If you buy stock in... say... Google, there's a certain intrinsic value because, if they were to liquidate, they'd have their racks of hardware, their office space, etc. There's money to be hand to buy up the patents and trademarks and everything else...
Much the same way as there's a certain intrinsic value in real estate. You need to remember that part of real estate is all about location, which is not intrinsic.
In both cases, the price you pay is the intrinsic value of the item, plus all of the abstract hard-to-quantify stuff. If all of the tech firms moved out of Silicon Valley, there would be a lot less demand for land in the area, for example. The value of the property goes down, even though "they aren't making more land".
My personal assessment is that it's really just a CPU with some of the instructions thrown out and some programming built in.
I'm betting that it's aimed at being included in a gaming console, or just on a cartrage, like certain 3D SNES games. It seems, to me, like if you were going to do something for the PC, you might as well just stick an extra CPU in... although I am finding the notion of a second, slightly slower CPU on a PCIe card vaugely appealing (could put Linux on it and make a beowulf cluster!)
The point is, however, that the core melted down at TMI. It melted down, but there was no "China syndrome", no melting-through-the-containment-vessel, no melts-till-it-hits-groundwater-and-explodes, nothing like that. It shows that the level of over-engineering we use in our power plants results in safe power plants. TMI was the worst case scenerio.
But yeah.... they'd thought of everything else. It's only natural that the only thing that could go wrong and cause a meltdown is operator error.:)
I found a dimmable flourescent torch lamp 3 years ago at a lighting store. Dono if I could find 'em again.
There are also starting to be 3-way and dimmable CF bulbs on the market.
It's easier if you go to a "real" lighting place. It seems that dimmable lighting is a specialty item or something right now.
My longer term plan is to replace as many of the light fixtures as my wife will let me get away with without having a fit with dimmable white neon (also called cold cathode) using a switching electronic transformer. But then, I've got access to neon working gear.
But it's great stuff. Can be made in arbitrary shapes, the tubing's cold to the touch, etc. And it can be made to last for decades.
Unfortunately, most of them revolve around irrational whackos getting in the way.
We don't shut down coal or oil or natural gas power plants after 30 years, we upgrade them. Yet we worry about how to decomission power plants properly?
More people are killed each year in accidents at non-nuclear-related plants, mines, and processing facilities than are killed at nuclear plants, mines, and processing facilities.
The radiation put out by the thorium and uranium in coal is greater than the allowable amount of radation allowed out of a nuclear power plant.
We don't build Chenobryl-style reactors anymore. Three Mile Island was about as bad as things could get with our reactors and a pebble bed or IFR is even safer. Remember, if TMI was so bad, why wasn't there a cancer spike?
Nuclear waste is only a problem because we're not allowed to reprocess it. We already know how to reprocess the fuel to get more use out of it. We also have a good line about how to deal with the really toxic stuff -- bombard it with neutrons in a controlled fashion to reduce all of the stuff that won't burn in a reactor will be transmuted to lead.
Remember, the really radioactive stuff that makes it dangerous to be around and hot to the touch is much decayed after periods as short as 10 years.
Yep... Only rational reason to be wary is just the problems caused by irrational folk.
First, the lifespan of a tube is directly related to the amount of Mercury in it. Over time, as impurities work their way into the tube, the mercury will combine with them. Once all of the mercury is combined and unavailable, it's just Argon gas, which doesn't look so hot -- it'll flicker and be reddish.
What did the EPA do? Made a big deal about the mercury in landfills and kept forcing, through a variety of ways, the manufacturers to put less mercury in each tube. Meaning that the tubes don't last as long as they used to. Put a good sized blob in there, the tubes suddenly last much longer. Although that sounds scary, consider what happens if your average tube lasted 20-30 years... you wouldn't be complaining very much if you had to put it in the special disposal bin like a TV.
Oh yeah, and they made it impossible for folks to put some neon and krypton with the Argon in the flourescent tubes, to make them able to light up at colder temperatures.
Next fun bit..... hot cathodes. There's not much of a difference between a switching hot cathode "balast" and a switching cold cathode "transformer". Except that the cold cathode transformer is 990 volts instead of 110 volts. It works even better if you can get a few thousand volts, but that's not allowed for perminant residential instalation. Well, the fun bit is that a properly made cold cathode tube will work, literally, until you break it, because the electrodes generally do not wear out. I saw an exhibition of neon beer signs from the 50s and 60s (neon is another name for cold cathode) that were the origional glass and sometimes even the origional transformer. Furthermore, you can dim them down as low as 5% of full illumination with cold cathode and they start up instantly.
