The Space Thread

They both rely on tech that's theoretically possible but hasn't actually been developed right now. The main advantage of moving it first is that it lets you do all the complicated work in Earth orbit, where it's easier to supervise in (nearly) real-time and much easier to repair if something goes wrong. The downside is that the actual rocketry of moving an entire asteroid is more difficult (you need bigger engines and more propellant), but since you already have to be pretty good at rocketry to get to the asteroid in the first place, that's probably not as big a barrier.

Really from Jupiter, but not an alien.

Is asteroid mining more complicated than steering a rover on Mars? Landing on Titan? Intercepting a comet? A close approach pass bt Pluto?

Is sending a couple humans to the asteroid more expensive than bringing the asteroid here?

Yes, yes, yes, yes, and yes.

Really from Jupiter, but not an alien.

I dont believe it. Sources?

Steering a rover on Mars has the advantage of 1) being a small scale project, and 2) dealing with a relatively static situation. It's one rover doing one thing at a time, and the things the rover on Mars has to deal with are unlikely to change in the time it takes to send messages back and forth. If you're trying to do industrial-scale asteroid mining, neither thing is true anymore. Your project is going to have a lot of moving parts (collecting ore, smelting it, storing the finished product, occasionally sending the stored metal back to Earth, etc), and many of these things are time-sensitive and the situation can get away with you if you're not able to monitor it in real time (what if your ore collector accidentally causes a rockslide? what if your smelter has an issue and doesn't turn off when it's supposed to, so starts cooking itself? what if a return launch fails and an exploding rocket lands on the rest of the facility?)

Okay, so you send some humans to keep an eye on things in real-time. The problem is that human presence makes everything vastly more complicated, because you have to add "while keeping several humans alive in a situation which can kill them very quickly if something stops working properly" to whatever else you're doing. The farther you are from Earth, the worse it gets, because the longer your backup plan has to last. Going to the moon? If something screws up and you have to abort, you just have to last for three days before you get back to Earth. Coming back from Mars? That takes takes eight months under ideal conditions. Hope you planned for that.

Landing on Titan, intercepting a comet, or making a flyby of Pluto is all just rocketry. You're going to have to do that sort of thing for asteroid mining regardless of whether you're doing the actual mining there or bringing the whole asteroid back. But if you're moving the asteroid, all you're doing is landing a rocket there and then doing some more rocketry to bring it back. The only technical challenge here is bringing enough propellant along (which, to be fair is not a small challenge, but it's pretty much the only one). If you're doing something like an ion thruster or a solar sail, then you don't have to carry literal tons of propellant with you, but you do have to wait a few years before your asteroid gets home.

If you're going to do the asteroid mining there, then suddenly your payload has increased massively. You've got to bring not only all the mining equipment, but all the mass dedicated to the care and feeding of humans, which is going to be a lot. Then you have to bring enough propellant for your humans to come home eventually anyway, which by itself negates much of the savings of not trying to move the whole asteroid. You're presumably getting your refined ore home somehow, which means either more rockets and more propellant, or something like a mass driver, which is not only yet more stuff to schlep up there in the first place, it means you also have to build some sort of receiving system in Earth orbit anyway or else your payload just burns up in the atmosphere. (The other option is making your payload-return ship capable of reentry on its own, but that adds a ton more mass, and you have to drag it all the way out to the damn asteroid in the first place, which boosts your costs of setup even higher.)

If you're going to run this for more than one crew cycle, you need to ship more people out to replace the original crew, which increases your costs again. (Alternatively, all the infrastructure you invested in to get the process started is wasted because there's still ore and still equipment to mine it, just nobody there to run it.)

the super-tldr version is this: moving stuff through space is hard. The farther you're moving it, the harder it is. Human spaceflight requires a lot of stuff, and the amount of stuff increases the farther you're going, which only compounds the problem. Moving the asteroid allows you to reduce the amount of stuff you need to travel long distances to a minimum (one rocket to go there and bring the asteroid back), and then have all the actual mining stuff move a relatively short distance (just into orbit instead of all the way out to the asteroid).

