Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Interstellar Flight: Perspectives and Patience

centauri-dreams.org

Post reply on HN
Print view View original

61–70 of 196 posts

Re: Interstellar Flight: Perspectives and Patience

#61

Post by sorcerer-mar »

JumpCrisscross wrote: post #38
sorcerer-mar wrote: post #20

Earlier quoted context omitted.

What resources are on asteroids that justify the energy expenditure to get from space and back? Can't be many of them...

> What resources are on asteroids that justify the energy expenditure to get from space and back? With chemical rockets, not much. With "a propellant-less propulsion propulsion system such as solar sails or electric sails," bringing water (propellant) to low-earth orbit starts making sense [1], as does mining platinum, but only if "the quantity of platinum from space would substitute an equal quantity of terrestrial…

Just skimmed but does this answer the question of getting to and from the surface of earth? Or are we just stockpiling platinum in LEO for some reason?

Re: Interstellar Flight: Perspectives and Patience

#62

Post by JumpCrisscross »

sorcerer-mar wrote: post #61
JumpCrisscross wrote: post #38

Earlier quoted context omitted.

> What resources are on asteroids that justify the energy expenditure to get from space and back? With chemical rockets, not much. With "a propellant-less propulsion propulsion system such as solar sails or electric sails," bringing water (propellant) to low-earth orbit starts making sense [1], as does mining platinum, but only if "the quantity of platinum from space would substitute an equal quantity of terrestrial…

Just skimmed but does this answer the question of getting to and from the surface of earth? Or are we just stockpiling platinum in LEO for some reason?

> does this answer the question of getting to and from the surface of earth?

Yes. (Deöbiting from LEO is cheap, like 90 m/s for the Space Shuttle, because you can use the atmosphere.)

Re: Interstellar Flight: Perspectives and Patience

#63

Post by JumpCrisscross »

sorcerer-mar wrote: post #56
tejtm wrote: post #49

Earlier quoted context omitted.

"What resources are on asteroids that justify the energy expenditure to get from space and back? Can't be many of them..." I suggest re-framing the the question as the cost of preserving the objectively limited and to the best of our knowledge singularly unique in the Universe resource, which is the surface of Earth. Acquiring resources that do not deplete or spoil the future of life on this planet should be in every…

Yeah no. Unless someone can answer basic questions like “what even comes close to net positive in energy expenditure to mine elsewhere,” then this is just a cover story. The reality is that saving our environment will be a whole set of difficult and profoundly boring solutions to real, known problems. Would be cool if we could solve it with badass rockets, explosions, big noises, and adventure, but the complete lack…

> We need to develop better plastics, proteins, and pesticides. Not send protein blobs to other planets because it looks cool in sci fi movies

The reality is more people get passsionate about working on things that look cool in sci fi movies than developing plastics, proteins and pesticides for a mediocre paycheque. This lesson--that the path to groundbreaking technologies is through inspirational moonshots, not committees prescribing what is and isn't necessary--is so thoroughly repeated throughout history that it's a wonder we keep missing it.

Re: Interstellar Flight: Perspectives and Patience

#65

Post by rbanffy »

sorcerer-mar wrote: post #22
AnimalMuppet wrote: post #17

Earlier quoted context omitted.

There was a time when there was nothing (European) in the entire New World. There was a time when there was nothing known (to the US) about what was in most of the Louisiana Purchase. There was a time when there was nothing (European) in, say, Ohio. And then Nebraska. And so on. There was literally nothing there? Why go all that way? To see what was there. And then to make something there. [Edit, because I'm rate lim…

They didn't believe there was literally nothing there. They went all that way to find unclaimed riches. The hypothetical riches were quite obvious: same stuff we have over here, but not owned by someone yet. What are they hypothetical riches of outer space? This is a question we should think about clearly and logically without resorting to stuff like "oh tally-ho the adventure!" type nonsense.

There is many times more water in gas giant moons than on Earth. If we develop the technology needed to make a multi-generation ship we also have the technology to make deep space habitats - enough for trillions or quadrillions of people.

Just imagine the economic output of a civilisation a million times the size of ours.

Re: Interstellar Flight: Perspectives and Patience

#66

Post by rbanffy »

agentultra wrote: post #12
cryptoz wrote: post #4

Earlier quoted context omitted.

All life on Earth is going die. Humanity has never been content with staying put, why would we start now? And what do you mean "literally nothing there"? The universe has a loooooot of stuff in it.

It's mostly empty, isn't it? By "literally nothing there," I mean there's literally nothing for us. Three stars and a few Earth-sized planets in the habitable zone that are, more than likely, uninhabitable by humans. There's nothing there worth going all that way for. I like sci-fi as much as the next person but the reality of the situation, it seems to me, is that the universe is mostly empty, vast, and inhospitable…

The difference between a multi-generational interstellar ship and a self-sustaining space colony is the engine. They wouldn’t need inhabitable planets - they would need raw materials to build more ships and habitats.

I’m not sure that after spending a lifetime in an ample space colony its inhabitants would feel nostalgic of the time we spent sitting on round rocks cooking around a star.

Re: Interstellar Flight: Perspectives and Patience

#68

Post by sorcerer-mar »

JumpCrisscross wrote: post #63
sorcerer-mar wrote: post #56

Earlier quoted context omitted.

Yeah no. Unless someone can answer basic questions like “what even comes close to net positive in energy expenditure to mine elsewhere,” then this is just a cover story. The reality is that saving our environment will be a whole set of difficult and profoundly boring solutions to real, known problems. Would be cool if we could solve it with badass rockets, explosions, big noises, and adventure, but the complete lack…

> We need to develop better plastics, proteins, and pesticides. Not send protein blobs to other planets because it looks cool in sci fi movies The reality is more people get passsionate about working on things that look cool in sci fi movies than developing plastics, proteins and pesticides for a mediocre paycheque. This lesson--that the path to groundbreaking technologies is through inspirational moonshots, not comm…

Nobody referenced any sort of committee.

Groundbreaking technologies are not created via moonshots. They’re created by decades of slog. Moonshots can launch from an unremarkable platform of slog, but the slog had to happen. You just cannot speedrun the vast majority of questions that need to be answered to power a breakthrough.

That’s why I’ll question glory-chasers who want to sit on the rocket but can’t take a few thousands of pay cut to stare for a few years at a true problem that needs solving.

Our species’ actual heroes are those who powered through the slog.

Re: Interstellar Flight: Perspectives and Patience

#69

Post by rbanffy »

bilbo0s wrote: post #46
zppln wrote: post #36

Earlier quoted context omitted.

And those stars will go out as well.

Well true. That's the fallacy in the given argument.

By then we’d better understand how to implement a “Let there be light” procedure.

Might very well be the last question we need to ask ourselves.

Re: Interstellar Flight: Perspectives and Patience

#70

Post by sorcerer-mar »

JumpCrisscross wrote: post #62
sorcerer-mar wrote: post #61

Earlier quoted context omitted.

Just skimmed but does this answer the question of getting to and from the surface of earth? Or are we just stockpiling platinum in LEO for some reason?

> does this answer the question of getting to and from the surface of earth? Yes. (Deöbiting from LEO is cheap, like 90 m/s for the Space Shuttle, because you can use the atmosphere.)

… Presumably the problem is mostly getting up…? Is the plan to just drop hunks of platinum or do we need to put reentry vehicles up there?
Post reply on HN