And The International Space Station, which provides a microgravity environment for as long as we care to strand someone up there.
The ISS is the only one of these that can provide the data we need to go to Mars. Its first crew arrived five years ago. There have been ten crews, about six of which have spent six months or more on the station. That, plus whatever we gleaned from Skylab and whatever the Russians have told us about Mir represent our entire data set re: true long-term exposure of humans to the space environment.
Regarding radiation, “intractable” to me means “provably insoluble within the constraints of any reasonably forseeable available time and/or resources.” Please provide a cite for the proof.
Even if it were true that they only did stuff for schools, you’re saying that 1/50,000th of the Federal budget is too much to provide some of our own students with a research opportuniy they could never otherwise get? You have no heart.
Yes, there are some high school experiments. There are even some middle school experiments. But the bulk is hard science. When the ISS was preparing for its first crews, the science community made a lot of noise about how inadequate the new station was for a variety of things they wanted to do. What the papers didn’t tell you is that nobody cancelled their ISS experiment in light of their griping.
We don’t even know how well a person will fare on Mars after a six-month journey, and suddenly we’re going to strand them on a literal rockpile (an airless one at that) twice as far away in the Asteroid Belt?
Asteroid mining only makes sense if you’ve got a functioning Mars base that swings by every 2 earth years or so to check up on things. Running a mining operation from Earth would be a logistical nightmare.
Baby steps. Think baby steps. Just because they show something on the Sci-Fi channel doesn’t mean it’s easy to do.
Manned only cuts into non-manned in the current budgeting environment where it is apparently verboten to spend more than two-thirds of a penny per federal budget dollar on space. Surveys are showing that the biggest problem in Iraq right now is the American presence there and its effect on the populace. Scale back operations, take some of the cash and fund the stuff that people imagine space research is leeching vital dollars from, and save a couple of cents to double or even triple the NASA budget. Then we can both be happy.
You are right. Unfortunately, every few years, some “expert” comes along with a magic bullet to fix everything. No matter that it is completely idotic and impossible to implement. We are then ordered to fully understand every subtle nuance and apply it to every situation. In short, we are ordered to force it to work. When it doesn’t, it is our fault. Nevermind that it can take three years or more to get started, change procedures and rules, codify it, and try to make some sense out of it. About a year or two after we are just starting to force it to work, some other damn “expert” comes along with a new magic bullet, and we have to start at square one all over again.
Asteroids are not present only on the asteroid belt; some have orbits that put them uncomfortably close to the Earth, getting to one of them (either on a manned or unmanned mission) would be much easier than Mars; also, lifting off from it would be trivial compared with the Mars equivalent.
All this talk about the effects of free-fall on human bodies, and the six-month trip to Mars… It’s true that we don’t know exactly what weightlessness does to us, but it doesn’t look good. And it’s true that it’s a long way to Mars. This is only a problem if, for some reason, we insist on sending men to Mars in weightlessness. We know a heck of a lot more about how to spin a ship than we do about the human body in zero-g (or even in 1 g).
Back to the Shuttle, if we had the opportunity to go back and do it all again, knowing what we know now, we should not have built the Shuttle. We would have been better off with Apollo hardware, and much better off with a more mature development of that hardware. But we don’t have the opportunity to go back, so we work with what we have. What we have includes three completely designed and fully functional Shuttles, so we may as well use them.
And by the way, every payload which has ever been flown in space, manned or unmanned, has carried hardware which would be considered obsolete by ground standards. The design for a spacecraft takes long enough, and technology advances fast enough, that this is inevitable. And you can’t just plug in a new computer, say, in place of an old one just before launch, because then you’d have to redesign everything else to accomodate that change. This is not a valid criticism of the Shuttle or any other space system.
This is correct. I think there are also some arguments for using “obsolete” technologies even at design outset which have little to do with the lag from inception to completion, the simplest being those parts are often more robust than state-of-the-art designs. If it’s serviceable and time-tested to survive the harshness of outer space, there’s no reason not to use it. A lot of what is considered “advanced” in terms of microprocessor design would be inappropriate for use in the Jovian magnetosphere, for instance, without impracticable bulky shielding.
