/sci/ - Science & Math

Basically, if we assume that the ships doesn't have some meme antigravity generator or some shit, something like pic related is impossible

or

https://www.youtube.com/watch?v=UrSiT1sAWgo

no reason for a realistic spaceship to enter an atmosphere. and since there's no need for aerodynamics in a vacuum, the spaceship's appearance corresponds to the function of its components.

>>9672520
But if we look at the most common sci to designs, like in the OP pic, how would that shift move up/down in space? I understand that different power to different thrusters would yield turning left/right, but how would one go up/down with that design?

>>9672514

>space opera "boats in space" shit

Try this:
>build interstellar probe from the atomic level on up, via nanotechnology
>this ship is composed of machine "cells", designed to both compute and "digest" matter to create copies of itself, like hot-rodded brain cells, but infinitely tougher, more flexible and smaller than living cells
>they can also create other types of machine "cells", and even organic cells
>interstellar probe is only a few grams in mass
>use enormous EM accelerator to launch it at nearby star (or stars)
>leaves solar system at an appreciable percentage of light speed
>sacrifices part of its mass to decelerate (again, in the grams, due to its tiny size)
>upon reaching nearby star, first mission is to build a transmitter from a captured asteroid or comet it "eats" and establish data link to "home"
>then build more duplicates of itself to launch at more stars (a la Von Neumann)
>it will never be necessary to send more than one successful probe...all it needs to "build" another civilization around the target star (whether its biological, or more likely, virtual...this would likely be a Matrioshka Brain) is information from the data link to "home"
>galaxy and universe eventually enveloped by this machine "organism", either at light speed, or something faster, it that's at all possible
>this is, of course, unless the AI uncovers the truth about base reality and learns how to create universes on its own, negating the need to expand indefinitely into our universe, in favor of building one of its (our) own

Should be possible in ~100 years, definitely 1000.

>>9672553
Something that small would be shredded by space debris and dust.

>>9672523
Why would you move up or down in space is everything else is either in front or behind you?

>>9672571
But it's not. Space is a 4d plane or some shit. There is no proper up or down, but you still have to move up and down.

>>9672514
They literally use magic antigravity drives in Star Wars, Halo, etc.

Check out The Expanse, ships in that series have super efficient engines that can provide constant thrust the entire trip, but are otherwise quite realistic.

https://www.youtube.com/watch?v=6yKn_EqA0ik

Well first you have to decide on a plausible Isp, thrust, thrust to weight, and size of your fictional fusion engine.

I think you'd be looking at a cylindrical ship, because wasted mass will never be a thing.
Engines mounted on the side, able to gymbal around for control.
With a good amount of radiators around your large fusion engines.

Do large cruise ships have small boats to carry crew? No that sucks and is wasteful. Instead they just dock where they are able.
So these fancy ships would only land on low grav worlds, such as the large moons, Mercury, Ceres, Pluto, etc

Perfectly aerodynamic will not be necessary, however you still will build ships that maximize internal size for materials used.

>>9672582
>ships have literally infinity delta-v
>even shitty smugglers can afford these engines that could destroy whole worlds
>plot based around shipping water around the solar system

It's ridiculous

>>9672596
>ships have literally infinity delta-v
Not infinite, just really efficient
>even shitty smugglers can afford these engines that could destroy whole worlds
They're shown to be expensive and difficult to acquire, mostly owned by big corporations
Also the military is shown to be more than capable of intercepting any civilian class ships
>plot based around shipping water around the solar system
That's part of it but not the main focus of the plot

It's not super hard scifi, but it does a pretty good job of being realistic, especially in regards to the way the ships maneuver.

>>9672523
they'd move the same as they do it right now. with an RCS. Basically little rockets that are placed in strategic places that allow the ship some translation and rotation.

>>9672608
>Not infinite, just really efficient
Why not just call it antimatter engines and be done with it? Its the only "reaction mass" that has high enough energy density for the fuel to fit into ships.

>>9672593
I'm a retard. what is an lsp?

>>9672618
I know of this, but you would need massive ones to make "elevation" changes quickly in space, no? They would essentially have to be rockets by this point to be able to move a super massive battleship or transport, no?

>>9672638
>I'm a retard. what is an lsp?
Specific impulse. It's basically the efficiency of the engine, the higher the better.

>>9672638
Yes, the more massive the vehicle the larger RCS thrusters you would need to move it at the same speed.

>>9672648
> the higher the better.

This is of course, not true
There is a trade off between thrust and Isp
Isp increases linearly with exhaust velocity(aka its essentially the same thing), however kinetic energy increases with the square of velocity.

And, of course, you would need RCS thrusters to potentially counteract an overextension. It seems like the most viable spacecraft would be a mess of RCN thrusters on a long chassis attached to a pair of rotary, main thrusters. Also, it seems, if the ship is meant for warfare, one would have to have RCN thrusters to counteract weapons discharge (if you use traditional weaponry). God damn, space ships are a logistical nightmare and we've only just scratched the surface

>>9672520

>no reason for a realistic spaceship to enter an atmosphere

Wrong, aerobraking provides great benefits in terms of reducing delta-v needed for the trip. Any realistic spaceship will most likely be aerodynamic.

Picture shows how a realistic interplanetary spaceship design looks like.

>>9672570

no it wont, space is emptier than you think

however it better be very radiation resistant, because something that small has no radiation shielding

>most logical spaceship design
>Star Wars, Halo, or Mass Effect
just no
go play some children of a dead earth then come back

If your flight takes longer than a year (like going beyond Mars), then the ship needs to spin for artificial gravity and also needs at least several meters of radiation shielding against galactic cosmic rays around the habitat portion.

