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Rand points out that you can carry a lot to orbit without a space elevator for some number of billions of dollars. You can also carry a lot of people in a ferry for the cost of a bridge. But once traffic gets high enough, you get economies of scale. There are actually several confounded questions about the cheapest way to GEO and beyond here.
First, it is very cheap to go from GEO to the planets with an elevator since you are on the downhill side of GEO and you slide out to the planets without any lasers or propellant.
Second, optimal energy to obtain orbit might be better to be hauled along. Maybe a climber could generate enough electric power to climb itself by burning LOX and kerosene in an internal combustion engine. No energy lost to air resistance. No energy lost to following an imperfect trajectory.
Third, optimal propulsion system might be a rocket engine. A rocket designed to go up an elevator would be a lot more capable than one that goes in free space.
Fourth, staging can be used with elevators cars to increase payload fraction in elevator cars. Stage 1 could just slide back down the elevator. Stage 2 could hit the brake and do a full systems checkout before moving up. The occupants could even get out and manually disengage the stages or something.
Fifth, the thing could even be refueled at 50,000 ft by some kind of a hovering balloon or vto refuelling craft. The balloon could even make it so that the last 50,000 feet of elevator at the bottom wouldn't weigh down the thing. This is analogous to air launch or balloon launch.
Finally, there is the economics question. Will there be sufficient demand to justify a high capacity lifter of any sort? The marginal cost of ELVs is high. But the average cost may be lower for low mass to orbit (and beyond). This gets back to the bridge vs. ferry question. If it can be shown that the bridge is more profitable than the ferry, it is worth the billions that terrestrial bridges cost. Or it might be justified anyway via tremendous national prestige and driving down marginal costs even if it is a money loser (like, say, the Chunnel which cost $15 billion or so). I think demand is surely a matter of when rather than if. Demand for orbital space tourism will grow as the number of centimillionaires grows even if nothing else does.
The business case for elevators has not been scrutinized nearly as much as the one for rockets. For example, why not leave the spool for the second strand at the bottom of the elevator and send a climber up unreeling from the bottom as you go and send another "zipper" unit up after? What about suborbital jaunts for folks that don't want to go all the way to orbit? It might even be cost competitive with airplanes for skydiving. As long as you are sending a newspaper roller up, you might as well print something in ink that will evaporate before too long. How much to print a 100,000 kilometer long love letter? Point-to-point hypersonic drop ships.
It is not necessarily true that space cannot warrant two pork infrastructure projects: a cheap RLV and an elevator. If you put it in the highway bill, you only have to compete against the dubious last $500 billion of infrastructure where trillions have already been invested. Bridge to nowhere indeed. The GEO elevator stop could even be called "the Middle of Nowhere".
A space elevator also can be thought of as a national work of art. A modern pyramid. The longest film strip. The longest playing highest fidelity 8,000 track tape. So Bill, would you like to say to Paul, "Keep your laughing gas and rubber, mine's made of diamond."? How many carats in dozens of twenty ton strands? Work it right and get the ends of the nanotubes to join up and the whole thing can start as a single molecule, a single CNT lightyears long.
The promise if we can get orbit and deorbit down to a small multiple of the fuel cost whether via awesome RLV or awesome elevator is substantial. The cheapest way to get there will be a matter for competition to solve. Whether it is competition for Government projects or commercial service will hopefully be decided in favor of the market by capitalizing both projects in the st0ck market and proceeding to get them built.Posted by Sam Dinkin at March 16, 2006 11:27 AM
Maybe a climber could generate enough electric power to climb itself by burning LOX and kerosene in an internal combustion engine.
No, this is not practical, for the same reason an SSTO to GEO using LOX/kerosene is not practical. It's actually even worse, since rocket engines are more efficient than conventional internal combustion engines.Posted by Paul Dietz at March 16, 2006 11:40 AM
Hm... interesting comparisons - how much does maintainence of the Bay Bridge cost? I think the maintenece load on an elevator will be higher than the amortization.
