RE: An interesting response
-Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of hkhenson Sent: Friday, April 11, 2008 3:43 PM To: brin-l@mccmedia.com Subject: RE: An interesting response At 12:00 PM 4/11/2008, Dan M wrote: (Keith wrote) Takes 10 200 ton payload rockets each flying once a day to do it and with a blank check perhaps under 5 years to work up to this production rate and 6-7 years from start to get to a $50 billion a year revenue stream increasing at $25 billion a year. OK, let's do the math on that. At the present time, the cost of lift to geosynchronous orbit is $20,000 per kg or $20M per metric ton. Ten 200 ton payloads would be about 40 billion per day or 14.6 trillion per year. That's roughly the GDP of the US. And the analogy would be how impossible it is to build a dam sending all the contents in Fed Ex envelopes. The trick is, as it always has been, to lower launch costs. Unfortunately, even in inflation adjusted dollars, launch costs haven't dropped much over the past 40 years. I agree with you. The question is why? I wrote a blog on that general topic at the Scientific American website http://science-community.sciam.com/blog-entry/Dan-Ms-Blog/Unfortunate-Promin ent-Misconception-Concerning-Tech/34870 The essence is that when the engineering community starts working on something, it starts working on the obviously solvable problems first. Then, progress slows as the easy problems are solved and harder problems are faced. The point at which this happens, and the manner in which it happens is based on what is found. The speed of sound barrier is rather significant, and we have not found a way to develop efficient planes that go at Mach 1.1 almost 60 years after we first went above Mach 1. It's not the cost of energy. No, it's the cost of the system. A nearly hundred percent efficient space elevator lifts about 2400 mt a day Of course you have the cost of the elevator and cleaning up the space junk as capital costs. It can't be done at all now because we don't have the cable, but just for analysis put a $1000 billion price tag on it. Sure, if the cost were that low, it would work. But setting a figure like that reminds me of the story of the engineer, the chemist, and the accountant who were all stuck on a desert island with cans of food and no can opener.I'm sure you've all heard the jokebut the punchline is the accountant, after hearing suggestions from the engineer and the chemist that don't work gives his solution that starts with first assume we have a can opener. I've invented a few things that are used worldwide and am still engaged in practical science/engineering. I've worked close to guys who's inventions have reduce world costs for producing oil by about 250 million/day. So, I think I'm fairly familiar with processes that are economical and that work. I have not seen anything in what you have written on this subject that gives an indication of an understanding of the nature of practical solutions to problems. Done with rockets of this sort http://www.ilr.tu-berlin.de/koelle/Neptun/NEP2015.pdf the energy input is about 15 times that high, or from $15 /kg down to $1.50 as you get less and less expensive energy. I went to this website, and it looked like a speculative conference. Vaporware is easy to build. Doing something that works is hard. Most things we wish we could do we do not know how to do. I think that this is the absolutely fundamental difference you have with folks who argue for nuclear reactors vs. space based solar power. We've demonstrated safety mechanisms, Can you be specific about what you mean here? Sure, to be effective, power would have to be transmitted down in a fairly dense fashion. One needs mechanisms that provide feedback to turn the power off should the aim stray. Plus, it costs money to build the actual arrays. That's true, but with just mild concentration you can get at least 10 times more power out of a solar cell in space. We have an overwhelmingly fundamental difference here. I have looked at the solar arrays for the space station and they are expensive. If concentration were trivial in space, don't you think they would have used it? We know on earth that techniques that use concentration have practical problems that have prevented them from being cost effective. If you can find a way to drop launch costs a factor of 100 to 500, then space based solar becomes a player. There is nothing like that on the horizon. There doesn't seem to be any reason a really huge throughput transport system should not be able to give you that much reduction. Then, why hasn't it happened with the scores of airline industries? 747s were brought online in the '60salmost 40 years ago. 747s remain competitive. The airline industry is huge, and we've only seen incremental improvements over the past 40 years.
