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Comment by NeoTar | Hacker News Reader

Another point for anyone considering whether we should send a space-probe there...

The current fastest man-man object is the Helios 2 space-probe, reaching something like 25 000 kilometres per hour. Proxima Centauri is 1.3020 parsecs away from Earth.

So, just diving one by the other, we'd looking at something like 18 000 years as a rough order of magnitude for sending something from Earth to Proxima Centauri.

You'd be much better off waiting, well, even a thousand years for technology to improve rather than sending something now.

Note: this is a very dodgy line of reasoning. The Helios probe got a massive speed boost from a close encounter with the sun. But even if the speed is wrong by a factor of ten, we're still looking at somewhere between a thousand and a hundred-thousand years.

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A probe based on nuclear pulse propulsion could do it in around 50 years, with today's technology. It's not that we can't do it fast (within one average human lifespan), it's that the project would be very expensive and something like Nasa has a relatively tight budget.

I mean we, as humanity, have to have an eccentric billionaire start a Martian fire (SpaceX Starship) under our lazy asses to even start to think about getting to Mars in a reasonable timeframe and in reasonable numbers (to start a colony). We are not funding making our species multiplanetary for the last few decades because we were too lazy, how can anyone expect us sending anything to the closest star (other than the sun)... You can't.

Maybe an unpopular opinion, but Musk is just plain wrong when he thinks there is any urgency to Mars exploration (or it's just vicarious arguments because rockets are cool).

Basically, the tech you need to make a Mars colony truly self sufficient is something like a compact fusion powerplant.

Before we have that, no point in worrying about using Mars as a "backup plan", because if Earth was screwed, Mars would have a couple of years to live at most.

And obviously it would be vastly better for humanity if Musk spent money on zero-emission large scale energy production, than on rockets.

He should really thing about making a company to do solar, and maybe an Electric Car company that outsells every other USA EV company 10:1

This is hopeful negativism.

- They don't need fusion. A StarShip can deposit hundreds of solar panels and put them on the ground. No, dust isn't an issue because they'll bring a roomba. No, this isn't a joke, NASA martian probes' solar panels were cleaned by a light Martian breeze.

- They will be able to become self-sufficient rapidly. They're not going to send 1M tons of cargo to Mars without a deployment plan. SpaceX and Tesla have already demonstrated effective vertically integrated supply chains and manufacturing. They have the institutional knowledge to mine raw materials and build factories that build complex parts.

- There are plenty of other Earth-bound governments and billionaires that could devote funds to zero-emission large scale energy production projects. Musk, his companies and assets amount to a very small fraction of the global economy. Your ire is misdirected: your anger about the situation is properly directed at the rule of corrupt imbeciles and their questionable resource allocation decisions (Netflix, coal, etc.) here on Earth rather than one team of folks who seem extraordinarily mission driven and effective.

Mars has dust storms which last months or years, it has no ionosphere, and that dust contains enough perchlorates to poison anything we could eat, including us. Ok, that sentence went somewhere odd at the end but, it's true.

A large asteroid has only one of these problems, by virtue of not coming with any atmosphere, ionic or otherwise.

I kinda hope Elon is bluffing and actually plans to head to the Belt. I've penciled it out and and he'd have to be insane not to. Surely he has pencils as well.

What's the story on navigating in the belt? Approach specific target from above or reasonably safe to traverse it and explore?

Isn't long term zero-g pretty hostile to our biology?

Hollow out the asteroid and spin it.

That tech is decades in the future.

Is it? Assuming an asteroid of appropriate structural strength, it's just a question of time + propulsion. And acceleration adds up pretty quickly when you're in a vacuum and have all the time you want.

This wouldn’t work, asteroids are like gravel there isn’t really anything to hollow out and even if you did when you spun it the asteroid would just shoot these rocks out in all directions.

Mars is 0.3 G, which is just as hostile for long-term habitation. No human child conceived, born, and raised in that environment would have the ability to stand on Earth without an Aliens-style rigid exosuit. Their heart might not even be capable of pumping blood to their head.

Nobody knows what 0.3 g does to the body because we've spent 20 years on the ISS doing zero-g "science" even after the most important question was answered:

Q: What does zero-g do to the human body?

A: It's really really unhealthy.

The Martian dust storms are pretty tame. Nothing like portrayed in the movies. The atmosphere is 1% of what it is here on earth.

So while it is a “storm” it isn’t like a tropical force hurricane or anything. More like a very minor annoyance that deposits a bit more Martian dust on your stuff over time.

>They're not going to send 1M tons of cargo to Mars without a deployment plan.

Can this happen? I imagine before we can settle on Mars we first should be comfortable flying there, and the latter should be sufficient for asteroid mining. But, right, our technology is just not at a comfortable level yet.

Comfortable comes much later than possible. When it's possible to go, that's the time to go. The early Atlantic crossings weren't comfortable, just possible.

Unlike Atlantic, Mars isn't habitable, you can't settle there with merely possible crossing. Maybe first establish a colony at 1km depth in the ocean; we are relatively comfortable going there, but what it takes to run a colony there and would it be possible with only possible crossing?

There is an inherent urgency in all of his plans, mainly because he wants to see it done within his lifetime. He's got 40 years left tops, but more like 20 during which he could still theoretically do anything significant in. Rockets take decades to develop.

The urgency is because you can fool enough people only so long before they catch on and recognize what they are being sold.

> Musk is just plain wrong when he thinks there is any urgency to Mars exploration (or it's just vicarious arguments because rockets are cool).

Mars might not be sustainable in our lifetime but in a century or two? I think it's within the realm of possibility.

As for the urgency, the last two years has demonstrated the exact opposite to me. Modern civilization is a hop, skip, and a jump away from instability and disaster. When you say that we should instead spend resources on large zero-emissions energy production, well, we've had Nuclear Fission for half a century. The reason we didn't use it to prevent Climate Change is 90% political, not technical, another problem that having a self-sustaining colony, outside the sphere of Earth's influence, would solve.

> The reason we didn't use [Nuclear Fission] to prevent Climate Change is 90% political, not technical

Eh. The physics and proliferation risk are pretty intertwined.

Who's to say we would have been better off with greater historical nuclear weapon proliferation risk but lower climate risk?

We know the path we chose, limited global use of fission power, mostly avoided nuclear weapons proliferation, and did avoid nuclear exchanges. So it's provably a successful (or probably successful) path. Whether an alternative would have gotten the same outcome?

>We know the path we chose, limited global use of fission power, mostly avoided nuclear weapons proliferation, and did avoid nuclear exchanges. So it's provably a successful (or probably successful) path.

Only if you value the lack of nuclear exchanges over the impacts of climate change. Which one of the two is more likely to cause a mass extinction type issue on the planet, one puts the control in the hands of people and the other the forces of nature.

I'd say I do. Climate change is colossal in problem magnitude, but temporally slow and distributed in impact. Nuclear weapons are terrifying fast and centralized in impact.

Unfortunately, our civilization is also mostly centralized. Cities, ports, highly productive land : total land area.

If you're talking persistent radioactive effects for a decade+, it doesn't take many to severely cripple the world.