As a starting point, the Golden Gate bridge cost $35M (1932 dollars) to build, and supposedly would cost $1.2B to build today. Toll income for the bridge is $84M/yr, which is presumably very close to the operating costs of the bridge (the debt used to construct the bridge has been paid off in full).
So, as a basis to start conversation, a ten billion dollar bridge could be expected to cost about a billion a year to maintain. Since you also have to pay about a billion a year for the construction debt, a space eleveator needs about $2B a year income to break even.Posted by David Summers at March 16, 2006 12:25 PM
A bit more: that $2B/yr at $100/lb would, of course, be 10,000 tons/yr.
If I were designing an elevator, I think I would design it using modular cars spaced a few thousand km apart. Each car would have a nanofiber on a winch on top, which connects to the next car in the series. It operates by having alternate cars meet together, transfer cargo, and then separating. The advantage is that it can move cargo in both directions simultaneously, and has nice abort (and possibly contruction) modes - if something goes wrong, all the cars separate, winch in all cable, and reenter per normal (albiet at 20 Gs). At least the first failure doesn't throw away the entire cable. (OK, I'll stop playing around now)Posted by David Summers at March 16, 2006 12:43 PM
I'd build the elevator in Equador (with their cooperation). The base should be huge, like the Eiffel tower, on top of a high mountain near their capital, just about on the equator. You've already got railroads and airplanes up there because of the capital so cargo could be brought in easily and to the east a lot of Amazon in case the thing falls during construction.
This avoids the problems associated with an ocean platform (anyone can cruise up, built at sea level, bad weather). Of course you're in trouble if Equador starts getting attitude but they'll have so much invested in the project and their future that probably won't be a problem.
I'd build it so that cars go up on one side and down on the other like lanes of traffic. Possibly four lanes, two up and two down if you want to increase capacity and have redundancy in case of a problem.Posted by rjschwarz at March 16, 2006 01:21 PM
I'll try not to completely restate what's been said in the other threads...
First, the key things to remember about elevators is that they are only rated for a certain max capacity. The baseline design only holds ~20 tons, which has been assumed to be ~8t crawler and ~12t cargo, ISTR.
The reason for launching 2 spools and then zipping them up is that the zipped ribbon would then be strong enough to hold the first crawlers carrying 60,000 miles of nanoribbon. That, I assume, is why you need both and can't just go with one (unless you make it 40t+ in one launch).
Likewise, if at full build the baseline only has ~20t capacity, you need to minimize the amount of that dedicated to fuel. That implies offboard power, or beaming. Now, if there's a way to put a 1-ton nuc on a crawler that provides all of the power that it needs, then fine, do that (good luck with the nuc nuts).
The big disadvantage of the elevator is that it takes 2 weeks to put cargo in GEO and recover the crawler. During that time, you can't use the elevator for anything else, because it is only rated for so much on the line at one time. Conversely, I see the low-g launch as one of the elevator's biggest long-term selling points. Increasing the maximum speed of the crawler or adding extra parallel ribbons are possible alternatives to boost annual lift capacity. As I've mused elsewhere, taking a rocket just out of the atmosphere and launching it there may also be a possibility, but again, you can only start with ~10 tons, so your payload drops when you add in the fuel.
One thing that I don't know at all is how the math works out for enlarging the ribbon past the baseline, increasing the load. I also don't know how fast we can make the crawler go.
I strongly believe that there is a place for the space elevator. I just have come to believe that there is also plenty of room for rockets, even after the eleator is built, because of its annual capacity limits and long launch times.
The real point of the bridge/ferry tradeoff is that if you assume the huge amount of capital available for building space elevators, there are many other options available: it's not an either/or choice. For example, consider that the best way to build a space elevator may be on its side: that is to say, a long electromagnetic accelerator (if you build it long enough, you can boost at human-tolerable G-loadings). This could be built with current technologies and materials, more or less, and it would be a hell of a lot cheaper to build. All it needs is sufficient potential traffic to justify the investment, but that number is much smaller than with an elevator. And (having actually authored an Environmental Impact Statement for a space launch system) I'd sure as hell rather do the EIR for an accelerator than for a space elevator, or have to negotiate the liability insurance premium for one (having also done that for a launch vehicle).
