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So you are saying the US Army should assemble all the rockets, build the space vehicles and launch the mission because it is more efficient than the private sector? The US Army does have a large supply of manpower. Instead of fighting and shooting, they could be put on an assembly line and trained to do a number of tasks that are required to get to Mars, and if they don't follow orders, they get court marshalled.
I'm not sure where you are getting this from at all. I've said nothing of the sort. Please don't set up strawmen of my arguments.
What is $30 billion to the US economy? It is about 1% of Federal spending, but as a part of the economy as a whole it is a much smaller fraction. Last I looked at the figures Gross Domestic Product for the USA was $12 trillion, as a fraction, it would be a mere 0.25% of the US economy, and I didn't say foreign firms couldn't compete. NASA will give US firms access to US technology such as the Ares rocket, but the Russians can come up with their own technology and spend their own equivalent of $30 billion.
$30 billion is a lot of money, even to the US economy. That kind of capital isn't just lying around for just anyone to snatch up and grab. There is actually very, VERY little money just sitting around not being used. Money is infact worthless unless it is being used/invested in something. So what this ultimatly means is that you're money will have to be moved from some other (presumably less profitable) investments. It actually is slightly more complicated than this as the fed/banks do have the power to issue more money, but this doesn't change the competativeness of the money market one bit.
Lets look at that market for a little bit, shall we? Assuming the prize is $60 billion (the figure you start of with) and the actual cost to the company is something like $30 billion. Mars Mission don't happen overnight, so lets assume a 10 year time frame from the start date, which means that you are only getting a ~7% return, which frankly, given the risk compared is pathetic. Putting that money in the stock market would give you an average return of somewhere around ~10% over any 10 year time span, and the risk would be IMMENSLY lower. You would need a return a prize of $70 billion dollars just to be competative with the stock market. But again, you're risk is MUCH higher then that of a stock market investment.
I again stand by my point. If there was in fact a point that the risk of the investment was offset by the potential gain, the goverment could then probably do it for less money itself. This is even more likely since the goverment already owns all the launch infastructure it would need.
The only castasrpophic risk is if something bad were to happen in space because the corporation launched the mission too early. Haste makes waste as they say. With greater risk, greater reward is demanded. The prizes would just keep growing over time until their sufficient to induce activity on the part of the private sector. A billion dollars is not as much as it used to be, both in terms of inflation and as a proportion of the US economy. Multi-billion dollar companies fail all the time, witness Enron, and the US economy has survived them. There is no such thing as too big to fail, if there is, then it becomes a government run corporation and it ends up just as inefficient as any other government agency.
You are right that greater risk requires greater reward. My point is that the risk is SO great that the reward that would be needed to provoke private investment would be larger than the cost for the goverment to do it itself. And in a way, the goverment endures no risk, as it can keep going at it untill it is succesfull, which a private company cannot do.
And while the faliure of a multi-billion dollar company would not bring down the US economy (I never said it would, another strawman), that doesn't mean their wouldn't be serious human suffering as a result. When Enron colapsed, thousands lost their jobs, investments, and retirement plans. Furthermore there IS a noticable impact on the economy at large from such effects. The US's GDP is not generate overnight, but over the course of the entire year, if 30/60 billion dollars was to disapear on any given day, it does create waves that cycle through the system causing effects elsewere. It in the goverments intrest to promote a smooth operation of the US economy, not jerky starts and stops.
Funny thing, if you said Texas is a red state in the 1980s, they would have laughed and reminded you that Cuba is red, Russia is Red, and China is Red, but not Texas!
Yeah, less funny if you live there. Especialy if you live in a district (like I do) that was gerrymandered to get more republicans elected. Thanks, Tom DeLay.
The government only pays for success and the private companies worry about the risks.
The bold part of you're statment higlights the problem with this plan. Risk. Space travel is VERY risky. Both from a simple human point of view, and even more so from a finacial point of view. Rockets malfunction, blow up, people even die. These sorts of failures are costly both in terms of human life and (more importantly to a coporation) capital. Space-X is struggling with this very issue right now.
Now for the goverment, this risk is managable. The gov. has basicaly limitless pockets and does not demand immediat tangible results (ie money) as a return on its investment. This is not true for a corporation, which has both limited finacal resources, and must show a return on it's investment. And when dealing with the billions of dollars you are talking about as 'seed' money for a space enterprise, coporations (or any other finacer with that kind of money) are very averse to risk. The private sector simply cannot afford to throw away that kind of money on a failed mission attempt.
Simply put, the risk is to great for a private coporation to attempt without some sort of guaranty on a return on its investment. We have a system for providing such guarantys already, they are called goverment contracts, which is how most space work has already been done.
I think with private companies, if the prize is big enough, they will take the risk, if the prize is not big enough, they will wait for it to get bigger before making the attempt, but if they wait too long, some other company may make the attempt and take the prize away from them.
You might have a point if we were talking only mere millions of dollars here like with the x-prize (which hasn't been achive in a finacialy succesfull way BTW), but when you scale that up to billions, the finacial sectors tolerance for risk of this magnitude dwindles, and their expected return goes up. And so no one will bite.
You see their is a market for money, just like there is for everything else. It is represented by the stockmarket, bonds, bank loans, ect... but it is a market none the less. Diffrent buisness and entrepreneurs compete for this money, and so to get the seed money you need you're offer has to be competaive. The supply of billion dollar level financing is VERY tight, and so to get that kind of money your prospect has to be VERY attractive. But this investment isn't. It's VERY high risk and the returns are only marginal compared to the alternative options. If there is a point where the returns are high enough to justify the risk, the Goverment could then do it for less money.
Again dealing with risk is one of the few places the goverment has a critical advantage over private coporations. Because of the reasons I pointed out before, deepest pockets and no need for immediat financial return. Private coporations can't match this, and frankly don't want to. If you look back in history, virtualy every large scale, high-risk program (like Apollo, Dams, Canals, transcontiental railroads, ect) were either goverment run or basicaly goverment financed.
Many companies will fail, and thus write off the cost of the attempt, stock prices will go down,
Another problem. When you are talking about failures meaning billion dollar investments go belly up, it's not a minor problem for our economy. When a billion dollar venture goes south, people lose their jobs, alot of them. Obviously alot of investors lose their money as well. The goverment absourbe the kinds of losses no problem, but when it happens to a private coporation the effects and major. People are realy hurt. It is probably not ethical (and defiently not finacialy wise) to encourage this kind of behavior in the market.
I've read his "space prize" idea and I am skeptical to say the least. The only succesfull (so far) bid for the X-prize cost far more to accomplish than the prize was worth. And it goals were VERY modest.
