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[Aseaheru]

a fusion reactor will be required someday, if a colony is to become completely independent. many precision bits require a byproduct of fusion. not much, but some.
and if we are on, lets say mars, there is always wind and what little geothermal is available.

[Aseaheru]

true.

[GreatWyrmGold]

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.

Somehow, I had not considered that...Point to you.

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.

...Okay, leaving the ship spinning around relative to the space station...should be workable...Another point to you.

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.

Now I have no idea if it's centrifugal or centripital!

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.

Rather limited; even if we settled the Asteroid Belt, it's only 4% the mass of the Moon. Total. That means that if you could mine the entire asteroid belt, you'd still have less than 1/20th of the ore you would have from mining the whole Moon--which is easier than mining the whole Belt, because the Moon is all in one place.

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.

As a backup or secondary source? Sure. As a primary source? No. Especially if we're planning long-term, which we really really should be.
Point on the X-Ray stuff, though.

Solar is going to be the best power source for a while, unless we can tap geothermal wherever we are (yet another reason not to rely on space stations) or somehow use some massive resource like gas giants to power power plants.

[Aseaheru]

or wind.
and parachutes have been used on mars. aided by rockets and air bags, but still used...

[Thecard]

Wind power in some place with almost/no atmosphere?

[Aseaheru]

there is wind.

there are dust storms.

there is alot of wind.

thickness of the atmosphere has almost on affect of wind.
unless there isn't any.

[Flare]

...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?

Ah, the without expending energy bit. It honestly wouldn't require that much energy. A small nuclear reactor is all the ISS needs for the gyros inside of the station to keep itself stable against all the movement of those on board. My argument isn't that it doesn't need to keep up the spin, but that even if the rotation slows down over time, it can be countered in a very cheap and very easily manageable way.

In any case, I don't really understand what you're asking me in that first response you wrote to me. Can you tell me what is it that you're confused about? The questions you're asking have a lot of variations as to what assumptions it is making. And I don't think I can address all of the iterations in a timely manner.

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...

I think you're thinking too literally. People on my side are putting forward that the craft dock in the middle of the donut. Not on the outside of it. Imagine me picking up a donut with a stick going through that hole. That is where the direction of the dock will be- from the hole, facing outward perpendicular to the rotation motion.

Solar is going to be the best power source for a while, unless we can tap geothermal wherever we are (yet another reason not to rely on space stations) or somehow use some massive resource like gas giants to power power plants.

I beg to differ. Fission and fusion are the best sources of energy in space. For the amount required to fulfill life support. The other option if you're going to go with a a low amount of power in space, is to live in a spacesuit for almost the entire time to save up on energy.

To be more specific actually, there is likely a large deposit of uranium on mars.

there is wind.

there are dust storms.

there is alot of wind.

thickness of the atmosphere has almost on affect of wind.
unless there isn't any.

Only in dust stoms evidently.

Because of the thinness of the air there, the air would have to have more energy in it to generate energy in a wind turbine, in other words, it needs to move faster. Lets say on earth, it takes wind approximately 10mph to generate a unit of electricity, on mars it would need to be around 30mph.

According to NASA's own reports, and this article: http://marstrekaas.weebly.com/alternative-energy-needs.html

Wind is not reliable in that environment as you'd have to wait until a dust storm blows over, and a strong one at that, to generate any electricity. It might even turn out to be the case that, putting the wind turbines there be much more energy intensive than the energy it puts out over a long period of time.

[GreatWyrmGold]

Wind power in some place with almost/no atmosphere?

That sounds improbable.
...I didn't say that, did I?

...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?

Ah, the without expending energy bit. It honestly wouldn't require that much energy. A small nuclear reactor is all the ISS needs for the gyros inside of the station to keep itself stable against all the movement of those on board. My argument isn't that it doesn't need to keep up the spin, but that even if the rotation slows down over time, it can be countered in a very cheap and very easily manageable way.
In any case, I don't really understand what you're asking me in that first response you wrote to me. Can you tell me what is it that you're confused about? The questions you're asking have a lot of variations as to what assumptions it is making. And I don't think I can address all of the iterations in a timely manner.