As an example, a 100kt weapon (or smaller dirty) could knock a port out of action. Now look at a list of ports [0] and imagine what would happen if one or more of them dropped off the global trade grid for multiple years.

[0] https://en.m.wikipedia.org/wiki/List_of_busiest_container_po...

How would the increase in the number of nuclear power plants lead to more nuclear weapons? There is no direct connection besides edge cases like Iran using it as a cover to develop nuclear weapons.

Someone please correct me if I'm speaking inaccurately, but early reactor design (1950s/60s/70s) focused on light water reactors, which meant enriched U-235 fuel (@ ~3%?). By design, these reactors also convert a portion of their U-238 to P-239, only some of which is then consumed in the reactor.

Consequently, for widespread nuclear reactors (read: in many countries), you also had widespread proliferation of lightly enriched uranium (in the fuel) and proliferation of plutonium (produced in the fuel as the reactor runs).

Both of these remove the most time and energy consuming step (low level enrichment) as an obstacle to state nuclear weapons development.

And they're fundamental to the way light water reactor technology works, especially with the limitations of the period. So the only way you could have had proliferation-resistance would have been to have some sort of global fuel-control and -custody agreement (presumably run by the United States, USSR, and maybe France, depending on the time period). Which sovereign countries would have likely felt some kind of way about.

The number of new nuclear reactors only stopped growing in the 80's. In any case I don't think access to material is the limiting factor in nuclear proliferation. If we're talking about the US and USSR, it's completely irrelevant, even if they had 100x more reactors since they already have more than enough bombs to more or less to blow up the entire world. Other western countries either have enough nukes already or don't need or want them and I don't see why would they export technology or material to countries which are hostile to them.

It's not obvious to me that having more nuclear reactors in the US, Britain or Germany would had made it significantly easier for rogue states like Iraq, Iran or North Korea to developed nuclear weapons.

So you're talking about having more nuclear power, but only in First World economies?

That seems... ethically dubious.

Why is it anymore ethically dubious than having more solar or wind power in first world countries? But no, I'm not necessarily saying that. I just disagree with the claim that if nuclear power continued growing at the same rate as it did prior to 1979 that would somehow have lead to higher proliferation of nuclear weapons.

It's ethically dubious because solar or wind power wasn't an option in the 50s-70s. So you're effectively gating the majority of the world off from nuclear power, enjoyed by developed economies. Which would have developed economies of scale (see: France) with the end result of developed countries having access to cheaper power than developing ones.

And I'm confused. Your reasoning around why more reactors wouldn't have increased nuclear weapon proliferation was contingent on only the US, USSR, Britain, and Germany (and presumably countries like them, to an approximation) having more reactors.

Either you get to say that (a) all countries, or (b) only "responsible" (for lack of a better word) countries should have used more nuclear power.

If (a), then you have increased proliferation risk. If (b), then you're establishing (and presumably militarily enforcing) a two-tier ability to access cheap energy, that favors developed nations.

There are relatively few countries which wanted to develop nuclear weapons over the past ~60 years and were unsuccessful in doing so. I see nothing wrong with banning the export of technology and equipment needed to develop them to those countries (AFAIK: Iran, Iraq & Libya). In fact that is already the case and Israel and US already used/are using military or clandestine means to prevent those countries from developing them. So basically I find it hard to imagine that the situation would be significantly different than it is now.

But lets I assume you're right and 'a' is somehow correct (I don't agree with the premise that increase in global nuclear power generation capacity would somehow automatically result in a higher risk of nuclear weapons actually being used) that would still mean that the western world, Russia, China, India, Pakistan and all other countries in their sphere of influence or aligned to them would have access to cheaper power (which is at least 80-90% of the global population). And I don't consider 'because Iran does not have access to nuclear power then it would be unfair for anyone else to have' to be very good argument.

In fact even if only developed countries had access to nuclear power (which is obviously not fair and not realistic anyway, good luck preventing Russia and China export their reactor to whoever they want) I still think that would be preferably to nobody having it.

Even if we completely screw up liveability on earth, it's probably still going to be way more hospitable then most planets we can reach.

In addition to the fact that there's almost nothing you could do to Earth that would make it less liveable than Mars, any political problem that plagues the Earth is going to plague Mars just as easily. Earth didn't create human political problems, humans did. The only way to keep political problems from plaguing Mars would be to keep humans off of it.

> As for the urgency, the last two years has demonstrated the exact opposite to me. Modern civilization is a hop, skip, and a jump away from instability and disaster.

I mean, you would somehow have to make Earth less hospitable than Mars to make the effort worth it.

>And obviously it would be vastly better for humanity if Musk spent money on zero-emission large scale energy production, than on rockets.

Classic zero sum thinking. Spacex doesn't cost money, it makes it. How much money do you think Musk put into it? The answer is ~100 million seed. It is now worth 35,000 million.

How far do you think that 100m would go to develop fusion. The ITER project alone costs 65,000 million.

While US gov't put in $billions. But who kept ownership? Mars hype turns out to be good for drawing money out of governments.

ITER is a dead end, no matter what, so not a useful data point.

>While US gov't put in $billions.

There is a difference between buying something and putting in money. If I buy a cheeseburger, I can't say I "put in" $5 to McDonalds and should have some ownership. If I pay my contract plumber to fix my toilet, I don't own their business either.

I think you will be hard-pressed to find any substantial examples where the US gov wasn't buying something from SpaceX.

McDonald's won't go bankrupt if you elect not to get the large fries. SpaceX would have gone bankrupt several times if NASA hadn't kicked in at a crucial moment.

So they deserve equity for being a critical customer? I still don't follow the logic.

You won't.

The Mars backup plan seems kinda dumb to me because Mars is worse as is than all but the very worst post-apocalyptic Earth scenarios.

Just build bunkers here and staff them in shifts. Much cheaper.

Your remaining threats for which Mars would be better than "ruined" Earth are something like a grey goo event, or an asteroid so large that it liquefies much of the crust (killing everyone in all your bunkers). So, a fair bit bigger than the one that killed the Dinosaurs.

I am very interested in watching people try to colonize Mars, but find the "backup for Earth" argument ridiculous, especially if presented as something urgent.

One conceivable reason to colonize Mars is real estate.

Perhaps in the near future life extension technology will become common place, people may continue to have kids, but natural deaths may be rare; the human population will increase exponentially and need somewhere to live and something to do -- terraforming Mars in exchange for property may be reasonable.

I don't think that a compact fusion powerplant specifically is needed. But I do agree that a truly self-sufficient Martian colony (I.E. able to exist for more than a few years without ships coming from Earth) would need a gargantuan level of infrastructure to have even a small chance of being viable.

From a standpoint of reducing emissions on Earth, it would be cool to see Elon Musk's best take on how to build a practical fusion generator though. I've heard of a few potential paths that could lead to net power much faster and cheaper than ITER. Supposedly superconducting magnets have gotten considerably better since ITER was proposed, and since power output in a tokamak reactor is something like the third or fourth power of the magnet strength IIRC, there's potential for a newer and smaller reactor design to outdo it in both timeline and cost.

