In 2022 a Moonrush will begin in earnest | Hacker News Reader

In 2022 a Moonrush will begin in earnest

economist.com

75 pointsaxiomdata316138 comments

My great hope in these cold war-esque times of tension between China, Russia, and the US is that the field of battle becomes competition in Great Achievements for science, engineering, and space exploration.

Permanent human-staffed moonbases are a good goal to strive towards.

Agreed on the hope that the new cold war spurs more scientific achievements (just hopefully fewer Manhattan Projects).

However, I don't grok the point of human-staffed moonbases. I'm just a casual layman, but asteroid mining's the only thing I know of with a clear ROI in space. Or is the idea a moonbase would be like the ISS/Antarctica, an international scientific outpost?

> but asteroid mining's the only thing I know of with a clear ROI in space

I dont think asteroid mining at current transportation costs is a clear ROI - the same amount of resources could be used to mine the earth for a lot more.

I see ROI in micro-gravity manufacturing - stuff that is impossible to do in gravity could be the future! Things like nano particles that would not be possible to create under earth gravity, fine structures that could collapse easily could be sustained in space for example.

Also, a 2nd human habitat (moon or otherwise) as a backup isn't a bad idea, even if it doesn't generate an economic return for a while. We are one asteroid impact away from extinction!

I’m not an expert in any of the following, but a couple reasons might be: 1) Living on multiple bodies would do wonders for the imagination and further space exploration. 2) reduced gravity launches for spacecraft to places other than earth 3) a test environment for developing technologies in a completely different space. The ISS serves this somewhat, but it seems like the scalability is very limited, especially manufacturing.

The sooner we can permanently keep even a couple eggs outside our single basket, the better.

We're currently 1 real plague or 1 big asteroid away from ending our species. Up to now we've been very lucky.

I'd like to see in my lifetime our species able to live outside Earth in a self-sustaining way, with enough resources, infrastructure and know-how to make microchips, edit DNA, etc without calling upon Earth to do it.

That'll require tens of thousands of major innovations, not least of which will be the ability to survive lots more radiation than humans normally get exposed to, plus concerns like how space squishes eyeballs and ruins a person's vision.

If humans end up living on luna or somewhere between here and luna, they'll either be augmented with tech we haven't thought of yet or with DNA we haven't invented yet.

I'm excited to see us try, and I don't care which 21st century nation-state makes it happen.

Why do some people place such importance on humans continuing beyond Earth? Is it not just the ultimate hubris to think that we know that doing so is even a good idea?

Aside from some major religions mandating the expansion of humanity (or at least their faithful) - which I suppose could be hubris in the religion - why is it excessively prideful to want our species to continue to exist? What moral framework accounts for a desire to continue our existence in the negative column?

Why not? Seriously, why wouldn't we try to preserve and upgrade our species for as long as physically possible?

Would we complain if whales said "we don't want our species to end"? Or ants, for that matter?

"No whales, it's the ultimate hubris that you think you have a right to exist and continue existing."

Why is it hubris for humans, like all other species on Earth, to want to exist, propagate, and, since we're intelligent, learn and grow our intelligence, and spread it beyond home base?

We are descendants of people who had strong survival instincts. No surprise here.

An intelligent species consisting of individuals who do not value their continual existence would disappear fairly soon.

Humans seem to be real, real self preserving fkers.

I know a 70 year old in the US who, after the 2020 election, made a survival plan for living in Australia because the world was going to crumble.

All the while I'm thinking... at 70...why...

I barely understand a young person doing it, but definitely don't understand such planning for like 5 extra years of end life.

There are a lot of things that we as a species have gotten wrong and are not worth preserving.

There are a lot of things that we as a species have gotten right and are worth preserving.

In the words of Prof. Brian Cox, it would be a tragedy if Earth is the only place in the galaxy where consciousness exists, and it would be wiped out by an asteroid.

Staffing humans on the moon requires efficiencies and innovation in rocket launches, landing, inhospitable settlement, and transport of goods and people between the Earth's surface and the moon.

It is a good stepping stone towards further exploration farther out.

Moon's gravity is much weaker than ours, which makes it an attractive starting point for missions to the rest of the solar system.

Launching anything from Earth's surface costs a lot of fuel. In case of Falcon 9, max payload is about 5 per cent of the total weight of the stack on ramp.