It's probably been answered by now. Sorry about that.

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...

I think you're thinking too literally. People on my side are putting forward that the craft dock in the middle of the donut. Not on the outside of it. Imagine me picking up a donut with a stick going through that hole. That is where the direction of the dock will be- from the hole, facing outward perpendicular to the rotation motion.

I think this was settled, too.

Solar is going to be the best power source for a while, unless we can tap geothermal wherever we are (yet another reason not to rely on space stations) or somehow use some massive resource like gas giants to power power plants.

I beg to differ. Fission and fusion are the best sources of energy in space. For the amount required to fulfill life support. The other option if you're going to go with a a low amount of power in space, is to live in a spacesuit for almost the entire time to save up on energy.

Au contrare. Solar energy will be about two and a half times more efficient in space, and while I can't remember the exact stats I seem to recall something like 1,367 watts per square meter available. Even at 10% efficiency (and current photovolkaic cells can get a bit above 17%) would generate over 50,000 watts with just two 5x5 meter squares.

To be more specific actually, there is likely a large deposit of uranium on mars.

I'm a bit skeptical about fueling a whole fleet on uranium deposits. I guess I'm just thinking a few centuries/mellenia ahead of everyone else. Millenia? How do you even spell that word?

there is wind.

there are dust storms.

there is alot of wind.

thickness of the atmosphere has almost on affect of wind.
unless there isn't any.

Only in dust stoms evidently...

...Yeah, this. Yet another reason we should have gone to Luna with the Bay12 Space Program.

[Spinning Fly]

If you're using nuclear reactors, where do you dump the byproduct radioactive junk?

[Thecard]

Millennia.  Mil means the same thing it always does as a prefix.

[Pnx]

If you're using nuclear reactors, where do you dump the byproduct radioactive junk?

If you're using a breeder reactor there really isn't one, but even if there is it shouldn't be that hard to just shoot it into deep space.

[Flare]

If you're using nuclear reactors, where do you dump the byproduct radioactive junk?

Fourth generation nuclear reactors reuse "spent" nuclear fuel. Most of the fuel that old nuclear reactors put out isn't entirely unusable. Far from it, IIRC the only bits that can't be theoretically reused is less than a percent.

In any case, supposing that the craft uses a really old school nuclear reactor (diesel punk ftw), you could always just toss it out of the ship. Space, within the region of star is already dangerously radioactive already.

Au contrare. Solar energy will be about two and a half times more efficient in space, and while I can't remember the exact stats I seem to recall something like 1,367 watts per square meter available. Even at 10% efficiency (and current photovolkaic cells can get a bit above 17%) would generate over 50,000 watts with just two 5x5 meter squares.

Ah, I thought you would use it on the surface of mars . Around earth solar would be great even with the theoretical limit we have reacted with today's tech. Another way to harness solar energy is to simply skip the solar panel thing. Sticking out copper rods into the vacuum of space can absorb a lot of energy, and can operate like that of nuclear reactor, albeit with a lot more moving parts.

To be more specific actually, there is likely a large deposit of uranium on mars.

I'm a bit skeptical about fueling a whole fleet on uranium deposits. I guess I'm just thinking a few centuries/mellenia ahead of everyone else. Millenia? How do you even spell that word?

Well a nuclear reactor doesn't need that much fuel to power it. New models of nuclear reactors can be engineered to the size of a large freezer (trouble being funding and the general public's fear of loading nuclear fuel into it every few years). The energy density of uranium is incredibly high, and is vital in areas further from the sun, where sun exposure is limited, and when the star ship might encounter situations that simply call for more power, or consistent power.

As for mining, I'd imagine it'd be pretty simple actually. Most of the energy used to mine out uranium is used to ensure that it doesn't kill the people mining it, and that it doesn't pollute the environment. Neither of which is going to be an issue on mars. The only issue on mars, is that it would have to be sent into orbit and require a lot of energy to be done so, even if it's smaller than the earth. A more practical solution is to mine it outside of a large body. Mar's moons are relatively unexplored, but our moon does have uranium, and can be mined and sent into orbit with relatively little energy cost because of the low gravity. Asteroids are another contender. Though they might be mined for other more valuable metals than fuel.