Oh yeah, and LEDs. Those are GREAT. The LED manufacturers are trying to build an economy of scale, so they are convincing people to replace their efficent flourescent and cold cathode tubing and signs with less-efficent LEDs. And you trade the simple problem of collecting mercury for the larger problem of disposing a wide variety of semiconductor manufacturing polutants. You still end up wanting some sort of semiconductor-based driver circuit. You still end up with not-exactly-healthy phosphors. And blue LEDs are less efficent at producing the blue+UV light that argon and mercury does.
Furthermore, the big contribution to the environmental mercury problem isn't flourescent tubes. It's coal stacks that are not just putting out mercury, they are putting out mercury compounds (for reference, mercury the metal is relatively harmless, unable to cross the blood-brain barrier, and can be excreted. Mercury compounds can cross the blood-brain barrier and, depending on what the mercury is bound to, can kill you in amounts as small as a drop or two). Whereas flourescent tubes in the dump merely mean that you don't want to let landfills contaminate groundwater.
This rapidly descends into an argument why we are really stupid for letting whacko environmentalists who don't know what they are talking about talk the country into not building nuclear plants.
I still want somebody to tell me if it's more efficent for me to use up a few paper towels instead of those hot-air thingies after I wash my hands, though.
Well.. Um... yeah, and most of us don't go out and actually learn about penis pills, oxycontin, or dead African dictators. Does that mean we want to hear about all of those things?
The problem is, there's already a format for these folks to "Get the word out" without pissing people off. In fact, there's several. Qualified candidates are given lists of voters in a reasonably secure fashion (after all, we want to make sure that people will still vote, even if they are deathly afraid of their ex-whatever tracking them down) so that they can mail campaign information to them. Or radio/tv/newspaper advertisements. Or actually *gasp* going around and meeting real people.
All of which are much more self-regulating than email. Mostly because they cost a larger amount of money, so they have to be focused better.
Which means that if a candidate uses a Dutch server to spam people, they can still fine him or force him to drop out of the race. Remember, if an American goes to Thailand and has sex with a 10 year old hooker, they can still face charges upon return to the states. Same deal.
I'm damn sick of getting spammed by candidates. Oh yeah, and pre-recorded messages on my answering machine.
The part that sucks the most is when both of the leadng candidates spam, which means that I can't use it as a way to simplify my voting decision process.:/
They are good if you want to go within a certain range of speeds within the atmosphere. The problem is, they still need air to function, so you'd still need to carry oxidizer and you'd still need to carry a rocket engine.
The scramjet program doesn't get killed repeatedly because of ill-timed plans. It gets killed because we haven't been able to do a good set of tests on them... until last year. And they are the sort of thing where if you get 'em wrong, you've just wasted a LOT of money. So every time we've tried to do any sort of air-breathing engine -- scramjet, ramjet, turborocket, or intercooler -- it ends up getting pushed off because it increases the design risk too much. The problem is that the scramjet partisans make it sound so good that you forget that they are so far from production that they could be totally wrong and not realize it. And, yeah, scramjet money is money well spent in the same way as money on FTL travel research, teleportation, cryonics, fusion, and other far-out stuff. It may very well be money down the drain, much like trying to transmute lead into gold was in days gone by, but it would be so useful to have that it's dumb to not at least take a good solid scientific look at it.
The Falcon I is memorable because it's the lowest cost, per launch, so far. The Falcon V will be the lowest cost, per pound, so far. With the decided potential to lower the costs further over time, as they realize the economies of scale and also the advantages of partial reusability and (hopefully) improved reliability.
The problem with any air-breathing vehicle is that you change your trajectory in such a way as to create more drag. Remember, a conventional expendable booster can be aluminum, which gets soft and melts at astonishingly low temperatures, as space-age materials go. Why? Because it goes up first, to get out of the atmosphere, and then starts to accelerate.
Air-breathing vehicles require a longer time in the atmosphere, or else you are wasting the weight and whatnot involved in making it airbreathing. Now, this helps because your thrust-to-weight ratio doesn't need to be so high because you can use wings to create lift and whatnot. But this still creates drag and heating. This makes the heating worse, in fact, because you are accumulating far more energy. This also means that you need to output more energy to overcome the drag.
The problem is we have way too little information to really make a good determination as to weather a scramjet is going to work or not. I'm not trying to say that scramjets won't work... I'm just trying to say that they are not a sure bet.
The interesting part about our knowlege of engines since the SSME is that the main thing we've learned since then is that the SSME is too complicated. The real tragedy of the X-33 is that nobody's EVER flown an aerospike engine. We know that there is the potential for trouble... theory dictates that in certain mach ranges, it will have inefficencies. Like scramjets, folks THINK that it won't be a problem, but only flight testing is going to tell. And because NASA picked the most experimental design and Lockheed Martin tried to snow-job NASA into believing that they could make some of the experimental things work that bit them in the butt....
Oh yes, we did kinda learn a LOT about Titanium fabrication because of the SR-71.