Even if the prize money was increased to reasonable levels, I don't think it would work. The risk is to great and the potential for return is to small. If you had several hundread million dollars to vest you would not put it into a contest in which success is very difficult and if you're competators beat you you get nothing.
It also assumes that comerical intrest can get things done at vastly cheaper prices then NASA. But much of NASA's work is done by commerical intrests like Boeing and others. While their is probably a great deal of pork and ineficency in this commerical work, every dollar they can drive their price down means more profit for them, so you can be sure they are taking every pratical effort to reduce costs. But space is still just plan difficult.
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As for Newt himself, I rather like him actually. Which is odd because I am fairly libral and almost always vote a straight (D) in elections. However, I agree with him on many aspects of foriegn policy and I appricate his fiscal concervatisim. Since I live in Texas, and my democratic presidental vote is meanigless (since the state is bound to go Red) I'd vote for him if he ran on a third party ticket. Unless he split the vote and made it likely for a dem to win the state, but that is unlikely. I would certianly perfer him to our current neo-con leadership.
Would you want a rover that couldn't go any faster than an astronaut could walk?
I guess its not expected that astronauts would ever be in any hurry for whatever reason, but lets think about it for a second. Lets say the astronauts have a base and a rover. Probablythe only place the rover can refuel is at the base.
No, not really. The two key aspects to the rover are reliability/safey and range/fuel efficency. These needs are best served by keeping the speed down, 30mph, tops, generaly much slower. Rember, ALL of mars is unimproved terrain. There are no roads or highways anywhere on the planet. Attempting high speed travel over rough, unexplored, completely virgin territory, millions of miles from a repair shop is foolhardy. In these conditions high speed travel is far more dangerous than delay in arrival could cause. The rover has to be no-fail or fail-safe anyways. If somethink breaks when the crew is 300km out, they are boned, end of story.
Now what if the rover crawls as fast as an astronaut can walk? Remember the Astronauts are going to stay here for two years. During the early part of the mission, the astronauts might concentrate on the area around the base, but later on they might want to go further and further out. If the rover crawls, its going to slowly pass through terrotory that the astronauts have already explored, before getting to those sites that are of interest.
High speed does not equal more exploration range, in fact it means quite the opposite. The rover will be constrained primarily by it's fuel supply (not it's crew consumables), which is best preserved by going slow and steady. Furthermore, a rover driven at walking speed is still going to cover a lot of ground during it's 2 years on Mars, and since all of it is virgin territory to us, it is all of intrest.
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Again I repeate, the Rover is more like a heavy-duty recreational vehicle/tractor then some sort of off-road dunebuggy or whatever.
Another vote for electic motors, but not necessarily based in the wheels. I'm not opposed to axels, whichever solution is the most reliable and masses the least should be used. Their are certianly pros and cons to both solutions.
The mars rover's engine is going to need lots of torque but will not likely be driven at high speeds. So even if we were going to use an ICE engine (or even a nuclear turbine or something else) a heavy transmission typical of automobiles probably would not be needed. The engine needs lots of toqure and little else, so one gear or maybe two is all that would be needed. The rover is more like an overgrown tractor than a car realy.
GCNR, eventually would air cooling work for reactors? I doubt we'd want to use it on the first missions. A cubic meter of martian air masses about 0.1 kg, I think. A two meter in diameter intake with fans blowing the air at 50 meters per second would push about 15 kilograms of cold air (average, 50 below) past a radiator per second. That could provide a decent amount of cooling.
-- RobS
I disagre with GCRN here. Harnesing the martian air to help augment cooling is highly logical and practical. As we all know their are only 2 ways for us to get rid of heat, radiation (which is the only method the SP-100 uses) or conduction (wicking away heat with something like water or gas), or to simply through the heat away with something.
Radiation is the default answer, but is not very practical. Radiation is a very inefficent way of getting rid of heat, unfortunatly, it's the only game in space or the moon, where conduction is not practical (only thing to conduct the heat to is the ground).
Convection on the other hand is much, much more efficent than radiation. This is why power-plants and the like are cooled with river water rather than massive radiators. It is true that Martian air is probably not a very good conductor of heat compared to Earth Air or much less water. But it is still vastly superior to vacume radiation.
Happily the design requirments for radiation cooling and air-conduction cooling are fairly similar. Both are dependant on the hot body having a lot of surface area. Also good radiators are also generaly good conductors. So not much modification is necessary to let you're radiator harness the power of convection, putting a fan in front of it to blow the thin (but very cold) martian air across it's surface would increase the efficency of the system greatly, and could thus lower the mass of the radiator.
The disadvantage is that if you're fan breaks, you're cooling slows down. Which can obviously be a bad thing for the reactor. I would solve this in two ways, firstly I think such a critical item like the reactor should have a back-up anyways. Secoundly, the reactor should be able to moderate itself (I know pressurised water reactors like the navy uses can do this, I'm not sure how self-moderating liqual lithium ones are), and decrease their power-output in case of a fan failure. The Mission should be surviable on this lessened amount of power.
I'm sure we could do it with just Radiation, but since we don't have to, it makes little sense to ignore the options avaliable to us.
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Long term Air-cooling makes even more sense, but their may be even better alternatives in the future. Importing ice for cooling the reactor (or drinking), tapping into underground water and/or ice supplies for cooling, or most likely heating the ground and permafrost on Mars using Martian air as the working medium.
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Also I wouldn't dis submarine nuke technology so much. Obviously the power plants use by the navy are not appropriate for use on Mars. They are much to heavy, generaly produce more power than we need, and don't have to worry about the cooling issues. However, the relability and simplicity of these systems is something we do well to emulate. Also, nuclear subs have been the birth place for much nuclear technology that we certianly need, such as liquid metal cooled engines (some Russian subs have some) and self moderating pressurised water reactors.
I think you are missing Roberts, point and it is a decent one. The Hubble is not needed for simple detection of NEA, our conventional systems on the ground can do that quite well currently, but it might be well suited for doing spetroscopic analysis of nearby asteriods to determine their composition. I'll grant that this might be a very valid reason for a Hubble like telescope. Asteroid mining concurns aside, the data is probably valuable in and of itself.
However, that doesn't necessarily mean that we need the Hubble to accomplish this. Those asteroid aren't going anywhere. They will still be in orbit 10, 20, 30 or 100+ years from now. It's not a time critical issue. The Hubble, on the other hand, is not likely to be around for the next 10~15 years new service mission or not. So for a prolonged study of the compositoin of NEA Hubble is still not the best investment. A purpouse built device, placed in an appropriate orbit would no doubt both last longer, give better results, and would likely be less expensive.
