Logan Selmes
Well-Known Member
- Joined
- Dec 31, 2023
- Messages
- 66
Note: I posted this in Writing Discussion but I think this might be a better place, so I crossposted it here too.
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As far as I know science fiction authors have stopped talking about Bussard Ramjet starships the way they used to (Vinge, Niven, etc.). That idea is compelling but probably not realistic. Apparently, a recent study has shown that drag would beat any thrust created. It doesn't make all those stories bad, in fact that's some of the best fiction I know of. It just means writers are going back to the drawing board for the next-most-feasible thing.
One that seems very possible and has actually been tested in real life with success (small-scale) is nuclear pulse propulsion.
You use fission or fusion or fission-fusion or even antimatter-nuclear "pulse units" to push against a shock-absorbing plate which accelerates an attached crewed module on the other side of the plate. You can get to a good small percentage of the speed of light. With some artistic license, let's say you can get up to 15% accounting for the fact you have to brake at the halfway point and maybe even later if you brake using solar sail, magnetic sail, or both.
Simple version: You're attached to the top of a dinner plate and bombs keep going off under the plate, which sends you faster and faster in a given direction.
For simplicity, you're going 15 LY between 2 stars which should take you about 100 years at 15%, right?
Problem is that (if I understand correctly) for both the first and second half of the flight, you're not under constant acceleration to simulate gravity. Instead it's a steady pulse, which means you might need spinning modules to simulate gravity for crew.
I'm trying to wrap my head around this. A few ideas:
1) The pulses are timed closely enough that the crew gets the sensation of a constant simulation of some level of gravity?
2) If you're in a non-spin crew module you're basically floating around in between nuclear pulses that jolt the "downward wall" towards you every time? (This seems like it would be very annoying.)
3) Even if you're in a spinning module, every time the drive pulses, you still feel the jolt, because the pulse is suddenly accelerating the entire ship? (Still annoying.)
In essence, it's an elegant, workable concept even for long-distance travel, but it seems hilariously uncomfortable for the crew, perhaps even more so than relying entirely on simulating gravity with spin instead of with acceleration. Unless I'm getting something wrong. Thoughts?
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As far as I know science fiction authors have stopped talking about Bussard Ramjet starships the way they used to (Vinge, Niven, etc.). That idea is compelling but probably not realistic. Apparently, a recent study has shown that drag would beat any thrust created. It doesn't make all those stories bad, in fact that's some of the best fiction I know of. It just means writers are going back to the drawing board for the next-most-feasible thing.
One that seems very possible and has actually been tested in real life with success (small-scale) is nuclear pulse propulsion.
You use fission or fusion or fission-fusion or even antimatter-nuclear "pulse units" to push against a shock-absorbing plate which accelerates an attached crewed module on the other side of the plate. You can get to a good small percentage of the speed of light. With some artistic license, let's say you can get up to 15% accounting for the fact you have to brake at the halfway point and maybe even later if you brake using solar sail, magnetic sail, or both.
Simple version: You're attached to the top of a dinner plate and bombs keep going off under the plate, which sends you faster and faster in a given direction.
For simplicity, you're going 15 LY between 2 stars which should take you about 100 years at 15%, right?
Problem is that (if I understand correctly) for both the first and second half of the flight, you're not under constant acceleration to simulate gravity. Instead it's a steady pulse, which means you might need spinning modules to simulate gravity for crew.
I'm trying to wrap my head around this. A few ideas:
1) The pulses are timed closely enough that the crew gets the sensation of a constant simulation of some level of gravity?
2) If you're in a non-spin crew module you're basically floating around in between nuclear pulses that jolt the "downward wall" towards you every time? (This seems like it would be very annoying.)
3) Even if you're in a spinning module, every time the drive pulses, you still feel the jolt, because the pulse is suddenly accelerating the entire ship? (Still annoying.)
In essence, it's an elegant, workable concept even for long-distance travel, but it seems hilariously uncomfortable for the crew, perhaps even more so than relying entirely on simulating gravity with spin instead of with acceleration. Unless I'm getting something wrong. Thoughts?