I'm not going to deny that.
And yes, we know more about it and are better able to produce it now than we were before. Cheap inverter-based TIG welders and easy supply of the right gasses means that the equipment to do it right is much more frequently observed than before.
My point is and continues to be that if you are going to do something like a reusable launch vehicle, where most projects die because they ran out of money too fast, that you need to view Titanium as more of a last resort. Even though it's not THAT hard to work with, it's still signifigantly more challenging than Alumium or steel. It adds risk, which, given how most reusable launch vehicle projects have failed, is the last thing you need.
Also, Titanium is not the only material like that. Crystal growth does interesting things. Remember, the Saturn V pulled a few tricks like chosing an alloy that gets stronger (for the purpose at hand -- strength of materials is weirder than you'd like to think it is) as it chills to working temperature. It's just that if you don't think of those sorts of things, you have hot-shortened Aluminum or you lose a carefully obtained and preserved tempering.
The Falcon I is currently assumed to be expendable -- they are able to get low launch costs simply by reducing complexity and R&D expenses. But there's a parachute on the side of the first stage and it is going to be active on every flight, to parachute the first stage back to ground. Worst case scenerio, they've got a bunch of scrap metal. But best case scenerio, they will be able to push the launch prices down further.
In other words, SpaceX is doing what they should have done instead of the shuttle.... Building something that's cheap and potentially reusable now, but leaving room down the road for incremental improvements.
The thing to remember about the X-33 is that it's signifigantly less dense than the shuttle. As a general rule-of-thumb, the less dense your vehicle, the less thermal load it needs to deal with. It doesn't make sense at first glance, but if you think about it, it does. If you have two craft, the same weight, but one larger than the other, they are both going to have the same amount of orbital energy to dissapate, but the larger one is going to have more area to work with, therefore the localized heating is less. You'd have to check the sci.space.* archives to be sure about the exact details. And, yeah, even the Russians did a better job on their TPS by changing how the tiles were structured to prevent the tiles from zippering off, but it's still refractory ceramics.
Basicly, there is no way to "upgrade" the shuttle or anything even mildly similar to the shuttle with a better TPS at this point.
The list of things that must be fixed in order to give the shuttle a signifigantly lowered maintenence cost is far too long. Not only do you need to add non-toxic propellants and a more robust TPS, but you also need to build an LFFB in order to save money on the SRB refurbishment, you need to stop removing all of the replacable parts from the shuttle after each flight for maintenence, etc. Remember, they remove the engines, tear 'em down, and put 'em back together. Airliners have this too, but they do it after a large number of flights, not after each flight.
Part of the reason why we are in a pickle right now is that everybody realized that the LFFB and most of the other shuttle upgrades would be useless for any future vehicles. And, at the same time, NASA was unable to even launch a scaled test prototype of a potential shuttle replacement.
The problem is that you are going on and on about a properly built reusable. I'm not trying to say that it's impossible to build a reusable booster. I'm merely saying that, in the 70s and 80s, we didn't have the sort of technology to do it with the budget NASA has. We might have been able to do it with several times the budget and fewer restrictions on features that must be all included in one single vehicle. I'm also trying to say that you can't just tweak the design of the shuttle and fix the problems.
Don't get me started with scramjet boosters. We haven't tested them yet as a full-fledged concept, but the trade-offs for orbital launch don't look so good. By the time you add in all of the heat-dissapating structures necessary for a sustained flight through the atmosphere (Remember, rockets have the luxury of going above the atmosphere immediately), the structural modifications to shape and gulp that much air in, etc. using rockets and carying your own supply of oxygen starts to look awful good.
The problem is that we're so obscessed with building a revolutionary booster that will solve all of the problems of current space travel, we're ignoring reality. Change is not necessarily to be metered out in bursts of revolution. Even revolutionary change comes as a continuous stream of minor changes and improvements until it finally hits critical mass.
Take, for example, the Internet. TCP/IP was made decades ago. We added SMTP, FTP, etc. Then we added Gopher. Then the Web beat Gopher. We added stuff to the web like graphics and better f
No, I'm not saying that we should go back to the Saturn. I'm saying that we shouldn't have bothered with the shuttle until we were able to do it right. Now, with our current technologies, it's entirely plausable to start with a clean sheet of paper and do a reusable booster that would work. The resulting booster would look nothing like the current shuttle, however.
One of the main reasons why the shuttle upgrades never made sense was that most of them were shuttle-specific and wouldn't have carried over to the shuttle-successor that was always a decade away and has continued to be a decade away for the past 20 years.
