4 ms·

I thought the nuclear propulsion options were viable and relative simple.

by tokai 5y ago

rbanffy 5y ago
Even if you get a very high specific impulse, you still need to pack a lot of reaction mass. You'll also need a lot of supplies (or a biome) because even if you get to 0.1 c, it's still 40 years to get there.
- grishka 5y ago
  I'm not losing hope that there are ways to travel faster than the speed of light that we haven't yet discovered, like bending the spacetime around the spacecraft, or wormholes, or something else of that kind. If various forms of rapidly ejecting matter out of a nozzle really are the only physically viable option for spaceflight, it would be an extremely disappointing universe.
  - rbanffy 5y ago
    > If various forms of rapidly ejecting matter out of a nozzle really are the only physically viable option for spaceflight, it would be an extremely disappointing universe. Indeed. If that's the case, the universe is an infinitely big and infinitely boring place. OTOH, our future uploaded selves may be able to slow down their clock rates and make the trip so much shorter. And you don't need to leave your dear ones on Earth - just bring forks of them along you (chances are a fork of you will remain on Earth anyway).
    - grishka 5y ago
      Frankly, I believe that any form of mind upload or consciousness transfer is a much harder problem than both rejuvenation and interstellar spaceflight. Looking at current aging research, there's a good possibility we'll see rejuvenation in the next decade or two and it'll profoundly change our society. In 20 years, everyone will be looking 25 years old and pointing at frail people with wrinkly faces and laughing, same way we do today with antivaxxers. Once that's out of the way, we'll eventually get comfortable with building arbitrarily large objects on orbit, and we could as well build a huge spaceship with an onboard self-sustaining ecosystem and fly that to other stars, the boring way. Yes, it will be a very long journey, but it's possible without the reliance on yet to be discovered new physics.
      - virgildotcodes 5y ago
        Any chance you could link to some stuff that's making you so optimistic about rejuvenation on that timeline?
        grishka 5y ago
        https://old.reddit.com/r/longevity https://old.reddit.com/r/longevity has a lot of links to various articles and papers, and I also collect relevant videos and talks into a playlist: https://www.youtube.com/playlist?list=PLLvA7pB41pDk27XOjqbXi4sSvPfLOu1zW https://www.youtube.com/playlist?list=PLLvA7pB41pDk27XOjqbXi...
        roveo 5y ago
        Look up the stuff David Sinclair is doing with his team. They are already rejuvenating and regrowing severed optic nerves with Yamanaka factors in mice and are preparing to start human trials. It's not rock-solid that this is going to happen for the whole body soon, but some truly breakthrough things are happening right now in this field, nothing like the previous decades.
        rbanffy 5y ago
        That doesn’t solve the issue that the passengers will need to live on the ship for a thousand years, even if their relatives will be on Earth for twice as long. Even a very big ship can be boring after a sufficiently long time.
      - HWR_14 5y ago
        > pointing at frail people with wrinkly faces and laughing, same way we do today with antivaxxers. Except those people are more likely to be too poor to afford it instead of unwilling to take it.
        psd1 5y ago
        Or, worse, the young will never get any power because the old will not relinquish control. Then you have the "surfeit of princes" problem. This isn't just grand political power: imagine being unable to progress in your career because geriatrics above you aren't retiring. That's just one possible secondary effect. We could enumerate many others.
    - aerique 5y ago
      What would that fork think of it?
      - rbanffy 5y ago
        If I were to fork myself in this situation, I'd make one fork who thinks that making the trip will be awesome and another that will think that staying home is the coolest thing. If we can, from time to time, merge our memories and refork, this wouldn't be a big issue, as both forks would experience both lives. I think that, at this point, we wouldn't be that much human anymore.
        s1artibartfast 5y ago
        You don't even have to modify it. If you are a person that thinks going and leaving a fork would be cool, and also thinks staying and sending a fork would be cool, the job is done.
    - Cthulhu_ 5y ago
      At the moment I have more faith that our AI overlords - or, future self-replicating robots, insert various levels of intelligence and self-reliance here - will be the ones going interstellar, not so much us unless we revolutionize spaceflight. That said, the picture of the future that The Expanse investigates seems to be the most realistic, just minus the somewhat magic propulsion system.
      - rbanffy 5y ago
        Not a huge problem if, after the robots terraform the planet and build our settlements, I can opt to be printed into a new organic body. We'll still need some form of magical propulsion or, worse, some magical power source. There aren't many things that can keep providing energy for thousands of years. I'm pretty sure fission is a non-starter here and even nuclear fusion designs would need a source of tritium because, after a couple thousand years, there won't be much left of the initial fuel.
natechols 5y ago
All of the descriptions I've seen were "viable" in the sense of "we could hypothetically accomplish this in a few decades a for around $100 trillion". At least that was the estimate for Project Daedalus, which designed a nuclear pulse propulsion probe to do a 50-year flyby of Barnard's Star. Fun to think about but it's going to be a while before even the largest governments can afford to fund a project that most of its creators will never see completed.