I understand the anxiety people face with respect to their work. They want to get results and action today (or yesterday if possible) and not weight 5 years or so untill a better device can be built. In most fields of study human time is valuable enough that it is worth it to pay extra cost to get instruments to our people quickly. Unfortuantly, this is not the case in astronomy. The stars are not going anywhere, neither are the asteroids. Even asteroid mining is serveral decades out at best. And building telescopes, especialy space telescopes is monumently expensive. It may be painful to wait, but economicaly it is the best solution.
On the positive side, pushing to get new instruments instead of trying to recycle the old is probably a positive thing for astronomers in the new end. Congress is not going to fund a program for a new (and better) space telescope as long as we have one currently up there in orbit. In the search for new and better instruments to explore our universe, scientist should always be pushing for new toys instead of upgrades or life-extensions of the old. Happily, in this case the quest for new & better instruments and economic realities are harmonious. So by not pushing to extend the life of the old Hubble, we may end up getting new and better instruments that we never would have recieved had it stayed up in Orbit.
All the effort spent over the hubble which is actually a very old instrument. Seriously, the design of the hubble dates all the way back to the origins of the Space Shuttle in the 1970's. It's ~30 years old design wise. Even if it was a ground based instrument, we would be looking at replacing it by now. And in space it is even less cost-effectivness to service a device. And if we do service it now, when does it end? The Hubble won't be getting any younger, yet the arguments for preserving it don't seem to be loosing any momentum, will we be fighitng about this again 10 years from now?
I truely wish it was possible (as originaly planend) to return the Hubble to Earth to sit proudly in the Smithsonian or something, but it isn't. Lets let the old boy die with some dignity instead of dragging it along for another 10 years or, god forbid, kicking it up into a "graveyard" orbit where it will never be recovered.
Any effect that allows information to be transfered from one point to another FTL can cause a granfather pardox (ie. a causality violation) in the right circumstances. It has nothing to specificly to do with the exact method by which that method if information is transfered, and everything thing to do with the way time dilates (slows down) as you approach the speed of light.
In other words, the causality violation is not necessarily so much an effect of the object being observed (you're space-ship) as the an effect of the ones doing the observing. This is because of two principle factors of special relativity.
#1. The speed of light is constant for all observers: Which means light doesn't speed up if you're craft starts traveling faster.
#2. All observers frame of refrence are equaly valid: Which means there is no 'galatic universal time, the time I see as taking place is just as valid as the time you see as taking place.'
These two principles combine to create the concepts of relativity with which we are familar. Such as time slowing down as you approach the speed of light, and the grandfather paradox. Their is litteraly mountains of observational evidence backing up this theorie. But again, the key is that the violation lies not so much with the one doing the violation, but with the people that observe it.
There is a great page going into depth on this principle here, but I'll post the relevant exert below.
"We can describe this effect by idealizing FTL to be "instantaneous", and describing how the more familar time dilation implies this effect. But remember, the same points apply to any FTL speed, you just have more messy arithmetic to grind through.
Consider a duel with tachyon pistols. Two duelists, A and B, are to stand back to back, then start out at 0.866 lightspeed for 8 seconds, turn, and fire. Tachyon pistol rounds move so fast, they are instantaneous for all practical purposes.
So, the duelists both set out --- at 0.866 lightspeed each relative to the other, so that the time dilation factor is 2 between them. Duelist A counts off 8 lightseconds, turns, and fires. Now, according to A (since in relativity all inertial frames are equally valid) B's the one who's moving, so B's clock is ticking at half-speed. Thus, the tachyon round hits B in the back as B's clock ticks 4 seconds.
Now B (according to relativity) has every right to consider A as moving, and thus, A is the one with the slowed clock. So, as B is hit in the back at tick 4, in outrage at A's firing before 8 seconds are up, B manages to turn and fire before being overcome by his fatal wound. And since in B's frame of reference it's A's clock that ticks slow, B's round hits A, striking A dead instantly, at A's second tick; a full six seconds before A fired the original round. A classic grandfather paradox.
Note, this is NOT a matter of when light gets to an observer, it is NOT an optical illusion. It is due to the fact that, in SR, the question of what occurs at the "same time as" something else is observer dependent.
As A fired that first shot at tick 8, the bullet effectively teleported from A's gun to B's back instantly --- instantly according to A. But for B, who was moving at 0.866 lightspeed WRT A, B was hit in the back by the bullet 4 seconds BEFORE the bullet was fired. And again note, this is NOT due to the optical illusion of lightspeed delay in viewing A's turn-and-shoot; the light form that event wouldn't reach B until MUCH later, not tick 4."[/url]
I read this type article before
http://www.rattlesnake.com/notions/chinese-orion.html
I'm not sure how much is true and how much is alarmist hypebut a Chinese Project Orion would certainly get people's attention
Whats the point of building an atomic bomb spaceship if all you want to do is nuke your enemy with those atomic bombs? Its much easier just to build the bombs alone, and not build the Orion spaceship. The kind of bombs you'd want to use in anycase would be thermo-nuclear devices, not the fission devices used by Orion. An Orion Starship would use thermo-nuclear devices, but that would be too big to launch from the ground.
No it makes LOTS of sense militarily to put bombs in space, Orion or otherwise. The US (and Russia for that matter) defense/detection systems are all dedicated to tracking weapons that follow a pretty set patern of balistic orbital paths. Over the north poll primarily. This gives the nuclear powers some time to ready their own strategic forces and launch counterstrikes, making MAD (and the deterent it provides) possible.
Orion changes all that. Put a nuke in actual orbit and you could theorticaly bring it down however you like, without giving your target a chance to see it coming and retaliate. This allows you to "win" a nuclear war. Obviously all the other nuclear powers are none to thrilled with this thought.
Their fears are not entirely groundless. I won't speculate on any of the nuclear powers desire to proceded with such an option, but any Orion type vehicle could certianly pull it off. They are designed to lift hundreads to thousands of H-bombs into orbit. Once in orbit Orion should have the Delta-V to go whereever it likes. And the containment vessles for the bombs could easily double as re-entery vehicles.
The Russians developed a similar system in the past, the fractional orbit bombardment system, which was designed to launch such a strike, but thankfully was never deployed.
So I belive that for political reasons alone are killer for Orion. The engineering difficulties are just a bonus.
Ion drive has two main drawbacks for Lunar travel besides the fact that it can't get anywhere in a timely fasion to deliver time sensitive cargo (eg liquid hydrogen).
You're right GCNR,
I for one wouldn't want to be using ion-drive for sensitive cargo, but as other people say rockets have been around for a century or millenium of years if you're counting the Chinese scientific history but our Ion thruster are still in their early stages of development and it still could be used to transport other materials.