I'm saying that the shuttle should be viewed as something like a supersonic seaplane or a afterburning turboprop. We thought that both of those made sense at one point. The Navy built a supersonic seaplane and the Air Force built an afterburning turboprop and also a part-jet, part-turboprop. The thing is, we also built all-jet fighters and non-seaplane naval aircraft and increases in some areas of technology meant that a lot of the weird wrinkles they needed to put into the other designs weren't necessary anymore. Wheras, the only time we've tried to build a reusable booster so far was the shuttle (and the Russian-clone Buran, which only had minor increases in functionality) so we really have no idea what would have happened were the Chrysler version or the Lochkeed version or the DC-3 version or the Delta Clipper of more recent times, or the Venturestar, or any number of others were to be tried. About the only data points we have of shuttle alternatives is the DC-X and the SpaceShipOne. We know that the aerodynamics of SS1 weren't quite right and we know that DC-X was far more feasable than most of the shuttle folk would like to admit. We've never tried any aerospike engines in flight.
The problem with your analogy is that the Comet didn't have anything wrong with it. Sure, the engines burried in the wings was a feature not carried into later aircraft, but the only problem was that they didn't quite grasp metal fatigue. The Comet airframe, just like the 707 airframe, is still flying regularly.
You have to remember that the thermal protection system from the X-33 wouldn't work with a shuttle -- it's too dense and, therefore, too hot. Developing a Alchohol and Lox RCS would have increased the development cost because you'd need to develop entirely new thruster designs to work. And the reason why they have the APU is because when they developed the shuttle that was the best they could do. And they did design an unmanned version of the shuttle, but nobody wanted to foot the development cost. All of these sound really simple, but they really aren't very simple for NASA to do and certify for manned use. And, given the budgetary problems and everything that the shuttle was going through back then, it would have just made things worse.
The problem is that they could have used LFFBs, a more robust TPS, non-toxic propellants, a better APU, and many others, and the shuttle would STILL be really expensive, simply because there is no margin for error. Even if there wasn't anybody inside of the shuttle, the spaceframe needs to last for long enough to recoup the added costs over expendable boosters. There are too many things that must be exactly right or else it blows up.
Everybody has all of these arguments about how if.... was done, the shuttle would have been fine. I used to, too. But, in the end, I realized something. The shuttle shouldn't have been built. Not to say that it brought a tear to the eye when Columbia ended up strewn across Texas instead of being given dignified retirement in the Smithsonian, but had we stuck with expendable boosters, we'd probably have gotten more done in these past 30 years. And that doesn't even count making the Saturn V or II designs reusable from either the top down or the bottom up.
Titanium sounds like a super-metal.... until you try to work it.
It has it's own set of stress-fractures, although these are brought out mostly by impurities. It reacts to all kinds of stuff that Aluminum doesn't, and, even better loses structural integrity after being splashed by a variety of useful chemicals.
We've come a long way, but it's still a pain. For the same quality of weld, you are going to spend a lot more time welding.
So, yeah, we could have built a much lighter shuttle with Titanium. But that wouldn't have fixed most of the other problems, most notably the cost problem.... and given that they probably should have spent between 2 and 4 times as much money, even with standard Aluminum.....
Remember, sometimes asking questions from ignorance, asking "well, why DO things need to be that way?" is the route to a good idea.
And sometimes, you are just asking programmers why they keep putting bugs in their code and telling them that they need to put more features in, instead.
A good non-technical manager for a technical company needs to be more of the first and less of the second.
Um, can you imagine how obnoxious it would be to distribute wikipedia content over the 'net? Remember, the content changes enough that you can't just have a simple mirror. Do you realize how much network load it would take, just to keep up with updates and transport locking information, etc? Fine for ethernet, bad for a distributed network.
Make it a 4-hour-old mirror? Right. That means that a crank who posts at just the right time gets 4 hours of unadulterated crap, instead of the usual astonishingly-few-minutes before discovery and removal.
Split the content set up? Yeah, but you'd end up with basicly no ability to match the different content sets above. It would break the wiki model and prevent future enhancements.
I'm mostly hoping that they get to flight-testing an aerospike nozle at some point.
I think the biggest advantage that Armadillo has is that their expenses are so low by comparison. Which means that they can actually afford to try things that other folks don't, write up how well it worked publically, and maybe help out the market in general.
Slashdot Mirror
No, it's the exact same thing.
If you buy stock in... say... Google, there's a certain intrinsic value because, if they were to liquidate, they'd have their racks of hardware, their office space, etc. There's money to be hand to buy up the patents and trademarks and everything else...
Much the same way as there's a certain intrinsic value in real estate. You need to remember that part of real estate is all about location, which is not intrinsic.
In both cases, the price you pay is the intrinsic value of the item, plus all of the abstract hard-to-quantify stuff. If all of the tech firms moved out of Silicon Valley, there would be a lot less demand for land in the area, for example. The value of the property goes down, even though "they aren't making more land".
Yeaaaah.