Also, you've got it backwards about a Third World nation and infrastructure investment -- the more capital that has gone into fixed infrastructure, the more the project is at the mercy of the government. The smaller the infrastructure investment is, the more credible the threat is to walk away and do it again somewhere else. Actually with an accelerator the incentive to be right at the equator isn't all that big -- you are probably better off building it across northern Queenland where the infrastructure and skilled workforce is way better, which probably offsets any operational cost savings from equatorial advantage for a long time to come.
Once the accelerator is built, you can access the Moon pretty cheaply, and build the first, experimental space elevator there, where you can use existing materials (kevlar will do, I believe) and work all the bugs out of the system in a minimum-liability environment.Posted by Jim Bennett at March 16, 2006 01:58 PM
Second, optimal energy to obtain orbit might be
If I'm understanding your intent here, this is a non-starter. People have looked hard at every physically plausible alternative for "take your energy along," and none of them -- combustion, batteries, solar photovoltaic, nuclear, flywheels -- is dense enough to do the job and leave any cargo capacity. Edwards was forced to the laser-photovoltaic kludge not because it's efficient, but because it appears to demand the least mass on the climber per kwh applied to the task of climbing.
The crucial advantage is not in efficiency. As Paul says, rockets are highly efficient, and a space elevator would use considerably *more* front-end energy (whatever its source) per kg to GEO than a rocket. The advantage is that the working-end energy all goes into lifting payload and structure, whereas most of a rocket's energy goes into accelerating the remaining fuel until late in its trajectory.
There's also a bonus of "free" energy stolen from the angular momentum of the earth-elevator system, but it's really important only for the beyond-GEO "sling" to escape that you mention. Unlike the case for LEO, which requires much more kinetic than potential energy, the energy required for GEO is mostly climbing -- which is the same no matter how you do it.
To put it another way: once you're past the major miracle of the CNT ribbon material, the minor miracle of multiple MW lasers, and the aerospace feat of initial deployment, the rest is "just" a matter of very reliable electrical and mechanical engineering, in a performance domain that's less demanding and more forgiving than the balls-to-the-wall norm of orbital rocketry.
On terrestrial transportation pork: oh, yeah. I once worked for the design engineers on several Interstate construction projects in the Hudson Valley, and one day in the site trailer came across some programs from county and state annual party banquets. An amazingly high fraction of the ad space (and banquet tables at $NNN per seat) represented contractors, equipment rental firms, sand and gravel and cement and asphalt suppliers. Of course, my company was in there too. People who think NASA plumbs the depths of "jobs for the district" have no idea...Posted by Monte Davis at March 16, 2006 02:24 PM
Big D: The big disadvantage of the elevator is that it takes 2 weeks to put cargo in GEO and recover the crawler.
It's still an open question whether recovering the climbers makes economic sense -- until there's lots of stuff to bring home from space, it could be cheaper to re-use their materials in space, or even throw them away, rather than devote ribbon time to bringing them down.
Jim B: the best way to build a space elevator may be on its side: that is to say, a long electromagnetic accelerator (if you build it long enough, you can boost at human-tolerable G-loadings)
What's the speed and altitude (implying also "what's the heating and aerodynamic stress?") at exit from the accelerator? And don't you still need significant rocket thrust to circularize? I could be wrong, but so far the analyses I've seen suggest that unless your vehicle is a streamlined nickel-iron meteor, accelerator launch buys you all the challenges of the Fabled Hypersonic Spaceplane without doing all that much more for you than a super-White Knight... or a first stage.
