/sci/ - Science & Math

>>10619797
Related.

>>10619800
Also, ponder THIS.

>>10619797
It's a pressure vessel. The amount of materials you need isn't actually that much in the grand scheme of things. It's much more efficient utilization of mass than a planet.

SIEG ZEON!

>>10619807
Pressure vessel?

>>10619797
https://www.ovalkwiki.com/index.php/Credomar
I'll check out the webcomic.

This thing is going to start tumbling

>>10620593
What does that mean?

probably something spherical so you can have the best surface area to volume ratio

>>10620683
https://www.youtube.com/watch?time_continue=7&v=1n-HMSCDYtM

>>10620711
If you spin it for gravity, you also get a nice gradation from whatever you decide to have at the "equator" to zero at the poles. Bond to be useful things you can do with that.

>>10620753
no, its long axis is its 3rd principle axis, it wont tumble

>>10620817
it will, very slowly, attempt to start tumbling end over end in order to lose it's energy somehow while preserving angular momentum
they, of course, have dedicated much power to actively stabilizing it

>>10620867
Or you could just not be retarded and have two counterrotating cylinders

>>10620895
>not be retarded
the whole thing's a big fictional gun barrel that works on handwavium, it's much too late to not be retarded

>>10619797
>especially if transporting things from Earth into space is still expensive
No no no. You don't make a giant space station with ground based resources.
You send up a couple of fabrication facilities that can make more fabrication facilities and start grinding up asteroids until you've got a space-station.

>>10620895
I like the idea of an o'neill cylinder with bernal sphere's on both ends spinning in the opposite direction.
You could keep the same center axis for everything. The bernal sphere is also nice because the farther up the walls you go, the less effective gravity you feel, so rock-rats from the belt or mars or the moon can acclimatize to normal g.

This is a great webcomic.
I make a great job showing covering a lot of cheesy science fiction tropes in a serious why, like why most of your Star Trek level magical technology can be used as weapon of self-replicating genocide.

Especially for Cremodar, btw.
But I'll keep the spoiler away

>>10623125
>ever forgetting The Kzinti Lesson
A reaction drive's efficiency as a weapon is in direct proportion to its efficiency as a drive.
The point was starfleet were paragons of virtue who had access to those kinds of things, but chose not to pursue them as they're weapons of genocide.
Plenty of grey and black markets in the galaxy where you can get metaphasic biogenic weapons.

>>10620683
Banning porn.

>>10623384
>A reaction drive's efficiency as a weapon is in direct proportion to its efficiency as a drive.
I've never understood that claim. Unless your target is at point-blank range, a weapon needs to be focused. But most propulsion jets have a fairly wide arc, because narrowing the exhaust provides little benefit.

>>10623469
i think the point was more in comparing completely different technologies, not comparing within one particular technology. in the story the humans are basically jetting around on a UV-laser torchship.

>>10623384
Preaching to the choir here, but Star Trek didn't make good point that you needed such paragons of virtue precisely because those tech are ridiculously dangerous. There were just here to justify the plot. Teleportation itself was just a ways to save money.

Schlock Mercenary is literally built as a Reverse-ST, our "peaceful explorer" became mercenary, their starfleet is ridiculously corrupt and those techs are used as weapons anytime they can be. But as a result the plot is built precisely around those tech and extremely regulated.

>>10623469
The original claim started by using LASER-powered photon-sail which are functionally no different from laser weapon.
http://www.larryniven.net/kzin/worlds.shtml

Now, this still work the same for most speculative spaceship propulsion, narrowing the exhaust does provide benefit: The more you send in an exact direction the less kinetic energy you lose. The effectiveness is just a ratio between the mass added to focus and the propellant lost due to spread.

The point isn't that they make the best weapon, it's that they can be used as one and kill people who forgot that an unregulated transport spaceship is one captain away from being a weapon.

>>10623515
No that's not a comparison. It's that something don't have to look like a weapon for you to be deadly.

>>10623528
>No that's not a comparison. It's that something don't have to look like a weapon for you to be deadly.
that was the point of the story but I meant the paraphrase about efficiency

>>10623530
Same thing, to rephrase it: the point is that when you channel incredible amount of energy for a peaceful usage it can also be channeled in a very destructive way.

>>10623572
yeah, and if you're just comparing two different types of chemical rockets, that's not the same thing as comparing a chemical rocket to some bomb-pumped solar sail monstrosity

>>10623581
Chemical rocket are still directly efficient as a weapon, it's just outdated now.
Your analogy don't cover the Kzinti lesson unless you assume the chemical rocket is (or make them plural) equally as energetic as the bomb-pumped laser.

>>10620867
No. The principal axis has the lower moment of inertia.

>>10623528
Nice picture.

>>10619845
a vessel that holds pressure. Like a gas cylinder

>>10623572
A car can also be used as a deadly weapon, but all things considered, I'd rather have a gun.

>>10625161
How is that relevant to the thread topic again?

>>10623663
i don't think you're reading what I'm saying. i'm saying the chemical rocket ISN'T as powerful as the laser, and that's why the chemical rocket is less effective as a weapon than the big laser drive. any one rocket might be more or less efficient as a rocket and more or less efficient as a weapon, but that's just noise when you consider the efficiency as a weapon and a drive of that relative to a laser drive.

>>10626645
On my side I think you are still missing the point. Of course the laser discussed here was vastly higher in tech to the chemical rocket.

Let's start from scratch:
>A reaction drive's efficiency as a weapon is in direct proportion to its efficiency as a drive.
>direct proportion
(in a typical space setting) the chemical rocket drive is not extraordinary as a drive, so it's not extraordinary as a make-shift weapon either. But the point is that it can still be used as such and NO not just "vaporizing target with the exhaust", using it as a kamikaze missile still count.