If I had to guess, I would guess that the space industry is going to move away from the Earth before, say, 2070. Among other advantages, energy in space is dirt cheap. You get the full solar constant when not in shade, no clouds, no rain, no wind or hail to damage your solar panels etc.

The gold rush of the moon is helium-3. It's supposed to be a clean and efficient form of energy. I expect it will be critical for expansion.

Before Helium-3 has any value you first need reactors to fuse it. We're not investing a lot into building those, and right now it looks a lot like renewables+storage will be cheaper.

I know what you mean, and I think the parent comment suggests that getting to the moon will empower enterprise and government to seriously consider further investment in those types of reactors. It is just one step to make it possible.

With the progress we are seeing in launching modules and supplies to space I think the calculus on what is cheapest might change (though I am all for investing heavily into renewables and improved storage as soon as possible)

This is a chicken-and-egg situation.

Without Helium-3 available, you do not have any incentive to sink money into reactor R&D.

A lot of the R&D also applies to fusion reactors with more mundane fuels.

That's a fantasy:

https://www.thespacereview.com/article/2834/1

Super-short term, or longer term?

Moon has a similar crust to earth, has never been mined before in all of human history, and doesn't have an ecology to ruin.

But the kicker is that the Delta-V requirements for moon->earth transport are quite modest; even to begin with. [1]

Delta-V requirements scale exponentially with gravity. With the inverse, at 1/6 of earth's gravity and effectively no atmosphere, all kinds of exotic transport and launch solutions that would be ludicrous on earth would be rather pedestrian on the moon. So the theoretical lowest possible price for shipping moon->earth would be very low indeed.

Assume there's mining/manufacturing on the moon already. Then at some point as people build out infrastructure, there's going to be a threshold point. First one factory might start to be able to build things and ship them to some of the more remote places on earth for cheaper than a similar factory on earth can do. At that point demand would increase and the price would keep dropping as volume increased.

Said factory just needs to be very careful to set things up so that at no point in time (past commissioning at least) they need to ship so much as a paper-clip from Earth, because that would immediately crater their budget. [2]

So long term moon-earth ROI is pretty good I'd say. Just getting to that particular threshold would be hideously expensive, since it requires a lot of earth launches. Possibly some intermediate steps might be needed.

[1] To slightly misrepresent the situation but give an intuition: The Saturn V rocket was needed to get to the moon; but the tiny spaceship-stack at the top of the rocket [LM ascent stage + CM/CSM] was sufficient to get back.

[2] Which is not to say that you can't sometimes ship things from Earth. While shipping from Earth is (comparatively) insanely expensive, one-off costs can always be amortized. But you can't practically include earth-launch as an integral part of your on-moon production or shipping processes and still expect to make a profit. This is part of the challenge.

Scientific outpost at first, sure.

But moon poles are eventually very valuable near earth real estate for storing vast amounts of volatiles and manufacturing. Not only craters, it can be extended by building a circumpolar wall that can also support uninterrupted solar energy. The permanent shade inside will provide cryogenic environment for free.

And just like a cold war, China is making a strategic move.

The lunar south pole seems to be prime real estate. One of two always lit / always dark positions, and it has more water ice and craters than the north pole. Definitely the better of the two spots.

Unless they're willing to share, they're shafting the rest of the world.

https://en.wikipedia.org/wiki/Lunar_south_pole

It'll be useful leverage to get 7 south pole claimants, and 8 arctic states to share land / transit rights.

Interesting to speculate if moon claims will intermingle with that on earth.

Source on them making a "strategic move"?

I see that they completed a landing a couple years ago, but India made the same attempt.

Nothing we do on the moon in the near term will require that it be to the exclusion of other countries. Landing a rover, or creating a moon base of a few hundred square meters still leaves a lot more moon for others.

Nothing except human nature ... see the current controversies in the South China Sea.

States are very territorial. There are emotional reasons for it, but also the exclusive claim for natural resources.

If water is found in mineable concentrations in only a few spots of the Moon, I bet there will be a serious conflict over those spots. It is literally a matter of survival for the future colonists.

I had recently read the coverage on Slashdot [1], which makes mention of territorial claims. China and Russia oppose the US' claims.