Speaking of ferries... didn't the channel ferries (as well as cut-rate air carriers) successfully compete with the Channel Tunnel, which is teetering near bankruptcy? Sometimes the little guys do stay on top.Posted by Paul Dietz at March 16, 2006 02:53 PM
The advantage is that the working-end energy all goes into lifting payload and structure, whereas most of a rocket's energy goes into accelerating the remaining fuel until late in its trajectory.
However, realize that the energy that is being put into the remaining unburned propellant can be largely recovered later in the launch. This is because the rate of change of the kinetic energy of the vehicle increases as its goes faster, for a given thrust. The energy 'stored' in the propellant is in some measure returned to the vehicle when the propellant is expelled. Ideally, if the Isp of the engine is variable and is made proportional to the speed of the vehicle, then (ignoring gravity losses and drag) all of the energy produced by the rocket engine ends up in the kinetic energy of the vehicle at burnout (granted, this is impractical, particularly close to launch, but it shows there is no reason in theory why rockets have to be inefficient.)Posted by Paul Dietz at March 16, 2006 02:58 PM
Ecuador? Sure. But I still like Singapore.
= = =
Given the cost of capital, I cannot imagine how it would make sense to routinely bring capsules back down. Two weeks of interest on $10 billion at 12% is $500 million.
If a capsule is sufficiently valuable then lift some shielding and a parachute and dump it in the atmosphere for re-entry, just like Apollo or Soyuz. Now, a dedicated down strand for people coming back makes sense and you can re-use capsules for that purpose but I am thinking 3 or 4 or 5 ribbons going up (people and cargo) for every 1 coming down (people and ultra-high value cargo).
Low value down cargo just takes the gee-forces of a ballistic re-entry.Posted by Bill White at March 16, 2006 03:14 PM
Using the equator is about more than leverage.
Actually with an accelerator the incentive to be right at the equator isn't all that big -- you are probably better off building it across northern Queenland where the infrastructure and skilled workforce is way better, which probably offsets any operational cost savings from equatorial advantage for a long time to come.
Low inclination orbits (maybe +/- 5 degrees or +/- 3 degrees) will simply space traffic control, debris tracking and launch window rendezvous opportunities as well.
Also, if China were orbiting a million ton skyhook over North America ever 90 minutes or so ballistic missile defense would be rather pointless, no?Posted by Bill White at March 16, 2006 03:23 PM
Paul: Gotta ponder that one -- I have a strong but as yet unmathematical impression your argument is double-dipping somehow.
...if the Isp of the engine is variable and is made proportional to the speed of the vehicle...
Let's make a deal: You tackle highly variable
Correction: Northern Queensland may well be close enough to the equator for these purposes.Posted by Bill White at March 16, 2006 03:26 PM
I like floating. No hassle with the local government, can actively maneuver the base to dodge satellites, which is going to be a constant issue. Sure, most passes won't be within a couple of klicks, but all it takes is one that just happens to be dead on...
I would expect the crawlers to be fairly expensive and not replaceable at the rate of 50/year. Let's assume that, though. So, a baseline elevator could lift 52*~10=~520 tons/year of cargo, plus about as much again of salvageable crawlers at GEO. I wouldn't feel as bad about the waste if the crawlers were intentionally designed to be dismantled and reassembled into station structure. Hmmm, has anybody given any thought to doing just that?
Of course, I expect one of the first things lifted by the first completed space elevator to be the starter ribbon for the second. By the time the first is sufficiently expanded and strengthened to reach baseline capacity, it will be proven enough to pretty much guarantee funding from *somebody* for a second.
Bill, it doesn't really affect the essentials of your argument, but two weeks of interest on $10 billion at 12% is more like $50 million.Posted by Dick Eagleson at March 16, 2006 03:56 PM
Hm... interesting comparisons - how much does maintainence of the Bay Bridge cost? I think the maintenece load on an elevator will be higher than the amortization.
