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[vadia]

simpler would be to dock in the middle

That was what my entire posts have been recommending .

sorry, skimmed the first section as I came in the middle and mistook your complicated ball bearing thing for at the side, but really in the middle no ball bearings would be needed.  It would really be like docking into a giant hour hand.  The spin is virtually nil in the middle.

I can easily see a problem with the 'whole station is rotating' idea.

Namely, it's be harder for something to dock with it. Not impossible, but a lot harder.
It's be like Elite. A lot of dying. Or at least, it would be like that with me.

Why not have the dock in the middle of the flywheel. The docking apparatus just needs to be place on ball bearings and a motor to counter act the small amount of friction and you now a stationary, self adjustable dock.

Friction. Unless you want to spend a load of fuel keeping the station rotating, the central part will, eventually, slow down the whole station.

It is true, movement inside of this ring craft will have a bearing on whether it keeps spinning or not. The donut hole dock in the middle is no exception. The important thing to keep in mind is that rotating on an axis in a near zero gravity environment can be achieve easily by using gyros. In other words, the mechanisms that keep vehicles that shouldn't be standing up, standing up. Like the things in segways, and the one wheeled bike. If you have a power generator on board the ring-craft, powering gyros would not be a problem. As such, whatever small constant force is causing it to slow down can be counteracted.

They don't turn rotation among the axes into forward momentum though, doing so would violate physics. It's like as if I were floating in near zero-g and I rapidly swing my legs about. I can't change my trajectory or anything if there's no air for me to push myself from, but I will be able to cause myself to spin myself.

Or by ejecting waste that cannot be reasonably recycled in the direction to correct spin -- whatever direction that could be.

[Flare]

They don't turn rotation among the axes into forward momentum though, doing so would violate physics. It's like as if I were floating in near zero-g and I rapidly swing my legs about. I can't change my trajectory or anything if there's no air for me to push myself from, but I will be able to cause myself to spin myself.

Which leads me to further confusion for me...
How exactly can you simulate the acceleration from gravity, against the pull of real gravity, without expending any energy?

But you do expend energy, the energy comes from the reactor/generator on board. This energy is turned into kinetic energy by the gyros. All you need to do is to produce enough centrifugal force to overpower the near nonexistent gravity from a giant body. Imagine a ferris wheel that goes 30 rpm, it completes one rotation every 2 seconds. People will be pinned to the bottom of their rides as each carousal flings outward from the centrifugal force. Or using a smaller example, do you know what motorcarousal is? A gyro can replicate that spinning motion without being anchored to the ground. As you can see, if the carousal was a little bigger, they could have stood up if the rpm was great enough.

Imagine this. I am floating in near zero-g. When I kick my legs over and over again, I will begin to spin out along the axis that more or less pierces both my kidneys. I will be tumbling head over heels. It's like that diving board sport, people can spin on their axis when they contort parts of their body. As my spin starts getting faster and fast, blood will rush to the bottoms of my feet, as well as my head due to the centrifugal force.

The same applies to the ring-craft. As the gyros that replicate this kicking motion in some way, it will be able to accelerate or decelerate the speed of the ring-craft's rpm. As I understood the conversation, the main kicker against the ring craft was that it will eventually slow down.

It would really be like docking into a giant hour hand.  The spin is virtually nil in the middle.

If the craft is under several hundred meters, the spin will be problematic for docking procedures, but then again, what space craft can't turn on its axis ? Matching it shouldn't be much of a problem. It's more or less an elementary engineering problem.

[mainiac]

nvm

[GreatWyrmGold]

They don't turn rotation among the axes into forward momentum though, doing so would violate physics. It's like as if I were floating in near zero-g and I rapidly swing my legs about. I can't change my trajectory or anything if there's no air for me to push myself from, but I will be able to cause myself to spin myself.

Which leads me to further confusion for me...
How exactly can you simulate the acceleration from gravity, against the pull of real gravity, without expending any energy?

But you do expend energy, the energy comes from the reactor/generator on board. This energy is turned into kinetic energy by the gyros. All you need to do is to produce enough centrifugal force to overpower the near nonexistent gravity from a giant body. Imagine a ferris wheel that goes 30 rpm, it completes one rotation every 2 seconds. People will be pinned to the bottom of their rides as each carousal flings outward from the centrifugal force. Or using a smaller example, do you know what motorcarousal is? A gyro can replicate that spinning motion without being anchored to the ground. As you can see, if the carousal was a little bigger, they could have stood up if the rpm was great enough.