There is thought next to no water on our Moon, and almost no atmosphere but like the planet Mercury there is some there on our Moon- some of the deep craters are thought to contain ice and it does have atmospheric components of Na and Argon. The solar wind has been sweeping the small lunar atmosphere away leaving next to nothing there. Yet if the tiny atmosphere of the Moon were 200 times greater it could remain stable for hundreds of years. Larger human activity on the Moon could push the total mass over the limit and create a stable artificial atmosphere. The European Smart-1, Japan's Hayabusa and NASA's new HiPEP are pushing out the boundaries of ion technology. This year the ESA reportedly made a new type of ion propulsion with four times higher exhaust velocity than previously achieved.
I'm not sure what your getting at here, but the point remains that Xenon, Argon, and Neon are not present on the moon in economicaly recoverable quantites. There may be some there, but only in trace amounts.
In addition, while advances in technology may increase the ISP of an Ion engine (best measured by it's exahust velocity), they are unlikely to provide dramatic increases in it's thrust/weight ratio. An ion engine will never be practical for lifting off from a planets surface, or even the moon.
That said I don't think they should be ruled out as a method of transporting "sensative" cargo to and from the moon. The moon is close enough that the additional time penalty is not that great. And if our ion-tug was nuclear powered, it might have additional energy left over to recondense hydrogen making it's transport more pratical.
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Magnetic levitaion is not a bad idea, but it sounds borderline to the plain rail-gun proposal. Still no harm in combining a rail-gun with a lunar rocket...
You are correct, magnetic levitation is pretty much the same as a rail-gun. I think the killer problem with this is building the infastructure to support a multi-ton rockets acceleration to such high velocities.
Don't underestimate the threat of meteoroids. Those sails are still supported by struts so a critical hit can bring down a LARGE section which starts affecting your plans...
The struts or ropes connecting the sail to it's cargo are tiny in comparison. While the sail takes multiple sq km, the support structures take um a few square meters at best. So a metroid strike on them is unlikely. Might as well worry about a meteroid drilling through your capsle and hitting a passenger of something, it's as about as likely. In addition some redundency could be built in here as well, though at a more substantial mass penalty.
es, cargo obviously if anything. Problem is solar sails need to be very light or else you require obscenely larger sails. You need to slowly deploy those sails...and as Skylab and the ISS have demonstrated the compartely squat solar panels prove unfluring sail like structures won't be 100% perfect 100% of the time. It starts becoming an ineffective balancing act worse than propellant loads on chemical rocket launches.
I would argue that we have already developed solar sails light enough to do a very effective job. Commonly avaliable films are in the 10g/m^2 range and some new experimental ones are less than 5g/m^2. Deployment still may pose and issue, but most researchers are convinced it is one engineers can solve, not a show stopper.
Again regarding those ground stations, too much stuff here on Earth will be in the way, whether its built by NASA or SpaceX. Giant mirrors or giant laser beams don't come cheap and their beams will be blinding if not occassionally lethal. The Moon would be a better site to use but don't expect immediate contruction. Also what happens if your target is NOT Earth or the Moon? You'll need multiple stations to slow you down, save perhaps Mercury or Venus where the light pressure increases.
This topic was mainly focusing on methods of going from the moons surface to orbit. Persumably once the vessle is in orbit it could use a diffrent method of propultion. As for setting up such stations, a mirror based one could be rather simple to set-up. The moon gets lots of sun and mirrors can be cheap and light. The biggest problem I see is focusing them all on our departing space-craft, which might be tricky.
I certialy don't agree that solar-sails are a joke, they may prove to be an immensily pratical method of moving things about the solar system. They are slow, but they require no fuel (having an infinate) ISP and are reusable. Certianly in the inner system they are pretty much unbeatable.
As for Solar Thermal propulsion, I was refering to a system where the solar energy was "beamed" or reflected to the craft from a ground station, rather than carrying it's own mirrors. Only a secoundary reflector might be required. Alternatively Laser or Microwave power could be used, however these would require eletrical power generation, while reflected light is pretty much free, and mirrors could be light and cheep.
Ok two problems I immediately see with solar sails that would keep me from supporting it: extremely slow thrust - they make ion propulsion look like a Ferrari by comparison; a solar sail a few square kilometers in area makes a pretty fine target to a swarm of micrometeoroids - I don't care if kevlar struts support it I just can't trust a propulsion system thinner than the plastic in my garbage bags. I could see an unmanned interstellar spacecraft making some use of it, but it is, sadly, the epitome of impractical.
Depending upon the size of the sail and the mass of the payload a solar sail may or may perform better than an ion engine in terms of thrust. In terms of specific impulse the solar sail is without equal. As for swarms of micrometeroids damging the sail in some way, this is extreamly unlikely.
Firstly space is mostly empty. Especialy the deep space that a solar sail would spend most of it's time in. Micro-meteriods are few and far bettwen. The odds of the sail hitting a single micro meteroid, even a sail several square kilometer in area, are pretty low, much less a whole swarm of them.
Secound even if the sail did encounter a micrometeroid or worse a whole swarm of them, it is unlikely to have any signifigant effect on it. Solar Sails are huge and the holes created by micrometoids are tiny. As long as an acceptable margine is left in the sails size/weight ratio to compinsate for these microsopic holes, there should be no effect worth mentioning. Indeed, the wholes would be so small that the extra strength margin necessary to compinsate for them is hardly worth mentioning.
Such a tiny whole in the sail is no more likely to cause failure then poking a pin-whole in your garbage bag is likely to make it fail. The big problems with a solar sail lie in stearing it, and deploying the sail.
NASA or any space agency is not going to contruct ground stations for remote propulsion. Worse still, just like laser pen lights, a beam like that would blind any stray airplane or satellite in its path.
I'm not sure we are talking about the same thing, I'm talking about a beam station on the moon to provide for lift to orbit. Blinding airplains and satellites would not be an issue (not that it would be on Earth either).
If a propulsion system takes more than 10 days to reach simply the Moon from LEO or vice versa I have to say it is "out of the race" for human passengers.
Well I mainly advocate solar sails for unmanned cargo transport, but 10 days from Earth to the Moon isn't that bad really. If we start to maintain a long term base on the moon, this should only be a small fraction of the journy.
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It is this problem that has more or less meant that the only real effective method would be to create a magnetic levitation system for use on the Moon. The benefits of magnetic levitation are that there is little friction with the ground. Control of the object to be propelled is easier and that the only energy source needed is electricity which with ample sunlight is very available. The creation of such a system uses a very high majority local material so insitu works and there is also the fact that there is little or no working parts so wear and tear are kept to the minimum, which is very useful when considering the enviroment.