It is not possible to conceive of a path that would not lead to net power before ITER. ITER has no intention of generating so much as a milliwatt, ever.

The only humans who will be utilizing space in earnest are the Martians. Terrans will be confined to their local space with overwatch on the Moon.

> ... overwatch on the Moon.

I'm pretty sure not even that.

Going to Mars seems pretty useless to me at this time. It’s a super hostile environment and we don’t have the technology yet to have a self sustaining base there. Give it a few decades and progress in robotics will make a Mars base much easier. There is plenty of work to be done on Earth. We have to solve clean energy production and in general reduce pollution. These are massive technological challenges that deserve massive funding.

Tbf, it'll also take us a few decades to get human Mars transit figured out so sounds like we're on schedule.

It sounds like a very chicken or egg problem to me, who's to say that progress in robotics doesn't come from trying to establish a base on Mars? Progress is often times non-linear, I mean here we using computers and communication technology based on Integrated Circuits technology furthered by the Apollo program; say we never went to the moon, computing technology and Moore's law might have been set back a decade or two.

I am not against Mars but I just think it’s premature. Build up robotics for a while and Mars will be much easier. There is no rush to become a multi planetary species. There is no credible threat of a big asteroid or volcano in the next decades. All threats we may be facing are self made.

My favorite moonshot project would be to create robotics that can clean up the environment and handle recycling. Having the technology to pick up dog poop and plastic bags in an efficient and affordable manner or separating recycling items would be a huge technological challenge that would create a ton of spin-off opportunities including a base on Mars. Or clean up the pacific garbage patch with robots.

I think all of this is premature. Focusing on life extension technology and life science would see a lot of other technological benefit, and in the worst case just mean we can wait it out.

Totally agree!

However, it's likely that one task (going to Mars, even sending a couple rich bozos there) is small enough that you can probably do that and work on fixing things "at home".

In fact, one could argue that one set of big companies that exist this decade that didn't exist last decade is just a shopping list of "Crap I'll need for my martian condo"

Did you know NASA only get 0.36% of the US Federal budget? Everything else gets "massive funding".

Makes sense though because earth is a dump and extremely corrupt. Even if you were able to substantially decrease military funding (the usual scapegoat) without massively changing the world order we still probably wouldn’t spend more on nasa, we would spend it on healthcare, infrastructure, economic bailouts, education, green tech, etc.

Do you expect traveling multiple light years to an alien world to be easier or less hostile? You have to start somewhere, and the selection is pretty thin.

Traveling multiple light years is out of the question. You can think about some concepts but it’s simple not doable at this point no matter the budget.

Going to {the Middle East, Europe / Asia, Australia, the New World, interior South America, the North American West) seems pretty useless to me at this time. It’s a super hostile environment and we don’t have the technology yet to have a self sustaining base there. Give it a few decades and progress in {insert technology} will make a base much easier. There is plenty of work to be done on {current place}. We have to solve {current problems}. These are massive technological challenges that deserve massive funding.

... has been said for the entirety of human history. And in all that time, they've only ever been right about Australia. (J/k Aussies!)

Only one technology matters: that which enables transportation.

Animal husbandry. Sailing. Railroads.

In the end, humans are plentiful. As long as it's done in full disclosure and as an uncoerced individual choice, who the hell are we to stand in the way of adventurers taking a chance on a better life?

Mars is multiple orders of magnitude more difficult to survive on than the Middle East. Its not really comparable at all.

I like to think we've improved our technology a few orders of magnitude in the last 1.8 million years.

And so you think you can just mush those two claims together and come to the conclusion that sustaining life on mars must be achievable?

Not must be. Is probably achievable, and is worth attempting, even at the cost of lives.

You can argue from either the perspective of futility of attempt (no chance of success) or futility of outcome (success wouldn't be worth it), but I'm pretty convinced both would be weak arguments, both logically and historically.

I'm probably an optimist on Mars travel. I think, with a fuck ton of starships, you could get people living on Mars. But there's some big asterisks on that. You'd more or less have to live in the starships, dependent on shipments from earth, with self sufficiency failing on pretty much every category. Over a very long period, most people would probably die a bit earlier from radiation and dust. Not much would be produced of value. It would cost hundreds of billions of dollars, at least. And interest in it would rapidly decline.

The suspicion I have about self sufficiency pessimism is that it's an apples to oranges comparison. Are there any modern analogies? As near as I can tell, it hasn't been required after the 16th century, due to access to relatively timely transportation.

And if it hasn't been required, then how are we to look at existing practice and say we're bad at or incapable of it?

Comparison to what? We don't need an analogy. This is a novel environment and it can be evaluated on its own.

Self sufficiency failing on Mars vs what kind of self sufficiency we can manage now (while living on Earth and no needing to prioritize it)

Sounds like the early days of Australia. Maybe build a new Botany Bay? (Only half joking.)

There is no survival advantage to us on Mars. What are we all arguing about? This site is staring to feel a bit unhinged when it comes colonizing the solar system. Like SGC Ori unhinged.

This is absolutely, objectively, incorrect.

You might as well argue that you can build a self-sustaining base on Antarctica.

Of course you can't, because Antarctica can't support life. No amount of shouting into a bullhorn about adventure will change that.

It might be possible with an absolutely epic effort to airlift soil, nuclear reactors, nuclear and other fuels, machinery for every eventually (including chip fabs), raw materials that aren't locally available (which means almost all of them), and habitable structures.

At the end of that epic effort you'll have something that will barely have a toe-hold on long-term survivability. Possibly. If you're lucky.

Not only is Mars far colder, it also doesn't have air. Or surface water. So all the challenges are at least an order of magnitude harder.

And it's much much further away.

Rhetoric and wishful thinking are not going to give you a better life if you can't deal with the reality of the challenges.

If we really wanted to, i don't see why we couldn't establish a self-sustaining base in Antarctica. Of course, it's forbidden.

Then create one in the Sahara or the Atacana desert at 5000m elevation. Still way easier than Mars.

They are certainly easier, but how useful are they? A base on Mars will bring down the fuel requirements to exploring and exploiting the belt and outer planets tremendously. Missions that are impossible or uneconomical to do from Earth could be made possible and cheap if launched from Mars.

If you are concerned about a launchpad for other missions the moon is much better. Lower gravity, easy to reach.

How would you produce fuel and propellant on the Moon? SpaceX plans on producing methane and lox from water and CO2 on Mars.

You could produce oxygen and hydrogen from the water ice and the carbon dioxide cold traps on the Moon.

There may also be more carbon below the surface, see https://phys.org/news/2020-05-carbon-emissions-moon-theory-b...

Anything that seems easier from Mars is overwhelmingly easier without stopping at Mars first. Even Phobos would be a better choice.

The only thing Mars has going for it is hype.

You need some way to make fuel and propellant, though. Phobos would be a great choice for a launchpad, but in such a scenario you would do ISRU on Mars and lift fuel and propellant there - which will be much more efficient than on Earth, since there's less gravity and less atmosphere.