Re: An interesting response
On 17/04/2008, at 3:14 AM, Dan M wrote: The speed of sound barrier is rather significant, and we have not found a way to develop efficient planes that go at Mach 1.1 almost 60 years after we first went above Mach 1. So-called supercruise. The biggest problem with going over Mach 1 is political and legal, not technological - had Concorde not been killed by politics, its successor would have been an efficient supersonic plane. It's not the cost of energy. No, it's the cost of the system. Yep. Can you be specific about what you mean here? Sure, to be effective, power would have to be transmitted down in a fairly dense fashion. One needs mechanisms that provide feedback to turn the power off should the aim stray. Current designs seem to show a wide collection with a diffuse beam, so that it's relatively safe to be under the beam. There doesn't seem to be any reason a really huge throughput transport system should not be able to give you that much reduction. Then, why hasn't it happened with the scores of airline industries? 747s were brought online in the '60salmost 40 years ago. 747s remain competitive. The airline industry is huge, and we've only seen incremental improvements over the past 40 years. And 747s, beyond the basic airframe and control systems, are very different to what they were in the 70s. (by the way, they were brought online in 1970 - maiden flight was '69, but it wasn't delivered 'til the following year). There isn't a need for that many huge airliners, only around 1400 747s have been built, and it's taken 'til last year for the 747s size and efficiency to be surpassed by the A380 (which is an incredible plane) - improvements in the mid-size airliners have been marked, however, mainly because there's a lot more competition. Point on this part is that there is huge inertia when there's huge capital expenditure - if you've spent a few tens of millions on a plane in 1970 or 1980 you're going to keep using it as long as you can, 'cause a similar plane costs a few hundred million in 2008. All that said, I'd like to see you, Dan, try to put together a cost- analysis on a powersat project. You're very good at using your tenacious posting to naysay, so I'd like to see you attempt to solve the problem so I can see where the problems are. C. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
An interesting response
At 12:00 PM 4/16/2008, Dan M wrote: (Keith wrote) At 12:00 PM 4/11/2008, Dan M wrote: (Keith wrote) Takes 10 200 ton payload rockets each flying once a day to do it and with a blank check perhaps under 5 years to work up to this production rate and 6-7 years from start to get to a $50 billion a year revenue stream increasing at $25 billion a year. OK, let's do the math on that. At the present time, the cost of lift to geosynchronous orbit is $20,000 per kg or $20M per metric ton. Ten 200 ton payloads would be about 40 billion per day or 14.6 trillion per year. That's roughly the GDP of the US. And the analogy would be how impossible it is to build a dam sending all the contents in Fed Ex envelopes. The trick is, as it always has been, to lower launch costs. Unfortunately, even in inflation adjusted dollars, launch costs haven't dropped much over the past 40 years. I agree with you. The question is why? I wrote a blog on that general topic at the Scientific American website http://science-community.sciam.com/blog-entry/Dan-Ms-Blog/Unfortunate-Promin ent-Misconception-Concerning-Tech/34870 It was an interesting blog, though *social problems* are in a very different class than engineering ones like going to the moon. At least they are now. Ask and I will point you to a dark story about how they might be solved. The essence is that when the engineering community starts working on something, it starts working on the obviously solvable problems first. Then, progress slows as the easy problems are solved and harder problems are faced. The point at which this happens, and the manner in which it happens is based on what is found. The speed of sound barrier is rather significant, and we have not found a way to develop efficient planes that go at Mach 1.1 almost 60 years after we first went above Mach 1. It's not the cost of energy. No, it's the cost of the system. A nearly hundred percent efficient space elevator lifts about 2400 mt a day (on less than a GW) snip I've invented a few things that are used worldwide and am still engaged in practical science/engineering. I've worked close to guys who's inventions have reduce world costs for producing oil by about 250 million/day. Since there are around 80 million barrels a day produced, that's a reduction of about 3%. So, I