/sci/ - Science & Math

>>5841051
>and would be a warship/convoy guard capable of significant intra-system travel speeds
Build the floors perpendicular to the direction of motion. Done.

>>5841056
This and make sure the velocity of the rotation is correct.

>>5841056
I haven't done the math on that yet, but I know that it will not always be accelerating.

>>5841051
1. Obviously, you would choose the exact rotational speed that gives just the right amount of outward force.
2. What kind of question is that? Yes.
3. The centripetal force is on a local scale just a homogenous force proportional to mass, and thus Gravity for all practical purposes.
4. The coriolis effect might generate a wind that blows rotational-forward at the ceiling and rotational-backward at the floor. Don't know about the severity though, it might be unmeasurable.
5. As per the coriolis effect (you haven't picked up the rotational speed yet as you go down) you will be pushed rotational-backward, adjusting you to the new ambient velocity.

>>5841051

If you know how to calculate the central acceleration at a given point, you're done.
Following Einstein's equivalence principle gravity IS acceleration. No more talk needed.

>>5841070
Barring external friction with spacedust and such, the continued rotation requires no energy upkeep. You could even get a way to change the rotational speed as needed without exerting more than minuscule amounts of energy: A simple method that comes to mind is attaching a heavy rock to the center of the ship via a spring, such that the springs pull and the rocks centripetal force cancel out exactly. (Spring force and rock centripetal are both proportional to distance of the rock from the center of the ship). To speed up the turning, effortlessly "roll" the rock to the middle of the ship, quickening its rotation like when you're spinning on your feet and pull your arms in to get a speed boost. Vice versa for slowdown.

Two other questions:

Let's say that the spinning portion was completely hollow and when it isn't moving, you position yourself a few inches from the 'floor' in the wheel. Would you still be floating just above it after it is spun up?

If the central axis wasn't moving, could electricity be supplied to the spinning portion from the non spinning portion (think: a nuclear reactor in the back of the ship) using a set of copper rings that slide against each other lubricated with a liquid conductor?

>>5841126
I like this idea.

It all depends on getting the objects accelerated in the first place.

>>5841135
Just after it was spun up, you'd be floating above the floor. You'll want to spin the people up with it, obviously.

Also, OP, for your electricity-supplying idea- look up "slip rings." They're used to transfer power and data from rotating objects to non-rotating objects, and they work much like that.

>>5841051

Watch "2001 a Space Odyssey"
Seriously.
It answers many of your questions.

>>5841051
>a warship/convoy guard

That's already not realistic.

>>5841051

OP, please ask more questions, because realistic spaceship design is nearly an obsession for me and I got here after the original questions had all been given satisfactory answers.

>>5842080
>Just after it was spun up
this is correct. After a while though, the air would start circulating with the wheel (friction) creating a force that would push against you like if you'd hold your hand out of the window of a car. This would slow you down and eventually you'd hit the floor like a rocket falling out of orbit.

it would be more realistic to design a viable economic system for earth first

>>5842476
>This would speed you up
fix'd

>>5842495
I meant in relation to the wheel/tube/w/e. Of course you'd go faster from an outside perspective.

>>5842499
I was pretty sure you meant it like that, but I felt clarification was in order.

>>5842492
The status quo economically seems impenetrable. Human greed gets in the way of everything that is good. I should know I am greedy. OP just make an colonizing rover devery system, that is what we need right now, for Moon, Mars and Titan.

>>5842505
Oops i meant Europa not Titan. Sorry for the confusion.

>>5842505
>rover devery
uh...?

>>5842505
>Human greed gets in the way of everything that is good.

For whom?

>>5842521
For people who claim to have an IQ of 150 (according to an online test they did once), but can't figure out why they've spent the last 5 years working at mcdonalds.

>>5842430
>That's already not realistic.
Why not?
Do you really think that conflict will be gone in 100 years?

>>5842454
The next area I was going to tackle was the power supply of the ship.

Does anyone know what kind of nuclear reactor puts out the most kWhrs? (between uranium/plutonium water reactors, salt (thorium) reactors, inertial confinement fusion, and plasma fusion)
or at least have predictions on which would be the most powerful?

>>5842983
87 years*

>>5842983
>Do you really think that conflict will be gone in 100 years?

No. There are lots of reasons why that isn't realistic, but that's not one of them. For one thing, humans will be cargo, not crew. A manned warship is ridiculous. As are "convoy guards." A war in space would take place at the range of light minutes.

Something that puts me off about science fiction is the way ships can travel freely in any direction. No paths are easier than any other, because, apparently, gravity doesn't exist in space! Writers figured out faster-than-light travel, why not this? Consideration of orbits and escape velocities would do much for the realism of any space-borne fiction, not to mention games.

>>5842983
Fusion uses a smaller mass of fuel to generate the same energy, but hydrgoen on its own is a pain to handle so your storage method will probably eliminate your gains in that area. Hydrogen is a lot cheaper than uranium, but fuel costs are a small part of the total cost of a nuclear reactor, and overall I'm inclined to believe that a fission reactor would be a fair amount more robust than a fusion reactor, given the relative difficulty of building one.

>>5843019
I would think that storage if Hydrogen would be easier (you can store it at very high pressures)

>>5843013
Don't sci-fi frequently make use of the "slingshot around that satellite" scenarios?

>>5843019
You can fuel nuclear fusion with only air.
The tricky part in nuclear fusion really just is ignition and containment, not the fuel.