My personal assessment is that it's really just a CPU with some of the instructions thrown out and some programming built in.
I'm betting that it's aimed at being included in a gaming console, or just on a cartrage, like certain 3D SNES games. It seems, to me, like if you were going to do something for the PC, you might as well just stick an extra CPU in... although I am finding the notion of a second, slightly slower CPU on a PCIe card vaugely appealing (could put Linux on it and make a beowulf cluster!)
Indeed.
:)
The point is, however, that the core melted down at TMI. It melted down, but there was no "China syndrome", no melting-through-the-containment-vessel, no melts-till-it-hits-groundwater-and-explodes, nothing like that. It shows that the level of over-engineering we use in our power plants results in safe power plants. TMI was the worst case scenerio.
But yeah.... they'd thought of everything else. It's only natural that the only thing that could go wrong and cause a meltdown is operator error.
I found a dimmable flourescent torch lamp 3 years ago at a lighting store. Dono if I could find 'em again.
There are also starting to be 3-way and dimmable CF bulbs on the market.
It's easier if you go to a "real" lighting place. It seems that dimmable lighting is a specialty item or something right now.
My longer term plan is to replace as many of the light fixtures as my wife will let me get away with without having a fit with dimmable white neon (also called cold cathode) using a switching electronic transformer. But then, I've got access to neon working gear.
But it's great stuff. Can be made in arbitrary shapes, the tubing's cold to the touch, etc. And it can be made to last for decades.
I bet that'll make the anti-globilization folks happy. They've been wanting something to happen to the world bank. :)
You don't know what you are talking about. I can provide more evidence, but that was what I could find right off the top of my head.
Yeah.
Unfortunately, most of them revolve around irrational whackos getting in the way.
We don't shut down coal or oil or natural gas power plants after 30 years, we upgrade them. Yet we worry about how to decomission power plants properly?
More people are killed each year in accidents at non-nuclear-related plants, mines, and processing facilities than are killed at nuclear plants, mines, and processing facilities.
The radiation put out by the thorium and uranium in coal is greater than the allowable amount of radation allowed out of a nuclear power plant.
We don't build Chenobryl-style reactors anymore. Three Mile Island was about as bad as things could get with our reactors and a pebble bed or IFR is even safer. Remember, if TMI was so bad, why wasn't there a cancer spike?
Nuclear waste is only a problem because we're not allowed to reprocess it. We already know how to reprocess the fuel to get more use out of it. We also have a good line about how to deal with the really toxic stuff -- bombard it with neutrons in a controlled fashion to reduce all of the stuff that won't burn in a reactor will be transmuted to lead.
Remember, the really radioactive stuff that makes it dangerous to be around and hot to the touch is much decayed after periods as short as 10 years.
Yep... Only rational reason to be wary is just the problems caused by irrational folk.
Here's the fun one...
We've made it worse.
First, the lifespan of a tube is directly related to the amount of Mercury in it. Over time, as impurities work their way into the tube, the mercury will combine with them. Once all of the mercury is combined and unavailable, it's just Argon gas, which doesn't look so hot -- it'll flicker and be reddish.
What did the EPA do? Made a big deal about the mercury in landfills and kept forcing, through a variety of ways, the manufacturers to put less mercury in each tube. Meaning that the tubes don't last as long as they used to. Put a good sized blob in there, the tubes suddenly last much longer. Although that sounds scary, consider what happens if your average tube lasted 20-30 years... you wouldn't be complaining very much if you had to put it in the special disposal bin like a TV.
Oh yeah, and they made it impossible for folks to put some neon and krypton with the Argon in the flourescent tubes, to make them able to light up at colder temperatures.
Next fun bit..... hot cathodes. There's not much of a difference between a switching hot cathode "balast" and a switching cold cathode "transformer". Except that the cold cathode transformer is 990 volts instead of 110 volts. It works even better if you can get a few thousand volts, but that's not allowed for perminant residential instalation. Well, the fun bit is that a properly made cold cathode tube will work, literally, until you break it, because the electrodes generally do not wear out. I saw an exhibition of neon beer signs from the 50s and 60s (neon is another name for cold cathode) that were the origional glass and sometimes even the origional transformer. Furthermore, you can dim them down as low as 5% of full illumination with cold cathode and they start up instantly.
Oh yeah, and LEDs. Those are GREAT. The LED manufacturers are trying to build an economy of scale, so they are convincing people to replace their efficent flourescent and cold cathode tubing and signs with less-efficent LEDs. And you trade the simple problem of collecting mercury for the larger problem of disposing a wide variety of semiconductor manufacturing polutants. You still end up wanting some sort of semiconductor-based driver circuit. You still end up with not-exactly-healthy phosphors. And blue LEDs are less efficent at producing the blue+UV light that argon and mercury does.
