this post was submitted on 31 Jul 2023
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Any launch from the moon would require launch back from earth to retrieve the rocket so it can be put to use again.
Space elevator and orbit launch is an interesting thought. I think it's a tough sell. In that case we would be launching uncontrolled asteroid-like dumps towards the earth. Sounds like a nightmare waiting to happen. Every city would need a missile defense system 🤣. The resource dumps would have to be big enough to warrant the investment in the space elevator and not burn up in Earth's atmosphere, or, we would need a space elevator on earth too (which would be the biggest engineering and political feat humans have ever done).
Mass driver. That's another cool idea. From some research it looks like most metals have a temperature which they stop being magnetic and getting into Earth's atmosphere would put most metals past that. Having a mass driver on top of a space elevator, or just a giant mass driver, also sounds like a head scratcher if most resources we would want can't be 'slowed down'
The problem with all these cool engineering ideas is that they seem to require a united human race. The universal earthling concept is probably lifetimes away or until we face some (un)natural disaster that causes countries to unify. With the way the world is right now, I am having a hard time imagining uniting for 'progress'.
If you launch a rocket from the moon it doesn't have to be a reusable one. It can be a cheap, one-use rocket that burns up in atmosphere and crashes into the ocean. Like most rockets in history.
A space elevator is actually the best bet for launches. The resources we would send from the moon wouldn't be unrefined clumps of regolith, we would have foundries on the moon to process the lunar resources into a refined state. That would make payloads a lot smaller and neater than moving ore to be smelted and processed earth-side. And it's very possible to aim a payload at a specific landing site. They did that in the 60's for the moon landings, for the exact reasons you mentioned. Not to mention a lunar space elevator can be constructed of cheap materials like kevlar, and would pay itself off after a few payloads. Not to mention it can be used for other purposes, like servicing spaceships headed out of the earth-moon system, or as a transit hub. And while atmospheric re-entry gets hot, it's not hot enough that it destroys everything. Remember, people go up and down to space all the time, like with the moon programs, the space shuttle program, every space station, and a few satellite maintenance missions like Hubble.
A mass driver is essentially a big cannon, but instead of a chemical propellant it uses electromagnets to launch a payload. But like a normal cannon, it stops acting upon the payload after it's launched. It doesn't project a constant stream of magnetic energy onto the payload to propel it. All the necessary kinetic energy for the payload to reach earth is imparted onto it by the mass driver during launch.
Firing a cannon at the earth might sound dangerous, but it's only as dangerous as launching a small rocket from the moon, like we did during the moon landings. The "bullet," or payload, would consist of the main cargo, in this case processed resources, and a guiding system like any rocket has, if simpler. It only needs to do some course corrections to make sure the payload lands where it's supposed to, and doesn't crash onto a city. And putting a mass driver on a space elevator wouldn't be much better than having one built on the lunar surface.
And none of these ideas are such massive undertakings that they need global unity. They would be very simple when you get down to it, because every nation knows how to build an elevator, or a cannon.