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Roadmap to Alpha Centauri (nautil.us)
147 points by dnetesn on Aug 29, 2014 | hide | past | favorite | 63 comments



Read Charlie Stross's "High Frontier Redux". It's simply not that easy (and a. cent. is the wrong target).

And no, it's not a simple matter after budget priorities either. Physics, bitch.

http://www.antipope.org/charlie/blog-static/2007/06/the_high...


This ignores using closer targets. Suppose a small group on starts living in space and they mine asteroids and a become reasonably self sufficient. Now, they have no real reason to go outside of the solar system any time soon, but self sufficiency is a hop skip and a jump to growth and there are plenty of useful materials in the Ort cloud if you can self sustain on say fusion instead of just solar energy.

And thus a long slow boat to the stars starts off as simple resource extraction. Sure, long term we might only be looking for gas giants as a ready supply of fuel vs planets to live on but there are other paths to the stars than a one shot moon landing style.


Stross also addresses interplanetary flight in another essay.

While that is clearly possible, it remains an endeavor for which all but the very closest targets (Moon, Mars, Venus) remain years away. I don't know that anything other than very cursory human travel will be possible. No targets are particularly hospitable (Venus especially not, Mars barely), the total land area available in the _entire_ solar system is pretty modest (as usual, xkcd has a visualization: https://xkcd.com/1389/), and the benefits of travel are relatively modest.

My prediction is that we'll likely see more robotic missions, might land humans on Mars (and will likely return them to Earth), but long-duration settlements are relatively low-probability. Perhaps on the Moon. Possibly Mars. Beyond that, doubtful. And they'll likely be little more than research outposts -- I don't think space will prove commercially viable other than for communications (largely Earth-orbiting satellites) and information (again: largely weather forecasting, sensing, GPS, and imaging, mostly aimed at Earth).


Long term, I don't see much value in dropping down another gravity well. The astroid belt might only mass 4% of the moon, but mining even 1% of the moon or earth is vary difficult unless you start dumping mass into space.

As to the bennifits on the long term, aka 100,000+ years. It's less a question of economics but possibility. Can we have an independent space based economy and there is plenty of energy and raw materials so justifying no is difficult.


A lot of the mineral mining questions revolve around how the economics of heading out a few AU to find stuff compares with heading down a few hundred, or thousand, meters into Earth's crust.

Our understanding of geology now suggests that a great deal of the heavy and rare elements in the Earth's crust were deposited during the late heavy bombardment -- after the Earth's crust had formed (and hence, after the heavy stuff had sunk toward the Earth's mantel and core), but before there was a lot of life. Which means that a large chunk of the asteroid belt is actually scattered across Earth.

Modulo plate tectonics, previous mining, and other activities.

There are arguments that, e.g., pretty much anything you could want to get is obtainable from seawater, modulo energy (and a significant filtration system).

That said, yes, there are some rare minerals which are useful that might be present in high concentrations in specific asteroids, possibly tracing their own origins to very specific conditions of supernovae explosions which both created those specific atoms and grouped them together.

But moving even a few hundred kg of matter, let alone thousands of kg or tons, is a hugely different proposition. That's a lot of energy to expend, and complexity to support.


He’s talking about colonisation, so that’s a bit of a different topic. Also, the references to travel time measured in millennia should everyone clue in that it’s not easy, even in the linked article.


What would the "right" target be?


Alpha Centauri is actually the right target for our first interstellar probe since it's the closest system. There's just no inhabitable planet there, as far as we know.


Stross answers that.

My response is "under your feet".


Stross says Gliese 581c on the grounds that it's the closest currently known vaguely-habitable exoplanet. Most likely there are others closer and we haven't found them yet.

Probably not Alpha Centauri since it's a binary system.


A habitable plainet would require a vaguely Sun-like star. Odds of one hiding between us and a. Centauri are low. Gleise or a neighbor are best bets, and near exoolanets are also generally easier to spot.


Not one hiding between us and Alpha Centauri (which is unlikely), but one of the hundred or so stars between us and Gliese 581.

Closer exoplanets aren't necessarily easier to spot, we've spotted those around Gliese 581 because they have a nice short period of a few days.