think I'm fairly familiar with processes that are economical and that work. I have not seen anything in what you have written on this subject that gives an indication of an understanding of the nature of practical solutions to problems. What do you want? The current 747 cost about $300 million and dry masses out to about 185 mt or $1.6 million a ton. Produced in similar tonnage, do you see any reason these rockets would cost more than per ton than a 747? If so, why? First and second stage mass 619 tons, (third stage is mostly power sat parts) so if they cost on a par with a 747, they would cost just a hair over a billion each, with one coming off the production line every 20 days, or about 31 mt a day. That might sound like a lot, but I have worked in a locomotive factory that made 30 times that much a day in product (8-9 locomotives a day at 113 mt each). At peak production 747s were coming off the line at a slightly higher tonnage per year. If you use them for 200 flights the capital cost per flight is $5 million /200,000kg or $25/kg. This number is excessively rough, but could be refined without a lot of trouble. At a nickel a kWh, a kg of power sat generates $200 of electricity a year. Done with rockets of this sort http://www.ilr.tu-berlin.de/koelle/Neptun/NEP2015.pdf the energy input is about 15 times that high, or from $15 /kg down to $1.50 as you get less and less expensive energy. I went to this website, and it looked like a speculative conference. Vaporware is easy to build. Doing something that works is hard. Most things we wish we could do we do not know how to do. The .pdf was recommended as a good reference by Hu Davis of Eagle Engineering. Look him up. I think that this is the absolutely fundamental difference you have with folks who argue for nuclear reactors vs. space based solar power. We've demonstrated safety mechanisms, Can you be specific about what you mean here? Sure, to be effective, power would have to be transmitted down in a fairly dense fashion. One needs mechanisms that provide feedback to turn the power off should the aim stray. The power level for power sats was set at about 1/4kW/square meter back in the 70s so it could not be used as a weapon. There was also concern that the ionosphere could go non-linear and short out the beam. As far as sending the beam down densely, it's an optical problem--see the math behind Airy's disk. If you want to get a tighter beam you have to go to a larger transmitter or higher frequency or both. The beam requires a pilot beam up from
RE: An interesting response
-Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Charlie Bell Sent: Wednesday, April 16, 2008 6:49 PM To: Killer Bs (David Brin et al) Discussion Subject: Re: An interesting response On 17/04/2008, at 3:14 AM, Dan M wrote: The speed of sound barrier is rather significant, and we have not found a way to develop efficient planes that go at Mach 1.1 almost 60 years after we first went above Mach 1. So-called supercruise. The biggest problem with going over Mach 1 is political and legal, not technological - had Concorde not been killed by politics. Well, Concord was a political animal from the very beginning wasn't it? It was a tax subsidized showcase for Britain and France from the start. IIRC, it never really was a profit center. its successor would have been an efficient supersonic plane. I don't doubt that a successor would have been better, but you putting efficient in quotes seems to indicate that you aren't arguing against the fundamental increase in cost per passenger mile when a plane goes at Mach 1.05 compared to Mach 0.95. That's not political. The decision to use tax money to subsidize the travel of the richest businessmen is, of course, political. Can you be specific about what you mean here? Sure, to be effective, power would have to be transmitted down in a fairly dense fashion. One needs mechanisms that provide feedback to turn the power off should the aim stray. Current designs seem to show a wide collection with a diffuse beam, so that it's relatively safe to be under the beam. OK, then there would be the cost of a wider array, earlier designs had cheaper local receivers with feedback required to keep the beam on. I'm not saying that this would be a showstopper, it's just that it's part of the price that has to be figured in. http://en.wikipedia.org/wiki/Boeing_747 And 747s, beyond the basic airframe and control systems, are very different to what they were in the 70s. (by the way, they were brought online in 1970.. OK, the first commercial flight was Jan, 22, 1970...my apologies for rounding. But, the 747 is still in competition, sometimes on the same routes