David that's a good question - and one that needs to be answered. But you can't simply toss in numbers from a terrestrial bridge and say "there, done". There just isn't much to compare between a bridge and a space elevator.Posted by Brian at March 16, 2006 05:43 PM
When you climb the elevator, you get mgh. Do you have any friction problems that cause you to also need to get the mv^2 associated with orbital velocity, or do you get that free?Posted by Sam Dinkin at March 16, 2006 06:08 PM
There will certainly be friction--entropy being what it is--but it can be minimized with good design and lube. As far as the different flavors of energy go, at geosynchronous altitude, mgh equals mv^2/2. You are at orbital velocity.Posted by Rand Simberg at March 16, 2006 06:39 PM
Bill, it doesn't really affect the essentials of your argument, but two weeks of interest on $10 billion at 12% is more like $50 million.
Yup. :-)Posted by Bill White at March 16, 2006 06:47 PM
There will certainly be friction--entropy being what it is--but it can be minimized with good design and lube.
Me, I'm thinking the fellow who scores the WD-40 concession is going to make out like a bandit.Posted by Brian at March 16, 2006 07:57 PM
Me, I'm thinking the fellow who scores the WD-40 concession is going to make out like a bandit.
I'm thinking fifty-gallon barrels of astroglide myself...
But that's just me, with mind in the gutter.Posted by Rand Simberg at March 16, 2006 08:15 PM
The big problem is how you get the thing up there and stable! It would take more than the Great Eastern for this job.Posted by A.Syme at March 16, 2006 10:18 PM
What are the failure modes?
How much will a failure cost? Not just in terms of amortizing the construction expense, but in terms of lives and property?Posted by Mike G in Corvallis at March 17, 2006 01:07 AM
What are the failure modes?
It breaks, and the part of the debris is in (noncircular) earth orbit and collides with all the other equatorial elevators that have been built, breaking them, too.Posted by Paul Dietz at March 17, 2006 02:09 AM
It breaks, and the part of the debris is in (noncircular) earth orbit and collides with all the other equatorial elevators that have been built, breaking them, too.
Yup. And the word "failures" encompasses both accidental and non-accidental destruction modes.
In other words, you might just as well hang a 22,00-mile "KICK ME" sign on it.Posted by Mike G in Corvallis at March 17, 2006 02:21 AM
Maybe it's elevator retraction capability we need to be investing in. A big winder at GEO that can reel this puppy in in the event of someone else's elevator disaster. What's the speed of sound in this material? How fast could it be wound without ripping? How big a generator do we need at GEO to do the winding? A space hotel sized winding wheel?
Or maybe a trash pickup plan and a prepositioned new elevator to string if all the others fail.Posted by Sam Dinkin at March 17, 2006 06:06 AM
If you make a "fuse" at low altitude, (say, 100 km) and ensure it breaks from there first (put a self-destruct cutter fired with electrical signal), the whole ribbon should fly out beyond GEO, no? (Since it's center of gravity is beyond GEO and moving faster than the orbital velocity there.) In tangential direction, not hitting the other elevators.
Then the low 100km part comes crashing to the ground but it's relatively light compared to face cross section (so little depth), so maybe the speed wouldn't be devastating... or would it burn?Posted by meiza at March 17, 2006 06:13 AM
now I realize if it doesn't have Earth-escape velocity, it can go into a elliptical orbit with the perigee at the breakpoint COG and a higher apogee on the other side... A menacing tether on orbit. It could generate huge amounts of dangerous space debris too. Somebody should make simulations and graphics out of this.
If you make a "fuse" at low altitude, (say, 100 km) and ensure it breaks from there first (put a self-destruct cutter fired with electrical signal), the whole ribbon should fly out beyond GEO, no?
Only if there are no breaks elsewhere. But you can't assume that. Collisions with random debris, or meteoroids, or manufacturing defects, or catastrophic climber failure, or deliberate sabotage, could cause breaks anywhere along the length of the cable.
