Since we're speaking of planets light years away. The only way for humans to get out there, is to stay in some kind of spaceship with gravity.
Floating around on the International Space Station is nice for an hour. But after that, I bet it gets boring real quick. Especially, if you need to go use the restroom, and handle liquids and solids.
So, having artificial gravity is nice. It will keep liquids down. You can drink out of a cup. Food doesn't float away. You can surgically operate safely. You can use the restroom normally.
But, you would need a very large structure, to spin around, in order to not get the effects of Coriolis Force. And since it is currently difficult to build such a large structure in space, then I wondered if we could cheat.
The method is to apply a constant force, but at an angle. This angle will allow the space craft to simulate a rotation, like it is being spun around with an invisible tether. This angular force will push all the occupants inside, to feel 1 G of gravity. And after one full rotation, then the space craft will return to the origin point.
So, the idea is to apply an angular force, to cause a space craft to rotate in place, to simulate artificial gravity.
This is similar to the idea of constantly accelerating a spacecraft, so that the occupants feel 1 G of gravity. But that acceleration would shoot the occupants straight into deep space, which is not what we want.
Instead, this method would be like simulating a Ring World, but instead of rotating the space station, it would use constant angular force to cause the rotation, in order to simulate the artificial gravity.
I was thinking something like an electric-ion engine could be used to provide the constant thrust. It would need to be computer controlled, to automatically administer the right force, at the correct angle, at the correct time, in order to rotate and simulate the artificial gravity. And it can be powered by nuclear, or possible solar. And of course, the thrust can never be turned off, otherwise, the space craft would shoot off into deep space.
One idea I thought was to have this be in a large orbit around the earth. The other location would be at the Earth-Moon Lagrangian Point.
Any space infrastructure architects want to take a stab at this idea? Possible or not?
You should watch The Expanse, a very good TV show.
Their ships accelerate at a comfortable level to generate gravity for half of the destination, and then "flip-and-burn" by accelerating in the opposite direction at the same comfortable level to generate gravity.
That only works inside the solar system. The energy requirements to accelerate for a year are enormous. With 100% efficient engines, you would need something like a reaction mass the size of Jupiter.
On the plus side you quickly approach c. At constant 1g acceleration / deceleration, Andromeda is about 28 years away.
Right, the people onboard the spaceship will only perceive 28y to have gone by. People on Earth will perceive the spaceship accelerating away for millions of years.
The ISS weighs 440t and to get 1g there by acceleration you'd need to constantly apply a force of ~4.4MN (meganewton), that's a tenth of a Saturn 5 at lift-off.
Not sure we can do that for an extended amount of time (read: a few hours) without bringing along lots of fuel
That or we invent that special drive of that dead Martian.
Ultimately, gravity is a relatively small problem in terms of interstellar travel. It's an implementation detail, so to speak. The main problem is that there is no energy in space.
> About 1 atom per cm³ and enough photons to read by.
Do you have a citation (or better yet, a calculation) for this? I’ve been searching for about 10 minutes and and it doesn’t quite make sense.
The full moon typically casts about 0.05 - 0.1 lx.[1] With perseverence and some eye strain, I think I could read by that on a particularly clear night. This isn’t a perfect heuristic, but it seems reasonable to start with as a baseline.
Per this calculation[2], 1 lx is approximatly equal to 5 x 10^15 photons per second per square meter. The best moonlight you can typically expect from a full moon is approximately a tenth of this luminosity.
Then per the notes here[3], there are only something like 450 photons per cubic cm in space on average, which seems reasonable for a first approximation of diffused light in interstellar space. That’s vastly lower than 0.1 lx, and that’s before considering that the majority of those photons aren’t actually visible light.
Sorry it doesn’t work. The correct force angle is always directly inwards towards the center of the circle the craft is tracing, and that force would need to be 1 G. Think of it as swinging a ball on a string—the ball is the craft, and the force on the string is your thrust force.
If you can generate 1 G of force (which is far beyond the capabilities of an ion engine), you’d be better off accelerating directly toward your destination and doing the “flip and burn” half way.
Since we're speaking of planets light years away. The only way for humans to get out there, is to stay in some kind of spaceship with gravity.
Floating around on the International Space Station is nice for an hour. But after that, I bet it gets boring real quick. Especially, if you need to go use the restroom, and handle liquids and solids.
So, having artificial gravity is nice. It will keep liquids down. You can drink out of a cup. Food doesn't float away. You can surgically operate safely. You can use the restroom normally.
But, you would need a very large structure, to spin around, in order to not get the effects of Coriolis Force. And since it is currently difficult to build such a large structure in space, then I wondered if we could cheat.
The method is to apply a constant force, but at an angle. This angle will allow the space craft to simulate a rotation, like it is being spun around with an invisible tether. This angular force will push all the occupants inside, to feel 1 G of gravity. And after one full rotation, then the space craft will return to the origin point.
So, the idea is to apply an angular force, to cause a space craft to rotate in place, to simulate artificial gravity.
This is similar to the idea of constantly accelerating a spacecraft, so that the occupants feel 1 G of gravity. But that acceleration would shoot the occupants straight into deep space, which is not what we want.
Instead, this method would be like simulating a Ring World, but instead of rotating the space station, it would use constant angular force to cause the rotation, in order to simulate the artificial gravity.
I was thinking something like an electric-ion engine could be used to provide the constant thrust. It would need to be computer controlled, to automatically administer the right force, at the correct angle, at the correct time, in order to rotate and simulate the artificial gravity. And it can be powered by nuclear, or possible solar. And of course, the thrust can never be turned off, otherwise, the space craft would shoot off into deep space.
One idea I thought was to have this be in a large orbit around the earth. The other location would be at the Earth-Moon Lagrangian Point.
Any space infrastructure architects want to take a stab at this idea? Possible or not?