as smaller planes...and there are still a number on order (see site given above). Point on this part is that there is huge inertia when there's huge capital expenditure - if you've spent a few tens of millions on a plane in 1970 or 1980 you're going to keep using it as long as you can, 'cause a similar plane costs a few hundred million in 2008. I understand that, but there was a huge inertia All that said, I'd like to see you, Dan, try to put together a cost- analysis on a powersat project. Sure, be glad to. The cheapest commercially available launch to geosynchronous orbit (GEO) that I know of is the Russian Zenit program. For about 90 million, one can get a payload of just over 1800 kg into GEO. That's just under 50,000 per kg. http://en.wikipedia.org/wiki/Zenit_rocket OK, so lets calculate output per kg. of weight. From a site that is promoting their solar cells for use in orbit http://www.mdatechnology.net/techprofile.aspx?id=226 we get an output of 150W/kg. That gives us a launch cost of about $325 per watt (I'm rounding down now instead of up). Nothing works 100% of the time, but lets assume a 95% efficiency, or running 8322 hours/year. The cost is, then, about $39 per kWh. Dan M. tenacious posting to naysay, so I'd like to see you attempt to solve the problem so I can see where the problems are. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
Re: An interesting response
On 17/04/2008, at 12:26 PM, Dan M wrote: So-called supercruise. The biggest problem with going over Mach 1 is political and legal, not technological - had Concorde not been killed by politics. Well, Concord was a political animal from the very beginning wasn't it? It was a tax subsidized showcase for Britain and France from the start. IIRC, it never really was a profit center. All aircraft mfrs are subsidised. Yes, it was supposed to be a technology its successor would have been an efficient supersonic plane. I don't doubt that a successor would have been better, but you putting efficient in quotes seems to indicate that you aren't arguing against the fundamental increase in cost per passenger mile when a plane goes at Mach 1.05 compared to Mach 0.95. Fundamental? No. Substantial, yes. That's not political. The decision to use tax money to subsidize the travel of the richest businessmen is, of course, political. The politics came in when a swathe of countries banned the Concorde from overflying. That's what killed it. Didn't take long before the only route for Concorde was the transatlantic shuttle, and even then, only the very rich could afford it. That's a scale issue. When only a handful are ever built, the RD isn't every going to be repaid. You seem to think the subsidies were aimed towards Concorde's final fate. They weren't, they were aimed at getting the time of long-haul flights down. Even today, it takes a day to get from London to Sydney. Concorde was supposed to halve that. Can you be specific about what you mean here? Sure, to be effective, power would have to be transmitted down in a fairly dense fashion. One needs mechanisms that provide feedback to turn the power off should the aim stray. Current designs seem to show a wide collection with a diffuse beam, so that it's relatively safe to be under the beam. OK, then there would be the cost of a wider array, It's chicken wire on poles, Dan. Strung over land that can still be used for other stuff. The rectennas are by far the smallest costs in the whole thing... Point on this part is that there is huge inertia when there's huge capital expenditure - if you've spent a few tens of millions on a plane in 1970 or 1980 you're going to keep using it as long as you can, 'cause a similar plane costs a few hundred million in 2008. I understand that, but there was a huge inertia ...? All that said, I'd like to see you, Dan, try to put together a cost- analysis on a powersat project. Nothing works 100% of the time, but lets assume a 95% efficiency, or running 8322 hours/year. The cost is, then, about $39 per kWh. Right. So, how do you improve that. OK, say we can get the launch cost halved by mass producing rockets and stuff. That's still $20/kwh. Coal's a few cents a kwh. Even with carbon sequestration doubling or tripling that, it's still a big gap. Roof-mounted solar, I can get a 1kW system (grid connected) for AUD5200, with 20 year warranty. So say it's doing that 1kw 6 hours a day (paper napkin calculation here), that's 43,800 kw across the life of the system, that's about AUD8/kwh ($7.50/kwh). So still a lot better than a powersat, and that's not factoring in the launch pollution. So... how to bridge the gap? Charlie. ___ http://www.mccmedia.com/mailman/listinfo/brin-l