Put the cutter at GEO. The bottom will drop fast in less than one orbit. The top will head off into space.Posted by Sam Dinkin at March 17, 2006 06:33 AM
Well, as long as there are only a couple of elevator sites (each of which can have multiple ribbons), I don't think a catastrophic failure is going to be that disastrous on LEO. Space is big, and all that. Worst case, I wouldn't expect to lose more than a couple of satellites before the lower end falls and the upper end is dragged away. Once they start popping up all across the Pacfic, then there's a risk of dominoing. Remember, though, that the lower end is still attached to the platform, which may have a winch, and the upper end definitely has one (although maybe slow), but more importantly, has stationkeeping thrusters that can be turned full on and used to clear the ribbon and possibly recover the upper end to an L-point.
A.Syme: The big problem is how you get the thing up there and stable!
Edwards' proposal, which has become a de facto baseline for discussion, requires about 80 tonnes lifted by rocket to LEO: 100,000km of narrow "seed" ribbon on a spool, an MPD thruster with reaction mass and photovoltaic array, and controls.
Use ground lasers to power the MPD for a slow spiral up to GEO. Unspool the ribbon up and down, keeping the CG near GEO; anchor it at the base. Then use the lasers to send progressively larger climbers up the ribbon, each adding another "tape" of CNT material as it goes. The empty climbers get parked at the outer end as a counterweight. After 230 of them, you have an 800-tonne ribbon strong enough to hold several climbers at a time, each ~7 tonnes with ~13 tonnes payload, climbing at ~200 kph.
Gross stability is not a problem -- the whole system is basically a jointed pendulum, with the portion below GEO hanging down and the portion beyond "hanging out." There's more than enough restoring force to keep it essentially vertical despite the small, steady transverse push it exerts on the climbers as they rise. (That's how they acquire 7000 mph -- orbital velocity -- by the time they reach GEO.) The earth's rotation, dragging the equatorial base station along at 1040 mph, makes up the angular momentum transferred to the climbers.
Internal stability -- the dynamics of all the ribbon's oscillations from wind near the base, light pressure, thermal expansion, climber forces etc -- is another matter, and needs a lot more analysis. It doesn't look like a show-stopper at first cut... but Physics 101 plucked-string intuition is a poor guide when the string is 100,000 km long and the waves take days. (Can you say "chaos"? I was afraid you could.)
Steven Patamia has tackled that, and at the ISDC panel he will be talking about how the oscillations complicate (or could be co-opted for) the task of debris and satellite avoidance, along with debris maven Vladimir Chobotov of Aerospace Corp. CORDS.
Posted by Monte Davis at March 17, 2006 07:38 AM
Big D: Once they start popping up all across the Pacfic, then there's a risk of dominoing.
Combine that with your earlier thoughts about scaling up a given ribbon, and you've put your finger on a nice (if remote) dilemma. At ~8 kg/km, the Edwards-model ribbon is too light to pose a threat if it breaks: the falling lower portion either burns up or "flutters" down. But to scale up throughput to orbit, you have to choose between more elevators -- increasing the risk and stakes of fratricide by a broken segment -- and heavier ones -- which at some point do become dense enough to pose a threat to the ground.
That's the bad news; the good news is that one first-generation elevator could take ~1500 tonnes/yr to orbit, which I guesstimate at 3-5 times what the whole world sends up at present. (I would welcome more detailed numbers from defense departments worldwide :-)Posted by Monte Davis at March 17, 2006 08:03 AM
one first-generation elevator could take ~1500 tonnes/yr to orbit
On orbit construction could get us some awesome Moon and Mars missions assembled at GEO.Posted by Sam Dinkin at March 17, 2006 08:15 AM
On orbit construction could get us some awesome Moon and Mars missions assembled at GEO.
Going back to the earlier posts... what about building crawlers so that they could be dismantled and recycled into station structure? You'd have more than you needed at GEO in the first year, but you could haul a couple of disassembled crawlers on an assembled one out beyond GEO and from there to L-points or LLO for use in stations there.