Think of it like this: the only real benefit of doing the asteroid mining on site is that you don't have to move the ore slag and mining tailings (the parts of the asteroid that aren't the actual metal you want, basically) back to Earth. The downside is that you do have to move all the equipment, supplies, etc out to the asteroid. Which is going to have more mass overall? The asteroid parts, or all the stuff you need to mine it (including crew and all their supplies and equipment, rockets and propellant for travelling there and back, rockets and propellant to send the mined material back, etc) over the lifetime of the entire project?

If we're talking about a reasonably pure asteroid (and we should be, because if we're not then why are we mining it in space instead of on Earth?), then moving the impurities is going to be cheaper than moving everything but the impurities.

Really from Jupiter, but not an alien.

Thanks for that in-depth explanation.

There is one other big advantage for the "mine onsite" idea though. Safety. When a big mining disaster happens beyond Mars, you lose your astronauts and equipment and investment. When it happens in Earth orbit, you've got all or most of the same, plus the potential for deorbiting asteroid chunks and/or Kessler Syndrome.

Which is why you do it up in lunar orbit or L3/4. It doesn't provide all of the advantages of LEO but still vastly simplifies things and once you're that far out you have so much space to work with even the worst fragmentation possible won't create a significant navigation hazard.

L4/L5. Those are the really stable orbits (the so-called Trojan orbits). L3 is the one on the opposite side of the moon.

But thank you Jovian for laying out what in detail what I was trying to get away with summarising.

Jovian: I am going to add this to my collection of effort posts because it is a good explanation and makes a handy short hand reference.

Who watches the watchmen?

Ah, I see, you're assuming that the asteroid in question is going to be relatively pure, that is, that it will consist almost entirely of valuable material, so that transporting the entire thing at once costs more or less the same as moving little pieces of it over time, since the total mass is nearly the same in each case.

The trouble is I dont think thats true. The most abundant minable material that asteroids are made of is nickel-iron, but n-i is so abundant on Earth that I dont see anyone going out to the asteroids for it anytime in the foreseeable future. The material most often discussed as being worth the cost of traveling through space to get it is platinum, which is relatively rare and valuable here on Earth. There are supposed to be significant deposits of platinum on asteroids, but in no case does platinum make up a majority (or even a significant portion) of the total asteroid mass. So, transporting an asteroid here would involve wasting a lot of fuel moving nearly valueless nickel-iron (valueless because the transport costs would exceed the market value).

All of this presumes we are mining the stuff for use on Earth—mining material for use in space is a totally different ballgame.

Anyway, I dont think the answers to all my questions are "yes". I dont see how deploying automated, remotely controlled, or some sort of hybrid design mining equipment is more complicated than, say, the Mars rovers. What if a wheel had fallen off? Or if a motor had burned out? Or if it had been buried in a duststorm? Or any of a million other things that could have gone wrong. I think you underestimate the complexity involved in unmanned space exploration.

As for humans—once your living in a space hab, your living in a space hab. It isnt inherently any more dangerous, complicated or expensive to live in one in Earth's orbit as it is at an L point, or in orbit around Vesta. The downsides are the additional transportation costs, and the difficulty of returning someone during an emergency.

The costs of transporting a mining team would have to be paid for out of the savings of not having to move the entire asteroid. I dont have any rigorous figures, Ill try to find some. The danger is simply a matter of psychology—offer enough pay and I dont think we will have any trouble finding qualified volunteers. This would be the kind of exciting adventure that thousands of peopke would be eager to try—the spirit of adventure calls.

It certainly has to be relatively pure (otherwise, as I said, why are you bothering?), but only to the point where the mass of everything you have to ship out to the asteroid over the entire life of the project is greater than the mass of the non-useful parts of the asteroid.

