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I have figured out a plausible maneuver drive for my space world!
I noticed that the rockets I was looking at were all thermal drives. That means there was a heat source (fusion) used to heat up a reaction mass (hydrogen or water).
Exhaust velocity is a little limited.
I did more digging into the theoretical and found that a drive that released just fused helium from the containment field was possible and gives insane specific impulse. Exhaust velocity is about 6% c.
That's how it operates in high impulse mode. In high thrust mode you dump a lot more reaction mass on the furnace and sacrifice impulse for gees.
The amusing thing is I was trying very hard to emulate the ship technology from Steven Gallacci's Erma Felna universe and at every turn when I dig I find exactly how well he'd done his research.
Funny, that's how I thought fusion drives worked, because that's how stars have been working for billions of years....
ReplyDeleteIt's funny because there was no math involved in my conclusion. :)
Pithy.
ReplyDeleteHow large is the drive? How much smaller can we expect it to be with advances in technology? How much fuel is required given that 0.06c exhaust velocity? I now know those answers, or at least enough to give plausible responses. That was the whole point of the exercise.
I too was surprised to find that nearly everyone assumed that we'd be spraying reaction mass past a fusion heat source not venting fusing plasma directly.
Just to give a bit of perspective on teh suxxor of realistic. The ship design I came up with is about 7,000 Traveller tons. It can average 0.41g for two weeks in high impulse mode (more delta V) or run for it at 1g for three days (but 1/6 the delta V).
It's tragic that you made your little math point there. It's like bragging that you managed to write an entire short story without punctuation or spelling.
Just out of curiosity, I commented on the previous post, but that comment seems to have disappeared. Any particular reason?
ReplyDeleteCaught in the spam trap, I've released it.
DeleteDude, chill. I wasn't bragging. I was trying to say that sometimes it's possible to overthink stuff.
ReplyDeleteThis isn't overthinking at all. This is establishing fundamental technology and determining what is possible in this world.
ReplyDeleteIf the trip to Jupiter takes hours then you can't have a story that takes days occur while en-route. Oh, the trip to Jupiter is best handled with a short jump with my tech rather than spending it in normal space.
Like I said, I am trying to make a plausible space world with just one miracle, the jump drive. Plausibility means checking out what's possible.