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If the justification investing into space/moon infrastructure will make constructing further space/moon infrastructure cheaper, then that's a circular argument,

If the justification investing into space/moon infrastructure will make constructing further space/moon infrastructure cheaper, then that's a circular argument, it's the "how, not why" about the most efficient way to produce some terminal goal, but it does not assert how large the benefit of that terminal goal is going to be. For earth needs, it's cheaper and simpler and more efficient to mine titanium right here. There's a reasonable argument that mining all these things for space needs could be more efficient if done "on site", however, what are those space needs that will ultimately somehow benefit the people of Earth in a way that's more efficient than doing it down here? If the end goal is to produce power, no matter how you invest into space tech, IMHO it's going to be much more efficient to build large quantities of solar panels on Earth and place them in Sahara desert, than to construct a large-scale solar panel industry on the moon to have the same quantity of power through satellites. Sure, they'd be cool, but that's not a justification. When/if there's a resource shortage on earth causing some minerals to be orders of magnitude more expensive than today, then it would be worthwhile, but not yet.

outworlder 6y ago
> If the justification investing into space/moon infrastructure will make constructing further space/moon infrastructure cheaper, then that's a circular argument Not really. If we have mining AND manufacturing capabilities outside Earth's gravity well, we can manufacture things very cheaply. Either things that require microgravity to be made, or things to be used in space. For instance, satellites. It would be much cheaper to build and launch them from the Moon. We could manufacture components which require vacuum and or microgravity on lunar orbital stations. > IMHO it's going to be much more efficient to build large quantities of solar panels on Earth and place them in Sahara desert How are you planing to send that power to, for instance, the United States? Disregarding the massive infrastructure requirements, there are serious power losses.
- elihu 6y ago
  > How are you planing to send that power to, for instance, the United States? Disregarding the massive infrastructure requirements, there are serious power losses. I just got into this discussion the other day here: https://news.ycombinator.com/item?id=26599340 https://news.ycombinator.com/item?id=26599340 A commenter estimated the losses from North Africa to the United States to be about 33% with high-voltage DC. Wikipedia says this: Depending on voltage level and construction details, HVDC transmission losses are quoted at 3.5% per 1,000 km, about 50% less than AC (6.5%) lines at the same voltage. https://en.wikipedia.org/wiki/High-voltage_direct_current https://en.wikipedia.org/wiki/High-voltage_direct_current North Africa to North America is somewhere in the ballpark of 10,000 km. (1-0.035)^10 is almost exactly 70% (i.e. 30% loss). So, that actually sounds pretty reasonable.
  - stcredzero 6y ago
    Using microwaves to transmit power to receiving rectennas has already hit 70% efficiency. Exceeding that is very feasible. Once there is full industrial infrastructure on the Moon and in Earth orbit, building microwave antennas and ground receiving rectennas is going to scale a lot better than building more and more 10,000 km lines. For a community in the middle of nowhere building a rectenna will be relatively inexpensive, but the benefit will be like getting their own fusion plant!

outworlder 6y ago

> If the justification investing into space/moon infrastructure will make constructing further space/moon infrastructure cheaper, then that's a circular argument Not really. If we have mining AND manufacturing capabilities outside Earth's gravity well, we can manufacture things very cheaply. Either things that require microgravity to be made, or things to be used in space. For instance, satellites. It would be much cheaper to build and launch them from the Moon. We could manufacture components which require vacuum and or microgravity on lunar orbital stations. > IMHO it's going to be much more efficient to build large quantities of solar panels on Earth and place them in Sahara desert How are you planing to send that power to, for instance, the United States? Disregarding the massive infrastructure requirements, there are serious power losses.

elihu 6y ago
> How are you planing to send that power to, for instance, the United States? Disregarding the massive infrastructure requirements, there are serious power losses. I just got into this discussion the other day here: https://news.ycombinator.com/item?id=26599340 https://news.ycombinator.com/item?id=26599340 A commenter estimated the losses from North Africa to the United States to be about 33% with high-voltage DC. Wikipedia says this: Depending on voltage level and construction details, HVDC transmission losses are quoted at 3.5% per 1,000 km, about 50% less than AC (6.5%) lines at the same voltage. https://en.wikipedia.org/wiki/High-voltage_direct_current https://en.wikipedia.org/wiki/High-voltage_direct_current North Africa to North America is somewhere in the ballpark of 10,000 km. (1-0.035)^10 is almost exactly 70% (i.e. 30% loss). So, that actually sounds pretty reasonable.
- stcredzero 6y ago
  Using microwaves to transmit power to receiving rectennas has already hit 70% efficiency. Exceeding that is very feasible. Once there is full industrial infrastructure on the Moon and in Earth orbit, building microwave antennas and ground receiving rectennas is going to scale a lot better than building more and more 10,000 km lines. For a community in the middle of nowhere building a rectenna will be relatively inexpensive, but the benefit will be like getting their own fusion plant!