Just for some context here, the International Space Station weighs almost a million pounds, and all it does is let six people survive in space (with regular resupply, so they're not storing much in the way of consumables) for a few months at a time and do some relatively low-mass experiments. You want to ship heavy industry equipment. I admittedly don't know how much that would weight, but saying it'd be an order of magnitude more doesn't seem unreasonable to me. So that's ten million pounds of stuff. And that's just to get there. You want to bring stuff back, you're shipping an insane amount of propellant up there (something the ISS doesn't have to worry about, because the only things it brings back are trash to burn up in the atmosphere and crew returning home, and the propellant costs there are cheap because all they have to do is break orbit and then aerobrake back to Earth).

I'm also assuming that we're talking about an industrial-scale operation, here. If you want to send a mission out and return with a few pounds — or even a few hundred pounds — of platinum, then yeah, you're going to be better off with the "going there and coming back" plan. But if you want to start churning out useful metals by the ton, then the equation changes.

Ultimately, the problem is the tyranny of the rocket equation. tldr, to go anywhere in space, you've got to bring enough propellant with you to to carry all your stuff... including your propellant. So you add more propellant in order to be able to carry all your propellant. But the extra propellant for that also requires more propellant. And that propellant requires more propellant too, etc etc etc. This doesn't go on infinitely, obviously, or it'd be impossible to get anywhere with a rocket. But it does mean that going twice as far (or carrying twice as much stuff) doesn't require twice as much propellant — it requires exponentially more propellant. Which means that the cost of moving mass around adds up real quick.

So yeah. Ultimately the answer is "it depends". If you're grabbing choice bits of rock that only amounts to a tiny fraction of the total mass of the asteroid, then you're probably better off shipping your whole operation out there and shipping the finished product back. But if you're using a significant portion of the asteroid's entire mass, then you're probably better off moving the whole damn asteroid. My assumption is that since space industry is difficult and expensive, you're not going to bother with asteroid mining at all unless we're talking about reasonably pure ore in reasonably large quantities (otherwise it's going to be cheaper to just mine it on Earth), which is why I argue for the latter scenario.

Not really — it's still about delta-V budget in the end. Which is better, shipping stuff up from Earth, or in from the asteroid belt? (The boring answer is that delta-V costs from Earth orbit to the asteroid belt are higher than Earth's surface to Earth orbit, so you're probably better sending things up.) Sending things back to Earth or using them in space changes the variables, but not the equation.

I'm not saying that unmanned space exploration isn't complex. I'm saying that running an industrial-scale mining operation is more complex than running a science probe. The sort of science that Mars rovers do is the kind of thing that could be done by one guy if it was happening on Earth. Taking pictures, taking samples, analyzing samples (with on-board equipment whose operation boils down to "insert sample, press start button"), moving somewhere else where they can take more pictures and more samples. It's pretty basic stuff, it's only hard because it's on another damn planet.

Now compare that to the mining and refining industry. Those are complex tasks even on Earth, involving dozens of people and a complex logistical framework even for relatively small-scale operations. You want to do that remotely (or with a small crew), in friggen space. That's going to be really, really hard. Doing something in space makes it exponentially more complicated on Earth, and a mining/refining operation is already exponentially more complicated than basic science like taking pictures and samples.

You're contradicting yourself here. The additional transportation costs and difficulty in reacting to emergencies is what makes it more dangerous, complicated, and expensive.

Really from Jupiter, but not an alien.

His whole point is the vast majority of any asteroid is dead weight iron and other common materials.

If anything your while rocket equation bit is against Your point. We're going to ship enough fuel out to a rock to bring back the entire rock including the worthless parts? You need to bring all the fuel to move that asteroid too. There's literal tons of dead weight that serves no purpose.

A ship capable of limited mining/sorting would reduce the amount of mass you'd have to bring back ridiculously.

edited 8th Apr '18 6:39:31 PM by Joesolo

I'm baaaaaaack

Well, as to "why bother", it's entirely possible that we wont. The idea that asteroid mining can ever be financially viable for Earth importation is still speculative. We may have to invent some new drive technology in order to make it work, chemical rockets arent exactly the most cost effective option.