Ease of finding an exoplanet, among other things, increases with proximity.

A close and attentive reader of my original comment might possibly note that my argument wasn't for Gliese but against a. centauri. The salient point being that you'll need to schedule and budget for markedly more than 4.6 light years.


Yes, I've thought that, too. Just give up on manned interstellar travel, and redefine the Earth as your spaceship. It may be the only answer, but it's a bit sad all the same.


I think Earth has to be closed enough from the Sun to get heath, otherwise the whole mankind will die from cold.


I didn't mean take the earth and move it, i meant just call the earths natural motion your "exploration", i.e. give up on manned interstellar travel.


Article passed through Readability: https://www.readability.com/articles/bxlkncll


It's sad that the biggest barrier to space travel remains the inability to mobilize large amounts of money to fund ambitious projects. We have no difficulty funding the most nugatory military operations at ten times the cost of a manned mission to Mars. But peaceful projects, whether on Earth or in space, run out of political support at a fraction of that price.

It's a lot more fun to focus on the technology because the technical obstacles to space flight are potentially tractable. The human obstacles seem to resist any solution.


Uneducated guess:

Military spending hits a sweet spot of being a tried-and-true generator of middle-class jobs, responding to a perceived urgent national need, and also functioning as a sort of insurance policy, in the sense that we're often paying for something not to happen, making it hard to assess value.

A space program doesn't necessarily hit any of these notes. It requires specialized talent, responds to no immediate need, and, perhaps perversely, because you can measure the success of a space program, it's too easy to foresee things going wrong.

I think you could make a similar case for why we don't plow $500bn into curing cancer, which is a manifestly better idea (even just from an actuarial perspective) than spending 10x more than the rest of the word on defense.


I'm not sure what you would do with billions of dollars thrown at cancer. At least with guns and rockets there's hardware to build. I suspect breast cancer research, for example, can't usefully absorb more money.

I think you're overlooking an emotional component to military service. For a lot of people it ties into issues of heritage, national and personal identity. For many Americans it's synonymous with the idea of national service.

If our grandfathers' Space Corps had stood strong and unbending in the face of the Martian landing pods, we would likely not have any trouble getting the cool missions funded now.


>I'm not sure what you would do with billions of dollars thrown at cancer.

Giving every cancer research on earth the freedom to actually research instead of preparing grant submissions would probably be enough to substantially decrease the amount of time before significant strides are made. Especially if the money would pay for research assistants, statisticians, and quants to parse the data being collected. Outfitting labs with the latest in high throughput robotics, microfluidics, sequencers, etc. would amplify their efforts.


I doubt all that would take more than a billion or two. For the entire world. And giving more liberty to researchers will probably lead to savings, not expenses.

It's both sad and great that we probably can not spend those $500B in cancer research, yet there is so much to improve.


"Cancer" is also simultaneously a narrow and broad field. Computer technology improvements has probably done more to advance modern biology and microbiology then other single advance - but would receive no funding at all under the banner of cancer research.

Broad funding for scientific research is important.


But our grandfathers' Space Corps existed, and still exists [1]. And it stood strong. It's just that the force it stood against was the United States and NATO (or, from the opposite perspective, the Soviet Union and the Warsaw Pact), and the landing pods were the tens of thousands of nuclear-tipped ICBMs built with the same technology that was showcased in programs like Apollo and Soyuz.

One of the literally marvelous phenomena of the twentieth century is how good people were at pretending that this wasn't happening. It's not just nostalgia: People ignored the militarization of space in real time. Werner von Braun was able to literally drop ICBMs on people's heads, then move to the USA and continue developing ICBMs, all the while maintaining, and apparently sincerely believing, that the ICBMs were not the real story, that the real story was the impending colonization of space. And everyone went along with that, except during Tom Lehrer concerts, when they permitted themselves a little chuckle at the irony of it all.

(I blame World War II. I don't think it's possible for young folks like me to really understand how apocalyptic World War II was. The aspects of the 1960s that scare me witless, like the Cuban Missile Crisis, felt normal to people who had lived through World War II.)