Problems are that the system will direct cargo's to only a very limited area and the system will need construction.
Certianly magnetic levitation could help solve the problem. It's not a perfect solution because it still might be possible for the large craft to get jared and end in diaster. This is no small bullet we are dealing with but a large multi-ton vessle. The energy requirments will likewise be signifigant to levitate such a vehicle. I think magnetic levitation would certianly work, but I think the rocket sled approach would be more ideal if it could work as less infastructure is required.
Austin Stanley,
Ion drive is another, NASA has been testing this already and the Dawn mission should soon use this method.
I think an ion-drived vehcile could make an ideal orbital tug, but they lack the thrust to lift of from the moon surface, which is what I was focusing on here.
Austin Stanley: I especially liked your description: "... a rail-road track could be laid out for a lunar dust fired rocket which would thunder across the lunar plains at unheard of speeds ..." Sorry, it's unforgivable of me, but that got to my funny bone. Good post.
Thanks, but I am quite serious with this suggestion. As we all know, it is horizontal velocity which is most critical to a rocket reaching orbital velocity. On Earth is is simply impossible to achive these sorts of velocity in the low atmosphere, which makes the rocket-sled/train stage impossible. The moon obviously has no such limitation, so it may be very possible to launch a vessle via a rocket-sled/train. It could certianly be a first stage.
There are several possible problem I see with this approach, firstly the frictional limits on the speed. The moons escape velocity is some ~2.4km/s, which may be to fast for a rail-track to sustain without damage. In comparision, the fastest bullets travel at ~1.5km/s, though I am not sure if this is the upper limit of possible velocities. Trains and Cars obviously travel much slower. Friction from the track may also create a limit of the velocity the rocket can achive as well.
Another serious issue is the length of track necessary. A metal-oxygen rocket is likely to have a fairly poor thrust/weight ratio and lowsy ISP. In addition friction with the track/ground adds a signifigant amount of drag. All this adds up to the rocket sled stage likely being very large and slow to accelerate. Which means a fairly long, well graded track must be created for it to use. It might even have to be reinforced to handle the weight, though with the moons lower gravity this will be less of an issue then on earth. In any case, while the infastructure requirments are still substantialy less then a rail-gun or similar method of reaching orbit, they are still fairly substaintal.
The last problem I forsee stems from traveling at hyper-sonic velocities (though that term is not realy apt here) on the ground. Keeping control of the vehicle will be absolutly critical. Any disturbance could lead to a terrible accident, and at these velocities I fear that any slight jarring or disturbance could lead to such an accident.
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Nuclear propulsion could be applied to the Moon, but I fear finding and refining the uranium fuel rods nessicary will impose engineering, economical, political, and even security risks. Even if oxygen alone is the working propellant I doubt uranium will be easily obtained.
While Uranium is certianly present in the moon, I doubt we would need to go to the incredible expense of minning or refining it their to use a NTR. Depending upon the design of the NTR its radioactive core could be good for years to decades. A NTR generaly reacts at a higher rate (and uses more enriched fuel as well) then a conventioal reactor, but it is also functional for a DRASTICLY shorter period of time, a matter of hours each month at most. So I think importing the cores from Earth and deploying native fuel could be a praticle approach.
Solar thermal propulsion is only a slightly smaller joke than solar sails. Too much flimbsy hardware that needs to be deployed, angled, and even repaired versus the constant power from either fuel cells, solar cells, or nuclear power that's simply 'turned on'.
I certialy don't agree that solar-sails are a joke, they may prove to be an immensily pratical method of moving things about the solar system. They are slow, but they require no fuel (having an infinate) ISP and are reusable. Certianly in the inner system they are pretty much unbeatable.
As for Solar Thermal propulsion, I was refering to a system where the solar energy was "beamed" or reflected to the craft from a ground station, rather than carrying it's own mirrors. Only a secoundary reflector might be required. Alternatively Laser or Microwave power could be used, however these would require eletrical power generation, while reflected light is pretty much free, and mirrors could be light and cheep.
In space the Solar Thermal concept (carrying it's own mirrors this time) is viable, but inferior to NTR.
How about a rotovator? (correct term?) With the lower gravity, orbit height, nd vacumn I read somewhere that it could be built using current materials like some sort of kelvlar rope. This has the added bonus if I understand it right of being able to throw things out at escape velocity from lunar orbit. It's basically a twirling rope or cable that is turning in the opposite direction that the middle of it is orbiting. It's also as long as orbital height so that for brief periods it appears to be stopped at the surface. Of course it will need to have a center base station and some sort of engine to make up for flinging cargo into orbit, but if the middle mass is large enough this could be a relitivy low thrust engine that runs continiously, like solar thermal.
I certianly think a rotovator could work, but the infastructure requirement is again rather large. We could creat a conventional space elevator with modern materials as well (buckytubes not required), but it would be immense. The only issue I see with a rotovator is the problem if one of the cables hits the ground, which could cause a serious issue.
Not only that, Helium is incredibly rare on Mars (not that it's that common here on Earth). But without a flamable atmosphere, there's no reason not to use Hydrogen, whcih is more accessable.
With lots of talk about a possible resuable lunar surface assent module (LSAM), I thought it might be worth some time to identify the various methods we might use to get to lunar orbit.
#1. Conventional Rockets
The obvious plan, and the method NASA currently plans on using for their (no-reusable) LSAM. It's also the method used in Apollo, so it has relability and simplicty going for it.
The problem of course is that it isn't very reusable. Rocket fuel (no matter the type) must be exported to the moon, where it can be leveraged with lunar produced oxygen. Since great quantities of fuel are still needed, the savings here are sub-optimal.
#2. NTR
Nuclear Thermal Rockets are probably not pratical for lift-off from earth, they don't have the necessary thrust/weight ratio. However, the moon gravity is much lighter so it is probably practicle for a NTR to take off from there. Hydrogen would still have to be imported, but the advantage in ISP puts it ahead of chemical rockets. Lunar Oxygen might also be added during the early stages to increase thrust at the price of ISP.
#3. Lunar Dust Rockets
Most metals will burn/combust in the presence of pure oxygen in the right conditions. The classic example of this is the thermite reaction many of you may be familar with, but virtualy all pure metals will burn (oxidise really) in the right conditions with oxygen.
This fuel has the advantage of being virtualy free on the Lunar surface. Any extration operation that removes oxygen from the soil will leave behind pure metal which can be used along with that oxygen as a fuel source for the rocket. So if we mine oxygen in the rocks, we are bound to get lots of metal as well.
