Okay, this is a little complicated and my understanding of physics is rather shaky so please bear with me. Basically, one of my stories is set on a spaceship that has a rotating section to generate gravity. It has it because it's a really long trip, muscle atrophy is something that they really want to avoid, and the alternative means of generating an approximation of gravity in a reasonably hard sci-fi setting, acceleration, isn't feasible due to continual acceleration not being a viable option since as I said above it's a really long trip. Problem is that they still need to accelerate at the start of the journey to get up to cruising speed and decelerate at the end of it, which would result in two sets of g-forces going in different directions. How do I go about minimizing the problems that this may cause for those inside the ship? At the moment my leading idea is to have the ship accelerate/deceleration at a rate that generates fewer Gs than the rotating section so that there's always a dominant direction for "down" but I'm unsure if that would work and even more unsure how big the difference would need to be.
How long do they need to accelerate and decelerate? If it's a short time (less than a week or so) they could just forgo the gravity for a while, but if it's half the trip, you could build the "floor" in your rotating section at an angle to take advantage of both thrust and spin, kind of like a velodrome track.
I think it will be depend a bit on how effective your propulsion system is. An ion drive will not be your friend when the time comes to decelerate. The spinning part might be turned off during the first few days to not have a negative effect on the process of slowing down. Better safe than being thrown of course by the grav forces such a thing can produce, and will save a bit on wasting a ton of thruster fuel to keep on course.
Interesting i have read a few hard sci-fi books over the years. Joe Haldeman's Forever War. They talked about acceleration/deceleration during battle at... close to speed of light? I forget. My thought is this, the ship once in deceleration would cause the spinning section, as well as the rest of the ship to experience forward gravity in the direction of the deceleration. Anyone not secured would go flying forward as soon as deceleration began. I believe. I could be wrong. Most likely wrong. I had the idea if your spinning section of the ship was like a gyroscope it could, orientate itself and it's passengers so they would experience planetside like gravity while in deceleration. The ship would possibly take a while to decelerate, just as a train has to start stopping far in advance because they do not stop on a dime. For your amusement a japanese anime with a science lesson, though this one does not talk on acceleration/deceleration. It's still very well thought out science. skip to 30 seconds in they do talk about different types of propulsion drives.
Maneuvering at those speeds would kill everybody onboard if they are accelerating to those speeds rapidly. The g-forces would literally smash their poor bodies into bulkheads, and at a certain point they become a fine paste of people goo. However if they are fighting alongside each other, then being at those speeds would not be too problematic. They would just need to lead their shots to hit their mark. The first rule in practical space warfare is not how fast you are, it is being bigger than the other guy. Keeping your distance, and making small course corrections so that the guy shooting at you is more likely to miss.
Depending on how many Gs they pull while doing so, between almost three weeks and well over three months (I've got the exact figures written down but not to hand, credit to Greg's Space Calculations for making it easy for me to find out what they are). Also, as I said before, it'd be convenient if down is always in the same direction since there's a lot of things that would be complicated by it changing, especially for a prolonged period of time. It should probably also be noted that everyone on-board (well, everyone who's biological anyway) is supposed to spend the journey having a decades long nap, but pretty much the whole plot involves that not being the case. I was thinking that it'd be something more high-tech/currently theoretical than a ion drive since there probably isn't anything around today that's up the the task and the story's set some distance into the future so it's kind of expected.
Maybe I am misunderstanding, and it depends how technologically advanced you want your people to be, but you could fudge a bit of Mach's principle They know it is a mechanism as the data shows, but they don't understand why the reference frames work. I would paraphrase the video, but prof merrifield explains it perfectly.
The floor of the rotating portion could be inside a tube, and the floor of the tube could rotate in sections where important rooms/buildings are. During acceleration, the floor is perpendicular to the force (did I say that right?) and during periods of no acceleration, the floor is on the floor farthest from the center of the rotation.
It is u likely that spinning will ever be used to simulate gravity. I’ll post more later about my thoughts on how this could work. The reason that the force generated by spinning is not the same as the force of gravity. It introduced torque so if you are standing still it will feel like gravity hit if you accelerate or turn you will twist relative to the “ground”. So like in order to move forwards, you’d need to walk diagonally and if you turn along your axis, you’ll have to lean into it. Angular momentum must be preserved.
According to legend, the issues you're talking about would diminish if the radius of the circle is sufficiently large.
You seem to not have heard of the mysticism behind science. Don't feel bad I am worried by the 'According to Legend' thing too.
It would, but how large are we talking? It wouldn't be noticeable on something the size of Halo, but on a ship a hundred yards across, the effect would be very noticeable. The distortion effect will disappear at a rate of the square root of the radius. I calculate that you'll need an object about a half a mile across for the effect to disappear. Besides torque, you'll also contend with a gravity gradient (the floor will feel greater gravity than the ceiling. As for getting there, why would a large acceleration at the beginning be preferable to a long slow burn? In space, it doesn't matter how fast you are going, if you can continue to accelerate, you'll eventually reach very very high speed. It is also significantly more efficient to burn fuel slowly. It produces less heat waste. This would be true for any type of population: rockets, ion thrusters, nuclear pulses, and antimatter. If I were a designer, I would give it an engine that used a single atom hydrogen and anti hydrogen and send them into the chamber at a regular rate. It'd result in a very slow acceleration over a long period of time. Of course, then you can throttle the antimatter rocket up for a deceleration burn.
Oh and don’t be scared of antimatter. It’s not as sci-fi as people think. Our ability to make antimatter now greatly exceeds our ability to create refined uranium in 1935. If we had a sudden reason to create a lot of it like we did with uranium, the industrial power of the USA could easily create large amounts of antimatter in a decade.