Imagine this. I am floating in near zero-g. When I kick my legs over and over again, I will begin to spin out along the axis that more or less pierces both my kidneys. I will be tumbling head over heels. It's like that diving board sport, people can spin on their axis when they contort parts of their body. As my spin starts getting faster and fast, blood will rush to the bottoms of my feet, as well as my head due to the centrifugal force.

The same applies to the ring-craft. As the gyros that replicate this kicking motion in some way, it will be able to accelerate or decelerate the speed of the ring-craft's rpm. As I understood the conversation, the main kicker against the ring craft was that it will eventually slow down.

...I don't think that answered my question.
Yes, you'd get the energy from the reactors; no, it wouldn't be infinite. Solar energy might be close but won't be infinite.
Your example has you expending energy to spin. Why wouldn't a spacecraft need a (probably small) amount of energy spent to keep the centrifugal force up?

It would really be like docking into a giant hour hand.  The spin is virtually nil in the middle.

If the craft is under several hundred meters, the spin will be problematic for docking procedures, but then again, what space craft can't turn on its axis ? Matching it shouldn't be much of a problem. It's more or less an elementary engineering problem.

1. It's not going to solve the problem by spinning the spacecraft as it docks; it'll need to actually have a curved trajectory matching that of the outside of the ship. That's kinda hard without gravity (nil between such small objects) or tethers or something...

[vadia]

They don't turn rotation among the axes into forward momentum though, doing so would violate physics. It's like as if I were floating in near zero-g and I rapidly swing my legs about. I can't change my trajectory or anything if there's no air for me to push myself from, but I will be able to cause myself to spin myself.

Which leads me to further confusion for me...
How exactly can you simulate the acceleration from gravity, against the pull of real gravity, without expending any energy?

But you do expend energy, the energy comes from the reactor/generator on board. This energy is turned into kinetic energy by the gyros. All you need to do is to produce enough centrifugal force to overpower the near nonexistent gravity from a giant body. Imagine a ferris wheel that goes 30 rpm, it completes one rotation every 2 seconds. People will be pinned to the bottom of their rides as each carousal flings outward from the centrifugal force. Or using a smaller example, do you know what motorcarousal is? A gyro can replicate that spinning motion without being anchored to the ground. As you can see, if the carousal was a little bigger, they could have stood up if the rpm was great enough.

Imagine this. I am floating in near zero-g. When I kick my legs over and over again, I will begin to spin out along the axis that more or less pierces both my kidneys. I will be tumbling head over heels. It's like that diving board sport, people can spin on their axis when they contort parts of their body. As my spin starts getting faster and fast, blood will rush to the bottoms of my feet, as well as my head due to the centrifugal force.

The same applies to the ring-craft. As the gyros that replicate this kicking motion in some way, it will be able to accelerate or decelerate the speed of the ring-craft's rpm. As I understood the conversation, the main kicker against the ring craft was that it will eventually slow down.

...I don't think that answered my question.
Yes, you'd get the energy from the reactors; no, it wouldn't be infinite. Solar energy might be close but won't be infinite.
Your example has you expending energy to spin. Why wouldn't a spacecraft need a (probably small) amount of energy spent to keep the centrifugal force up?

It would really be like docking into a giant hour hand.  The spin is virtually nil in the middle.

If the craft is under several hundred meters, the spin will be problematic for docking procedures, but then again, what space craft can't turn on its axis ? Matching it shouldn't be much of a problem. It's more or less an elementary engineering problem.

1. It's not going to solve the problem by spinning the spacecraft as it docks; it'll need to actually have a curved trajectory matching that of the outside of the ship. That's kinda hard without gravity (nil between such small objects) or tethers or something...

you do have to use energy to get the spin, but it's much less than the energy needed to decelerate to land on a planet safely.

You have to use energy to keep it spinning, but the modifications are insignificant in comparison to those of getting resources from Mars.  Probably the energy for one mission to get resources from Mars would use more energy than correcting the spin for the whole lifespan of the station. 

have you ever spun a top?  It spins hundreds of times, and only because of the friction of the table and gravity does the top stop spinning.  Without the FORCE of friction it would go pretty much forever.

Why would a ship have to dock on the outside.  put the dock in the middle and use an elevator or whatnot to get to the edges. 