The problem is that while these reactions are very energetic, they are not very energetic per unit of mass, especialy when compared to conventional propellents. So the ISP sucks. This is less important if the fuel is free, but there is another big problem, it is unkown if an engine with a sufficent thrust/weight ratio could be constructed to lift off from the lunar surface. They won't work on earth certianly. In addition new engines would have to be designed to deal with this kind of fuel, which do not currently exist.
#4. Oxygen Fueled NTR of some sort.
Again, assuming oxygen can be obtained for virtualy free on the lunar surface, it might be used for fuel in a NTR. Again, oxygen is much heavier then hydrogen so the ISP will take a large hit (worse then conventional rockets), but again if the fuel is free this is less important. The big issue remains if a rocket with a practical thrust/weight ratio could be designed for moon-lift-of.
#5. Solar Thermal Rocket
The moon, lacking an atmosphere, gets much more solar energy then the earth, for much longer periods of time. This combined with it's light gravity might make it possible for a rocket powered by reflected light heating a gass to lift off. A Solar Thermal Rocket. It might be hydrogen or oxygen fueled, and might combust oxygen at the early stages for added thrust. This sort of rocket is similar to a NTR, but might offer improved thrust/weight ratios since it doesn't have to carry a heavy nuclear pile and shielding.
The problem is mainly in engineering. Creating an array of mirrors/lasers/whatever to focus light energy on the rocket during it's assent would be very difficult and would entail a fairly large ground presence. In addition after the rocket passed over the horizon they could no longer beam it energy, so there would have to be multiple stations, or it would only be good for a first stage.
#6. Rail gun
A rail gun is a difficult concept on earth, since you have that nasty thick atmosphere to deal with. On the moon it is no problem, a rail gun could easily hurl objects into orbit. Some orbital correction would be needed, but this is a minor issue. The big issue is the length of the rail-gun necessary to keep acceleration down to acceptable amounts. Several km probably, which requires intensive infastructure. Ultimatly it is the obvious answer to our problem.
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My solution:
I'm not sure that the most promising options (oxygen fuled rockets) will ever become possible on their own, but staging these rockets could provide some of the answer to our problem. For example, a rail-road track could be laid out for a lunar dust fired rocket which would thunder across the lunar plains at unheard of speeds (upwards of 1km/s maybe), then towards the end it would angle it up where it would be launched into space with considerable horizontal velocity and a secound stage could finish the job. This eleminates the thrust/weight problem for the first stage and makes it entirely recoverable.
astronaut
n. A person trained to pilot, navigate, or otherwise participate as a crew member of a spacecraft.
[astro- + Greek nauts, sailor (from naus, ship; see nu- in Indo-European roots).]
I tend to agree. The astronaut == sailor analogy is probably the best one. Back in the age of sail many people travled by ship, but not everyone was a sailor. The distinction was that a sailor was someone who made his living traveling at sea, not mearly a passanger. By this definition, our rich tourist are not astronauts, because they certianly do not make a profession of space travel, and for the most part they do not participate as a crew member of the space craft. On the other hand, virtualy every non-tourist crew member does qualify, as they both make space travel a profession, AND function as a member of the crew. They are not passangers.
So I think no, traveling on a sub-orbital junket or whatever does not automaticly make you a astronaut any more than traveling on a ship makes you a salior, or a sub a submariner.
Protons aren't the only problem, despite there being lots of them and fast moving, the Apollo capsule's aluminum hull blocked a majority fraction of them, but Ritt didn't give the full picture and left out the real beasties: high-energy cosmic rays in the form of polynucleon ions. Nuclear fusion "events" and various stellar explosions. These are basically free atoms from Helium to Iron with the electrons stripped off and universally have extremely high speed. They have considerably more penitration and ionizing potential than even near-C protons and could be an issue for missions to Mars and beyond.
The danger from this particular type of radiation is a little different then plain old proton radiation since when a heavy ion hits shielding it creates a cascade of lighter particles by spallation, the effect becomming worse the higher the atomic number of shielding. Its actual effects are not that well understood.
There are ways for acounting for this. For some time now the scientific community has been arguing and trying to get people to use Sieverts instead of rem (Röntgen equivalent man). Sieverts generaly take into acount the greater ionizing power of protons, neutrons, and other heavy atomic particles in their calcuation of the equivlent radiation dose. In my calculation above I used the appropriet Sieverts for the situation, assuming all of the cosmic radiation was highly entergetic protons, giving a much higher effective radiation dose. This is fairly optimistic because not all cosmic radiation IS highly energetic protons.
As for the danger of heavy nuclei, this is more than balanced by their increased rarity. Sure high energy alpha particles and even heavier nuclei are much more ionizing than photons or protons maybe 100x more even. But they are FAR more rare, >1000x times rarer. Also, the heavier the ion, the more effective shielding is at stoping it generaly.
"Heavy" cosmic rays might have a synergistic effect with exposure to low gravity too; it is now believed that people get several cancers normally throughout their lifetimes, but the immune system recognizes almost all of them and destroys the runaway cells before they can become a problem. Some tests on astronauts show that zero-gravity supresses the immune system, which might have a multiplying effect on cancer risk.
There is also anecdotal evidence that relatively small doses cause cataracts in the eyes.
While the increased chance of cancer a Mars trip might result in is not negligable, the chance that it will manfest itself during the trip is. If we pick young, healthy people to be our explorers, the chance of their developing cancer during the trip is simply negligable. Heart attacks should be a greater worry for us. Cancer takes quite a while to develop into something life threatening anyways, even if exposure to 0g instantly caused one to occur.
I bet though that this problem is manageable; shielding can stop most of these nasty ions without adding too much mass, and exposure would be limited on the Moon (buried habitat, Moon itself blocking half) and Mars ("deep" atmosphere catches spalled particles). Astronauts could also be dosed with immune boosters, antioxidants, or advanced chemotheraphy drugs to reduce the effect, and perhaps even replace their corneas with advanced polymers that can't be harmed by radiation.
All else failing, we'll just have to get there quicker, and an advanced nuclear propulsion system developed.
I think the radiation problem is much ado about nothing. Aside from solar flares (which are a worry) cosmic radiation has very little short term effect on the Mars trip. Our explorers aren't simply going to suddenly die of radiation poisioning or develope cancers everywhere during their trip. Now, they may face a increased chance of cancer in the remainder of their lives, but this chance is fairly small increase (maybe as much as 10%) and I bet there are many qualified applicants who would be willing to risk it. I know I would. When you look at the grand sceam of risk for a Mars trip, radiation (aside from solar flares), realy doesn't figure into it.
First I'm going to have to call the major statistic of the study bogus. 80 REM/day (or about .8 Sievert/day) is enough for serious signs of radiations sickness to become evident, with the possiblitie of some fatalities, of course this didn't happen to Apollo. In addition we have sent several missions (and countless probes) out beyond the Van Allen belts into "deep space" and the results of the cosmic radiation don't match these figures either.