[1] https://science.slashdot.org/story/22/01/01/042219/china-spe...

Did you live during the Cold War? I struggle to understand why someone would want to live under that constant existential threat of nuclear annihilation.

I don't think he's saying "I hope a cold war brews so we can get better space exploration!!"

I think he's saying-- well, at least if geopolitical tensions get worse, maybe it will also at least improve space exploration.

> Did you live during the Cold War? I struggle to understand why someone would want to live under that constant existential threat of nuclear annihilation.

Ummm, we still live under that constant existential threat.

He didn't say he wants it. I think he means that times of renewed rivalry and tension are coming whether we want it or not, and he hopes some good can come from it.

Both Russia and the US still have enough nuclear weapons to wipe out much of humanity. All that changed is that we don't live under is the constant reminder of that existential threat.

My father worked on Safeguard. It's unfortunate to think that the last several decades of relative calm might have been temporary.

From a military technology standpoint, throwing rocks from the moon is probably the next technological step in warfare. The way cannons ended the era of the fortress, rocks will end the nuclear status quo.

I'm sure you already know, The Moon Is a Harsh Mistress by Heinlein is such a great book that deals with exactly this.

Also in The Expanse (possible spoilers?) it takes the Belters a surprisingly long time to realize they're holding the ultimate high ground in this respect.

I mean not really? That scene [SPOILERS AHEAD] always seemed like a plot hole to me - you need massive Delta V to change trajectories of objects in space to hurl them towards earth and you need them to be massive to not burn up in the atmosphere. That takes a loooot of juice.

It's much easier to use the "Rods from God" idea - that is more precise and minimizes collateral damage.

There's a surprising number of near-earth objects that might (almost) hit earth anyway, that really only need a nudge. And if you're not in a huge hurry, you can use high ISP electric powered rockets. And since you're in the inner solar system, solar power isn't very expensive either.

IRL you can use brain-power to avoid using muscle-power!

On the other hand, in-universe, they've got brute-force Epstein drives. For them this is Tuesday.

But if you want to "nudge" an otherwise near miss asteroid you gotta wait till however long till it comes around, which can be 1000+ years?

From https://www.britannica.com/science/Earth-impact-hazard/Frequ...:

> Because there are far fewer large NEOs and long-period comets in space than smaller ones, the chances of a collision decrease rapidly with increasing size. The impact-hazard community—primarily scientists with an interest in the issue—has defined a global catastrophe to be an impact that leads to the death of one-fourth or more of the world’s population. An impact by a 1-km- (0.6-mile-) diameter NEO, the smallest believed capable of causing such a catastrophe, is estimated to occur about once per 100,000 years on average, based on the assumed population in space of such objects. On the other hand, an impact by a 100-metre (328-foot) NEO, the smallest believed capable of causing regional devastation, is estimated to occur about once every 1,000 years on average.

I guess that link will underestimate the number of near misses but looking at https://en.m.wikipedia.org/wiki/List_of_asteroid_close_appro... the number of 100m+ objects isn't that common?

Well, look at it this way: https://www.youtube.com/watch?v=BKKg4lZ_o-Y [Asteroid Discovery - 1970-2015 - 8K resolution]

Take your pick!

And remember one doesn't need a tidy Hohman transfer. Rather the opposite in fact. The nastier the intersect angle the better.

(Hopefully we don't end up on some watchlist :-P )

No more plot hole than the Epstein drive. That's the handwavium there. Depending on the nature of the Asteroid, it wouldn't have to be larger than anything between a SUV or bus. Which even small private yachts could push on course.

INSTABANG!1!!

I don't really understand why this is the case. Nukes don't defend against nukes—MAD defends against WMDs. Why do new and fancier WMDs make MAD no longer effective?

"The nuclear status quo" is a balance made possible by MAD.

In an arms race there may be a period of technological superiority. During that period MAD does not exist.

Bombardment from space creates at least two scenarios that upset MAD.

1. First strike capability

Small projectiles sufficiently accelerated may escape detection from ballistic detection systems. This could give an actor sufficient confidence in their ability to eliminate return strike capability.

2. Plausible deniability

For a period it may not be possible to determine which actor launched a strike. This can cause sufficient hesitation (and the expectation thereof) for an actor to initiate a strike and the target to fail to retaliate due to insufficient confidence in their target.

