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#21
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CEV to be made commercially available
On 17 Oct 2005 11:26:57 -0700, in a place far, far away,
" made the phosphor on my monitor glow in such a way as to indicate that: What's lacking are companies that would be willing to do it as expensively as the use of a CEV would require. Then increase the flight rate. No such thing as a manned spacecraft that'll be "cheap" if only flown a few times a year. And there's no way that CEV will be cheap even if flown a thousand times a year, if it flies on top of an expendable. |
#23
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CEV to be made commercially available
Or, to put it more simply, the supply curve that the CEV system would
have, would be so far up the graph that it never meets the demand curve. -kert |
#24
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CEV to be made commercially available
In article ,
John Savard wrote: ...What's lacking are companies that would be willing to do it as expensively as the use of a CEV would require. ...are you claiming that there are ways, absent the development of far-future technologies such as a space elevator (or non-Newtonian propulsion!), to send personnel to the moon at prices that would be rational for even a *few* private companies to take advantage of? There's no fundamental reason why not. The only absolutely inescapable cost of doing so is fuel... and fuel is cheap. The fundamental cost of putting mass into orbit with LOX/kerosene is under $1.50/kg. Of course, most of that mass is vehicle; it'll be up around maybe $8/kg for payload. There will be some other operating costs, not large by comparison because rockets are so fuel-intensive. Call it $10/kg to LEO. Handily, the delta-V for TLI, landing, and return is about the same as for reaching LEO. So similar mass ratios apply, and we get a cost of around $1000/kg for payload to the lunar surface and return. That could be reduced significantly with refueling on the lunar surface, and perhaps further with lunar LOX exported to LEO, but I'll disregard those options. Figuring person plus spacesuit plus baggage plus odds and ends at 200kg, a return ticket is $200,000. Which is a lot for an individual and nothing much for a company. The trick is getting the overhead costs down to a small fraction of fuel costs. We are nowhere near achieving that; currently the overhead costs are utterly dominant and fuel costs are insignificant. It would take fully-reusable highly-developed hardware, greatly streamlined operations, and a high flight rate. There's not the slightest chance that NASA could do that. But there is nothing impossible about it. Of course, looking at prices in my local department store... if it weren't for the effects of the balance of payments deficit, perhaps the U.S. could just buy Shenzou rockets from China! Not that helpful, not on this scale. Cheap hardware, but it's still expendable... and it uses quite costly fuels, much more expensive than LOX/kerosene. (By the way, Shenzhou is the spacecraft -- the rockets are Long March.) -- spsystems.net is temporarily off the air; | Henry Spencer mail to henry at zoo.utoronto.ca instead. | |
#25
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CEV to be made commercially available
Pat Flannery ) wrote:
: Eric Chomko wrote: : "Yes your honor, it was a model project back in grade school that made : quit school and use and sell drugs." : : : There's a South Park episode lurking in there somewhere. : (Cut to image of Kenny impaled on a solar array.) :-D Yes, South Park dares to go where no other cartoon will. SP makes the Simpsons look like Saturday moring cartoons. Eric : Pat |
#26
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CEV to be made commercially available
Stick is fully reusable.
The stick is only planned to be partially resuable. Planned, yes. However, the simple fact is that the first solid stage is reusable, while the second stage goes to orbit, leaving large propellant tanks and the SSME available. The tanks would make a fine basis for a space station or an upper stage (or a propellant storage facility, hab modules for the lunar surface, raw materials for SPS, you name it); the SSME can be cut off and returned. It's only a lack of even moderate imagination that makes the 2nd stage expendable. |
#27
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CEV to be made commercially available
Really. As the man said: Don't think inside the box. The box is not
your friend. |
#28
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CEV to be made commercially available
On 18 Oct 2005 07:59:02 -0700, in a place far, far away,
made the phosphor on my monitor glow in such a way as to indicate that: And there's no way that CEV will be cheap even if flown a thousand times a year, if it flies on top of an expendable. Agreed. That's why you should fly it on the Stick rather than the EELVs. EELVs are fully expendable. Stick is fully reusable. Really? |
#29
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CEV to be made commercially available
Henry Spencer wrote: The fundamental cost of putting mass into orbit with LOX/kerosene is under $1.50/kg. Wait a minute; leaving the LOX out of the equation, I can accelerate 1 kg of mass to 18,000 mph and 100 miles altitude with the energy in around 2/3rds of a gallon of Kerosene? It's running around $2.75 at the moment. Price of LOX in 2001 was about $.67 per gallon. Pat |
#30
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CEV to be made commercially available
Pat Flannery wrote:
Henry Spencer wrote: The fundamental cost of putting mass into orbit with LOX/kerosene is under $1.50/kg. Wait a minute; leaving the LOX out of the equation, I can accelerate 1 kg of mass to 18,000 mph and 100 miles altitude with the energy in around 2/3rds of a gallon of Kerosene? It's running around $2.75 at the moment. Price of LOX in 2001 was about $.67 per gallon. Surprising, no? Do the math. Kinetic energy of 1 kg at orbital velocity is only about 75 megajoules. Burning a gallon of kerosene yields nearly twice that. I remember reading years ago that a beer can's worth of rocket fuel has enough energy to put the beer can into orbit. That was a neat concept. |
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