[Il Palazzo]

...I don't think that answered my question.
Yes, you'd get the energy from the reactors; no, it wouldn't be infinite. Solar energy might be close but won't be infinite.
Your example has you expending energy to spin. Why wouldn't a spacecraft need a (probably small) amount of energy spent to keep the centrifugal force up?

Once spun, the kinetic energy of every point of the rotating object remain constant(as in Newton's 2nd law for rotational motion). Barring outside influences, or the inhabitants' conscious cooperation to change it, the station will spin indefinitely with constant angular velocity.

1. It's not going to solve the problem by spinning the spacecraft as it docks; it'll need to actually have a curved trajectory matching that of the outside of the ship. That's kinda hard without gravity (nil between such small objects) or tethers or something...

Here's a famous scene from 2001: A Space Odyssey showcasing how it works.
http://www.youtube.com/watch?v=q3oHmVhviO8

Any good physics-based space game simulates this element of space travel as well. Try Elite 2 & 3, Orbiter, Terminus, Babylon5:IFH.

[MonkeyHead]

GWG, am I correct in assuming you want the docking port to be mounted on an equatorial plane of a body rotating to mimic gravity? Docking at the pole/rotation axis of a rotating body would be much simpler.

[vadia]

We've been looking at the negatives of stations, but what about negatives of planetary ones.

Gravity + meteor - atmosphere = shooting range.

[GreatWyrmGold]

Quote pyramid deconstructed.

you do have to use energy to get the spin, but it's much less than the energy needed to decelerate to land on a planet safely.

Not what I was asking, but I doubt this. How much energy was spent by Neil Armstrong and Buzz Aldren when they fell into the ocean?

You have to use energy to keep it spinning, but the modifications are insignificant in comparison to those of getting resources from Mars.  Probably the energy for one mission to get resources from Mars would use more energy than correcting the spin for the whole lifespan of the station. 

Yeah, it takes less energy to keep a space station spinning than it takes to perform a mission to gather resources from Mars, but it also takes more resources to make a space station than a spacecraft capable of reaching Mars. That comparison is much more relevant than yours, because A. the space station and space ship are being used for roughly the same purpose, B. have more technical similarities, and C. you need to go to planets or wherever for resources anyways, because steel doesn't grow on vacuum.

Why would a ship have to dock on the outside.  put the dock in the middle and use an elevator or whatnot to get to the edges.

The middle spins, too. Unless you want to make the ship even more complicated than it needs to be...

...I don't think that answered my question.
Yes, you'd get the energy from the reactors; no, it wouldn't be infinite. Solar energy might be close but won't be infinite.
Your example has you expending energy to spin. Why wouldn't a spacecraft need a (probably small) amount of energy spent to keep the centrifugal force up?

Once spun, the kinetic energy of every point of the rotating object remain constant(as in Newton's 2nd law for rotational motion). Barring outside influences, or the inhabitants' conscious cooperation to change it, the station will spin indefinitely with constant angular velocity.

Ah. The "spinning=gravity=acceleration=not allowed for free with thermodynamics" is what was tripping me up.

1. It's not going to solve the problem by spinning the spacecraft as it docks; it'll need to actually have a curved trajectory matching that of the outside of the ship. That's kinda hard without gravity (nil between such small objects) or tethers or something...

Here's a famous scene from 2001: A Space Odyssey showcasing how it works.
http://www.youtube.com/watch?v=q3oHmVhviO8

Any good physics-based space game simulates this element of space travel as well. Try Elite 2 & 3, Orbiter, Terminus, Babylon5:IFH.

Ah, I see now. Well, see below.

GWG, am I correct in assuming you want the docking port to be mounted on an equatorial plane of a body rotating to mimic gravity? Docking at the pole/rotation axis of a rotating body would be much simpler.

It's still spinning, just less. Which means there's the same problem, just less. Or maybe more, since the spin is more tightly curved.

We've been looking at the negatives of stations, but what about negatives of planetary ones.
Gravity + meteor - atmosphere = shooting range.

Oh, right, I forgot how there's no way to protect from meteors and how they're so common that Neil Armstrong said, "That's one small step for man an--CRCKzzzzzzz..." Oh, wait, he didn't.
Yes, maintenance would be needed. Guess what? That's true everywhere. Easy access to various resources should counteract that, especially since you would actually have the materials to make repairs. Oh, and by the way? There's meteors in space too.
Also, have you noticed that most of my suggestions for, say, Lunar bases have most of the bases underground? If a meteor can penetrate dozens of feet of solid rock, maybe hundreds, it could probably hit your little space station too.