Unfortunately, though, the USA wasn't actually paying von Braun for moon rocks, they were paying for ICBMs. And I don't think it's a coincidence that, once the ICBMs were finished, the money started drying up. Space research is stalled for the same reason that the US military still flies B-52s, designed in the late 1940s: Flight is a solvable problem, and it was solved. ICBMs ended up being overengineered: We have amazing ICBMs, with lightweight warheads, that remain perfectly capable of accomplishing their core mission of destroying all the major cities of the world. That research is finished, and our major concern today is the delicate political task of destroying our remaining ICBMs and never building any more.

In the absence of a military motive, there's a lot less money for space. [2] The good news is that the money isn't quite zero, and our amazing advances in robotics stretch it a lot farther.

---

[1] I've heard that it's the worst job in the Air Force and the personnel involved are absolutely miserable: Spending all day maintaining their doomsday weapons, never able to act, praying that they never have to act, knowing that nobody may be alive to admire them if they ever do act, constantly wondering what decision they'll make when the button gets pressed. Drinking, presumably. Watch the first few minutes of WarGames: Those soldiers are based on real people, and their reactions are based on real drills. They're the unsung heroes of the last fifty years. If they don't do their work with care, we might all die, and nobody wants to think about them.

[2] To be precise: There is still plenty of military motive to launch things into space, and plenty of money too. But we now know that the strategic purpose of space is to hold lightweight satellites that watch stuff on the ground, and those satellites are increasingly small and disposable. In the early 1960s we didn't yet know that we wouldn't have much use for gigantic launch vehicles the size of the Saturn V, and we didn't know how microcircuitry was going to happen.


Yes. If history of aerospace teaches us something, it's that humans can make pretty much anything from scrap metal and duct tape if they care enough about it. Lack of advanced manufacturing techniques didn't stop Soviets from building awesome supersonic jet fighters from plain steel and with hydraulic controls. Lack of computing power didn't stop us from landing on the Moon, even though the machines that got us there are a joke compared even to a pocket calculator.

The sad thing is, it's the same phenomenon that gave us all the growth and awesome technology we enjoy today that prevents us from ambitious space missions. Progress of technology is in a tight feeback loop with the economic system, and from the point of view of the latter, space exploration is a big no-no.


The economic and political system is Problem #1. It's not fit for purpose, and humans can forget about becoming a successful space-faring species until it's replaced by a system capable of rational long-term project planning, and which also rewards inventiveness, creativity, intelligence, and other talents.


I seriously doubt the lack of space travel is because we spend money on the military, if anything it might be the only reason development is still being done. Social programs are where the money is truly going, in the US alone there are over two thousand assistance programs at the Federal level.

Space doesn't get money because space doesn't get votes. Military accounts for a large portion of the science of similar hardware because its development and deployment can be spread around and people can relate to it easier.

Still giving the every day person a choice, go to the moon, protect us from the bogeyman, build schools, or free prescription drugs, I know pretty much the order it will go in.


The amount of money involved is not really the problem.

I've seen arguments from the end of the 80s (sci.space.tech, Henry Spencer et al) that if the launch costs went down, the costs of building hardware would go down. From that, there should be elastic demands when e.g. universities can send their own probes. They also discussed how to do it (Big dumb booster etc).

The point was, not that much more money would be needed for this (just check the really expensive launcher being developed by NASA now!).

To lower launch costs is the key and it might be rocket science but, well, not rocket science. The reason this haven't happened until Space X seems to be mainly NASA's need to protect the shuttle (which was really, really expensive) and oligopolies in the launch business for military contracts.

So maybe not the military, but the military contractors are involved.


That argument is not logical.

Military spending may or may not be justified, but if the whole world cut all military spending, it's not like space travel would get dibs on that money.

Space travel has to justify its existence on its on terms. Right now I'm pretty happy with NASA's science based program. The Mars rover strikes me as a great way to get a lot of science for the money, and learn a lot about operating autonomous robots in space.


You're rebutting an argument I didn't make.