I'm sure there are other scenarios as well.

Even with perfect space bombardment, USA/Russia/China/UK all have SLBMs waiting on submarines all around the world. No first strike could be sufficient.

Doesn't matter. Strike the submarines first by hitting the seas with some hard space hail. Splash. Blub. (We don't really care about the resulting Tsnunamis, do we?)

Yeehaa!

In terms of defensive technology, maybe. MAD isnt stopped by having bigger bombs.

Also, replacing nukes with moon rocks means that you don't have to worry about securing those nukes.

How do you secure the infrastructure that hurls the moon rocks?

> How do you secure the infrastructure that hurls the moon rocks?

You don't, although mobile launchers are not out of the question. A rock catapult is far easier to construct than a nuclear missile launchpad (given available materials). Notably the munitions are fashioned anywhere on the moon and the munition needs no guidance, other than the initial launch window timing.

> far easier to construct

Right but I’m not talking about construction. I’m talking about destruction. See an enemy building a catapult with your moon-orbiting spy satellite? Send your Space Force astronauts in a rover to dismantle or destroy it. Or send an unmanned rover with robotic, remote controlled arms when we get to that capability.

> I’m not talking about construction. I’m talking about destruction.

That's not very effective if you can fire and abandon, since it's very likely that someone could work out the locality of the origin, you have to assume there's no way to defend against that. So what? Another one pops up in a few days.

The only way to defend against kinetic bombardment is controlling material gathering/supply and pinpoint destruction and that won't even be an assured defense. In a year, someone could scrap together X materials to hurl another.

or target your sattelite-laser on it, no atmosphere to make it useless on the moon...

Anyone building mass drivers on the moon is going to bring up anti-satellite missiles along with other point defense (“anti-meteroid”) systems and sky-facing telescopes and radars on the first mission.

Several of these components are necessary even for a peaceful research base.

The same way we guard the nukes: floppy disks.

The easiest way is for governments to collude to prevent or stall space exploration.

Control access to the moon.

I think they're assuming only one functional moon base at a time, that is to say, whoever has the moon trebuchet isn't subject to MAD.

Not sure I buy it, but if it were taken seriously it could certainly light a fire under the collective keisters of the world's superpowers.

This is nonsense. Rocks don't throw themselves. If a moon rock smashes Washington DC then our missile submarines will still nuke Beijing or Moscow in retaliation. Nothing can end the nuclear status quo until someone builds a defensive system that can't be saturated by a massive retaliatory strike. MAD still applies.

No, what happens is that everyone rushes to the moon to recreate MAD in terms of rocks instead of in terms of nuclear weapons. During the transition period from atomic MAD to kinetic MAD, deterrent politics will become very complicated and war planners may make miscalculations. See also: prompt global strike.

First strike from kinetic bombardment can be far more devastating than first strike from ICBMs due to the surprise factor and simplicity of yield configuration.

Moon-based mass drivers can be trivially protected from Earth-launched counter attacks, since the inbound trajectories can be calculated, the projectiles take days to arrive, and can be intercepted by point defense systems that have lower delta-v requirements. Basic OODA loop supremacy stuff.

None of that is relevant to MAD. Boomers still provide a survivable second strike deterrent. Even if an adversary can defend their lunar weapons, it won't matter because their earthly cities will be smoking craters.

I agree with your point in the near term, but beyond that I disagree with you about the effectiveness of submarines for maintaining the second strike deterrent for two reasons.

First, there is some threshold amount of off-Earth allied population that will undermine and make irrelevant the SLBM deterrent. In the extreme case, consider a Martian opponent.

Second, there is a gamble that a first strike against military targets won’t provoke a return strike against the civilian population. In this case, a restrained first strike that takes out key submarine docks could degrade the advantage provided by Boomers. A limited attack on that kind of infrastructure is hard to pull off, but an asteroid strike might be one of the few ways that it could be done with sufficient plausible deniability.

Gravity-based kinetic weapons will force a rethinking of nuclear MAD — the history of war consistently shows that expensive hardened fixed positions are eventually made into vulnerable death traps through cheap technology.

Once we build the necessary infrastructure to detect a rocks-from-space attack, we might finally have the means to prevent natural asteroid impacts. We have far too few eyes looking for small, dark objects on a collision course with us.

