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Old 06-13-2019, 10:20 PM   #11
Johnny1A.2
 
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Default Re: Nuclear Age Space Exploration [Space/Spaceships]

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Originally Posted by Astromancer View Post
Orbital power generation isn't that much of a problem. Building and running a circumlunar infrastructure to build, maintain and operate orbital power satellites is a big problem. It is truly raining soup up there. Getting there at an acceptable price and surviving are the problems. But power generation would be easy.
There are a lot of unanswered practical questions associated with the SPS concept (or reactors in orbit or whatever).

Environmental effects of the microwave beams passing through the atmosphere on a steady basis. Practical cost of maintenance of the solar arrays in orbit. Degradation of the arrays over time. Vulnerability to sabotage/attack. Etc.

Advocates have their answers for these points, but all such answers are mostly hypothetical. We just don't know if there's any practical way to make SPS economically competitive with ground-based solar, much less ground-based nuclear and fossil fuel. It doesn't look hopeful.
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Old 06-13-2019, 10:32 PM   #12
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Default Re: Nuclear Age Space Exploration [Space/Spaceships]

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This is irrelevant to TL7 space industrialization. There is no way you're jumping from a Saturn V to a monster rocket the size of a Nimitx-class supercarrier. That's why I said this needed to belong to a highly variant alternate timeline.

As an example of the problems, even though your full production price appears to come in under a billion $ before the payload the prototype would of course have cost 100x that and that would be on the rough orsder of the entire cost of the Apollo program just for your first rocket. Not happening in our timeline.

What you need is some sort of timeline where space tech froze at TL7 for long enough to first build a SM+10 rocket and then work your way upwards. This would take multiple decades for each generation of rockets of increasing SM. That the TL would not advance past TL7 during this time period would be another anomaly that would need explaining.
Prototypes in GURPS are not necessarily 100x cost, the vast majority of that premium comes from R&D costs, not production costs. Heck, prototypes are at cost until you get a production line going, and then they are somewhat more reasonable. Anyway, I do not think that the Saturn V rockets were 100x cost, though they only made 13 of them, so they did not recoup all of the R&D costs.

As for the SPS, it only requires Saturn V technology, so there was nothing new required. It would have taken a few dozens launches to set up the lunar base, but they could have set up a few production lines during the late-70s if they had possessed the courage and vision. Heck, they might have even dusted off the old Sea Dragon design and just went with that 30,000 ton monster (scaling up from that to 100,000 tons would have been a piece of cake given the simplicity of the designs). With 3,000 tons every launch into LEO, building the lunar base would have been a piece of cake.
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Old 06-14-2019, 12:16 AM   #13
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Default Re: Nuclear Age Space Exploration [Space/Spaceships]

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Originally Posted by AlexanderHowl View Post
Prototypes in GURPS are not necessarily 100x cost, the vast majority of that premium comes from R&D costs, not production costs. Heck, prototypes are at cost until you get a production line going, and then they are somewhat more reasonable. Anyway, I do not think that the Saturn V rockets were 100x cost, though they only made 13 of them, so they did not recoup all of the R&D costs.
Hard to say, but the rocket motors were being hand-built still.
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Old 06-14-2019, 08:21 AM   #14
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Default Re: Nuclear Age Space Exploration [Space/Spaceships]

Which is just copying the prototype, which is covered in Basic (p. 474). It costs the retail cost of the object to create and half the time as the original prototype. In the case of a Saturn V, it would take 3d/2 to create each copy, assuming enough people working on the project, but you could always have multiple groups working on multiple copies. Remember, the Apollo Program employed 400,000 people, so they could have easily transformed everything into production lines had they had the need.

In any case, you could have easily designed a SM+10 reusable variant that would have been capable of delivering 300 tons to LEO for a launch cost of ~$30M, or $100,000 per ton. With 400 such vehicles, each launching once a month, you would have been able to move 1,440,000 tons into LEO every year at a cost of $144B per year, which is ~1% of GDP for the USA (GURPS constant $). If we assume a lifetime of 5 years per vehicle, you would need 10 production lines to sustain the fleet (producing 80 vehicles a year), and a ramp up time of five years, giving five years for creating the production lines, maintenance facilities, etc. It would have been quite possible for late-TL7/early-TL8, it was just that our leaders lacked courage and vision.
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Old 06-14-2019, 09:43 AM   #15
Fred Brackin
 
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Default Re: Nuclear Age Space Exploration [Space/Spaceships]

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P It would have taken a few dozens launches to set up the lunar base, but they could have set up a few production lines during the late-70s if they had possessed the courage and vision.
A Saturn V wil put 2 men on the Moon with only a few days supplies. There is no number of Saturn V launches that will get you a not only functional but industrially productive moonbase.