Is there a justification for space mining? What purpose would it serve other than to build space stations. How many space stations would we want/need? Would it be desirable in the next 100 years for us to build a space city?
When I think of space mining, I think it sounds like a patently ridiculous proposition. Why would you want to bring rock from one area to another? Wouldn’t it be simpler to just manage the resources on Earth, than to bring ore from an Asteroid across the solar system back here? The simplified cost/benefit analysis I am doing in my head says “That sounds retarded”. I just think the logistical nightmare compared to the amount of ore that can be brought back to Earth with each payload, would be out of hand. How many trips down to Earth would they have to make for us to actually have enough ore to have justified the expense? Why on Earth would we even need extra-terrestrial ore? Space Mining seems like it won’t have any practical application for a LONG ways down the evolution of space flight, which for all intents are purpose is still a fetus growing in the womb. Space exploration has yet to really be born.
We may not need it, but then again, it might just come in handy, and I’ll give you an example in which space mining might just make more sense than trying to utilize Earthbound resources. Admittedly, thecnological innovation may make this an unnecessary thing, but no one can accurately predict the various twists and turns tehcnological adnvance, so we need to be prepared to do something like this, at the very least.
Fuel cells use some exotic metals in their construction, like platinum and palladium, and given that fuel cell technology seems to be advancing much more rapidly than battery technology, it seems possible, that there might come a day when it makes more sense to switch to fuel cells than to continue to use batteries. We know that there’s plenty of exotic metals in asteriods (there’s one that has more titanium than exists on Earth), and one of the worries has been that if someone actually managed to snag one of those and started mining it, they’d flood the market to such an extent that whatever metal it was would drop to pennies a ton thus preventing anyone from making a profit off of it. However, if that metal is in great demand for something like fuel cells (which could not only be used in cars, but planes, electronic devices, anything that needs electrical power), then the price collapse is desirable, because it’ll make fuel cells cheaper, thus accelerating the adoption of the technology.
As for getting it from orbit to Earth economically, that’s not really all that hard to do when you think about it. 70% of the Earth is covered by water, all you need to do is slow the fall of the thing to less than a few hundred MPH, so it doesn’t burn up or create a tsunami when it hits and it’s there for the taking. A few strap on rockets and some parachutes ought to do it. After all, it’s not like there’ll be anyone on the thing to care if the landing’s at a cushy 2 MPH or not.
How close it comes to Earth has almost nothing to do with how easy it is to ‘get’. It might be easier to land on it, but if you want to capture it you have to apply enough delta-V to the rock to move it to a circular earth orbit. The fact that it comes very close to earth tells you nothing about how much energy is required to move it into Earth orbit.
Also, we have no idea how to ‘capture’ an asteroid. Moving something that weighs billions of pounds is something that is completely outside of our technical ability. I imagine that the answer would be to put a big nuclear reactor on the asteroid and heat its own material and eject it as a rocket, but that’s an engineering challenge much, much more difficult than anything we’re attempting now.
We’re talking about an asteroid, and you’re going to slow it down with parachutes? Not unless you cut it up into millions of chunks.
Something the size of an asteroid is going to cut through the atmosphere like it’s not there. Even if you could bring it to a dead stop over earth, it’s going to be going insanely fast when it hits the earth. I don’t think you want to just drop the thing from orbit.
More likely, We’re not even going to move the entire asteroid from the asteroid belt. It’s much more likely that we’d mine it in place, extract the really valuable stuff and leave the slag behind. Perhaps the slag would be burned for reaction mass to get the cargo back to Earth.
The neatest idea I’ve seen for mining a metallic asteroid involves putting a magnetic field around it, then spinning it and letting eddy currents in the asteroid heat it until it melts. The raw materials stratify into layers when they cool according to their density. THen you just peel it down to the valuable layers and mine them off.
Not necessarily. There’s ample numbers of asteroids out there the size of a school bus or smaller. The space shuttle is freakin’ huge, and we can slow it down fairly effectively. Not all asteroids are the size of Ceres.
Actually, no matter how big the thing is, it’s going to hit terminal velocity at some point in it’s fall to Earth, and if it’s allowed to simply drop into the atmosphere, it’s liable to break up into lots of small pieces because of the friction created by atmospheric heating.