To be honest, the asteroids that could smite us in an "end of dinosaurs" event are very rare. Most of them have been cleared out of their orbits by either Earth or other planets billions of years ago.

It is still worthwhile to watch the sky for them, but the risk per year seems to be lower than any man-made disaster I can think of.

Hm. When thinking about how pock marked earth is, I'm not so certain. Also space is dynamic. As I understand it, we only have a vague understanding of what happens in the https://en.wikipedia.org/wiki/Kuiper_belt , https://en.wikipedia.org/wiki/Hills_cloud & https://en.wikipedia.org/wiki/Oort_cloud and how the trajectories of objects therrin could be perturbed by https://en.wikipedia.org/wiki/Rogue_planet s and the movements of our nearest solar neighbours which probably have similar 'clouds' of objects around them.

And it wouldn't need to be as big as Dino-Ex, either.

Imagine what would happen if something like this impacted or air-bursted with the population density and fragile logistic dependencies of today:

https://phys.org/news/2008-03-cuneiform-clay-tablet.html

Also in that region, just a few thousand years earlier:

https://www.nature.com/articles/s41598-020-60867-w

Suspected as a possible cause for the onset of the Younger Dryas

https://en.wikipedia.org/wiki/Younger_Dryas_impact_hypothesi...

edit: https://en.wikipedia.org/wiki/List_of_possible_impact_struct...

Sort for age, look at diameter of crater in kilometers for the first dozen youngest and think about what that would do for any contemporary agglomeration.

I'm also concerned about asteroids that are not big enough to wipe out the dinosaurs, but big enough to kill a few million people. Those are a lot harder to detect.

>The coming year should see at least 18 NASA-sponsored lunar missions, some of which will deliver equipment and supplies for later use. Gateway itself is scheduled for 2024.

Correct me if I am wrong, but I don't think we saw any moon missions from NASA in 2021? Either way, it is exciting to think human stuff is going to the moon this year in a big way.

"While countries wasted time to profit from each other, China is about to land on the moon, they are now jealous and want to plan how to try to eventually catch up, maybe if they can stop sniffing profits"

There the correct title!

Lol canada with what appears to be an arm again.

No one has figured out safeguards against solar radiation. NASA does not permit any astronauts to live on the International Space Station for more than a year and the ISS is shielded by Earth’s Van Allen Belts which our moon does not have. Whoever lives on the moon will be exposed to elevated levels of radiation and develop irreversible cancer or radiation poisoning as a result until the fundamental problem is solved.

To be specific: the exposure during a day of lunar living would be equivalent to ~2.6 days on the ISS, or ~200 days on Earth's surface[1]. And that's the normal dose, before we even begin to worry about solar events.

[1]: https://www.science.org/doi/10.1126/sciadv.aaz1334

> To be specific: the exposure during a day of lunar living would be equivalent to ~2.6 days on the ISS, or ~200 days on Earth's surface

If we do nothing to shield occupants.

Yep, shielding will be critical. The paper linked above has this interesting note:

> Settlements on the Moon will provide additional shielding because they will be buried beneath layers of lunar regolith. While this would decrease the dose rate from charged particles, the absolute contribution from neutrons is expected to increase for shielding constructed from in situ resources, as borne out by measurements with the Apollo 17 Lunar Neutron Probe Experiment. These showed that the flux of thermal and epithermal neutrons increases significantly up to a depth of approximately 150 g/cm2 (31).

So plans to shield lunar occupants using the moon's own materials will need to compensate for the ionizing radiation that those materials are already emitting, separately from cosmic/solar radiation.

> So plans to shield lunar occupants using the moon's own materials will need to compensate for the ionizing radiation that those materials are already emitting, separately from cosmic/solar radiation.

It's not really that they're emitting them "separately" -- they're radioactive (with mostly short half lives) largely because of solar bombardment. Thin shielding can paradoxically make things worse by converting high energy protons into more, lower energy neutrons.

If your shielding is thick, the inner layers will rapidly become less radioactive (the important half lives are less than 30 days). The outer layers will keep getting hit by solar protons and creating more unstable elements.

Another major concern in the long term: radon gas. One had better have an inner hull and never rely upon sintered regolith to hold atmosphere.