Any fuel you could generate on Mars would be overwhelmingly easier and cheaper to ship in from Earth; and you wouldn't need to land a million tons of freight on Mars first. A million tons of fuel delivered to LEO would take you quite a long way, and you could start immediately.

If you want to go somewhere beyond Mars, stopping there and then starting again just sets you back. (Same goes for the moon, or lunar orbit.) "Stepping stones" have strongly negative value in space transport.

A million tons of fuel doesn't cut the delta v requirements down. You'd have to ship the required fuel to Mars orbit (or wherever you plan on doing refuelling) still.

If you need to refuel, send the fuel where it would be useful to get home with, i.e. where you are really going. Dumping it at Mars does no good. You would then have to stop at Mars to collect it.

That's assuming you have enough fuel to reach those destinations from Earth, let alone make it from Earth to there with enough payload for a return voyage.

I see you are finding this very hard. Try to think it through:

If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars. Stopping at Mars costs extra.

If you will need extra fuel to get home with, sending it to Mars is completely useless, because where you need it to be is not at Mars, but at the place where you will be at the time when you need it. That place is not Mars.

Is this really so difficult? Stop, breathe, and think.

> If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars. Stopping at Mars costs extra.

This simply isn't true. From Mars to Jupiter is a little over 6 km/s of delta-v. From Earth to Jupiter is almost 9. The latter is just barely possible with SpaceX's Starship. The former allows for not only some breathing room, but more payload.

If you will need more delta-V than you have on-board tankage for, sending another ship at the same time and acceleration, and refueling from it on the way, is overwhelmingly better than launching literally dozens of ships to get even more fuel parked at Mars, and then spending extra fuel stopping there to pick it up, and more again to get moving again.

If your true goal is to have crap on and in orbit around Mars, do that without pretending it has any other value. You don't fool anybody, but you make people wonder about you.

Or, hear me out, you get the available infrastructure set up on the surface of Mars to manufacture fuel and propellant, and then you can send a single ship from Mars to Jupiter. And, if you can bring payload, you can set up the infrastructure to do ISRU from one of the moons of Jupiter, and eventually bring your ships back with samples.

Versus, cannibalising several extremely expensive ships in order to get one ship to a destination it's never coming back from.

And this is just one example. The lower delta-v from Mars would allow extra payload to the belt, so if anyone ever intend to exploit those resources, starting from Mars will allow them to get heavy equipment there in less time and fewer trips (provided, of course, that they can manufacture that equipment on Mars).

You start by shipping a million tons of freight to Mars, while I do meaningful stuff at places that are not a waste of time and effort. By the time you are ready to supply fuel FOB at Mars, I have sent a million tons to places worth sending it to, instead.

Maybe my million tons of freight includes a liquid methane sump on Titan, where I don't even need to synthesize, never mind liquify the stuff; it is sloshing around in puddles everywhere. There is an interior liquid water ocean, and ice lava flows.

Seriously, if you need more delta-V for a Jupiter or Saturn trip than spaceship design A gives you, you are much better off making a spaceship design B with enough tankage to make the trip. (Maybe B is just A with an extra tank strapped on; or, a tug boosts A to escape velocity and then loops around Luna and back, aerobraking to LEO.) Park fuel depots at both low and high Earth orbits; you waste nothing by using those, unlike anything parked foolishly at Luna or Mars.

Luna, anyway, has stuff that is worth visiting, like craters in permanent shade at the south pole, and lava tubes where vapors have maybe drifted in and froze for hundreds of millions of years. Mars is the armpit of the Solar System.

You seem pretty contentious here; I'm just making a case that Mars makes sense as a destination, not trying to convince you that this is something you need to pay for. IMO, the numbers work out for it being a hub for traffic to the belt and outer planets. Maybe you don't agree. That's fine. Again, I'm not asking you, personally, to start backing this. Just stop spouting off nonsense like 'if you can't get somewhere from Earth, you can't get there from Mars'. It's a matter of fact that delta v requirements from Mars are lower than they are from Earth, and this would have been obvious if you had thought just for a second about any of this.

> You start by shipping a million tons of freight to Mars

The equipment for generating the electricity to perform ISRU on Mars is supposedly within the payload capabilities of a single Starship, 100-150 tons, not a million, and this should be enough for a ton per day, enough to resupply in the 26 month launch window. The equipment for collecting water and CO2 is another matter, and I don't see estimates on that, but with the above and some engineering margin, it seems plausible that this operation can get off the ground in under ten ship-trips to Mars.

I have said nothing even vaguely like that, and cannot guess where you got it from. But it is a simple fact that:

Any trip to the outer Solar System that stops at Mars is, energetically, much more costly that one which does not stop at Mars.

In addition, getting stuff to Mars is itself a huge expense that completely swamps any imagined benefit of extracting fuel and launching it to stop by for.

If you want to go to Mars, go without promoting obvious falsehoods about any value it has as a transport hub. It has none. Period.

If, to make sense, your Mars story needs for Mars to be a useful transport hub, then it fails, and you need a different story.

This is what you said:

> If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars. Stopping at Mars costs extra.

This is as asinine as saying, if you can't get somewhere without a stop at the gas station, then you really, really can't get there with a stop at the gas station. Stopping at the gas station costs extra.

After all, it costs fuel to take an exit on the freeway and go to the gas station. It costs fuel to leave and go back on the freeway. It costs extra! Energetically, any trip where you have to make a detour to a gas station, costs more than a trip where you don't make a stop there.

I am going to leave this here for you to be, on your own schedule, gravely embarrassed at having written it.

> Any fuel you could generate on Mars would be overwhelmingly easier and cheaper to ship in from Earth

Source?

Mars offers quite a few things that make it more inviting for a manned base:

- 38% of Earth's gravity

- 24.5 hour days

- lots of resources such as iron, carbon, oxygen, water (ice)

- aerobraking in the atmosphere saves fuel

- it's big (same land mass as Earth's). There's enough room for growth.

- temperatures are better than elsewhere in space (-63°C to +20°C at the equator)

- Lava tubes that could offer protection against radiation and meteorites for habitats

- good potential of life / former life

Also exploring Mars itself and establishing a base there (anywhere off Earth really).

Linear Reasoning

At the end of the day, profit determines reality. And that's where futurists have always screwed up, because profit funds solutions.

Nobody has colonized Antarctica not because it's impossible, but because it's difficult enough and useless enough that we all agreed on a treaty prohibiting it.

In contrast, we constructed the 63 radars (some with bases) of the DEW line in the late 1950s in under 3 years, with part of the Air Force's budget. Because it was useful.

Establishing a Mars colony is not impossible, it's just extremely hard. Which means expensive. Which means it needs a justification. Which is what I think the knee-jerk is really about.

And is a fair opinion. You may think interplanetary colonization should not be a priority. I think it should.

Fantasies. None of us will be known or remembered. We will never colonize the universe in these bodies.

Seems to me we are nowhere near the level of maturity needed to even suggest colonization.

Our basic priorities are not in order and that is true for a lot of the world.

Tons of people need solutions now to problems we can solve, and we do not solve them because those priorities are not in order.