Now a laser have a lower limit bellow which it's simply not useful as a drive at all. But if you reach a powerlevel where it become efficient as a drive, it's efficiency as a weapon increase as much.

Same goes for Fusion drive rocket. It's more powerful than chemical rocket but that's not the point. The point is that's efficiency as a makeshift weapon rose in direct proportion, and yes that include both vaporizing target or using it to push asteroid toward a target. It's only feasible because its efficiency as a drive allowed that same, greater efficiency as a weapon.

>>10626690
I don't understand how you can say i'm missing the point when we've been saying the exact same thing this whole goddamn thread. there is no difference between what we're saying.

>>10626705
>>10626690
>The point is that's efficiency as a makeshift weapon rose in direct proportion, and yes that include both vaporizing target or using it to push asteroid toward a target. It's only feasible because its efficiency as a drive allowed that same, greater efficiency as a weapon.
this is just a paraphrase of what I said in >>10623515 ! if you look at one technology that isn't very efficient as a thruster, it's not going to be very efficient as a weapon. if you increase its efficiency as a thruster, you increase its efficiency as a weapon.

>>10619797
most efficient design would be something like picture related

a fat short cylinder, because long cylinders are an inherently unstable shape during rotation

https://settlement.arc.nasa.gov/Kalpana/KalpanaOne.html

>>10626705
If >>10626712 isn't a better rewording for you, I propose we accept that further discussion on our nuance is meaningless and we go back to discussing Space Habitat Design.

While I love the concept of gigantic single area colony like Kalpana >>10626721 or O'neill colony, I think for a start we will want extreme modularity at the cost of all comfort so a critical failure somewhere (or a terrorist building a cheap bomb insitu, just in cane) can do less damage.
https://space.nss.org/settlement/nasa/Contest/Results/2009/ASTEN.pdf

How would flight in a massive oneill cylinder work? Weather?

>>10627150
Watch the beginning of "Gundam Unicorn" you'll have a nice demonstration of the physics inside.
https://youtu.be/Ob50GiXssQI?t=1142

To keep it short it will depend both of how close you are from the center and if you are trying to follow the rotation or not.
If you don't try to follow the rotation you should have a constant lateral wind but be otherwise floating without needing aerodynamic lift. You will keep floating like that even if you get close to the ground but the ground itself will be rotating very fast (for centripetal force) and you may risk a collision.
If you do try to follow the rotation of the colony however, the closer you'll get to the ground the more you'll need aerodynamic lift to keep flying. Near the center however you'll be floating.

For the weather I don't know.
I remember reading that there's enough room in a 3km wide colony for cloud to form

>>10627081
it's not about it being a rewording or not. it's about me saying basically the same thing as you and you saying "nah you don't understand it." this isn't some pissing contest to come up with the best expression of the concept, we were just two people who happened to reply to the same original question.

>>10627150
>How would flight in a massive oneill cylinder work?
You can do it, youd just want to raise up towards the axis (there you'd feel free fall) and have your runways going at an angle since the ground is moving under your feet.
Really though you should have a good mass transit system built into your habitat, something like rail that travels the length of your habitat where people can just walk the remaining distance.
Weather depends on more factors, like how big your colony is, and how much moisture do you have in the air at any one time.
There are some big stadiums, and buildings that exist right now that are big enough for clouds to form inside. It wouldn't be a bad idea to have plenty of green spaces and open water on your colony so you can have an oxygen and water cycle that's at least partially self regulating.
Thanks to how the colony is rotating, if you did have storms they wouldn't have cyclonic motion like we'd see here on earth, they would be turned on their sides because of the difference in the rotation between the surface of a convex sphere and a concave cylinder.
If you really want to paint a picture in your mind of how a giant rotating habitat would look and feel, read the book Eon by Greg Bear. The book is kind of meh, but where it really shines is that half the book is just exposition dumps and scenery porn about all the minutia of the cities in Thistledown.

>>10626555
Space colonies are spinning pressure vessels! Many of the same design principles which apply to gas cylinders apply to space colonies. There are actually some space colony designs which are short stubby cylinders with inward facing end caps, just like aluminum cans. Both are pressure vessels.

>>10623397
Ba-dum-tss.

>>10626721
The most efficient design is a fractalised matrioshka spheroid.

>>10629159
If we are talking of digital mind like >>10623125 I agree

>>10629750
What if you want to have at least SOME of the populace stay organic?

>>10631517
Then I'll challenge your definition of "stay" and "organic".

In the linked webcomic the population have physically distinguishable brain-node they can switch to and back-up is done faster than you can say "interruption of consciousness".
Those node-body would obviously be self-repairing and evolving just like an organic body would, except better, of you need to do anything physical you'd simply remote control your body or transfer yourself in one artificial body.

There's no point settling for an inferior form of organic body if you can have a superior one.

>>10629750
How to maintain consciousness through the upload...

>>10633745
How to maintain consciousness through sleep.
You can’t. If you think “uploading” would somehow “kill” you, you should acknowledge you get “killed” every time you sleep.

>>10633761

>>10633830
No argument seen. Hidden. Try again. :-)

>>10633761
the brain doesn't lose consciousness while you sleep so you maintain continuity

>>10633915
.......Yes it does. Sleep is literally defined as a state of unconsciousness.

>>10633745
Try defining what is consciousness in the first place.
I'm not convinced you aren't just biological automaton faking sapience while I'm the only sentient entity.

>>10633933
Thanks for that

>>10636315
I can't sleep now, thanks.