Any guesses as to how difficult/expensive that would be vs. taking an extra week to recover the crawler or an extra day to throw it away into deep space?
Big D: Any guesses as to how difficult/expensive that would be...
Sounds like a classic design trade-off: the structural components you'd design to make the optimum light/strong climber are not likely to be those you'd design as optimum "Lego" for re-use in other applications. OTOH, a number of the functional components -- photovoltaic array, power conversion package, radiator, electric motor -- are inherently modular.
There's still plenty of work to be done exploring the primary trade space for climber/cargo mass vs. frequency; arguably some level of consensus on that should precede work on the best schedule for handling empty climbers.
But hey, wouldn't it be a wonderful problem to have? "Too much hardware piling up in orbit, and more on the way 24/7, damn it."Posted by Monte Davis at March 17, 2006 12:55 PM
I continue to believe that the biggest issue for building an elevator (other than the current unobtainium building materials) is that it will never survive the environmental impact report.
Sam: On orbit construction could get us some awesome Moon and Mars missions assembled at GEO.
Yes, something like the 1980s "dockyard" version of ISS -- only not on that stingy scale, of course.
In the long run, missions per se are small potatoes. What I want most is to move humanity's messiest activities -- primary energy and resource extraction -- off planet. I want ugly, dusty, grimy mega-Ruhrs and giga-Guangdongs at L points and in the asteroid belt. I want countless hectares of pristine orbit despoiled with gleaming, soulless SPSats.
With a few honorable exceptions, space advocates have done a lousy job of selling that to environmentalists (I suspect because many of them are used to ritually blaming environmentalists and other "anti-space" bogeymen for taking their Apollo budgets away).
Mark: Your concern about terrorism -- which many have expressed -- really ought to be extended. Shouldn't everyone really stop building *anything* big or expensive or vulnerable to anyone's worst-case imagination?
Seriously, though -- don't you think something more prosaic that kills a lot of people would be more tempting to terrorists than breaking a space elevator? "Shock, Horror as Surviving Fragments of Nanotube Ribbon Flutter to Earth: 'Like a Gray Plastic Shopping Bag,' Sobs Traumatized Witness"
And let's think about what might make a "hard" target for terrorism: let's see, ideally it would be something way out in the ocean far from routine travel corridors, something hard to see more than a km away, something many countries and corporations would have a stake in preserving -- I know! Let's get science-fictional and say the base (and ocean) are ringed by big honking multi-MW lasers and a system to aim them precisely...Posted by Monte Davis at March 17, 2006 01:51 PM
It's a good thing the terrorist are basically stupid. Can you imagine the damage and chaos they could achieve in this country if they weren't? Of course, you always worry that they will get smarter.Posted by ken anthony at March 17, 2006 02:41 PM
Monte: It's hard to make common cause with people who think that launching a small RTG will destroy the planet.
Given that the crawlers will consist mostly of the panel/radiator motor and a superstucture, I would think that the weight wouldn't go up too much in making the superstructure lego-like. But, IANAE, and I don't pretend to be.
I'm also assuming here that panels optimized for maximum power generation at certain frequencies will still produce plenty of power on plain 'ol sunlight.
I want countless hectares of pristine orbit despoiled with gleaming, soulless SPSats. With a few honorable exceptions, space advocates have done a lousy job of selling that to environmentalists
Environmentalists don't want their problems solved! What would they complain about then?!
It's hard to make common cause with people who think that launching a small RTG will destroy the planet.
Gagnon and the Cassini protesters are a small fringe of a very large group. Environmental organizations have ~100 times as many members as space advocacy organizations (and an incomparably better track record at influencing policy and legislation).
If you think it's smart to blow off that whole group because of a few flakes, feel free. My thanks to you (and Sam) for providing good examples of exactly the self-defeating attitude I was talking about.Posted by Monte Davis at March 17, 2006 05:03 PM
Build the crew climbers out of Bigelow style habs
Uncrewed cargo climbers? No need to pressurize. No need to fully enclose, really. If we are lifting stuff that is similar to ISS-trusses for on orbit assembly, all you need is to grab the ribbon and bundle together.