Furthermore, the big contribution to the environmental mercury problem isn't flourescent tubes. It's coal stacks that are not just putting out mercury, they are putting out mercury compounds (for reference, mercury the metal is relatively harmless, unable to cross the blood-brain barrier, and can be excreted. Mercury compounds can cross the blood-brain barrier and, depending on what the mercury is bound to, can kill you in amounts as small as a drop or two). Whereas flourescent tubes in the dump merely mean that you don't want to let landfills contaminate groundwater.
This rapidly descends into an argument why we are really stupid for letting whacko environmentalists who don't know what they are talking about talk the country into not building nuclear plants.
I still want somebody to tell me if it's more efficent for me to use up a few paper towels instead of those hot-air thingies after I wash my hands, though.
Yeah.
And by don't put out a lot of light, they mean "barely more efficent than incandescent and much less efficent than flourescent"
Well.. Um... yeah, and most of us don't go out and actually learn about penis pills, oxycontin, or dead African dictators. Does that mean we want to hear about all of those things?
The problem is, there's already a format for these folks to "Get the word out" without pissing people off. In fact, there's several. Qualified candidates are given lists of voters in a reasonably secure fashion (after all, we want to make sure that people will still vote, even if they are deathly afraid of their ex-whatever tracking them down) so that they can mail campaign information to them. Or radio/tv/newspaper advertisements. Or actually *gasp* going around and meeting real people.
All of which are much more self-regulating than email. Mostly because they cost a larger amount of money, so they have to be focused better.
This is the FEC, not the FCC.
Which means that if a candidate uses a Dutch server to spam people, they can still fine him or force him to drop out of the race. Remember, if an American goes to Thailand and has sex with a 10 year old hooker, they can still face charges upon return to the states. Same deal.
Oh, that's refreshing.
:/
I'm damn sick of getting spammed by candidates. Oh yeah, and pre-recorded messages on my answering machine.
The part that sucks the most is when both of the leadng candidates spam, which means that I can't use it as a way to simplify my voting decision process.
Not necessarily.
Jet-A can be burned, more or less, in a Diesel engine.
If the car expects gasoline.... well.. that's a problem.
IIRC if you have a 50/50 mixture of gas and diesel, that's the perfect recipe for a fuel-tank explosion.
Well, they did have that happen for Burt Rutan's Voyager.
:P
But that may be like a manager asking a bunch of programmers why they keep putting bugs in their code.
Scramjets only look good under certain assumptions.
They are good if you want to go within a certain range of speeds within the atmosphere. The problem is, they still need air to function, so you'd still need to carry oxidizer and you'd still need to carry a rocket engine.
The scramjet program doesn't get killed repeatedly because of ill-timed plans. It gets killed because we haven't been able to do a good set of tests on them... until last year. And they are the sort of thing where if you get 'em wrong, you've just wasted a LOT of money. So every time we've tried to do any sort of air-breathing engine -- scramjet, ramjet, turborocket, or intercooler -- it ends up getting pushed off because it increases the design risk too much. The problem is that the scramjet partisans make it sound so good that you forget that they are so far from production that they could be totally wrong and not realize it. And, yeah, scramjet money is money well spent in the same way as money on FTL travel research, teleportation, cryonics, fusion, and other far-out stuff. It may very well be money down the drain, much like trying to transmute lead into gold was in days gone by, but it would be so useful to have that it's dumb to not at least take a good solid scientific look at it.
The Falcon I is memorable because it's the lowest cost, per launch, so far. The Falcon V will be the lowest cost, per pound, so far. With the decided potential to lower the costs further over time, as they realize the economies of scale and also the advantages of partial reusability and (hopefully) improved reliability.
The problem with any air-breathing vehicle is that you change your trajectory in such a way as to create more drag. Remember, a conventional expendable booster can be aluminum, which gets soft and melts at astonishingly low temperatures, as space-age materials go. Why? Because it goes up first, to get out of the atmosphere, and then starts to accelerate.
Air-breathing vehicles require a longer time in the atmosphere, or else you are wasting the weight and whatnot involved in making it airbreathing. Now, this helps because your thrust-to-weight ratio doesn't need to be so high because you can use wings to create lift and whatnot. But this still creates drag and heating. This makes the heating worse, in fact, because you are accumulating far more energy. This also means that you need to output more energy to overcome the drag.
The problem is we have way too little information to really make a good determination as to weather a scramjet is going to work or not. I'm not trying to say that scramjets won't work... I'm just trying to say that they are not a sure bet.
The interesting part about our knowlege of engines since the SSME is that the main thing we've learned since then is that the SSME is too complicated. The real tragedy of the X-33 is that nobody's EVER flown an aerospike engine. We know that there is the potential for trouble... theory dictates that in certain mach ranges, it will have inefficencies. Like scramjets, folks THINK that it won't be a problem, but only flight testing is going to tell. And because NASA picked the most experimental design and Lockheed Martin tried to snow-job NASA into believing that they could make some of the experimental things work that bit them in the butt....