I think it's a variant of bikeshed syndrome. It is (or seems) easier to understand the pros and cons of a military operation than a trip to mars, so it's easier to approve. Something weird will tend to get ignored to death. The cost figure doesn't even enter in, and is so huge to be out of the realm of reckoning for most people. This happens for earth-bound weird projects, too.


Money is just the unit we use to measure what we value. The less we value space travel, the harder it is to do.

It's a marketing problem, not an engineering one.


I don't see why it can't be both. If advanced space travel weren't a ludicrously expensive way of committing suicide, I'd support it more. But as best I can tell, the engineering reality is that we aren't ready to start accomplishing anything meaningful off the earth, so pouring money into that before the foundational technology exists is like funding alchemy. We don't currently have people living in a sealed-off bubble at the bottom of the Southern Ocean or something like that, so why are we trying to market a Mars mission or something even more outlandish?

In short, I think the problem is that the evident state of engineering makes the venture look somewhat unlikely to succeed. So no matter how awesome your marketing makes the cause sound, it has to be marked down in the final equation in proportion to the likelihood that it is just an expensive way to die.


The biggest barrier to space travel is our biology. We must create non-biological humans that can shut off and wait for the entire trip.


Or cyrogenics.

It's all starting to come together guys!


It's about more than just shutting down though. Biological complexity makes it infeasible to significantly engineer our biological bodies to e.g. make them smaller to reduce fuel costs, or make backups so that we can easily do potentially dangerous experiments involving ourselves (also reproducible experiments).

My prediction: humans will have to be 100% human technology to free ourselves from the Earth.



(not original with me): "The fastest way to travel to the nearest star is to wait 100 years and then go."

That's kind of depressing. But it's a lo-o-o-ng way to Alpha Centauri . . .


I've wondered about that, and how the break even point would be calculated. The soonest date that someone could get to Alpha Centauri wouldn't be on the same trip for the soonest date someone could leave for Alpha Centauri (and get there successfully).


And that will probably remain true at least until we have a functioning jump drive.


A little closer, I wonder how far we are from making something a little more mundane like a Babylon 5 spinning habitat, or even a 2001 spinning wheel station. Are these just a matter of money, or is there some other fundamental technology challenges to getting those things built?

I bet future Asteroid miners wouldn't mind a cheap place (relative to going down then up a planetary gravity well) to R&R between digs.


Depends what you mean by "just a matter of money".

If you could enslave the entire population of Earth to work full-time on the project for a couple of decades or so then, yeah, you could do it easily. In a world of free will and competing priorities I don't think it'll be possible until we reduce our cost-to-orbit. Certainly there are no big technological show-stoppers though.

As a vague guesstimate, I've read 1km proposed as a minimum viable radius for one of these things. So you'll need a rim about 6km long. The International Space Station is about 100m long, so if you staple sixty of those end-to-end you'd have a minimum-viable 1g station, at a cost of about six trillion bucks. But of course it would basically just be a thin tube, not much living space.

As for asteroid miners: I can't possibly imagine that this is the sort of thing that we're ever going to send humans rather than robots to do.


Well in an age of $19billion chat app acquisitions, $6 trillion ain't what it used to be. That's only a one time cost of 8% of the Gross World Product. Spread that over a 20 year construction time-frame and that's $300billion per year globally.

Something of that scale could reasonably be covered if the U.S., Europe and China/Korea/Japan all agree to Iraq War level spending each for that time period.


I've wondered the same - why don't we make artificial gravity up there? The best answer I can find is experts saying, "What's the point, after all the trouble of getting to space?"

The point is, living in zero-g is destructive to humans. Living in even 1/3 g makes a lot of things a lot better ... and a space station with a zero-g part as well as a small-g part would have the best of both worlds.


Or spin it at 2g and raise a generation of ripped space bros. Let's think big!


"Do you even lift?" has a new meaning in space.


If you're going to use a warp drive (or any other means of FTL travel), you'd better hope that Novikov's self-consistency principle [1] holds, or else be prepared to deal with the ensuing causality violations [2].

[1] http://en.wikipedia.org/wiki/Novikov_self-consistency_princi...

[2] http://www.askamathematician.com/2011/09/q-hyperspace-warp-d...