Not every upward bound capsule need have crew on board.Posted by Bill White at March 17, 2006 05:13 PM
Monte: Tell me again, how many nuclear reactors, which are far cleaner than burning coal, have been built here in the last 20 years?
If they can be convinced, fine... but I'm not holding my breath over it. At some point, we'll have to have reactors in space to progress, and I expect that to be contested all the way.
Bill: Most won't. The elevator will probably initially be used primarily for unmanned cargo, due to the van allen risk. Once that's resolved, I expect it to be the primary people launcher due to the soft launch, but there's no need to take 25 crews a year up and back.
As for using Bigelow habs... well, think of a crawler as a car frame with an engine and wheels attached (the fuel tank is in the garage with a long hose). The only structure there is what's necessary to hold all the parts (including the cargo) together. Seats, consoles, or anything else should really fall under the category of "cargo". A lightweight inflatable hab (what's Bigelow's again, 50t?) would certainly be an excellent piece of cargo to haul up early on--after launching the seed cable for the second ribbon, I'd like to see somebody spring for a GEO station from the start.
Monte: It is comfortable to not have to convince environmentalists to go to space. Robinson's Mars books do a good job. There ought to be plenty of quotable material to get the greens on board.Posted by Sam Dinkin at March 17, 2006 08:43 PM
While it is true that sensible environmentalists would agree that it is better to muck up space than this planet, they most likely could not act on that - similar to how they cannot advocate nuclear power. Although the crazy people are annoying, they are also the people that can get the attention of the press - so they are the basis of the lobbyist's power. The crazy people get the attention focused on the problem, then the "reasonable people" are consulted on how to fix it - so the "reasonable people" cannot do things that the crazy people disagree with.Posted by David Summers at March 17, 2006 11:46 PM
Correction: Northern Queensland may well be close enough to the equator for these purposes.
Well, if you can get permission from the native goatse tribesmen, Christmas Island would be even better.Posted by Chris Mann at March 18, 2006 01:19 AM
We need a few of us to create press personas that have excellent environmental credentials, but make a strong case for the environmental use of space to solve problems on Earth. Wingo might pass. The trouble with most of the people with such credentials now is that they advocate He-3 mining. We need to infiltrate the environmentalists!
In the US, at least, I think you can blame investors, coal mining interests and their kept politicians, and the until-recent low cost of natural gas for the lack of new nuclear reactors, rather than environmentalists.
Now that natural gas is expensive, we're hearing talk of building new reactors here.Posted by Paul Dietz at March 18, 2006 05:32 AM
blame investors, coal mining interests
Why blame anyone? The issue du jour is how to harness the environmentalist lobby to open space access.Posted by Sam Dinkin at March 18, 2006 05:54 AM
Sam: Now you're talking! I know some of that is tongue in cheek, but any engagement is better than the usual spacers' muttering about "%@$# tree-huggers..."Posted by Monte Davis at March 18, 2006 07:01 AM
Paul: I think you can blame investors, coal mining interests and their kept politicians, and the until-recent low cost of natural gas for the lack of new nuclear reactors, rather than environmentalists.
Nahh, too fact-based. In the Gospel according to Pournelle, you see, around 1970 mobs of obscurantist Greens imposed their anti-science, anti-technology ignorance on the world -- which is why all advances in IT, communications, biotech, smart weapons tech, etc., etc., have been suppressed since then. Space is just another victim of this cruel Dark Age.Posted by Monte Davis at March 18, 2006 07:11 AM
One cannot but honor the truthiness of the revealed word.
BTW, one of my favorite Pournellisms was his column in Analog in 1981 (I think it was) called, IIRC, 'Love That Shuttle!' His tune changed a bit in later years.Posted by Paul Dietz at March 21, 2006 08:47 AM
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