>>5843025
They use the "slingshot" thing in probes nowadays because fuel-efficient rockets (plasma, ion, fusion rockets) that are lighter than chemical rockets haven't been implemented yet.

>>5843013
You need to read yourself some old-school science fiction, bro. Pick up some Heinlein, or most classic hard sci-fi from the era when real SF writers had to do the math and work everything out.

>>5843024
For short periods you can, but hydrogen diffuses thought most metals over time. Fuel rods are easy in comparison, you put the them in the reactor during scheduled maintenance and they stay there until the next maintenance. For coolant, I think lead-bismuth is probably a good idea because it blocks a lot of the radiation, which means you can use less mass on shielding.

>>5843010
"A manned warship is ridiculous."
>what is communications delay across vast distances
>what is people deciding not to make autonomous killing machines

"A war in space would take place at the range of light minutes."
>implying light and/or particle beams will be the only weapons
>implying either would have much effect on a large spacecraft
>implying weapons like railguns and missiles won't be present as well

>>5843049
>hydrogen diffuses thought most metals over time
Would deuterium and tritium still do this?

>>5843052
>what is people deciding not to make autonomous killing machines

That's like someone now deciding to fight a war without using explosives or powered vehicles. Humans are ridiculously hard to keep alive and can't possibly compete with machines. There will be no human warriors in space in 2100.

>>5843062
The atoms are still about the same size, so probably. There's also hydrogen embrittlement to consider, which is a pain in the backside even today.

>>5843070

>>5843083

Nobody is talking about a singularity, dipshit.

>>5841126
Good one.
Of course there is some energy involved; pulling your arms in requires as much energy as is transferred to your faster rotation.
It is still an efficient and convenient way to do it.

>>5843070
Um, machines are stupid.

>>5841051

the main problem you should be worried about is propulsion

>>5843138
Humans are machines made of meat and bone.

>>5843146
Humans are stupid.
Well not really, but I always think it's a bit silly that people think the solution to computers making mistakes is to put a bored, stressed, quite possibly sleep-deprived human behind the controls and hope for the best.

>>5843138

Not as stupid as humans.

>>5843158
No, I agree with you.

One day machines will be at the very least as clever as Humans, if not far more so. Yet they will have very few of our weaknesses, such as the examples you have given.

>>5843146
>>5843158
>>5843187
>>5843176

Would you put a computer in charge of whether to use nuclear weapons or not?

>>5843187
>One day machines will be at the very least as clever as Humans, if not far more so.

That's almost definitely true, but they won't need to be for specific tasks. On passenger airlines, the pilot is already basically unnecessary. By 2020 we'll have self-driving cars that are better drivers than any human. I can't even imagine what we'll have by 2030, let alone 2100.

>>5843218
>they won't need to be for specific tasks
This is precisely why we wont be making robots as intelligent as humans (or at least, not one that thinks and acts like a human) in the next 100 years.

There is a demand for more processing power, but only for certain tasks (like monitoring the entire internet)

>>5843176
Two words: Turing test.

>>5843218
>2020 we'll have self-driving cars that are better drivers than any human
Yes but they won't be widely implemented until 2050 or later.

>>5843241
>Yes but they won't be widely implemented until 2050 or later.

No way. We'll see them way before that. There are some out on the roads already.

>>5843254
How often do people replace their cars?

Will they be economically feasible?

When do you think everyone in China and India will have them?

My point is that just because technology exists doesn't mean that it will be implemented. (see jetpacks, nuclear power)

>>5843146
True, but humans are much better machines than humans can build.

>>5843210

A rogue AI-scenario isn't a pleasant idea, but that doesn't really make the AI stupid, trying to make sure of your own survival, that is.

Ultimately it would be a human error if the AI responsible for weapons of mass destruction would go haywire. Lack in planning or an equipment failure, something like that.

>>5843278
Who said so?

>>5843301
Me. It's obvious.
Our machines are no where as good as the self-repairing, self replicating, auto-adapting wonders that live in a drop of pond water.
We are a long way from replicating even the simplest functions of life.

>>5843328
Not now, but 100 years is a long time where technology is concerned.

>>5843328
That's no proof of your statement
>humans are much better machines than humans can build.

>>5843334
shit dude, 50 years is a long time technology wise.

if we humans could get our shit together and spur another renaissance.

>>5843239
In a decade or two the average human will no longer be able to pass a turing test from sheer inanity.

>>5843352
just gimme my brawndo and violence channel now then.

>>5843010
>>5843146
>>5843239
>>5843278
thread derailed.

>>5841051

read this website

all of it

http://www.projectrho.com/public_html/rocket/index.php

>>5843336
>>5843334

Let me rephrase that more carefully;
Humans have yet to reproduce many functions common to even simple life.
The fact that AIs are so unconvincing in practice, that no one even talks about the Turing test anymore makes me suspect that we are as far from duplicating something comparable to a biological as we are from these simpler functions.
Mind you, I'd love to be wrong.

>>5843375
>http://www.projectrho.com/public_html/rocket/index.php
Holy Shit

Thanks

>>5842983
wtf are those?

>>5843425
>Humans have yet to reproduce many functions common to even simple life.

Ok, but that's quite irrelevant to this topic. What, on a "warship," requires human presence? Especially considering even an extremely conservative estimate of technology advance in the next 90 years? And also considering how difficult it is to keep humans alive in space, compared with unmanned probes, even TODAY?