Oh yes, we did kinda learn a LOT about Titanium fabrication because of the SR-71.
I'm not going to deny that.
And yes, we know more about it and are better able to produce it now than we were before. Cheap inverter-based TIG welders and easy supply of the right gasses means that the equipment to do it right is much more frequently observed than before.
My point is and continues to be that if you are going to do something like a reusable launch vehicle, where most projects die because they ran out of money too fast, that you need to view Titanium as more of a last resort. Even though it's not THAT hard to work with, it's still signifigantly more challenging than Alumium or steel. It adds risk, which, given how most reusable launch vehicle projects have failed, is the last thing you need.
Also, Titanium is not the only material like that. Crystal growth does interesting things. Remember, the Saturn V pulled a few tricks like chosing an alloy that gets stronger (for the purpose at hand -- strength of materials is weirder than you'd like to think it is) as it chills to working temperature. It's just that if you don't think of those sorts of things, you have hot-shortened Aluminum or you lose a carefully obtained and preserved tempering.
Ahh, but you forget about SpaceX.
The Falcon I is currently assumed to be expendable -- they are able to get low launch costs simply by reducing complexity and R&D expenses. But there's a parachute on the side of the first stage and it is going to be active on every flight, to parachute the first stage back to ground. Worst case scenerio, they've got a bunch of scrap metal. But best case scenerio, they will be able to push the launch prices down further.
In other words, SpaceX is doing what they should have done instead of the shuttle.... Building something that's cheap and potentially reusable now, but leaving room down the road for incremental improvements.
The thing to remember about the X-33 is that it's signifigantly less dense than the shuttle. As a general rule-of-thumb, the less dense your vehicle, the less thermal load it needs to deal with. It doesn't make sense at first glance, but if you think about it, it does. If you have two craft, the same weight, but one larger than the other, they are both going to have the same amount of orbital energy to dissapate, but the larger one is going to have more area to work with, therefore the localized heating is less. You'd have to check the sci.space.* archives to be sure about the exact details. And, yeah, even the Russians did a better job on their TPS by changing how the tiles were structured to prevent the tiles from zippering off, but it's still refractory ceramics.
Basicly, there is no way to "upgrade" the shuttle or anything even mildly similar to the shuttle with a better TPS at this point.
The list of things that must be fixed in order to give the shuttle a signifigantly lowered maintenence cost is far too long. Not only do you need to add non-toxic propellants and a more robust TPS, but you also need to build an LFFB in order to save money on the SRB refurbishment, you need to stop removing all of the replacable parts from the shuttle after each flight for maintenence, etc. Remember, they remove the engines, tear 'em down, and put 'em back together. Airliners have this too, but they do it after a large number of flights, not after each flight.
Part of the reason why we are in a pickle right now is that everybody realized that the LFFB and most of the other shuttle upgrades would be useless for any future vehicles. And, at the same time, NASA was unable to even launch a scaled test prototype of a potential shuttle replacement.
The problem is that you are going on and on about a properly built reusable. I'm not trying to say that it's impossible to build a reusable booster. I'm merely saying that, in the 70s and 80s, we didn't have the sort of technology to do it with the budget NASA has. We might have been able to do it with several times the budget and fewer restrictions on features that must be all included in one single vehicle. I'm also trying to say that you can't just tweak the design of the shuttle and fix the problems.
Don't get me started with scramjet boosters. We haven't tested them yet as a full-fledged concept, but the trade-offs for orbital launch don't look so good. By the time you add in all of the heat-dissapating structures necessary for a sustained flight through the atmosphere (Remember, rockets have the luxury of going above the atmosphere immediately), the structural modifications to shape and gulp that much air in, etc. using rockets and carying your own supply of oxygen starts to look awful good.
The problem is that we're so obscessed with building a revolutionary booster that will solve all of the problems of current space travel, we're ignoring reality. Change is not necessarily to be metered out in bursts of revolution. Even revolutionary change comes as a continuous stream of minor changes and improvements until it finally hits critical mass.
Take, for example, the Internet. TCP/IP was made decades ago. We added SMTP, FTP, etc. Then we added Gopher. Then the Web beat Gopher. We added stuff to the web like graphics and better f
No, I'm not saying that we should go back to the Saturn. I'm saying that we shouldn't have bothered with the shuttle until we were able to do it right. Now, with our current technologies, it's entirely plausable to start with a clean sheet of paper and do a reusable booster that would work. The resulting booster would look nothing like the current shuttle, however.