And with that, there goes that justification.

Higher priority items include:

Not shitting where we eat,

A much reduced focus on killing one another.

There are many others.

I agree with the other commenter.

It may be very frustrating and disappointing to get married to those ideas. No one reading here is going to see them.

> soil

Both aquaponics and aeroponics provide ways to grow plants without soil. Breeding insects or algae may provide nutrition with very small amounts of mass needing to be transported.

> nuclear reactors

Yes, these are a necessity but we've sent one to Antarctica before and we could send a more modern one to Mars.

> nuclear and other fuels

The good thing about nuclear fuel is that you need a very small amount of it to produce a lot of energy for a long time.

> machinery for every eventuality (including chip fabs)

Colonists by necessity must make do with less and that does mean a lower standard of living and higher mortality but you know what they do it anyways because some things are worth trading comfort and a decade or two of life for. English colonists didn't bring the entire industrial infrastructure with them to the New World. They brought what would fit on the boats and had to make do with what they could create from local resources or do without. They had the benefit of subsequent voyages but I don't think anyone here is imagining colonizing Mars or Antarctica with a single expedition.

> raw materials

Mars (and Antarctica for the most part) do lack anything biological in origin, no oil or wood or crops as feedstock for chemical reactions but there are always alternatives. We usually don't use those alternate sources here because they are too labour or energetically or materially expensive but when they are your only option price and effort become less of a concern.

> all the challenges are at least an order of magnitude harder

No one who is attempting to work towards this is doing it because it is easy. I remember there being a speech about that which ended up with some pretty spectacular results.

"We go to the moon not because it is easy, but because if we don't then some commie bastards will get there first."

I am all for exploration and science for the sake of science, but any talk of colonies is just wasted breath at this stage. We need to first explore how to live within our means on earth.

I'm of the opposite opinion. I think we need to spread out as soon as possible because it's not clear we can ever completely future proof our civilization here. There are simply too many things that can go wrong, many of which are not within our control. Take the pandemic for example, if it had been 10x worse it could have collapsed our current global civilization. There's no way of preventing it from spreading to every corner of the Earth without also destroying civilization as we know it. Same goes for asteroid impacts, super volcanos (consider Tonga a warning), tsunamis, solar flares, CMEs. Then there are the man-made disasters that we may or may not be able to keep under control such as war, terrorism, religious fanaticism, industrial accidents, pollution or even just apathy and hedonism.

I'm not saying we should ignore all the other things in favour of escaping to space. The Earth is the largest volume of habitable space that we have right now but it is also the only one and that's the problem. We should be building other habitats in parallel with solving our current problems. We need a literal backup plan in case things go seriously wrong.

Big picture, I think all this pushing to make everything perfect for every person on the entire planet Earth before expanding to space is a TERRIBLE strategy

Imagine a StarCraft/Factorio player who hides out in his starting base, building it up more and more and more forever, while talking about "living within his means".

There are effectively unlimited resources right there for the taking! Let's go take them!

Bit of a straw man - nobody said anything about pushing for perfection at home, just "we can do better than this".

Also - "right there for the taking" gets to the heart of my objection as it is nowhere near true. Space is vast and delta-v is expensive - even if we get past the problem of deadly radiation outside the ionosphere, we are incredibly far from being able to make space travel anything other than an enormous sink for money and resources.

Maybe I'm optimistic, but these are just problems to be solved. Space exploration is a big risk / big reward investment. Yes it would require a comparatively huge investment to mine an asteroid vs. open a pit mine in Brazil but "mining" an asteroid likely means carving off hunks of solid metal for transit back to the Earth's surface rather than processing megatons of rock by blasting, trucking, and smelting. Like many things about space, it boggles the mind that a single asteroid mining mission could produce more platinum group metals than have ever been mined on Earth throughout human history. How does the total amount of money and resources spent on mining those metals on Earth stack up against the cost of a single successful asteroid mining operation?

I think this argument extends to colonization efforts as well. What is the economic and cultural benefit of founding a new nation? It's not something that we are familiar with at this point in history so we are relatively blind to it. We just take it for granted that the nations in which we live have always been there since they have always been there for us. I have no doubt that once we begin colonizing Mars or the Moon or even just Earth orbit it will have as great of an impact as the colonization of the New World.

> Mars (and Antarctica for the most part) do lack anything biological in origin, no oil or wood or crops as feedstock for chemical reactions but there are always alternatives.

Ignoring energy sources (solvable using by a fission reactor), the entire Earth has a similar feedstock problem as Antarctica. There's plenty of hydrogen and oxygen there. CO2 can be mined from the atmosphere by plants. Nitrogen is the remaining building block of life. At this point, most of the nitrogen in human tissue was extracted from the atmosphere using the Haber-Bosch method (which, roughly speaking, converts atmospheric Nitrogen and energy to fertilizer).

I agree that Antarctica would be an easier (and safer) place to build the first self-sustained "moon base"

> Only one technology matters: that which enables transportation.

Is this tongue-in-cheek? I genuinely hope so.

Nobody ever believed that America is a super-hostile environment.

Roanoke, Ajacan, Fort Caroline, Sable Island, Charlesfort, Pensacola, San Miguel de Gualdape, Charlesbourg-Royal, France-Roy, Pensacola?

False equivalence, of course.

The fact that random groups people from the Old World decided to start colonies without any prior experience or preparation precisely shows that they didn't consider America to be "super-hostile".

If you think going to Mars is useless, don't go.

Just don't stand in the way of those who chose to go.

By all means, go. But pay for it yourself. If you can't personally afford Mars, the middle of the Sahara Desert is unoccupied and overwhelmingly easier and cheaper to get established in. Or, under the ice in Greenland. Or, revitalize an abandoned whaling station on an island off Antarctica. If those seem uninviting, I promise Mars will be a thousand times moreso.

Your "golly I'm on Mars!" euphoria would thin out very, very fast. "This place f'n sucks!" malaise would grow steadily and without bound.

So we have this thing called a government that we give money too. Different people want it to do different things. You can recognize that while you may pay for things you dont want, other people are paying for the things that you want but they dont.

I'm definitely not going. But I'm very glad others will go!

Maybe that's a confusing distinction for some.

I would not mind if they went somewhere. If they went to Mars they would immediately stop talking about what a great idea it was, even if they still had air. They would shortly thereafter try to get somebody to bring them back home.

Mars can already be useful as a springboard for space exploration. It's a literal stepping stone, both closer to the belt and outer planets in terms of distance, but also in terms of delta-v, since both the gravity well on Mars is smaller, and it's higher up in the Sun's gravity well, too. Any future space exploration and exploitation will be made tremendously easier if you can launch from Mars instead of Earth.

Mars is, even at absolute best, a dump: dry, cold, airless, at the bottom of a gravity well, and subject to dust storms besides.

We can build much better outside of gravity wells. Whatever you would land on Mars is more useful in solar orbit, parked next to any convenient asteroid.

Admittedly my knowledge on this matter derives from KSP, but I've found that rendezvous is much trickier outside of gravity wells.

And there's still the problem of ISRU.

We have ISRU right here, right now.