Apollo measured cosmic radiation rates of ~1mREM/hr or .024REM/day. Even taking into acount that high energy protons are more ionizing then photons (a factor of 5 in Sievert calculations), we are still only talking about .12REM/day or 1.2mSv/day (mSv=millisivert). This is considerably higher then the average dose you would get on Earth (2.4mSv/year or ~.0066mSv/day), but hardly show stopping.
Indeed, their are lots of areas on Earth where you get a much higher daily radiation dose due either to natural radioactive deposits (like Brazil), high altitude (Denver), or a combination of both. In fact, in the US due to the greater quantites of radioactive deposits, airline travel, and X-rays, the average is higher, some 3.6mSv/yr. In fact, people in Ramsar, Iran recive nearly 260mSv/yr or .71mSv/day without adverse effect. Indeed their have even been some study linking low-levels of radiation with decreased cancer risk, persumably because of increased excersize of the body's self-repair mechanisims.
Without reading the study in question, it's hard to comment on their specific concurns, but in general I think this is a red herring. The US's experience in space shows cosmic radiation to be a minimal hazard to astronaughts, with some minor impacts on their long term health (a few percentage points more risk of cancer). Not something to be dismised, but not a show-stopper either. The plastic vests and better protected sleeping quaters some have talked about should make a signifigant dent in the radiation explorers would have to face.
Hm. Good point... People riding bikes can easily consume 20-fold as much oxy than people resting...
Which is a BIG problem for people designing those spacesuits. Space suits (regardless of type) are likely use a pure O2 life support atmosphere, at realitivly low pressures, like Apollo did. This will likely be combined with some sort of re-breather system that will absorb the CO2 out of the air-supply. If the consumtion of oxygen raises drasticly, so will the production of CO2, possibly beyond the suits ability to supply and purify, which would be a very bad thing.
Another issue is how the extral thermal energy will be dissipated. Working hard means the body heats up and must cool itself via persperation. In a normal presurised suit there are limits to the rate in which this heat can be dissipated. In a tension suit, I'm not sure how the heat will be dissipated at all. The mechanical pressure the suit puts on the skin doesn't leave alot of room for the bodies sweat to be wicked away or idealy evaporated.
Oh, and then there are "political" issues with suborbital freight...
1: If you have to launch in a hurry, how does the destination country know that you are not a hypersonic ballistic missile reentry vehicle? With so little warning and all.
Diffently a problem, but maybe not totaly insolvable. The major nuclear powers (US, Russia, China, rest of NATO) are on pretty friendly terms right now. Some sort of agrement could be worked out. After all, the same worry takes place each and every time someone launches an orbital rocket, which could also very well be a nuclear missle.
2: If you crash at multiple mach numbers into a populated area, the explosion will be as big or larger then the USAF's "MOAB" superbomb. Who pays for that? And can you imagine the insurance?
I think you greatly overstate this. Certianly having your re-entery vehicle crash into a city would be a very bad thing, but it probably wouldn't be as bad as even the 9-11 attacks, much less the MOAB. The power of KE strikes is vastly overated, and a delivery vehicle would not deliver even that amount of power. As unlike a specialy designed KE penetrator, the big, draggy, delivery vehicle is not going to be slowed by friction to a much greater degree and so is not going to impact at those multiple mach numbers, it probably won't even be supersonic. It's not going to be designed for supersonic speeds in the lower-atmosphere which means if it did happen to enter it at supersonic speeds, it would most likely break up and disentigrate (as well as slow down).
Furthermore, after launch the delivery vehicle will be almost entirely balistic at this point, with big empty fuel tanks. Even if it did hit something, it won't have the power that even the 9-11 airplanes did, since it will likely mass less than a large airliner (at this point), and won't have lots of fuel to feed a resulting fire.
This is not to say that a crash would be a good thing (it most certianly wouldn't), but it wouldn't be the end of the world either.
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Another issue of course is what still demands fast transit, AND can withstand the journey. Modern telcomunications is making the transport of paper (a major fast transit payload for buisness and legal deals) increasingly obsolete. Other potential payloads (like virus/bacteria samples) might be to fragile to withstand the trip. And other time urgent goods might be to bulky to be transported this way (like medical supplies).
I'm still a bit skeptical about the added bulk of insulation like aerogel, which despite being very light might need to be awfully thick.
I don't think you are correct about this. The k values I used for thermal conductance constants are in W/(K*m) in other words, the measure the amount of thermal energy they transfer per unit of thickness. Aerogel, having an incredibly low thermal conductance (or a very high thermal reistance, depending upon how you look at it) requires LESS thickness to achive the same level of insulation then praticaly any other material might. My earlier calculations show this.
Don't let it's low density fool you in to thinking it must be bulky to be effective, when dealin with insulation the opposite is generaly true. In fact, vacume (which is as low density as you can get) is the best insulator possible, air is likewise a excelent insulator, provided you do not allow it to circulate (bringing convention effects into play).
Robots would need RTG power anyway if they were going to operate any length of time, since there is no light for solar power.
Totaly agree.
Setting the Sea Dragon issue (which I'm not a big fan of) there are a couple other issues with your last post.
- First, the fueling station in orbit. I think this is a difficult to impossible concept. In theory it is good, transport up the water (no problem) and Uranium Salts up in seperate bundles. However, transporting this realitivly highly enriched uranium salt up to orbit is no picknick. Undiluted in water the salt will go critical in even smaller concentrations than the diluted mixture would. In the right conditions it is even possible for it to go super-critical (ie. nuclear bomb). This means the salt must also be diluted in some way (mix graphite in with or something) or moderated in a similar method that the liquid fuel is.
Obviously the container for the Salt has to be very rugged, as not only is the stuff radioactive and probably toxic, it is also in more danger of going supercritical if the rocket should explode. If the containment system failed and the salt was compressed by an explosion (or by strong aerodynamic forces) a nuclear explosion in not impossible. This is a problem for the liquid form as well, but since the mixture is diluted it is less likely (though a major criticality accident is a real possibility).
After you get the stuff to orbit, mixing it together is by no means a simple and easy process, even less so in 0g. Rember, the neutron flux of this mixture changes as it's velocity changes, so their are some real hazards involved during the mixture process. A criticality incident could very well destroy your fuel depot and will definetly cause serious damage to it. I won't go so far as to say it's impossible, but it's far from easy, it's probably not an easy mixture to make here on Earth, with gravity to help simplify things, and much better safety percautions.