Possibly, but it’d be unlikely that folks would be supportive of sending humans out to do that, and our robotics technology isn’t up to snuff yet, so we couldn’t send robots out to do it any time soon.
Induction heating. It’s common practice in foundries to melt metal. It has the advantage of allowing greater control of the heating of the material. As for using the slag as reaction mass, that’s not a bad idea, but it’d take a lot of power to do that.
Four points:
First of all, as has already been pointed out, not all asteroids are in the Belt. There are asteroids all over the system, some in near-Earth or irregular orbits that bring them close to the Earth. Whether you could bring the asteroid, or significant chunks of it, into a safe static orbit near the Earth (say, at L5) is another question, but one need not travel several AU to visit.
Running an operation from any gravity well is a logistical nightmare. Having to transit in and out of a gravity well requires fuel and risk. Better to maintain the operation completely in free fall rather than attempt to base it on a planet or large moon. Of course, there are problems with long-term human habitation in free fall; a permenant manned presence would require some kind of simulated gravity, i.e. a rotating habitat, but that would be easier and less costly than a constant up-and-down.
Actually, the further you get away from the Sun, the better off you are in space. On Earth, we have the thickish atmosphere and the magnetic field to protect us from excessive radiation emitted during high solar activity (flares). In space, you have to carry extra mass for protection; you can use the propellent for protection on the way out, perhaps, but will have less for the return trip. Even with unmanned probes, paths and times have to be planned carefully to minimize exposure during periods of peak output. With a manned vessel, your window of operation is even smaller; depending on what assumptions you make about the resilience and resistance to mutation/cancer humans may not be able to even withstand 6 months of travel in the band between the Earth and Mars. However, travelling away from the Sun, solar radiation drops off as a square function. Radiation levels that might be dangerous in Mars orbit may be quite manageable in the Belt or Jupiter.
Also, your 6 month transit (each way) is going to require a considerable stay on Mars; something on the order of 19 months if I recall correctly, though I can’t find a cite off-hand. Mars has a minimal magnetic field and a very thin atmosphere. A crew would not only have to get to Mars but would probably need to burrow and maintain supplies for that period. This adds great complexity to an already complex mission, with a questionable knowledge payback relative to an unmanned mission.
Some resources, like the (heh) rare-earth elements are difficult to locate or extract. Others, like copper, are relatively abundant but dirty to process. Already, in the United States, much traditional mining has stopped because complying with environmental regulations is more expensive than the material is worth (for now). Other elements, like tantalum, uranium, and tungsten, are only found in a limited number of deposits and availability on the open market is subject to political and economic whims. (The Soviets were able to build several classes of submarines out of titanium, for instance, whereas the US couldn’t obtain enough on the open market, or at least at a competative price, to follow suit. As a result, the Alfa could dive deeper than an American sub and escape an engagement, despite its other technological limitations.) And then some elements are just plain rare anywhere, like gold, platinum, and the above mentioned rare-earths; they have a lot of technological uses but the cost drives us toward compromise solutions.
Arguing space mining on a strict economic basis, however, is futile. However much it costs for us to extract, say, gold, can’t even compare to the cost of developing vehicles and methods of mining it in space on quarterly balance sheet. The investment in space exploration and transportation is enormous. The payoff, however, are resources of unimaginable vastness. This has its own implications; mainly, that you’ll drive the cost of the material so low that it isn’t “worth” mining. This is a result of the present restriction on how much material we can access; like finding a vast new oil reserve, it has the effect of making a valuable commodity less valuable. One has to make the arguement for space mining on the assumption that it gives an ongoing reason to be out in space and to explore, and provides the materials to continue doing so to boot.
If that explaination sounds a little self-contradictory, well, I suppose it is. But then, it was once thought ridiculous to transport goods from the Orient to Europe by sea; the costs and risks were too great, despite the difficulty of overland transport on the Silk Road. Today, though, we think nothing of shipping raw ore to Japan and buying finished steel back from them; it’s significantly cheaper than buying steel milled in Bethleham. Considering space exploitation with current technology does seem absurd; the argument for doing so is that we’ll develop the technology to make it feasable, and along the way, do a bit of exploring and perhaps colonizing, too (though I doubt we’re going to be moving significant portions of the population off-planet any time soon.) What is difficult or impossible today may be tediously simplistic fifty years from now.