You can't do ISRU in orbit. I don't know of any resources available on the Moon that would allow you to do ISRU there either. Ceres might work, but the inclined orbit may make that impractical as a stop.

We do ISRU all day, every day right here, in the millions of tons.

"A stop" is not just useless, but is actively harmful in space transportation. You go, for free, until you get there, and then use up fuel stopping. Starting and stopping are exactly what costs. Stopping halfway makes the whole trip cost literally twice as much.

It's also 'for free' to continue from LEO to anywhere else, but it can still make sense to refuel in LEO rather than launch with all the fuel requirements you need for the mission from Earth surface. The delta v required from LEO to another body is lower than that from Earth surface there. Delta v required from lunar orbit to some non-terrestrial body is also lower than that from LEO, and it could potentially make sense to do refuelling from there in order to get the maximum possible delta v leaving Earth's gravity well. Finally, the delta v required to reach the belt and Jupiter from low Mars orbit is lower than that to reach them from Earth. That means bigger payloads can be sent to these destinations, or even potentially any payload at all; it is only barely possible to reach a Hohmann transfer to Jupiter from Earth with SpaceX's Starship's claimed delta-v, whereas from Mars there should be several km/s of extra delta-v to spare.

Refueling in LEO or high earth orbit is fundamentally different, in every single particular, from stopping somewhere halfway.

Until you understand this, everything you say about space travel will make zero sense, and furthermore will deeply embarrass you for long after you finally catch on. You make a fool of yourself by continuing in this vein.

You can do the calculations yourselves. Refueling in LEO is energetically more costly than a launch from the Earth surface to escape. You will end up using more fuel overall if you launch into LEO vs. if you take all the fuel you need from the Earth's surface in a single launch. If there is a difference, you haven't explained it.

I have, several times, and you have ignored it, several times. Other readers caught on long ago. Only you continue embarrassing yourself.

No, you did not. You have made such false claims as 'If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars.' This is a claim that is easily shown to be false by calculating the differences in delta v from Mars to belt/outer planet destinations vs from Earth. You then claimed what you meant was that it takes more energy - but so what? It takes more energy to refuel in LEO than it does to launch a ship from the Earth surface to escape. Basically this entire time you have simply just claimed 'no, you're wrong' without any calculation to back it up, and the few claims that you have made have been ludicrously wrong.

"When you find yourself in a hole, first stop digging."

Because it's there

https://blog.theclymb.com/out-there/because-its-there-the-qu...

agree, extreme temp variations and a toxic atmosphere would make living there very difficult(not to mention the journey!). Much better to try a moon station first as its a few days travel and then compare what went right/wrong and then think about replicating that for mars. Having water on mars does help its case though..

Not to mention that you would need to figure out how to keep the humans from having a mental breakdown. Myself, I would probably be clawing at the windows for a look at a non-existent tree in about two days.

The best thing we could do for space exploration is to figure out terrestrial fusion.

Why is it weird that a private corporation is doing space exploration & technology? Most of the biggest sailing expeditions were undertaken by private individuals and companies (although often under the funding of a royal family). Locomotives and airplanes were also created and perfected by private individuals / companies.

The 1950s-2000s NASA model for space exploration was unusual in its centralized approach.

There's an argument to be made that some of the current largest market cap companies in the world are analogous to royal families, in terms of centralization of capital vs freedom of decision making.

The notable difference is that they don't have a monopoly on violence

Most premodern states (at least) in Europe didn't really have a monopoly on violence in the strict sense either. Kings were constrained by a variety of laws and customs which they couldn't easily change without triggering violent opposition and had to co-opt the local elites (who usually acted as independent actors) whenever they wanted to impose their will outside of the area they directly controlled. Even an 'absolute' ruler like Louis XVI had very limited direct power compared to many modern governments.

Fair enough, it seems that you are primarily attacking the word Monopoly. What if we were to soften the claim to dominance. Rulers always maintained power based on their ability to resist violence from within and without. Economic leverage only existed as long as one could protect themselves from violent opposition. A trade embargo meant nothing if the opposition can seize your assets and production by force.

In today's world, mega corporations have no defense if a government actor decides to use force against them.

This utter defenselessness against violence is the main difference between a modern corporation and a feudal actor.

Good point. See: ARM China

I feel this is only a partially true, at least in democratic countries governed by rule of law, because the threat is mostly only theoretical. While modern states are significantly more powerful they are generally governed by more rational actors who (both because of that and better access to information) are much better at estimating the consequences of their actions compared to medieval kings or other autocrats. While the government could go ahead and take all the assets of Apple, Google, Facebook etc. both the government and the people in charge of those corporations know that that's extremely unlikely to happen, especially in a violent way, since the government has very little to gain and a lot to lose by doing that. So while modern corporations are technically utterly defenselessness against violence as you say, arguably this is by choice. Unlike feudal actors corporations have no reason to invest any resources in changing this since they are in a much safer position.

I think I totally agree, and see this as a substantial difference between corporations and feudal lords. They have entirely capitulated on force and are comfortable in this position. You say they only maintain this position by choice, but what choice do they have otherwise? It is hard to imagine Apple, Google, Facebook having any success if they changed their mind and decided to challenge national governments like US or China with direct force.

It has pros on both sides. MAMAA wouldn't have their profit margins if they had to fund a private security force to enforce their contracts and protect their assets.

They get the freedom to focus on their business, within the bounds of the law, by ceding violence authority to the government. And in return, the government establishes and enforces those laws.

Most of those private expeditions were seeking short term profit (of course there exceptions like the Arctic/Antarctic expeditions but their budgets were relatively insignificant compared to the resources required to send several ships to India or the Americas in the 15th century or a spaceship to Mars. Even if colonizing and exploiting the mineral resources on Mars could be profitable in the longterm being the first on Mars (unlike being the first to sail to India) is definitely going to cost more than it's worth (in financial terms) so no rational private company would do this.

Do you have any suggested reading about:

"A probe based on nuclear pulse propulsion could do it in around 50 years, with today's technology."

I was always under the impression that these vast distances were basically entire unreachable in several human lifetimes.

Is talking about detonating nukes behind a ship with a big shield behind it.

The canonical reference is Project Daedalus:

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

We do in fact have another billionaire, Yuri Millner, to push humanity towards the goal of reaching other stars with his "Breakthrough Starshot" initiative.

As far as I know this would be cell phone sized with no way of slowing down. It would cross entire solar systems within a few hours.

There's no way to slow down, true.

Let's see... Neptune's orbital diameter 8.3 light hours.

At 10% c (speed of light) you would need 83 hours. Yes, insane speed, yet hopefully enough time to take quite a few pictures.

Also the plan is not to send a single "disc", but many (thousands?). Together they could potentially provide a treasure trove of data from within the alien solar system.

"...with today's technology..."

So we have the ability today to move 50K tons of parts into orbit, and come up with vast quantities of helium-3?

Isn't Parker Solar Probe much faster than that? It's supposed to be going hundreds of thousands of km/h. [1]

[1] https://en.wikipedia.org/wiki/Parker_Solar_Probe

Yes, Parker breaks the 40+ year old record set by Helios. OP is using stale data.