>~200 days on Earth's surface

Where? there is a big difference between Miami, Colorado, Guarapari, and finally Ramsar

Here's the calculation based on the NRCP's 2009 estimates for the US[1]: the average US inhabitant is exposed to 3.11 mSv/year, or 3110 uSv/year. That's an average of 8.52 uSv/day, compared to 1369 uSv/day on the Lunar surface.

For the US, that's a factor of ~155x, not the ~200x that I saw in popular media, so I'm not sure where they got the latter from. But "over 150 times the daily exposure of the average American" isn't fantastic.

Edit: https://en.wikipedia.org/wiki/Background_radiation#Backgroun... has other numbers for "background only" exposure in various parts of the world. The US seems to be among the higher areas for latent exposure, so it's probably safe to say that the 155x number is on the lower side of things.

[1]: https://www.cdc.gov/nceh/radiation/cosmic.html

so we are talking ~5x Ramsar https://pubmed.ncbi.nlm.nih.gov/11769138/ where people live normal lives

n=35 for that particular study[1], which notes that results are preliminary and doesn't include any prescriptive language like "normal lives."

The theory they advance is the people of Ramsar are demonstrating an adaptive response to large amounts of background radiation. But there's no evidence (or even theorization) that said adaptive response extends to fully mature adults.

[1]: https://sci-hub.se/10.1097/00004032-200201000-00011

The ISS doesn't have a moon to bury itself inside.

You only have to go 2.5 meters down to provide the same level of protection as being on the surface of the earth.

Sounds good… do we still get to have skylights?

edit: I’m genuinely curious if it’s possible to allow sunlight while blocking harmful radiation, our atmosphere does it, can a thick window do the job?

If you want to live above ground and have other niceties then there's a great planet that's really close to the moon.

Yes, but if all humans are on that one, then if there's a catastrophic problem there: Houston, we have a problem.

Not one that’s likely to be solved by spreading to the moon. Personally I have much the same attitude about the eradication of the human race as I do about dying: it’s going to happen eventually, best to make out time here as good as possible rather than trying to extend it indefinitely at all costs. And giving up the earth seems like a huge cost to me.

Water blocks radiation, too. Keep the water supply in clear tanks above the base in spots.

You can put in a skylight if you really want to, but a lunar day is 708 hours long.

Simulated skylights are probably possible, but you may have to go a bit deeper to create the space for an effective simulation.

Mirrors, or even artificial sky lights are a thing.

Probably by delivering sunlight through a fiber.

Lunar lava tubes.

https://en.wikipedia.org/wiki/Lunar_lava_tube#Sites_for_huma...

I envision that and them some sort of inflatable shell insterted into it to make a quick habitat... maybe some sort of hardener is activated upon inflation or filled in between outer layers...

Yeah, lunar real estate will be one of the first things - Location. Location. Location.

That’s why you build in a lava tube, a permanently shadowed crater (bonus: ice!), or cover the base in regolith.

3d printed buildings. I'm not even kidding. I've been soft-offered a job to write software for this that might get deployed to space. I am seriously thinking about taking the job and using it to get into the astronaut program. It would be pretty badass to be the first person to build a permanent structure off the planet

DO IT! That sounds so cool!

Also is it possible to maintain muscle mass in space for over a year? What happens when you lose the bone density. Or could this been circumvented with a couple of hours of squats every day and other exercises using bands as resistance

Muscle loss isn't too bad. The real killer is bone loss. You lose 1% of your bone mass per month in space. NASA still hasn't figured out how to fix it. Valeri Polyakov spent 437 days on Mir in 1995. Nobody has come close to that record since then, and nobody will until the problem is fixed.

And no one knows how much gravity you need to fix this. That's one reason a moon base would be beneficial.

Does 16% gravity let you do exercises that let you keep most bone density? Is it pretty much the same as microgravity? Or is it somewhere between-- just slightly less bad than orbit.

I have some hope that 16% + an aggressive exercise program could be OK.

As someone currently learning how to lift weights, I would love to be the guinea pig of a lunar exercise program.

At 16% gravity I should be able to deadlift over 1500 lbs and bench 1000 lbs!

I bet having 6 times as much inertia for the weight makes things strange.

In all seriousness, it's going to be mostly resistance exercises. But we can probably do better resistance exercises with gravity to help posture and alignment.

