Technically, nothing about human space exploration is financially justified. We do it just because it’s the thing to do.
The Apollo programs were spending huge money just to say “we put men on the moon” and get a few hundred kilos of Moon rocks. Still worth it all though. Not everything needs $$ justification.
I thought the point of the Apollo missions was to suggest to the USSR that if the US could send a rocket to the moon, it could certainly send one directly to Red Square.
And a permanent manned lunar base may not need to be profitable to be justified but it does need a significant purpose.
Beats me. I’m not a proponent of it except in Sam Rockwell movies. I guess the current crop of enthusiasts is afraid that China will get there first and get all of the best moon rocks, or will turn it into a giant farm a la The Moon is a Harsh Mistress, or something.
The ISS (and its preceding proposal, “Freedom Station”) is a political fop and a jobs program to keep the NASA human spaceflight program going in absence of any other practical destination.
The purpose of the Apollo Program was to showcase American technical prowess and that ‘Capitalism’ was more effective than ‘Communism’ at innovation and achieving large goals. It was not technically military (hence why NASA was established as an independent agency, even though much of the technology and most of the original astronaut corps were transferred over from the military), and by the point that Apollo actually flew the US already had three classes of ICBMs fielded including the solid propellant Minuteman system with nearly instantaneous launch on command, the first and second generation of Polaris SLBMs in their ballistic missile submarines (‘boomers’), as well as Jupiter and Thor IRBMs in multiple European countries (actually retired before even the first ‘boilerplate’ Saturn I launch with a flight-representative Command-Service Module mockup). We could send nuclear weapons to Red Square or anyplace else in the Warsaw Pact for nearly a decade before Armstrong took ‘a giant leap for mankind’.
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If Elon Muskox wants to subsidize it, and they put him on one of the rockets, I’m down with that.
In high school I was fascinated by Gerard K. O’Neill’s plans for enormous manned space stations at the Lagrange points with the mass coming from the moon.
Well, I probably should have qualified my statement a tad more, but it’s about more than just light-water reactors–I was just giving that as an example.
Another example would be molten salt reactors, which often incorporate a fuse plug in the coolant loop, which melts in case of overheat and allows the coolant to drain into a reservoir–with the help of gravity.
Or Stirling generators, which like any engine needs some lubrication system, which may well use a gravity-fed oil reservoir. I’m aware of NASA’s efforts toward a “free piston” Stirling generator, which they claim has oil-free bearings–all well and good, but as far as I know hasn’t been tested in space yet and is still not at a high TRL.
Other tech which may be involved are heat pipes, which can use capillary action but at larger scales may require gravity to return the condensed liquid to the heat source.
Again, these are just some examples. And they can be designed around. But one can’t just assume that things will work in 1/6 g as they do on Earth, especially when fluids are involved. And almost all reactors use some kind of fluid, at least beyond a certain size/efficiency.
Which is why there is a multi-phase development program:
NASA plans to extend the three Phase 1 contracts to gather more information before Phase 2, when industry will be solicited to design the final reactor to demonstrate on the Moon. This additional knowledge will help the agency set the Phase 2 requirements, Kaldon says.*
…
After Phase 2, the target date for delivering a reactor to the launch pad is in the early 2030s. On the Moon, the reactor will complete a one-year demonstration followed by nine operational years. If all goes well, the reactor design may be updated for potential use on Mars.
Beyond gearing up for Phase 2, NASA recently awarded Rolls Royce North American Technologies, Brayton Energy, and General Electric contracts to develop Brayton power converters.
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Um.
Some of these rockets have a tendency to explode.
What if the rocket containing the nuclear material explodes on the launch pad? That’d be bad, right?
That’s why they’re going to hire Elon Musk to launch the reactor. He’s got a sterling reputation as a rocket designer.
Only if you’re worried about environmental contamination, wildlife destruction, and human health. That is why Elon is launching ‘Starship’ from Texas and planning to launch from Cape Canaveral in Florida, where they really don’t care about those kinds of issues.
He certainly has the pedigree:
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And he’s learning Chinese!
Turns out that my loop idea is very close to a technology in active use: submarine cables.
To power the repeaters, which have to be spaced every 50 km or so, they put ~15 kV across the cable ends. Each repeater is in series and induces a voltage drop of 30-70 volts. There’s only 1-2 amps on the cable, so even across the 7000 km length, the resistive losses are manageable.
Of course, this is a single (long) line and not a loop, and it’s only powered at the ends, but the principle is the same. High voltage, low amps, and all loads are in series. None of them actually see the max voltage since they only need to deal with whatever relative voltage is sufficient to power them.
I wonder if that crab in the image is singing about it.
The issue with your proposal isn’t the conductivity of the cable. It is the extreme difficulty of laying it out over hundreds of miles of Lunar regolith with the abrasive, electrostatically charged Lunar dust while navigating the rugged terrain and somehow powering the rover and keeping the human crew alive and functional for the months this would entail.
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No denying that. I just found it interesting that there’s a real-world implementation of the basic idea that’s a little bigger scale than Christmas lights. Not surprising since electrically, the idea is straightforward. But still neat to see in practice.
I’m tempted to flesh out the idea more and submit it as a NIAC paper. Always wanted to do that.
Dude… c’mon, pass the J… you just took, like, three hits in a row off it!
Now, on the actual subject of this thread–about how much would a workable reactor weigh? Since “workable” is so variable a notion–about how light could this thing be and still power the crucial facilities of a very basic and lunar base?
Are we talking tons? Or could it be made at hundreds of pounds? Less than a hundred lbs.?