The fastest crewed spaceship was Apollo 10 at 39,705km/h before reentry. After orbiting the moon they had lots of fuel left over so they just floored the engine on the way home. Not just falling back towards the planet but actively flying towards the ground for longer than any other Apollo mission.

This record can be broken with current technology, we just have to go back to the moon.

It achieved those speeds by falling into a gravity well. Reaching Alpha Centauri requires escaping one.

I very well may be wrong about this, but I believe thats not exactly true. Parker required the fasted launch as of its time because it had to shed the momentum of the earth that it started with to be able to fall into that gravity well.

quoting from reddit:

> You may be thinking of the Sun as a big gravity well and how you can just drop things in a well. But orbits don't work anything like that at all. Sure if you are stationary relative to the Sun then you'll fall right into it. But anything that leaves Earth is very far from stationary. You're going at 30 km/s 90 degrees off your target. Possibly the first idea many people think of if they want to hit the Sun is to cancel that 30 km/s of speed, and sure it'll work. But you need 30 km/s of delta-v. On the other hand, to escape the solar system from Earth you only need a velocity of 42 km/s relative to the Sun, of which you already have 30 km/s. So you only need to increase your speed by about 12 km/s. (And for both cases add one or two km/s to counter Earth's gravity.)

https://www.reddit.com/r/askscience/comments/wjv87/comment/c...

https://www.forbes.com/sites/startswithabang/2019/09/20/this...

I find it enjoyable to think about the technologies that might just be in the cards further into the future.

If we ever figure out light-weight fusion drives, we could build light hugger space ships that accelerate to a decent fraction of the speed of light. At 1g acceleration it takes about one year to get to 0.9c, which would make the Proxima system accessible with a travel time of about 6 years. Or 8 years at 0.5g. Or 9 years if we 'only' get to 0.5c.

The same goes for laser-driven light sails if we just wanted to send a probe, although deceleration would be an issue. (There is currently an aspirational research project for this called Breakthrough Starshot)

The exciting thing about these technologies is that they don't require new physics in principle, just a lot of engineering. Of course, uploaded minds would probably always be better suited for space travel, but it's neat to know that even biological people could in theory make these trips.

Is the 6 years measured in the time-frame of a passenger on the spacecraft, or as observed from Earth?

At 0.9c the relativistic time dilation is such that 2.3 days on Earth pass for every day shipboard time, meaning the crew would experience less than 4 years of travel in total: https://www.fourmilab.ch/cship/timedial.html

Since we aren't too fast yet, it would basically be the same.

Thank you for your optimism, now let me balance that out a little.

Propulsion maybe the easier part of engineering. Afaik we are nowhere near to life support and environment control that could be considered stable for a time period of maybe 10 years or more.

The biggest biological advantage, adaptation is meaningless for large organism on such a timescale and maybe dangerous on a microbial level.

You are correct that we are nowhere near that in life support technology, however, there don't seem to be an fundamental hurdles there. If we end up opting for a biological life support system, adaptation would not even enter the equation - it'd be a matter of genetic engineering. An obvious danger would always be onboard ecosystem collapse, of course.

IIRC, the limit with humans on-board is like .3c due to the red/blue shifting of the background radiation of the universe. At about .3c, it turns into microwaves/radar/x-rays and such, becoming quite bad for humans. There’s so much background radiation, there may be no way to adequately shield from it and/or travel may be limited only in the direction of less background radiation.

Maybe someone has a link to more information, that’s just what I remember from years ago.

That's a good point. I have no idea actually where the practical limits would be, especially considering options that arise if the ship has access to a lot of electrical power to generate a protective magnetic field. But even at 0.3c, the trip to Proxima could still be worthwhile for an unmodified human.

You still have the deceleration issue.

You need to use the same amount of energy and time to decelerate, as you did to accelerate.

So you'd only be able to sustain constant acceleration for half the distance. Then deceleration for the second half of the journey.

That would make the travel time much, much longer than your calculations, since you'd be traveling at relatively slow speed for both the first & last 20-25% of the distance.

Here’s a link to a Gizmodo article talking about the study… unfortunately I can’t get the original study to load: https://gizmodo.com/this-is-what-it-would-really-look-like-t...

Right, also the hull must resist the impact against hidrogen atoms at near the speed of light, which would apply tremendous forces. Dust will be like exploding nukes.

This is exciting stuff indeed. Imagine a year-4,000 spaceship reaching Centauri before another spaceship dispatched 1,000 years before it?

For the cynical or pessimists: I'm not optimistic about humanity reaching year-4,000, I'm just possibilistic about it (as in the philosophical meaning [1]).

[1] https://en.wikipedia.org/wiki/Actualism#:~:text=possibilism,...

This is more or less the plot of a story by Brazilian science fiction writer Roberto Luiz Calife.

And the story "Far Centaurus" by A.E. Van Vogt.

Will have to look that one up.

This is literally the plot of a very old computer game Alien Legacy. [0]

[0]: https://en.m.wikipedia.org/wiki/Alien_Legacy

I can't imagine humanity not making it to 4000. There are very few true existential threats.

> If we ever figure out light-weight fusion drives, we could build light hugger space ships that accelerate to a decent fraction of the speed of light. At 1g acceleration it takes about one year to get to 0.9c, which would make the Proxima system accessible with a travel time of about 6 years. Or 8 years at 0.5g. Or 9 years if we 'only' get to 0.5c.

No, we couldn't. The energy density of fusion isn't anywhere near close enough to make a lighthugger, you'd need insane mass ratios[1] and ramjets are probably unfeasible (as in, even-if-your-a-Kardeshev-II-civilization-unfeasible[2]).

[1]: http://www.projectrho.com/public_html/rocket/slowerlight3.ph...

[2]: https://www.sciencedirect.com/science/article/pii/S009457652...

Another atomic rockets enjoyer. I've killed so much time on that site. I don't agree with every one of Winchell's conclusions. But they are small things. And I don't know of a more comprehensive and grounded take on future spaceflight technologies.

I was saddened to hear about Winchell's cancer diagnosis last year[1]. I've wasted a ton of time there too, it's an oddity compared to the rest of the modern internet. I know very few other useful sites like it, and I love it all the more for its strange aesthetic.

I don't agree with everything there either, but usually it's only very minor gripes. In this case though, it's hard to argue with the reality of the rocket equation.

[1]: https://twitter.com/nyrath/status/1436010987086286853?s=20

Oh man, I hadn't heard about that. Best of luck to him but he's right prostate cancer is a pretty bad one.

What are the other few sites you do know of?

And you are absolutely right about the rocket equation. You can't really get around it.

I'm sure there's more but the first few that come to mind are Greg Egan's homepage[1], Xenology[2], and on a completely different topic "Gramadach na Gaeilge"[3] (Irish Grammar).

[1]: https://gregegan.net

[2]: https://xenology.info

[3]: http://nualeargais.ie/gnag/gram.htm

It's too late to edit, but the link to xenology should be http and not https:

[2]: http://xenology.info

Bits of dust or a pebble hitting ship at 0.5c would make for a bad day.

