At 12:00 PM 4/17/2008, Dan M wrote: (Keith wrote) >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? > >For the rocket itself, not counting all the other expenses associated with >launches, that's not an unreasonable cost. \
Agreement! > > 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. > >Here's where you throw in the unspecified assumption. A simple disposable >rocket, like the ones being used by all launch facilities but the shuttle, >could cost about what you said. But, then you talk about reusable rockets >and assume that the initial capital cost is the critical factor. No, that *is* the capital cost. I just have not discussed operating and maintenance costs which I have not estimated. This design uses 49 SSME in it and they are only expected to last 40 flights. How much labor is it going to take to pull 40 engines out of the first stage and 9 out of the second stage every 40 flights? On average they would be changing out 12 a day so they should get good at it. What's the closest model we have for airline operations? Or for that matter, railroad operations? A SSME has got to weigh less than a locomotive engine! >The fantasy of the space shuttle was that it could be reused easily. 10 >years into the mission, it was supposed to require a very small ground crew, >getting lift costs to near earth orbit down to about $25/kg or some such >number. But, the maintenance is very high and expensive. If you were flying them every day instead of ever 100 days could you do it with the same number of people? Part of the cost is the very low production rate for spare parts. Another big chunk is paper pushing. There is a neat trick using recent technology to virtually eliminate paper pushing. And a lot of the cost is for crew training. These things would be no crew, and maybe only one a week would carry passengers, if that. >The shuttle costs >a lot of money to fly, even though we are not buying new shuttles, the big >fuel tank is the cheapest part of the assembly, and the solid fuel rockets >are recoverable. Some years ago I read that the effort to recover and refurbish the segments cost more than just letting them sink. >So, I've seen no estimates for this, just the same arm waving I heard about >the shuttle years ago. I can think of Russia, Japan, the EU, the US, and >China all having significant lift capacity, and Russia is the cheapest >available one I know of. I tend to look at actual costs and their trends as >a guideline, not estimates that make unproven assumptions. 2000 tons per day is an entirely different model. You can't apply much of what we know about government space programs to it. >I realize that I'm considered a nay-sayer because of this, but I would argue >it's because I've had to design hardware/software systems that work remotely >under harsh conditions. What gives you the idea space is harsh? Now a wind generator standing in salt water, that's harsh. snip > > > > The .pdf was recommended as a good reference by Hu Davis of Eagle > > Engineering. Look him up. > >What has he built? The Eagle as in "the Eagle has landed." snip > > The main point is that there are very few options that are big enough > > and possibly low enough in cost to replace the bulk of fossil fuels. > >It depends on what type of calculation one uses. If one uses hard >engineering numbers for project X and arm waving unsubstantiated numbers for >project Y, then project Y should win virtually every time. When power sats are not considered (and they usually are not) then you get statements like this: "No combination of renewable energy systems have the potential to generate more than a fraction of the power now being generated by fossil fuels." -- Jay Hanson http://www.drmillslmu.com/peakoil.htm >I can think of a >number of different projects that are far more feasible for the 20-200 year >time frame. After 200 years, I'd argue that fundamental discoveries will be >sufficient to radically change what is practical. It would surprise me if there were any physical state humans left on the planet by 2100. Even though you sell it to the investors as long term, I can see it being abandoned when the singularity hits. This is about a project to start in the next few years and having the capacity to fill in the energy gap as oil runs out. >I don't have time now, but I'll put together, in the order I think is >likely, possible solutions to energy sourcing which do not increase >greenhouse gasses. Please don't unless you have some idea that's not been talked about before. What I would like is a critical discussion leading to a model for a pipeline to GEO large enough to build power sats in large numbers at low enough prices to deliver power at the ground bus bars at a penny a kWh. If we can do that, we can make synthetic gasoline for a dollar a gallon. If we can't, several billion people are likely to die in the toboggan ride down the back side of peak oil. Keith _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