The Moon at least has 0.16g, which is a lot better than 0g.

The powerlifter in me hopes mooners will just be deadlifting 1000+ kilos for reps to stay in ship.

Interesting - I wonder if it would feel different, with conservation of momentum being a bigger portion of the effort than gravity vs. on Earth.

What I mean is it would be something between lifting 100kg and pushing a car in neutral and stopping it.

I suppose the force curve might resemble that of reverse band lift?

Wonder if it's a matter of slapping on some bands to make it feel "earthy" or need mechanism like vacuum tubes they use in the ISS gym (Advanced Resistive Exercise Device). From what I read, it simulates the 1G lifting pretty close.

Spin the spacecraft. Done.

It works in principle, but it's a very big engineering task, and an enormous expense to boot. To avoid noticeably different acceleration between head and foot,* it's going to have to be substantially larger than any spacecraft we've ever built, and the biggest spacecraft we've ever built cost over $100bn. It's also going to have to withstand stresses larger than anything we've done before.

There's no reason to doubt we could do it, but it's a very big step from where we are now.

* And if we don't do that, then we stray into the realm of untested biological issues. We have no idea if people can live safely and comfortably like that.

Spinning a spacecraff is mostly hard because of the mass constraints, building a banked circular track on the moon should be much easier.

It is literally two things connected by a rope. A tether-based spun spacecraft is trivial from an engineering perspective, and can have as large a radius as you need to avoid differential “gravity” effects.

Off the top of my head:

- What material are you making the rope out of? What data do we have of that material's behaviour under tension in a vacuum?

- How is the craft connected to the rope? Is it a fixed bond or is there freedom to move? What are the tradeoffs?

- What happens when one of the two ends is accelerated? How do you reestablish a stable rotation?

- How do you manoeuvre it? Can you?

- What happens in the event of a catastrophic failure of the rope? What safeguards need to be in place?

And this is all on top of the fact that we're discussing two things connected by a rope under conditions that rope has never been tested in, doing something that's never been done. Space exploration isn't in the habit of trusting that our untested models are reliable, especially where human life is involved.

It is unknown if it will be that easy. For obvious reasons, there have been no long-term studies in partial gravity. If 0.05g stops bone loss, great. If a full 1.0g and nothing less is required, then that's going to be a really onerous design constraint.

I wonder if this unknown may, in the end, turn out to be a great reason to motivate space exploration. A full G is the norm on Earth. Micro-G in orbital stations have known long-term negative effects on health. What if fractional-G actually has beneficial effects, like say, increasing average human lifespan a lot. The human circulatory system tends to fail early, causing a disproportional amount of deaths due to strokes or heart failure. It's far-fetched speculation on my part, but is not hard to imagine operating in a fractional-G environment could decrease wear and tear here, acting as a sort of medical treatment. In the end, people would have a great motivation for leaving Earth. Just dodging death, the ultimate enemy of all living things.

If a full 1.0g is required, that also makes it a much more difficult challenge on the moon. Spinning a module of a space station in zero g is one thing... trying to get a portion of a moon lab at 0.16g to 1.0g is a different challenge.

The advantage I see on the moon is that you have local mass to use. Yoy can build a large, banked circular track underground ground and then add cars as you expand.

Uh, if human habitation on the Moon requires living inside a centrifuge, then there won't be a human colony.

It depends on how much gravity is needed for how much time to stave off the long term effects of zero gravity. If we're lucky, then just sleeping at a higher G may be enough and you just need the bunks built in a centrifugal train.

I’m always leery of solutions to complex problems that take the tone of “all you’ve got to do is…”

“There is a solution to every problem: simple, quick, and wrong.”

Lava tubes could help a lot.

What’s the environmental cost of a space launch?

This is pretty easily google-able stuff. Here's the Mars 2020 mission environmental impact report, for example.

https://www.nasa.gov/sites/default/files/files/Mars2020_Sect...

Low enough.

Earth is ultimately just another time-limited spaceship that will eventually loose the ability to support any kind of life due to the natural lifecycle of our sun. Over a long enough time span not expanding off-world is a death sentence for all life on this planet.

It's acceptable to do some small amount of damage to it as part of securing a future for our species (and all the other species we will carry with us) that is not dependant on a single, vulnerable and time-limited ball of rock.