Whenever I read discussions about space travel and trying to approach the speed of light for human travel I have the feeling there's a lot of tunnel vision (excuse the pun). It always seems to assume travelling along a linear path through space.

In my mind, using the admittedly poor analogy of space-time as a membrane that is distorted by gravity, my thinking is we'll find some way to effectively bring two points in space-time adjacent to each other and 'step' between them. Wormholes, Warp, or whatever you want to call it.

Think of a flexible membrane 10 meters long and we are going to travel from one end to the other. We can either travel in a linear fashion over its surface for 10 meters or we can wrap the membrane so both ends are next to each other and travel 0.01m across the gap between them.

Yes, I know there are all sorts of obstacles and arguments against this simplistic visualisation but this is how I've always imagined the physics of any science fiction faster-than-light travel - worm-holes, warp drives, etc.

If you want an actual, real, possible-right-now analogy, think of our current situation where the fastest way to travel from London, UK to Sydney, Australia (1/2 way around the world) is through the atmosphere in an aeroplane travelling ~17000 kilometers and taking at best 19.5 hours.

SpaceX (Musk) Virgin Galactic (Branson), other companies [0], and space agencies [1] have talked about, and are actively working toward, stepping outside the atmosphere into space to reduce the time element to around an hour.

So just like with supposedly faster-than-light travel, by 'stepping outside' the linear/conventional thinking/physics we reduce the time of travel element dramatically. The start and end points don't move but the distance travelled by the transport vehicle itself changes in order to enable the reduction in time.

[0] https://www.telegraph.co.uk/travel/news/new-flights-space-lo...

[1] https://edition.cnn.com/travel/article/hypersonic-flight-air...

I've never bought it. It will still involve being able to transfer information FTL, and then you're on to the Grandfather Paradox.

On top of it, let's handwave all of this away, poof. Any aliens anywhere in the Universe would also be using it once their technology got to that level. Just from the lack of visitors, we have three possibilities that are immediately evident:

1) Humans are among the first intelligent species to get to this technology in the entire Universe.

2) Other species have it, but all of them, every last far-flung one of them, even the renegade civilizations or the mad scientists at the individual level, abide by not using it around humans. Despite all of their numerous reasoning capacities and utterly inhuman motivations, every last sophont with access to the tech has agreed upon this, and has for thousands of years.

3) That tech can't exist.

The first and second are unlikely, statistically.

>something like 18 000 years

this is why we don't see any signs of life out there. there really isn't any point in trying to venture beyond your home. universe is just too big even at the speed of light when you start venturing beyond your local group.

I guess the assumption is their life span is similar to that on our planet. If the life span measured in thousand of years, it will be a different story.

Lifespan is one thing, but also the "cadence" of life. For a mammal, spending a year in a spaceship is hard. For a brick, spending a thousand years as part of a wall is the natural order of things.

> even at the speed of light

If you get really close to the speed of light (which is not really practical from a materials engineering standpoint) your time of transit is significantly shorter.

Once these (extremely hard) engineering problems are solved, a trip to the next star can be a week-long affair from your point of view, but your friends back on Earth won't see you for about a decade.

You'd have to get very close to the speed of light, before you'd see any really significant relativistic effects.

That just isn't practically doable with any technology within humanity's reach, probably for centuries. If it ever will be at all.

The amount of energy needed to propel anything at that speed is enormous.

Unless my math is very wrong, at 0.9c the passenger perceived time is more or less half the perceived time from the departure point. That's already quite significant, although not something I could do over a vacation ;-)

In order to spend a leisurely "cruise-ship" week to Proxima you'd need to go very close to c. At that speed, even friction with a non-ideal vacuum is a problem :-D.

> a trip to the next star can be a week-long affair from your point of view

You’d need to travel at around 233x the speed of light to make getting to the nearest star be a week trip, no?

From the passenger's point of view, yes. For everyone else you'd be veeeery close to c, but not quite there.

My point was it’s hyperbolic. You’d have to be going so close[0] to C that it’d be impossible.

[0] about 0.99999c if what someone else in this thread said is correct

Nope! If you obtain the full speed of light then a) you're not made of baryons anymore so congratulations on that and b) no time passes whatsoever between your being emitted in some tight laser beam on planet A, and being transcribed on planet B, from your perspective.

None. Photons don't experience time, they are time.

Not exactly. For you to think you are traveling 20x faster than light, your friends that stayed at home would have to see you traveling at 0.99995c. For 233x faster than light, that's a lot of 9's in that number.

There is no faster than light, I can't parse this statement.

Distance divided by [time experienced by traveler]. GP is not saying that traveler went faster than light.

I get 0.999c for 20x and 0.99999c for 220+

I'll trust your numbers more than mine.

But, for all intents and purposes, this is impossibly fast ;-)

Unless you are on the Bistromath, that is.

The effect is called time dilation. The section of interest here is „Time dilation caused by a relative velocity“:

https://en.m.wikipedia.org/wiki/Time_dilation

I’m aware of time dilation, my point was that a “week vacation” to something “over 4 light years” away is just hyperbolic.

That is assuming that the speed of light truly is the end-all-be-all. It is quite possible there are other ways of travel that we’ve yet to discover. I have no idea what they’d be but humans have really only been doing this space / astronomy thing for a few hundred years at most.

We have barely scratched the surface of what is truly going on out there. It would be incredibly “human centric” to think our current understanding of the universe is “it”, in my opinion.

I think you would need a kind of power that would have obvious hallmarks, like literally rewriting the rules that underlie the universe. But's that just my cynical perspective.

I guess that's why arthur c clarke said sufficiently advanced technology is indistinguishable from magic. I just think that kind of magic would be visible to us. Or maybe it is, but we just can't tell.

The formal name for this is the https://en.wikipedia.org/wiki/Interstellar_travel#Wait_calcu...

with how small you can make a probe today there isn’t any barrier to making something 100x faster or more. throw up a small camera and transmitter with a huge ion thruster thank on top of a saturn v sized rocket of your choice and you will get going very fast

The other problem with sending a space probe is that the devs will have to actually deliver the Proxima Centauri mod on time and on budget, which, let's be honest, probably isn't going to happen for another few years. Think about it, you have to skin the whole planet, make sure the AI isn't weird, make sure it doesn't conflict with the existing storyline or retcon all the earth NPC memories. It's a HUGE project. Right now we just literally return a light curve from the function when someone looks at it.

And even if we could get the adversial networks to model all this garbage, etc it needs to line up with the plan of the rest of the Universe from the franchise and the managers can't even decide whether the photon is going to be a wave or a particle. Jeez. Vaporware like HL2.

Another point for anyone considering whether we should send a space-probe there...

We should and do send probes anywhere that's practical. The question is more like when it will be practical to build star probes.

The current fastest man-man object is the...

The current fastest man-made object wasn't intended to reach the stars.

On the other hand, there are many challenges that make more sense to undertake as previous steps to develop the needed technology.

we need to send out a probe now before it's too late

> 25 000 kilometres per hour

252 792 km/h

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