"...but only to the point where the mass of everything you have to ship out to the asteroid over the entire life of the project is greater than the mass of the non-useful parts of the asteroid."

Pfft, 10 million pounds is nothing, dude. A mere 1 km nickel-iron asteroid is projected to weigh in over 2 billion tons (not pounds, tons), and that's just a middlin' asteroid. I think we can design an automated mining factory that comes in at a little less than that

So yeah, if it's a question of fuel to transport mass to and from the Earth, whatever refining we can do in situ will be well worth the cost and complexity. And we dont have to bring any of the equipment back. If it survives to the end of mining operations on the first asteroid, we just shunt it to the next one. We dont need it back here.

Now the scale of the operation is an interesting question. Currently platinum runs about $23-24K per pound, but of course that price wouldn't hold if someone brought back, say, several tons of it. The law of supply and demand imposes restrictions on the amount one can dump on world markets at any one time without the price crashing. You could easily bankrupt yourself by bring back too much (this same dynamic can be observed in any precious commodity market here on Earth, its the reason why OPEC only sells a limited amount or oil per year, or De Beers a certain amount of diamonds. Both control world prices partly via controlling the supply). Note that this is a human-created problem, you cant solve it with technology. It's inherent in the nature of capitalist economies. So whoever finances the first asteroid mining operation is going to have to calculate how much they intend to bring back, and at what cost, very carefully.

The long and the short of it is that there are a lot of imponderables here, and the most financially cost-effect scale of operation may not be knowable right now. But at current market prices a thousand pounds of platinum would be worth around 25 million dollars or so—and about 40 thousand pounds would yeild a billion dollars. As you point out, compared to, say, the ISS, that's not a lot of mass.

"So yeah. Ultimately the answer is "it depends". If you're grabbing choice bits of rock that only amounts to a tiny fraction of the total mass of the asteroid, then you're probably better off shipping your whole operation out there and shipping the finished product back."

OK, so we are mostly in agreement, then. But there is one scenario where most likely nearly the entire mass of the asteroid would be utilized as raw materials, and that's if its being used to support a relatively self-sufficient space-based colony (most probably an artificial hab in a zero-g environment), as opposed to shipping it to Earth. Waste not, want not, and a space-based habitat would find a use for just about anything, even gravel. They might find it worthwhile moving whole asteroids around.

"The boring answer is that delta-V costs from Earth orbit to the asteroid belt are higher than Earth's surface to Earth orbit, so you're probably better sending things up."

Here I disagree. The delta v required depends on total acceleration, not distance traveled. If you are willing to wait long enough, you can get by with low acceleration, which means certain types of very efficient drives become more viable, like solar sails. Anyway, the kind of self-sufficient space colony wont be located in Earth orbit, more than likely it will be at an Earth-Solar Lagrange point, or maybe an asteroid, or even Jupiter.

So I think we share some of the same underlying premises, we just disagree on what conclusions that leads to. We both agree that unless the majority of the asteroids mass can be utilized, it isnt worth bringing the asteroid back. You then presume that this means any asteroid we mind will be relatively pure, while I assume the opposite—that we wont bother with asteroid mining except for precious metals, and except for self-suffienct space-based habitats.

As for the rest, it would be fun to compare technologies, exploration vs. mining, but frankly I'm too tired right now to do the research. Maybe later. Suffice to say that serious exploration here on Earth always required a very extensive logistics operation (consider, for example, the exploration of any of the major continents, including Antarctica). Mining was once a couple guys with pick-axes. It all depends on how easy it is to find the stuff you are interested in, vs. the difficulty of getting there in the first place.

edited 8th Apr '18 7:57:28 PM by DeMarquis

This is incorrect. The vast majority of very large asteroids are dead weight, but those aren't the ones we're interested in. Moving Ceres into Earth orbit would be a losing proposition, certainly. But finding a chunk of space debris that's a few dozen meters across and 75% platinum? That's the sort of thing I'm talking about.

