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Comment by pjc50 | Hacker News Reader

Lunar resource extraction is unlikely to be viable for anything other than building on the moon - ever. The quantities of energy involved are simply too high.

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I highly doubt that’s true, sending it back to earth is fairly cheap. Getting stuff to the moon can be expensive, but there will def be certain resources worth sending back. For instance, 10Kg of gold is worth $750k. Probably could just send that back with a few astronauts.

That’s not to include the possibility that there’s certain manufactured goods that could be cheaper or only possible to produce at lower gravity.

There's a big difference between simply shooting stuff at Earth (or even simply off the moon into space) and actually sending it back. Yes, SpaceX charges $300k for sending 50kg to SSO as a rideshare but that's with all the infrastructure and logistics already in place.

Landing on the moon is a very different endeavour than simply reaching Earth orbit from Earth. In order to refuel and reuse rockets on the moon, you'd need to build out all the infrastructure for doing so first, not to mention the resources necessary for continuous operation. Even getting running water on the moon would be a huge logistical and infrastructure challenge, let alone operating a launch pad.

> Landing on the moon is a very different endeavour than simply reaching Earth orbit from Earth. In order to refuel and reuse rockets on the moon, you'd need to build out all the infrastructure for doing so first, not to mention the resources necessary for continuous operation. Even getting running water on the moon would be a huge logistical and infrastructure challenge, let alone operating a launch pad.

Anyone that wants to intuitively understand these challenges can simply play Factorio's Space Exploration mod (https://mods.factorio.com/mod/space-exploration).

And then also remember that Factorio is a game and thus makes this fun and easy compared to how grueling and boring the real deal would be.

One does not simply obtain gold from the ground by picking it up as it lies around

I thought the whole thing was He3 makes it viable.

Only if and when fusion reactors using He3 become possible, which for now is unpredictable.

Ok, I thought He3 was also useful for smartphone manufacture?

No, you're probably thinking of this: https://news.ycombinator.com/item?id=18340693 (He4 exposure temporarily messes up iPhones by glitching their MEMS clocks)

Imagine if we can send garbage to the moon and keep the earth clean, the ship returns with minerals.

You can send 50kg of garbage into orbit for $300k with SpaceX. I don't think sending it to the moon would be any more cost efficient (quite the opposite). Plus with the kind of garbage where you might find that cost acceptable (long-term radioactive waste, extreme biohazards) those are the kind of stuff you don't want to have to end up detonating in the air if the rocket malfunctions.

Why would we aim for the moon instead of aiming anywhere but the moon?

I guess it is where it is close, and I don't really care too much about it. I like Bezos idea of space rather than Musk's: use Moon as a production base or something, let's move the bad stuffs pollution, garbage, nuclear waste) to the moon.

What I mean is: if we're sending undesirable things like garbage into space, why do we want it on the Moon? Why not just launch it out of the solar system, or into the Sun? There doesn't seem to be a good reason to favor putting it on the Moon.

https://www.forbes.com/sites/startswithabang/2019/09/20/this...

From the article:

> Energetically, it costs less to shoot your payload out of the Solar System (from a positive gravity assist with planets like Jupiter) than it does to shoot your payload into the Sun.

This is kind of my point regarding the Moon. It's harder to hit the Moon than to miss it, so why aim for it?

Once you get into an orbit of the Earth, you are "halfway to anywhere" [1] in terms of fuel costs. Getting out of the Earth's gravity well is the hard part, once you're up there you might as well put the trash much further away than the moon. Especially because if we're shipping trash, we can just set and forget it on a trajectory to the dump site, we don't need to worry about it taking a long time or to land safely.

[1]https://projectrho.com/public_html/rocket/surfaceorbit.php

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