Complaining about lack of "courage and vision" among the people who actually managed those very difficult moon landings only serves to discredit your arguments.

Complainging about a lack of vision and courage among the politicians of the time (or current ones either) is not particularly outrageous but still rather like being annoyed that rain is wet.
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Old 06-14-2019, 10:02 AM   #16
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Default Re: Nuclear Age Space Exploration [Space/Spaceships]

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In any case, you could have easily designed a SM+10 reusable variant that would have been capable of delivering 300 tons to LEO for a launch cost of ~$30M, or $100,000 per ton.
The good old 'they could have easily built a fully reusable launcher, like nobody has ever managed despite decades of interest and economic motivation' theory?
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A Saturn V wil put 2 men on the Moon with only a few days supplies. There is no number of Saturn V launches that will get you a not only functional but industrially productive moonbase.
Why not? It's not like you need every launch to carry two men and their consumables. Most of them would, of course, be unmanned cargo flights.
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Old 06-14-2019, 10:36 AM   #17
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Default Re: Nuclear Age Space Exploration [Space/Spaceships]

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Why not? It's not like you need every launch to carry two men and their consumables. Most of them would, of course, be unmanned cargo flights.
Alright, be finicky about "no number" with its' implied absoluteness. Amend it to "no _practical_ number".

If you want some sort of number....

https://en.wikipedia.org/wiki/Apollo...Specifications

....near the bottom (5.2) has a brief mention of a proposed "LM truck" which would have been a one way descent stage to deliver cargo witha capcity of 11,000 lbs. That's still not a lot when you consider you started with an entire Saturn V.
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Old 06-14-2019, 10:52 AM   #18
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Default Re: Nuclear Age Space Exploration [Space/Spaceships]

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Why not? It's not like you need every launch to carry two men and their consumables. Most of them would, of course, be unmanned cargo flights.
I think the point is not that they couldn't put a moonbase there, but that any moonbase would not be industrially productive- there's not much you can mine or manufacture on the moon that can't be obtained far more cheaply on earth. We could have built a moonbase with Apollo-era tech, if we really wanted to, but it would have been done for the same combination of research and national prestige that motivated the actual landings rather than because it made "economic sense".
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Old 06-14-2019, 11:15 AM   #19
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Default Re: Nuclear Age Space Exploration [Space/Spaceships]

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I think the point is not that they couldn't put a moonbase there, but that any moonbase would not be industrially productive- there's not much you can mine or manufacture on the moon that can't be obtained far more cheaply on earth. We could have built a moonbase with Apollo-era tech, if we really wanted to, but it would have been done for the same combination of research and national prestige that motivated the actual landings rather than because it made "economic sense".
Well, since the poster already answered just above, I doubt that was the point being made.

This claim, though...it's certainly true if the place you want the goods is on earth. But that was never the proposal. The industrial purpose of the moonbase is to produce materials for the orbital power constellations - and for that there is a very large savings from not having to boost products from Earth's surface. Not necessarily enough to make a moon facility pay for itself (especially if you don't have a space source for water), but not trivially out of the question.
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Old 06-14-2019, 11:49 AM   #20
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Default Re: Nuclear Age Space Exploration [Space/Spaceships]

NASA already did the work up in 1977. Just look up NASA SP-413 Space Settlements: A Design Study. While they were thinking of using a space shuttle rather than a Saturn V variant, they built a dang good economic case for something that could have been done with 1970s technology.

So, what type of setting would evolve if the USA had built such an orbital solar power array? The USA could have 10 TW of electricity production under its control, enough to supply the developed world with all of its energy needs (assuming that plentiful and cheap electricity would have prompted earlier investment in electric vehicles). The space industry would be worth over $4 trillion per year by 2020, and the US government would have had control over the vast majority of it. What happens in a setting where the US government has no debt and it controls 60% of the energy production on Earth?
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