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I like what you say, but I think using the material of Mercury to build these spheres is beyond our technological base. What's not impossible is doing this with

by rnk 3y ago

I like what you say, but I think using the material of Mercury to build these spheres is beyond our technological base. What's not impossible is doing this with some of our asteroids. Send robots, start using the materials on the asteroid, hollow out the center, spin it, all of those things are at least conceivable today with probably the exception of figuring out how to work with the materials on site; engineering challenges but not impossible. A billion or two is probably enough to plan a robotic lander and do lots of fundamental material processing research, spend another billion to prototype it on the moon, another billion to build it and launch it to the asteroid, another billion to operate it. Elon or some other self-aggrandizing billionaire could do it today. Imagine all those billionaire sports team owners, if they weren't doing something stupid with their money they could do this.

jmyeet 3y ago
> ... I think using the material of Mercury to build these spheres is beyond our technological base This is presently true. My point is that it's a conservative estimate to say we'll be capable of it within the next 1000 years. Our biggest issue currently is the high cost of getting payloads into LEO. For Apollo and the Space Shuttle that cost was ~$50,000/kg. Factoring in reusability it's now estimated to be $1000/kg or less. There are paths to get this much lower (eg <$10/kg). Mercury has specific issues and advantages. The biggest advantages are access to energy, high orbital velocity and no atmosphere. A thin atmosphere like on Mars is the worst of both worlds. It really just makes landing difficult and creates dust storms to cover your equipment in dust. The high orbital velocity of Mercury is both an advantage and a disadvantage. It makes it really difficult to get there, which is why there have been relatively few missions there, but once you are there, it means the delta-V of getting anywhere else in the Solar System is quite low, whether that be finished products or just raw materials. Mercury is metal rich but probably lacks elements like oxygen for, say, smelting steel (and, of course, living). The long day/night cycle is an issue too. My point in relating the mass requirement to Mercury is because, even though 1% of Mercury is still a lot of mass, it would still leave Mercury relatively intact. It's also metal-rich.
- rnk 3y ago
  Thanks for that thoughtful answer! I have seen discussions of the energy to go around the solar system (starting with the tremendous energy it takes to get to leo vs go from there to anywhere else) but never heard that Mercury had an advantage. So the idea apparently is instead of trying to lift things to leo, we build it on mercury and it doesn't have our gravity well - that other notion of the orbital velocity of mercury giving things a good starting push is another cool thing to investigate. I had another vision, informed from science fiction. It was that we could send relatively small machines (self replicating using local materials on the asteroid) and they could do everything we want after we figure out the replicating w local materials part. And because we only need to send a small starter robot it doesn't use that much energy. What do you think of that? I mean we could do the same with materials to process them on Mercury.

by rnk 3y ago

jmyeet 3y ago

> ... I think using the material of Mercury to build these spheres is beyond our technological base This is presently true. My point is that it's a conservative estimate to say we'll be capable of it within the next 1000 years. Our biggest issue currently is the high cost of getting payloads into LEO. For Apollo and the Space Shuttle that cost was ~$50,000/kg. Factoring in reusability it's now estimated to be $1000/kg or less. There are paths to get this much lower (eg <$10/kg). Mercury has specific issues and advantages. The biggest advantages are access to energy, high orbital velocity and no atmosphere. A thin atmosphere like on Mars is the worst of both worlds. It really just makes landing difficult and creates dust storms to cover your equipment in dust. The high orbital velocity of Mercury is both an advantage and a disadvantage. It makes it really difficult to get there, which is why there have been relatively few missions there, but once you are there, it means the delta-V of getting anywhere else in the Solar System is quite low, whether that be finished products or just raw materials. Mercury is metal rich but probably lacks elements like oxygen for, say, smelting steel (and, of course, living). The long day/night cycle is an issue too. My point in relating the mass requirement to Mercury is because, even though 1% of Mercury is still a lot of mass, it would still leave Mercury relatively intact. It's also metal-rich.

rnk 3y ago
Thanks for that thoughtful answer! I have seen discussions of the energy to go around the solar system (starting with the tremendous energy it takes to get to leo vs go from there to anywhere else) but never heard that Mercury had an advantage. So the idea apparently is instead of trying to lift things to leo, we build it on mercury and it doesn't have our gravity well - that other notion of the orbital velocity of mercury giving things a good starting push is another cool thing to investigate. I had another vision, informed from science fiction. It was that we could send relatively small machines (self replicating using local materials on the asteroid) and they could do everything we want after we figure out the replicating w local materials part. And because we only need to send a small starter robot it doesn't use that much energy. What do you think of that? I mean we could do the same with materials to process them on Mercury.