronomy and telecommunication usecases (intentionally ignoring geoengineering), which I am also not downplaying, they are just irrelevant to our pressing issues. I kind of agree with one label you threw around: “distraction”.

Just pointing at

> progress in ways that aren’t always obvious at first but turn out to be game-changers.

> cost [drops] by another order of magnitude. [...]. That completely changes what’s possible.

> Just like how early computing looked niche and impractical until it took over everything, _space development is on that same trajectory_

> if history has shown us [...] ambitious projects often look like distractions — right up until they change the world.

does not impress me at all. To me, that is just vague gesturing at the sky. Except Computers, which can digitally model anything, which is why they pushed into every aspect of our lifes, space flight has limited use cases and unique constrains. That is the foundation of my pessimism.

To make myself clear: My point of view comes from the other side. I am asking how species/societies fail and from there I focus on sustainability as a key principle for any attempt of solving things. A cloud-castle as a promise of salvation and source of hope for our future does not work for me. On the contrary, space flight delusion _in a thread about the broken promises of carbon capturing_ – the lack of problem awareness generally – angers me every time. We should have sustainability departments with strong regulatory tools by now, but i think elon would disagre with me on that. I am slowly losing my hope living in this idiocracy. Thanks for questioning my objectivity.

[ETH_start]

I get that sustainability and long-term survival are critical. But space development isn’t an escapist fantasy — it’s already helping solve real problems.

Take climate science. Without satellites, we wouldn’t fully understand how CO2 moves through the atmosphere. Space tech tracks deforestation, ocean shifts, and extreme weather. Even climate models rely on it. Dismissing space as just billionaires playing with rockets ignores how much we already depend on it.

You say space-based industries — like orbital solar, asteroid mining, and colonies — won’t be competitive. But major tech shifts always start out looking impractical. Aviation was once a luxury. Early computers had "limited use cases". If people had written them off, they would have been wrong. Space is following the same trajectory.

I get the skepticism that lower launch costs alone won’t create large-scale space industries. But history shows that when costs decline, new demand emerges. Starlink already proves this. Starship is designed to push costs even lower, making things possible that never were before. That’s not hand-waving—that’s measurable progress.

Now, about closed-loop sustainability. You’re right that a space colony would need to recycle everything. But that’s exactly why we should invest in it. Perfecting closed-loop systems in space improves resource efficiency on Earth. The better we get at sustaining life in extreme conditions, the better we can solve sustainability challenges here.

Maybe space-based solar and asteroid mining won’t scale soon — maybe they will. But assuming today’s economics will never change is shortsighted. Early solar panels were inefficient and expensive, yet now they’re among the cheapest energy sources. The cost curve changed. Space industries are still young — dismissing them now is premature.

You focus on how civilizations fail, but the best way to prevent failure is through innovation. Expanding our toolkit, not restricting it, is how we solve challenges like sustainability.

I don’t think it’s unrealistic to believe space will be a major part of that.