As for it being ahead of everyone else, when you have a fleet of craft in the solar system, I imagine that it's about past the time there's any sort of heavy installation outside of the bounds of earth. Uranium rods are very small, and relatively easy to transport when you're not surrounded by a large population.

[mainiac]

Talking about the energy sources used on the surface of mars is like talking about what the inflight meal is going to be on a proposed jet airliner design, an afterthought.  The huge central problem is the transport costs to get to the surface of mars.  Every kilogram of non-human equipment you send to mars is going to cost as much as sending more then 10 kilograms into orbit.  Human cargo would be even more prohibitively expensive.  Power is a cakewalk in comparison, you could just crash some radioactive material into the planet without parachutes, dig it up then use radioactive decay power generation like deep space probes do.  That wouldn't be cheap but it would be a rounding error compared to getting functioning life support equipment onto the planet or getting living humans to safely touch down in such a thin atmosphere let alone landing the tools for industry.

The whole point to the space station colony idea is that it minimizes launch costs whenever possible.  As little of the work is done on the moon because its much more expensive to reach the moon then to go into orbit.  Bulk materials are launched from the moon by catapult rail because that allows you to avoiding using massively expensive rockets.  Keep your population and your work close to earth where they are easier to support.  Then when they develop their own industry they can build propulsion in space far more cheaply then sending it up from space.

Let your ideas live and die by delta-v costs.  If you can get those to work the idea can be made to work.  If they cant then nothing else matters.

[Flare]

The huge central problem is the transport costs to get to the surface of mars.

I disagree, the cost is going to come from the transportation out of earth's gravity. The only reason it would cost a lot of money to get to mars, from the moon for example, is that you want to get there as fast as technology can offer you.

Every kilogram of non-human equipment you send to mars is going to cost as much as sending more then 10 kilograms into orbit.  Human cargo would be even more prohibitively expensive.

Why? The only reason for this is if the craft is designed as a holiday cruise. The cost of this can go way down if the people on board made some sacrifices. Living mostly in one's space suit for a few months up to a year would cut down on cost dramatically, as will modification to the human body to make it easier to integrate it into a self sustaining system.

Power is a cakewalk in comparison, you could just crash some radioactive material into the planet without parachutes, dig it up then use radioactive decay power generation like deep space probes do.  That wouldn't be cheap but it would be a rounding error compared to getting functioning life support equipment onto the planet or getting living humans to safely touch down in such a thin atmosphere let alone landing the tools for industry.

I really don't see a difference between sending a piece of equipment of x mass, and a piece of rock of the same mass to mars from the same spot. I mean the landing stuff is comparatively cheap in regards to how much money it's going to take to escape earth's orbit. The best bet is to make a base on the moon.

The whole point to the space station colony idea is that it minimizes launch costs whenever possible.  As little of the work is done on the moon because its much more expensive to reach the moon then to go into orbit.  Bulk materials are launched from the moon by catapult rail because that allows you to avoiding using massively expensive rockets.  Keep your population and your work close to earth where they are easier to support.  Then when they develop their own industry they can build propulsion in space far more cheaply then sending it up from space.

I think if you're going to build a railgun powerful and big enough to send stuff to another planet, you might as well just build a self sustaining settlement there.

Building a space station will not solve your issue of cost. The main thing being that it costs thousands of dollars to put a kilogram in orbit. The reason it's expensive to go to the moon is because you need a huge enough rocket to provide enough power to fully reach the moon. The equipment needed to land on the moon is comparatively cheap.

[Thecard]

Err... If you shot stuff from the moon to earth, a couple of things would happen.

Cargo would burn up in entry.
Cargo would not be able to handle impact.


And... Er... Kinda important thing: you'd be shooting something at the Earth.  People live there, for cryin' out loud!