One of the main reasons why the shuttle upgrades never made sense was that most of them were shuttle-specific and wouldn't have carried over to the shuttle-successor that was always a decade away and has continued to be a decade away for the past 20 years.
I'm saying that the shuttle should be viewed as something like a supersonic seaplane or a afterburning turboprop. We thought that both of those made sense at one point. The Navy built a supersonic seaplane and the Air Force built an afterburning turboprop and also a part-jet, part-turboprop. The thing is, we also built all-jet fighters and non-seaplane naval aircraft and increases in some areas of technology meant that a lot of the weird wrinkles they needed to put into the other designs weren't necessary anymore. Wheras, the only time we've tried to build a reusable booster so far was the shuttle (and the Russian-clone Buran, which only had minor increases in functionality) so we really have no idea what would have happened were the Chrysler version or the Lochkeed version or the DC-3 version or the Delta Clipper of more recent times, or the Venturestar, or any number of others were to be tried. About the only data points we have of shuttle alternatives is the DC-X and the SpaceShipOne. We know that the aerodynamics of SS1 weren't quite right and we know that DC-X was far more feasable than most of the shuttle folk would like to admit. We've never tried any aerospike engines in flight.
The problem with your analogy is that the Comet didn't have anything wrong with it. Sure, the engines burried in the wings was a feature not carried into later aircraft, but the only problem was that they didn't quite grasp metal fatigue. The Comet airframe, just like the 707 airframe, is still flying regularly.
You are painting tits on a boar.
.... was done, the shuttle would have been fine. I used to, too. But, in the end, I realized something. The shuttle shouldn't have been built. Not to say that it brought a tear to the eye when Columbia ended up strewn across Texas instead of being given dignified retirement in the Smithsonian, but had we stuck with expendable boosters, we'd probably have gotten more done in these past 30 years. And that doesn't even count making the Saturn V or II designs reusable from either the top down or the bottom up.
You have to remember that the thermal protection system from the X-33 wouldn't work with a shuttle -- it's too dense and, therefore, too hot. Developing a Alchohol and Lox RCS would have increased the development cost because you'd need to develop entirely new thruster designs to work. And the reason why they have the APU is because when they developed the shuttle that was the best they could do. And they did design an unmanned version of the shuttle, but nobody wanted to foot the development cost. All of these sound really simple, but they really aren't very simple for NASA to do and certify for manned use. And, given the budgetary problems and everything that the shuttle was going through back then, it would have just made things worse.
The problem is that they could have used LFFBs, a more robust TPS, non-toxic propellants, a better APU, and many others, and the shuttle would STILL be really expensive, simply because there is no margin for error. Even if there wasn't anybody inside of the shuttle, the spaceframe needs to last for long enough to recoup the added costs over expendable boosters. There are too many things that must be exactly right or else it blows up.
Everybody has all of these arguments about how if
Titanium sounds like a super-metal.... until you try to work it.
It has it's own set of stress-fractures, although these are brought out mostly by impurities. It reacts to all kinds of stuff that Aluminum doesn't, and, even better loses structural integrity after being splashed by a variety of useful chemicals.
We've come a long way, but it's still a pain. For the same quality of weld, you are going to spend a lot more time welding.
So, yeah, we could have built a much lighter shuttle with Titanium. But that wouldn't have fixed most of the other problems, most notably the cost problem.... and given that they probably should have spent between 2 and 4 times as much money, even with standard Aluminum.....
...is when they are out of their knowlege base.
Remember, sometimes asking questions from ignorance, asking "well, why DO things need to be that way?" is the route to a good idea.
And sometimes, you are just asking programmers why they keep putting bugs in their code and telling them that they need to put more features in, instead.
A good non-technical manager for a technical company needs to be more of the first and less of the second.
I keep mine filled with my art. So there are ceramics, neon, and plasma in my cube.
Um, can you imagine how obnoxious it would be to distribute wikipedia content over the 'net? Remember, the content changes enough that you can't just have a simple mirror. Do you realize how much network load it would take, just to keep up with updates and transport locking information, etc? Fine for ethernet, bad for a distributed network.
Make it a 4-hour-old mirror? Right. That means that a crank who posts at just the right time gets 4 hours of unadulterated crap, instead of the usual astonishingly-few-minutes before discovery and removal.
Split the content set up? Yeah, but you'd end up with basicly no ability to match the different content sets above. It would break the wiki model and prevent future enhancements.
Things that work for a semi-controlled, editied Wikipedia don't work for the rest of the 'net.
On the other hand, maybe they could mine it for semantic information from the already partially tagged content somehow.
I'm mostly hoping that they get to flight-testing an aerospike nozle at some point.
I think the biggest advantage that Armadillo has is that their expenses are so low by comparison. Which means that they can actually afford to try things that other folks don't, write up how well it worked publically, and maybe help out the market in general.