[vadia]

Quote pyramid deconstructed.

you do have to use energy to get the spin, but it's much less than the energy needed to decelerate to land on a planet safely.

Not what I was asking, but I doubt this. How much energy was spent by Neil Armstrong and Buzz Aldren when they fell into the ocean?

You have to use energy to keep it spinning, but the modifications are insignificant in comparison to those of getting resources from Mars.  Probably the energy for one mission to get resources from Mars would use more energy than correcting the spin for the whole lifespan of the station. 

Yeah, it takes less energy to keep a space station spinning than it takes to perform a mission to gather resources from Mars, but it also takes more resources to make a space station than a spacecraft capable of reaching Mars. That comparison is much more relevant than yours, because A. the space station and space ship are being used for roughly the same purpose, B. have more technical similarities, and C. you need to go to planets or wherever for resources anyways, because steel doesn't grow on vacuum.

Why would a ship have to dock on the outside.  put the dock in the middle and use an elevator or whatnot to get to the edges.

The middle spins, too. Unless you want to make the ship even more complicated than it needs to be...

...I don't think that answered my question.
Yes, you'd get the energy from the reactors; no, it wouldn't be infinite. Solar energy might be close but won't be infinite.
Your example has you expending energy to spin. Why wouldn't a spacecraft need a (probably small) amount of energy spent to keep the centrifugal force up?

Once spun, the kinetic energy of every point of the rotating object remain constant(as in Newton's 2nd law for rotational motion). Barring outside influences, or the inhabitants' conscious cooperation to change it, the station will spin indefinitely with constant angular velocity.

Ah. The "spinning=gravity=acceleration=not allowed for free with thermodynamics" is what was tripping me up.

1. It's not going to solve the problem by spinning the spacecraft as it docks; it'll need to actually have a curved trajectory matching that of the outside of the ship. That's kinda hard without gravity (nil between such small objects) or tethers or something...

Here's a famous scene from 2001: A Space Odyssey showcasing how it works.
http://www.youtube.com/watch?v=q3oHmVhviO8

Any good physics-based space game simulates this element of space travel as well. Try Elite 2 & 3, Orbiter, Terminus, Babylon5:IFH.

Ah, I see now. Well, see below.

GWG, am I correct in assuming you want the docking port to be mounted on an equatorial plane of a body rotating to mimic gravity? Docking at the pole/rotation axis of a rotating body would be much simpler.

It's still spinning, just less. Which means there's the same problem, just less. Or maybe more, since the spin is more tightly curved.

We've been looking at the negatives of stations, but what about negatives of planetary ones.
Gravity + meteor - atmosphere = shooting range.

Oh, right, I forgot how there's no way to protect from meteors and how they're so common that Neil Armstrong said, "That's one small step for man an--CRCKzzzzzzz..." Oh, wait, he didn't.
Yes, maintenance would be needed. Guess what? That's true everywhere. Easy access to various resources should counteract that, especially since you would actually have the materials to make repairs. Oh, and by the way? There's meteors in space too.
Also, have you noticed that most of my suggestions for, say, Lunar bases have most of the bases underground? If a meteor can penetrate dozens of feet of solid rock, maybe hundreds, it could probably hit your little space station too.

Tons of energy was employed to stop the challenger from smashing into the ground.  All from friction via air resistance.

the difference in supplies in the space station vs. a settlement would be no need for motors to land.  And you can get resources by meteor mining via space station. This also allows potentially unlimited expansion. 

Sure the middle spins, once a day [assuming 1 mile diameter and 1 g].  The spin is minor.

centripital force (not centrifugal force) is the issue.  Every part of the ship wants to go straight.  But to do that it has to fly apart which would take too much energy so it pushes at a 90 degree angle -- energy conserved -- but you, not being attached feel this force as a push to the "ground"

Building a settlement underground is a potential solution but that's a lot of energy before being able to settle.  And they planned their missions in non-meteor shower times.

[Aseaheru]

i saw someone talking about ejecting waste. while that is done here, where they dont have to worry about maintaining water levels because resupply is at hand, for longer trips it is probably best to use the human waste and reclaim the water and nutrients.