[Edited to add second link.]


"(The stars) remind us of the puny distances we men travel; the nearest one, Alpha Centauri, is four light-years away, far beyond our capability to visit today or in our lifetime, yet beckoning, mocking us and our dreams." - Mike Collins (Apollo 11 astronaut)


"What is more, the ship would be impossible to steer, since control signals, which are restricted to the speed of light, wouldn’t be fast enough to get from the ship’s bridge to the propulsion system located on the vessel’s perimeter."

Would someone mind elaborating on what the author is saying here. I would have supposed the warp field would surround the entire craft. If this weren't the case the ship would be torn apart, no? Everything I think about warp drive is so coloured by Star Trek I observe myself having difficulty imagining it could be any other way.


Imagine a ship travels at 1.5x the speed of light. Now imagine the signal from the "steering wheel" travels to the ruder with light speed. You turn the wheel. Before the ruder gets the signal and turns (and let's ignore human reaction time) the ship has already traveled however much distance you cover when traveling at half the speed of light. You would have an enormous lag basically.

Something like that :) I'm rubbish at physics :)


It is extremely sad that we have not traveled beyond Earth orbit since the end of the Apollo program in 1972. Space exploration inspired many of us to study math and CS and fostered innovation. The majority of the most relevant people in tech in the last 30 years (Bill Gates, Jeff Bezos, etc.) have repeatedly commented how the Apollo missions were inspiration for the their studies and careers.


Correction: humans haven't travelled beyond low Earth orbit since 1972.

No human has ever travelled beyond Earth orbit. I believe the Apollo missions may have achieved Earth escape velocity, though their destination was Lunar orbit, which remains within Earth's.


It's a marvellous fact that the Apollo missions achieved escape velocity, or close enough that they could have done so with small design modifications.

The calculation is fun:

The kinetic energy required to escape Earth's orbit entirely is: G M / R, where G is Newton's constant, M is the mass of the Earth, and R is the radius of the Earth.

The kinetic energy required to get to the Moon is: G M / R - G M / r, where r is the distance to the moon.

To compute the ratio of the second quantity to the first, note that the GM factors cancel. So the ratio is:

(1/R-1/r) / (1/R) = 1 - R / r

The distance to the moon is about 60 times the radius of the Earth. So:

Kinetic energy required to get to moon / Kinetic energy required to escape Earth's orbit entirely = 1 - 1/60 ~ 98 %.

In other words, the Apollo missions had at least 98% the kinetic energy required to escape Earth orbit's entirely.


The program did serve as inspiration, no doubt, but the fair question to ask is whether it was a better way to spend money than .. you know, actual science. Was society better from this than for example developing nuclear fusion or cancer treatments, which probably weren't more outlandish ideas at the time than going to the moon?

What truly boggles the mind is that the US at the time was a country of housewives, racial segregation and prosecutions of gays and bisexuals. Yet, or perhaps because of that, they decided that the way forward was to build a moon ship. It says a lot about society at the time.


Why can't Orion take off with conventional rockets and then switch to nuclear drive once in space? Wouldn't that address the main drawback?


Lets hope this doesn't start like Sid Meiers Story ...


Interesting there is no mention to EmDrive or Q-Trusters.


It was calculated that 2 people would die from exposure every time Orion spaceship takes of. It is hardly 'nuking the earth' as article suggest. Millions of people die every year from background exposure.


> Load your starship with 300,000 nuclear bombs, detonate one every three seconds, and ride the blast waves.

Ooops! I cannot find the words "stop", "brake", "decelerate", or "slow down" in the article. I guess it is to be understood that you carry 300,000 more nuclear bombs with you and blast them in front so that you don't blow right by Alpha Centauri when you reach it.


Although the article doesn't mention it, the original idea, having been worked on by a host of scientists and not a random person on the internet, does take that into account: http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propul...


Decelerating in space is the same as accelerating, you just face the other way.


Or a magnetic sail to slow down. For that you might need a longer runway than Sol-Alpha Centauri though.


If you send automatic probe, you do not have to decelerate to take a few pictures and measurements.




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