The thrust to move such a mass need neither be constant or large; a small, continuous impulse (such as a large solar sail or mirror, or a high specific thrust ion drive), or occasional bursts of high thrust (Orion- or Daedalus-type propulsion) would be sufficient, over time, to move it into a near-Earth orbit, preferably in the outward Lagrange point. You need not accelerate the entire mass, either; assuming you’ve developed some kind of refinement capability in space (and there are a lot of benefits in doing so) you only need to move the mass of the refined materials.
Still, I don’t mean to minimize the complexity of such an undertaking. The project would be a tremendously difficult and challenging project, far beyond the means of any corporation, and functioning for decades before seeing a profitable return. That doesn’t mean that its not worth doing or planning for, but bopping around in near Earth orbit, or stunt missions to Mars aren’t getting us any closer. NASA just doesn’t have any vision for this, and that is partly by design, as they’ve outright refused commerical cooperation in the early years of the program, and have tried to justify the Shuttle as a satellite launcher even though dedicated boosters are cheaper and more capable.
If space programs were television stations, NASA would be PBS, complete with telethons begging Dr. Who fans not to let their favorite shows be cancelled for lack of funds while continuing to show season after season of “Masterpiece Theatre” and wondering why so many people are watching TNT and MTV.
This is true, as far as it goes. The problem with the Shuttle, though, is twofold: it was not designed to be modular or accomodate modifications, and as has already been noted, it was essentially a test platform that was driven straight into a flight-rated design.
On the first point, constrast the Shuttle with Apollo: it was known and accepted that during the program new technologies would be developed, and plans were made to integrate them into the vehicles and mission planning. The performance increases on the Saturn V, for instance, permitted taking a rover to the Moon (#15, I think). Other enhancements to the heat shield, flight control systems, et cetera were made concurrent to build and planning. Since each Apollo capsule and Saturn V booster was a one-off, the only cost in doing so was integrating the design. The Shuttle, on the other hand, is “reusable” (well, the spaceframe and flight controls, anyway), and so it was much more complicated to make design changes. Plus, with greater budget restrictions and oversight on expendatures, NASA was reluctant to make any changes for fear of incurring greater cost overruns, even technologies that would offer better performance or make the Shuttle more reliable. The booster blow-past problem was well known, and several engineers at Thiokol already had a preliminary solution, but nobody in charge wanted to hear it because of the cost of making a major design modification outweighed the (then thought) negligable reduction in risk. The Shuttle’s computer systems, too, were obsolete (in fact, some of their hardware actually predated the later Apollo systems), and because they used proprietary and largely undocumented code the systems were extremely difficult to upgrade or modify.
On the second point, the Shuttle really was an engineering prototype. While two test articles were built before Columbia (Pathfinder and Enterprise), Columbia was essentially identical in overall design. Later Shuttles followed the same pattern even though several flaws were found with the original design. While some improvements and enhancements were integrated into Discovery, Endeavor, and Atlantis, they are still essentially the same design. It would have been wiser to use the lessons learned from the first fleet of Shuttles to do a new design which avoided some of the compromises and integrated the then-current technology; but that would have been tantamount to admitting that the Shuttle design was suboptimal, something NASA has never really owed up to. A similar thing happened with the X Programs; initially, the Xs were supposed to be test articles, flown to and past design limits to learn about the problems of various configurations. Somehow, it came around to the Xs being scale models of intended flight designs, and then cancelled when they showed conceptual flaws.
NASA (or whoever wants to run a successful space program) should instead operate under the assumption that the design of a space plane or rocket will undergo constant evolution at this embryotic stage of development, and like Apollo, each vessel may be considerably different than the last. This approach lends itself more to single-use or limited-use systems like Apollo or Soyez, but perhaps, given the current infantile stage of spaceflight technology, perhaps we shouldn’t be focused on reusability as a realistic design goal for the near-term, any more than a parent would expect a toddler to use the toilet instead of wearing a diaper.