[vadia]

i saw someone talking about ejecting waste. while that is done here, where they dont have to worry about maintaining water levels because resupply is at hand, for longer trips it is probably best to use the human waste and reclaim the water and nutrients.

oh sure, I wasn't talking about sewage, I was talking like radioactive byproducts or whatnot.  The "I don't know how to recycle this at all and storage is dangerous or pointless" waste.

[GreatWyrmGold]

Quote pyramid deconstructed.
-snip-

Tons of energy was employed to stop the challenger from smashing into the ground.  All from friction via air resistance.

Um...unless I'm misunderstanding you, the energy came from the air resistance and not from fuel. Throw in a parachute and you're pretty much good. How much energy does that cost us, humanity?

the difference in supplies in the space station vs. a settlement would be no need for motors to land.  And you can get resources by meteor mining via space station. This also allows potentially unlimited expansion. 

That requires a fair amount of movement and probably also orbiting in the asteroid belt, where there is less sunlight for use in generating solar power. Seems like a big hassle. Yes, theoretically possible, but probably not ideal. And since I'm arguing that space stations can't replace planetary colonies, and nothing more, that's all I need to show.

Sure the middle spins, once a day [assuming 1 mile diameter and 1 g].  The spin is minor.

How fast is the docking and how close to the center are we talking?

centripital force (not centrifugal force) is the issue.  Every part of the ship wants to go straight.  But to do that it has to fly apart which would take too much energy so it pushes at a 90 degree angle -- energy conserved -- but you, not being attached feel this force as a push to the "ground"

I used "centrifugal" a while back, with a parenthetical that I wasn't sure if it was that or centripetal; why did no one correct me then?
More on-topic, I think I see now.

Building a settlement underground is a potential solution but that's a lot of energy before being able to settle.  And they planned their missions in non-meteor shower times.

You know what else requires a lot of energy? Boosting ore, or even metal, into space to turn into a massive space station.

i saw someone talking about ejecting waste. while that is done here, where they dont have to worry about maintaining water levels because resupply is at hand, for longer trips it is probably best to use the human waste and reclaim the water and nutrients.

oh sure, I wasn't talking about sewage, I was talking like radioactive byproducts or whatnot.  The "I don't know how to recycle this at all and storage is dangerous or pointless" waste.

I would advise against nuclear power for any long-term space station. Not because of radiation--any halfway decent engineer could copy the designs for Earth power plants and modify them as needed to stop that from being an issue--but fuel. It would be easier to just set up a bunch of solar panels, especially because you don't have to worry about space in space.

[andrea]

1) Parachutes would only work on few places. Since you seem to consider the asteroid belt far enough from the sun to not be worth the effort due to less solar energy, lets exclude from the list all the gas giant moons. That leaves us with Earth ( and obviously we don't need rockets to make a colony there) and Venus. And you really don't want to land anything on Venus, unless you plan to lose it.
Mars has some thin atmosphere, but it is not going to be enough for big stuff.

2)when we speak about docking in the middle, we don't mean "close to the center". we mean IN the center of the station. Distance = 0. sure, it spins. but all you have to do then is spin the ship at the same rate, which is trivial. if ship and station are properly aligned, you don't need any odd trajectory.

3) Centrifugal is fine for the kind of effect you are seeing. The key is that centrifugal force only exists in the frame of reference of the people on the station. But if we are speaking about artificial gravity, felt by people inside the station and spinning with it... I don't see the point of calling it anything else than centrifugal force.

4) Unlike what you previously stated, steel ( or, rather, iron; steel is an alloy) DOES grow in vacuum ( methaphorically. It is not a plant obviously). many asteroids are rich of iron. And if you don't feel like having a station at the asteroid belt, or moving metals back from there, I am sure Near Earth objects would be happy to provide the needed materials. Not all asteroids are in the asteroid belt.

5) solar panels are fine, but you would need some huge arrays. At some point, you might decide that you'd rather ferry some uranium ( or deuterium, if you have a fusion reactor) once in a while, rather than building an extra square mile of solar panels. Also, such a secondary power source allows the station to deal better with unexpected icnreases in power needs.
It should also be noted that radioactive materials are also used for X-ray generators for radiography. You might still get some radioactive waste even without using nuclear reactions as a power source.

[andrea]

edit: meh. lag and double post.