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> Can humans withstand 4 g non-stop for 9 days? They might if you keep rotating them, so the force is not along one axis all the time.
Aren't you always orbiting something when in space (however large or distant)? If you were to kill your orbital (lateral) velocity, you'd only be gaining radial velocity by being pulled towards the orbiting body, some form of thrust would be needed to compensate that.
TL;DR: can you really be "at a full stop" in space?
If a ship is capable of continuous 1g acceleration then it shouldn't be designed with rotating centrifugal rings for gravity. Instead, design the ship with the floor towards the engine and travel at a constant 1g to wherever it is that you're going. Decelerate at the same speed.
Assuming it's just moving in space away from any massive objects in a straight line...1 billion km/h.
Isn't it too fast?
If a ship is capable of continuous 1g acceleration then it shouldn't be designed with rotating centrifugal rings for gravity. Instead, design the ship with the floor towards the engine and travel at a constant 1g to wherever it is that you're going. Decelerate at the same speed.
⸻ 1. Which was actually a hollowed-out asteroid and used the asteroid itself as propellant to achieve continuous acceleration and deceleration for the trip. One of the better attempts at providing a plausible mechanism for interstellar travel. Good enough that I neither declared it magic nor spent a long time thinking that it wouldn’t work.²
2. Doubtless someone will reply here with a detailed explanation of why it wouldn’t work.
> Can humans withstand 4 g non-stop for 9 days? They might if you keep rotating them, so the force is not along one axis all the time.
Seems like that would cause terrible motion sickness. Rotating would cause centripetal force, so another vector of acceleration on your body PLUS a constantly changing vector of acceleration due to deceleration.
If a ship is capable of continuous 1g acceleration then it shouldn't be designed with rotating centrifugal rings for gravity. Instead, design the ship with the floor towards the engine and travel at a constant 1g to wherever it is that you're going. Decelerate at the same speed.
I'm really surprised by this oversight as other things (magnetic boots) from The Expanse were explicitly mentioned. In The Expanse, this is exactly how ships are set up. The "floor" is towards the engine and the continuous 1g acceleration provides "gravity". When a ship starts decelerating there is a "flip and burn" where everyone straps in while the ship literally turns around and starts accelerating at 1g in the op…
If a ship is capable of continuous 1g acceleration then it shouldn't be designed with rotating centrifugal rings for gravity. Instead, design the ship with the floor towards the engine and travel at a constant 1g to wherever it is that you're going. Decelerate at the same speed.
OP talks about accelerating at 0.1g on the outbound trip, and this is an emergency situation - maybe this ship isn't capable of continuous 1g acceleration without straining the engines past their operational parameters.
Although I can't imagine a ship with rotation ring segments built to withstand a year of 0.1g acceleration not immediately coming apart when suddenly subjected to a 4g load.
I don't think _my house_ would withstand a 4g load, and it was designed (and has successfully withstood) over a hundred years of a 1g load.
Take the g-force and multiply it by your body weight. That would be how heavy you feel when standing. If you are 70 kg (154 lbs) and under 1.5g of acceleration that is an extra 35 kg (77 lbs) of weight, which is about what we ask a modern soldier to carry. But the soldier gets to set their pack down when they rest, and the weight isn't applied to their internal organs. Perhaps gradual introduction of the acceleration over weeks would allow people to build conditioning, if all the crew is young and very fit.
Go higher and it gets even less plausible. 2.0g is like carrying your twin. Surely this is impossible to sustain for more than an hour or two without some kind of acceleration couch—setting cardiac health aside entirely—and injury would be very likely if you were active.
I think it would be impossible for humans to walk around at more than ~1.5 g of acceleration for extended periods of time, and even that is asking a lot. Take the g-force and multiply it by your body weight. That would be how heavy you feel when standing. If you are 70 kg (154 lbs) and under 1.5g of acceleration that is an extra 35 kg (77 lbs) of weight, which is about what we ask a modern soldier to carry. But the s…
FWIW there are people who weigh well beyond 150kg so I'd argue it would be plausible. Will people be able to perform at peak physical level? No. Will they probably manage for a couple of days? I'd say so.
One point is left out from this calculation: what's the reference point we're at a "full stop" from? Aren't you always orbiting something when in space (however large or distant)? If you were to kill your orbital (lateral) velocity, you'd only be gaining radial velocity by being pulled towards the orbiting body, some form of thrust would be needed to compensate that. TL;DR: can you really be "at a full stop" in space…