...at the cost of boosting the amount of mass you have to send out there enormously. That's the trade off.

That's basically my point, yes. Finding a relatively pure asteroid and bringing the whole thing back is a best-case scenario that has the most return on investment. If that's not a realistic option, then I think we pretty much default back to "just mine it on Earth", because space is hard and expensive and unless we get a really good ROI it's probably not worth the effort.

Which is why I'm not talking about anything even close to that size. I'm talking about a chunk of space debris a few dozen meters across made entirely or almost entirely of a single target material. That's still going to be a hell of a payload, and it would keep your orbital industry busy for a while, but it's not even remotely close to what you're talking about. This is why I was emphasizing that my hypothetical target would be relatively pure. I'm not talking about parking Ceres at L3 to dig a few tons of platinum out of it.

Now you've gone way the hell past anything I've been talking about. You want to build actual honest-to-god permanent space colonies, we're honestly at a point so far beyond our current capabilities that speculation is nearly impossible.

Really from Jupiter, but not an alien.

I only raise it as a speculative possibility. But placing a long term hab somewhere isnt any more beyond our technical capabilities than asteroid mining is.

Guys guys guys - Curiosity has found organic molecules on Mars. There's hope for the Martian populace yet!

That’s the epitome of privilege right there, not considering armed nazis a threat to your life. - Silasw

You mean what's already there or the speculative future space colonies?

I have a couple questions about Hawking Radiation

• When the supermassive black hole in the center of our galaxy finally dissolves thanks to Hawking Radiation, how large is the final energy release expected to be?
• What do scientists think happens to the singularity in the black hole once Hawking Radiation takes the space-time warp out? Does all the stuff still stuck in there finally get freed and space-time returns to normal?

• I belive it'd be the energy that a black hole with a radius or diameter on the scale of one Planck length would have.
• That's an unsettled physics question.

edited 14th Jun '18 2:27:55 AM by SeptimusHeap

"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman

As I understand it, stuff isn't "stuck in there", it becomes the black hole, ie the stuff that's slowly dissolving due to the Hawking radiation. It's not like a black hole is a gate to a pocket dimension and when the black hole finally evaporates all the stuff pops back into reality.

Really from Jupiter, but not an alien.

To paraphrase on your first question. Tiny. Hawking Radiation doesn't mean that a supermassive black hole suddenly blows up. It slowly evaporates. From my understanding of current models it will speed up as the black hole gets smaller, but it will be more of a "pop" than bang once it reaches a small enough mass.

E = mc^2. Energy equals mass times the speed of light squared. This is the equation you need to understand to get what's going on and why you're questions is not even wrong. Short version is that the mass of the black hole can be treated as energy and that energy is what is evaporating away in Hawking radiation

Would this mean that stuff like Wormholes are purely in the realm of Science fiction then?

So the black holes in space are going to end in an anti-climax, huh. Countless eons from now, when there's no life, not even atoms as all the protons decay, what's left is going to go out with a whimper more than a bang. That's kind of depressing

Another thought: If the theory that the universe will expand forever is true, the idea is that in bazillions of googolplexes of eons another Big Bang will occur through sheer law of probability and Eternal Recurrence...does that explain where the Big Bang came from in the first place? That Einstein was actually right in believing time is eternal, it's just that stuff is separated by 10^10^115 years of functional nothing?

Could be. No matter how unlikely something is, the longer the studied timescale, the closer probability becomes to certainty.

---

Just read an article that some scientist guy discovered that cianobacteria are able to photosynthesize infrared light, which ups the habitability of red dwarf systems and ultimately the chance of there being life out there.

A recent study published in Nature claims to have found the missing 30% of the universe's baryonic mass. Namely, spectroscopic analysis of a quasar's light with multiple satellites revealed highly ionized (~1000000 °C) streams of oxygen gas in the intergalactic medium that are dense enough to account for the missing mass if extrapolated to the scope of the universe.

edited 22nd Jun '18 5:13:04 PM by amitakartok