Considering these two factors, it seems to me that transporting the fuel up already-mixed is a much better solution then a fuel depot.
- Next, there is no reason the engine has to fire continusly. It has the potential to certianly, but in many ways using a pulsed system would be simpler. Obviously pulsing the detonations would give the engine nozzle time to cool of, and so it could be lighter. Additionaly an engine cone might be done away with altogether. This would reduce it's efficency, but could save a great deal of mass. It might be simpler for the pumping system to fire in spurts (maybe with a piston pushed design).
Pulsed firing is slightly less efficent than continuous firing, but not signifigantly so. A NSWR has absurd levels of thrust anyways, so extending the burn time to twice as long or more most likely will not signifigantly effect efficency. Even if the burn time was MUCH longer (days as opposed to hours) the diffrence in the oribtal path the rocket would have to take would not be that signifigant in terms of delta-V. It would be a slightly less efficent use of the nuclear fuel (the leading and trailing stream bits will have the lowest efficency), but again the NSWR ISP is so huge that this may be a saccrifice worth making, and this loss of effiency is probably not that great anyways (depends upon the length of the pulse of coures though).
- If the NSWR proves to heavy for ground lift (a possibility) then it might prove practical to launch the fuel and engine segments seperatly, or just the engine and crew portions seperatly. I don't know if we have addressed this, but the crew will need to be seperated and/or shielded from the engines not-insignifigant radiation as well.
Neilzero, I think the major problem with your plan is Venus's lack of hydrogen. The element is incredibly rare on Venus, with the majority of it having escaped the atmosphere some time in the past. There may be reserves still trapped up in the planets crust someplace, but they are not easily accesable.
Without hydrogen, biologial life is impossible, as is the creation of all those various diffrent hydrogcarbons. Even diamond requires hydrogen as an outer layer as well. As for diamond burning, while it certianly can (especialy in an oxygen rich atmosphere like we are talking about), but that generaly takes temperatures above ~1000K so it should be stable on Venus surface. It would be intresting to have floating diamond plants on Venus, slowly raining out a rain of diamonds hundreads of meters thick on the planets surface below.
Heating Venus up a bit more might be the best solution of all to dump atmosphere.
relatively small quantities of super greenhouse gasses added to The Venusian atmosphere could really heat things up to the point that co2 escapes.
I agree in general principle. Heating up the atmosphere till it reaches escape velocity seems to be the best solution. I worry about the time tables involved though. Unless we get it increadibly hot this process would still take a long time. But I agree that it is more pratical then trying to freeze then remove the CO2 (though freezing the CO2 out of the atmosphere could happen rather quickly).
I think mirrors are the best solution however. I'm not sure how effective additional greenhouse gasses would be. Venus's thick CO2 atmosphere already acts as a very powerfull greenhouse effect. Another approach would be to decrease the amount of sunlight the planet reflects by some method (I'm not exactly sure what). The planet reflects some 60% of the suns light, so reducing that percentage would scale up the heat and greenhouse effect proportionatly.
I came to the same problem with radiation to break the bonds of the co2.
The bonds do break easily with radiation, but with no input of energy the bonds rejoin.
Unless the o2 can bond to something else or the C can be locked into heat resistant things then its pointless.Trying to transport 45 atmospheres of something for o2 to bond to is not realistic.
At best with something that makes many 02 bonds we would still need 10 or so atmospheres importation, again not realistic.
I guess if you got the realy, REALLY hot the carbon and oxygen could exist as free radicals, but that would be way to hot. I've also though that it might be possible to tie up some of the oxygen in some of the metals on Venus. Things like Iorn Oxide and Titanium Oxide could (and probably do) exists on Venus surface. Of course, most of the metals in Venus are probably already locked up in varius oxides, so this may not actualy be that usefull. It would certainly need a huge mining opperation that wouldn't be easy to do on the planets surface.
No additional carbon on Venus vs earth, just in a bad form as co2.
The two worlds have very similar amounts of carbon.
Well I haven't run the exact numbers of mass of CO2 in Venus's atmosphere wrapped up in Earth's biosphere, so I'm willing to assume for now that the excess CO2 might be trapped up in that manner. However, building a biosphere will be an incredibly slow process, so importing the CO2 for the plants when you need it is probably an easier solution. We will have to import mass quantities of nitrogen and hydrogen anyways, so the small additional carbon is no great burden.
If we are just talking about converting the CO2 into other organic forms of carbon (alcohols, alkynes, ethers, and so on) then removing the CO2 is much more expedient. Chemical fuel isn't terribly usefull, especialy in mega-giga quantities you would end up with it. Creating it is an energy losing situation, and it's not like Venus is an energy poor planet. In fact the problem with Venus is that there is TO much energy. Furthermore, VAST quantites of hydrogen would need to be imported for this process.
Creating a constant radiation disaster on Venus or in orbit might be a promising way to lock co2 away or break the co2 bonds or create new heat resistant carbon chains.
With pretty high constant radiation in any spectrum we choose and a free source of power in the sun we should be able to alter the chemistry of Venus atmosphere.?
Trouble is, convert the CO2 to what? Sure you could breakdown CO2 into Carbon and Oxygen with sufficent radiation. It takes an incredible amount of energy to do this thermaly, but on Venus that's not that big a problem. Big mirrors or lenses could do the trick. I'm not sure about braking the bonds with radiation, the bonds are very strong so it would have to be very intense radiation, but I suppose that is possible as well. Venus is energy rich enough to make that possible as well I suppose.
But what can you convert the CO2 into that won't react back into CO2 in the energy dense venutian atmosphere. Especialy if there is any free oxygen floating around. Oxygen is highly reactive and on venus would burn with most forms of carbon back into CO2. Graphite, Buckyballs and tubes, and hydrocarbons are all far to reactive in a hot oxygenated enviroment to last. They all would simply burn back up. The only form of carbon that would work is diamond, which of course
For that matter even without the O2 to react with, Venus is to hot for almost all hydrocarbons. You won't find many plastics that can withstand the 700K heat of Venus's surface for long. Especialy not at 90atm of pressure. And those that might (Teflon for example) replace the oxygen bonds common in many polymers with the stronger bonds in Flourine, which would also need to be imported. OTOH you need to bring in huge quantites of hydrogen anyways, so maybe making some big blocks of PTFE or whatever isn't that big a deal.
But I still say simply dumping the stuff and starting fresh is the best solution. Dump the CO2 atmosphere, spin Venus up somehow, and maybe lower the amount of sunlight it recives and you are starting to get somewhere. Then just bring in a new atmosphere and you are set. I think this approach is much better than trying to manufacture huge diamond or teflon bricks, since you still end up having to bring in a new atmosphere anyways.