I thought the nuclear propulsion options were viable and relative simple.

by tokai 5y ago

I thought the nuclear propulsion options were viable and relative simple.

Even if you get a very high specific impulse, you still need to pack a lot of reaction mass. You'll also need a lot of supplies (or a biome) because even if you get to 0.1 c, it's still 40 years to get there.

grishka 5y ago
I'm not losing hope that there are ways to travel faster than the speed of light that we haven't yet discovered, like bending the spacetime around the spacecraft, or wormholes, or something else of that kind. If various forms of rapidly ejecting matter out of a nozzle really are the only physically viable option for spaceflight, it would be an extremely disappointing universe.
- rbanffy 5y ago
  > If various forms of rapidly ejecting matter out of a nozzle really are the only physically viable option for spaceflight, it would be an extremely disappointing universe. Indeed. If that's the case, the universe is an infinitely big and infinitely boring place. OTOH, our future uploaded selves may be able to slow down their clock rates and make the trip so much shorter. And you don't need to leave your dear ones on Earth - just bring forks of them along you (chances are a fork of you will remain on Earth anyway).
  - grishka 5y ago
    Frankly, I believe that any form of mind upload or consciousness transfer is a much harder problem than both rejuvenation and interstellar spaceflight. Looking at current aging research, there's a good possibility we'll see rejuvenation in the next decade or two and it'll profoundly change our society. In 20 years, everyone will be looking 25 years old and pointing at frail people with wrinkly faces and laughing, same way we do today with antivaxxers. Once that's out of the way, we'll eventually get comfortable with building arbitrarily large objects on orbit, and we could as well build a huge spaceship with an onboard self-sustaining ecosystem and fly that to other stars, the boring way. Yes, it will be a very long journey, but it's possible without the reliance on yet to be discovered new physics.
    - virgildotcodes 5y ago
      Any chance you could link to some stuff that's making you so optimistic about rejuvenation on that timeline?
      - grishka 5y ago
        https://old.reddit.com/r/longevity https://old.reddit.com/r/longevity has a lot of links to various articles and papers, and I also collect relevant videos and talks into a playlist: https://www.youtube.com/playlist?list=PLLvA7pB41pDk27XOjqbXi4sSvPfLOu1zW https://www.youtube.com/playlist?list=PLLvA7pB41pDk27XOjqbXi...
      - roveo 5y ago
        Look up the stuff David Sinclair is doing with his team. They are already rejuvenating and regrowing severed optic nerves with Yamanaka factors in mice and are preparing to start human trials. It's not rock-solid that this is going to happen for the whole body soon, but some truly breakthrough things are happening right now in this field, nothing like the previous decades.
        rbanffy 5y ago
        That doesn’t solve the issue that the passengers will need to live on the ship for a thousand years, even if their relatives will be on Earth for twice as long. Even a very big ship can be boring after a sufficiently long time.
    - HWR_14 5y ago
      > pointing at frail people with wrinkly faces and laughing, same way we do today with antivaxxers. Except those people are more likely to be too poor to afford it instead of unwilling to take it.
      - psd1 5y ago
        Or, worse, the young will never get any power because the old will not relinquish control. Then you have the "surfeit of princes" problem. This isn't just grand political power: imagine being unable to progress in your career because geriatrics above you aren't retiring. That's just one possible secondary effect. We could enumerate many others.
  - aerique 5y ago
    What would that fork think of it?
    - rbanffy 5y ago
      If I were to fork myself in this situation, I'd make one fork who thinks that making the trip will be awesome and another that will think that staying home is the coolest thing. If we can, from time to time, merge our memories and refork, this wouldn't be a big issue, as both forks would experience both lives. I think that, at this point, we wouldn't be that much human anymore.
      - s1artibartfast 5y ago
        You don't even have to modify it. If you are a person that thinks going and leaving a fork would be cool, and also thinks staying and sending a fork would be cool, the job is done.
  - Cthulhu_ 5y ago
    At the moment I have more faith that our AI overlords - or, future self-replicating robots, insert various levels of intelligence and self-reliance here - will be the ones going interstellar, not so much us unless we revolutionize spaceflight. That said, the picture of the future that The Expanse investigates seems to be the most realistic, just minus the somewhat magic propulsion system.
    - rbanffy 5y ago
      Not a huge problem if, after the robots terraform the planet and build our settlements, I can opt to be printed into a new organic body. We'll still need some form of magical propulsion or, worse, some magical power source. There aren't many things that can keep providing energy for thousands of years. I'm pretty sure fission is a non-starter here and even nuclear fusion designs would need a source of tritium because, after a couple thousand years, there won't be much left of the initial fuel.

natechols 5y ago

All of the descriptions I've seen were "viable" in the sense of "we could hypothetically accomplish this in a few decades a for around $100 trillion". At least that was the estimate for Project Daedalus, which designed a nuclear pulse propulsion probe to do a 50-year flyby of Barnard's Star. Fun to think about but it's going to be a while before even the largest governments can afford to fund a project that most of its creators will never see completed.