As for the remaining Shuttles, I agree with Chronos that we have them and in fact they are the only vehicle we presently have (Apollo is gone; much of the tooling was destroyed and I suspect that even a lot of engineering data on flight hardware is lost or in formats not readily accessible), so we should and have to use them until we build something to supplant it. Whether we risk further manned flights (and despite the 14 people lost, it still has a higher demonstrated record of successful flight than any other platform) or unmanned, it’s all we have.
A failure? Meh…it’s a baby step. One doesn’t expect a toddler to hop, skip, and jump; we’re just happy that he can walk without holding on to furniture. I don’t think we’re ready for long pants, yet. It’s a pity, 'cause I was really looking forward to those honeymoon vacations in the rings of Saturn. Oh well, given the dating situation it doesn’t look like I’ll be getting married any time this century, anyway.
I understand that, but the discussion has been along the lines of an asteroid big enough to depress the price of metals. That’s a BIG asteroid. And besides, a chunk of metal the size of a space shuttle is unimaginably heavier than a shuttle. Slowing one down with a parachute is not very likely.
And what would the terminal velocity be of a solid chunk of steel the size of, say, a skyscraper? A cube of steel 100 feet on a side weighs about 250,000 tons. in comparison, a 747 weighs about 450 tons. Whatever the terminal velocity of that block is, it’s probably close to irrelevant I’d think.
Well, you need some kind of reaction mass. No getting around that. Maybe the best way would be to make a big mass driver and just start throwing stuff off the back of the Asteroid. It would have the double advantage of lowering the mass of the thing with each ejection, making each launch more effective. Still, this is space engineering far, far ahead of anything we can contemplate doing in the near future.
It depends upon the metal. Metals that are fairly common on Earth would take a massive chunk of material. Something like palladium, not such much.
Especially if you happen to be standing at ground zero.
Only because of a lack of will. The challenges would be great, but we managed to go from strapping a guy to the top of a modified ICBM to landing on the Moon in less than a decade because we had the will to do it. If someone manages to develop a highly efficient fuel cell using rare earths, and a cheap way of extracting hydrogen from water, and we might be able to develop the will, especially if gas prices keep going up.
Yeah, the idea of space mining is cool, and I have a little better idea of it now, but my point still stands about it having nothing at all to do with the current space program. When we want to colonize the solar system, then sure I can see it being a necessity.
How many tons of titanium would be required to make a mission like this make any sense at all?
How many tons of titanium do you need? There’s one asteroid which is supposed to be made up of so much titanium that at current market prices for the metal it’s value is something like $70 billion.
Right but what I mean, is what are the mass/volumes that we could get back to Earth, and what would the relative cost be? I’m thinking of a cost-benefit analysis. I guess what I’m trying to say is how many tons could we bring back with current tech + some work on this as a dedicated project, and what would it take to cover the pricetag that’s gonna be 7-8 figures?
Well, according to this site, the current price for titanium is $23/lb. with costs expected to climb. As for how much it would cost to go out, find the asteroid, mine it, and dump the resulting titanium on Earth, well, that’s a toughie. It depends on how you’re going to do it. Ideally, you’d want to pick an asteroid that was either fairly close to Earth, or passed near Earth fairly regularly (assuming you can find one of those with titanium). Also, it depends upon if it’s a government job or not. In a government job, nuclear fuels would be easy to obtain, but impossible for private industry (unless it’s a joint program).
If you can snag an asteroid close to Earth, then the technology for getting there, getting the asteroid, basically already exists. This technology could probably adapted to smelting the ore out of the asteroid if you had to do it, non-nuclear. Best guess is that it would probably cost somewhere in the neighborhood of $20 billion to do the project, if it was close in, and non-nuclear. Add another billion if it’s a nuke powered mission, and another $10 billion if it’s a far mission.
So factoring in the fact that the Titanium would pull the rug out of the Titanium market, it would be a really tough thing to do to make it marketable AT ALL.
I think we’ve got a ways to go before we start looking at practical economic returns from mining ore in space. I don’t know how long, because I’ve seen so many damn advances in my life that who can predict?