A moon base is a step towards that.

These business space missions are using 60 year old propulsion technology and it's pretty easy to figure out the math that shows that a fuel tank the size of the planet cannot take you to any other habitable planet. Scientists -know- that the best way to learn about space and the universe at this point is to build huge telescopes. For profit companies will not save us.

No amount of telescopes will provide the off-world low-g manufacturing capabilities necessary to build the logistics we need.

The moon is both low-g and has wonderful built-in radiation shielding (one of our biggest current blockers) via the simple process of going underground.

I don't think you or I are qualified to make absolute statements about the involvement of for-profit companies in that.

You have not explained your plan on getting off of this planet but you're talking to me about logistics on the moon? No we don't need logistics on the moon. We don't need Elon musks dumb vanity missions to mars. No, we as a society do not need to continue pouring our scarce resources so that scifi-cultists and some rich white assholes can pretend like they can get out of here alive.

A rat done bit my sister Nell. (with Whitey on the moon) Her face and arms began to swell. (and Whitey's on the moon) I can't pay no doctor bill. (but Whitey's on the moon) Ten years from now I'll be payin' still. (while Whitey's on the moon)

A small factor more than aircraft in the short term. Zero in the medium term when launch companies vertically integrate propellant production based on renewables. A net positive once we start relying on non-terrestrial resources instead of poising our planet to extract metals and power.

Ignoring the positive externalities, there is still some environment cost when using synthetic CH4. You're still taking water from the ground and moving it into the upper atmosphere (CO2 + ground H2O -> CH4 + O2 -> CO2 + atmospheric H2O) - which contributes to the greenhouse effect.

It's not worth worrying about, given all the other more impactful ways we can move the needle on global warming, but it's not actually zero.

That's kinda like asking the environmental cost of driving 100 miles. Are you thinking of a big, dirty solid-fueled rocket, or an oxidizer-rich CH4/O2 rocket, or what?

Thinking of the number of rockets required to facilitate a “moon rush”.

"Moon rush" is far more a media hype phrase than an actual number of rockets launched, or tons of cargo landed, or lunar census.

And I'd bet that all the earth-bound activity involved in a "moon rush" - even one that actually resulted in a more-than-one-digit lunar census, long-term - would have a vastly larger environmental footprint than the rocket launches themselves.

Net negative.

Gets us on the path to more worlds.

I mean, wouldn’t the same argument imply that it’s more net-negative to spend the same amount reducing carbon on earth directly?

I’m all for space exploration but found these types of arguments specious

Can you explain more please? I don’t see the logic.

If human beings can expand to other worlds, or live in space easily, or even just access enough resources to stabilize at 10B human beings with zero poverty - then we can turn the Earth into an Eden - so conceptually nothing could be more environmentally beneficial. At least that’s how the optimistic vision goes.

We already have enough resources to support 10 - 11B with zero poverty we just need to improve economics and politics to do so.

Arguably, colonizing Mars is easier than uprooting ancient prejudices and dismantling a thick set of special interests that is the politics (worldwide, not just the U.S.)

Yeah sounds very optimistic.

The nearest star is incomprehensibly far away. It would take tens of thousands of years at least to get there assuming that was even possible.

I don’t see anything positive about living in space or on Mars. What would be so great about living on such a hostile world?

Space and the surface of Mars are hostile currently and will be early on, but that will gradually improve along with infrastructure. Mars will be easier to improve quality of life on, but space stations or other spacecraft could be made quite nice as well with access to resources like those in the asteroid belt.

If nobody gets through those early rough stages, it can never get better. So from that perspective, the sooner that ball gets rolling the better.

Mars offers no protection and not exactly rich on resources. I think, Venus sky cities[1] have bigger potential. There is a drove of resources plus free energy from Sun.

[1] https://bigthink.com/hard-science/how-to-colonize-venus/

I think Venus will eventually be very interesting, but the lack of access to its surface means that all mineable materials will need to be imported, which is a big problem.

For getting started on long term self sufficiency in space (which should be a goal, if we’re taking crewed spacefaring seriously) we can’t really do much better than Mars. Once there’s more infrastructure in place for in-space manufacturing other destinations become a lot more practical.

Reply on news.ycombinator.com