>>9672514

They really should be designed such that the engines are under you rather than behind you. That way you get a nice artificial gravity pulling you down when the ship accelerates instead of being pulled to the back wall.

>>9672659
>There is a trade off between thrust and Isp
No there isn't, not intrinsically. Higher specific impulse always means that you have more capacity to change your velocity for a given fuel mass. The engineering downside is that no one has a high specific impulse engine that actually produces a lot of thrust.

>>9672718
...with the caveat of Hydrolox engines, but hydrogen and liquid oxygen storage in space for extended periods of time is a huge pain in the ass.

>>9672706
I don't think you ever see it in-game, but the lore in Mass Effect describes human military ships too big for atmospheric flight as having internal floor structures more like skyscrapers than boats, whereas smaller ones like the Normandy expected to be landing innagravity have a more traditional layout.

>>9672706
Yeah, that's how they're mostly built in The Expanse. Most freighters and transports are set to run 1 g of acceleration while cruising, but there's military ones capable of running something stupid like 20 gs, which is really taxing on the crew.

>>9672721

I would not call hydrolox a high isp engine, it is still in the same ballpark as kerolox and methane

ion thrusters on the other hand..

>>9672721
>>9672718
kinetic energy is the square of the velocity
On any engine you can make a tradeoff between Isp and thrust, it will be most especially relevant on the very high Isp engines like electric/fission/fusion engines.

>>9672755
>kinetic energy is the square of the velocity
>On any engine you can make a tradeoff between Isp and thrust, it will be most especially relevant on the very high Isp engines like electric/fission/fusion engines.

The fuel volume and fuel mass is a much more important constraint than the amount of energy spent accelerating that mass. It frankly isn't a limiting factor, by comparison.

>>9672858
time is a far more important resource than fuel.
Also if you are taking off from a gravity well, you need a certain thrust to weight to escape it.

>>9672875
There are very good reasons to choose a propulsion system other than the most efficient, and time and raw thrust are among the most important. High specific impulse itself is not the limiting factor, rather, it's our available means of attaining it.

>>9672514
RULE 1: Spaceships should not have an "up-down" line at right angles to the direction of thrust! Star Wars, Star Trek, and most videogames and movies violate this rule. They all look like WW2 battleships with jets tacked on. And small "fighters" look like WW2 airplanes.

They all require magic "gravity generators" under the floor, "acceleration compensators" so everyone isn't pinned to the rear bulkheads, and most craft would spin like pinwheels when the engines fired. They ought to be reasonably symmetrical around the thrust-axis with decks at right angles to the line-of-drive.

If rockets, there ought to be fuel tanks showing. Engines are heavy. You don't need them pointing in all directions so you can weave and jink. You orient the whole ship with reaction-control thrusters (plenty of time) and then fire the main engines.

The "Camden Lock" was designed as a joke. It's essentially a famous telecommunications tower thrown into space. Nonetheless, it's saner than 99% of fictional spacecraft.

>>9672517 >>9672514
>meme antigravity generator

tfw no meme antigravity generator

meme antigravity generator when?

>>9672955
There ARE exceptions to the rule.
Here's a design which assumed some sort of efficient nuclear-electric converter. Power without insanely large radiator fins. Ion engines exert only milligees but can maintain that for weeks on end.
Ship spins around the axis of thrust for centrifugal "gravity". You want a large radius of gyration so the spin rate can be low and you avoid Coriolis effects. Rather than a ring habitat, they put the life-system out on one end of a truss, counterbalanced it with the powerplant (see the radiators at the far end?) and set the engines in the middle. Drive is at right angles to the spin-grav but is too small to "tilt" the floors noticeably.

If one of those aneutronic fusion charged-particle-to-electricity schemes ever pans out, this would work.
A ship like this could, of course, never enter an atmosphere or "land" on anything more massive than a large asteroid.

Bonus question; when we hopefully invent ftl drive how do we make sure the pilots can keep social relations when affected by time distortion?
Making some kind of relativistic shield?

>>9672958
Probably never. Equivalently, about the same time as the FTL drive.

>>9672972
That only matters when reaching insane velocities, which is not how any realistic FTL method would work anyways.

>>9672972
"Social relations" with the people back on Earth?
If you can make interstellar round-trips in days or weeks, there is no problem. Time dilation doesn't apply.

If you DON'T have FTL and "merely" travel at a good fraction of lightspeed, still no problem. Once telescopes and robot probes find a likely colony planet, you go and don't come back. Interstellar flight (barring the sudden overthrow of all physics) will be EXPENSIVE You have no "social relations" with the homebodies.

>>9672972
first people to leave on an FTL ship would fucking blow the planet up so the non-whites couldn't follow em
t bh

>>9672984
>implying they would be white

>>9672970

good realistic design, where are the propellant tanks tough?

>>9672993
It's using an ion drive. You apparently don't need big fuel tanks when using it.

>>9672596
Wouldnt warp gates be a better way to transport stuff. Imagine a warp gate is built orbiting Mars from too far for space dust to fuck it up. Well you no longer have to deal with moving through the interplanetary medium you get to Mars much much faster. Now imagine is a warp gate was built on an extrasolar planet then the travel is instant.

>>9673705
You've been watching Cowboy Bebop, haven't you?

A) This thread is about logical SPACESHIP designs.
B) No one knows how to build a warp gate -- assuming they're possible at all.

>>9672629
TLDR bc the number of people in their audience who are informed enough that the displayed technology breaks suspension of belief is so small it doesnt matter. The show has stealth ships despite that being utterly impossible but to realize that requires some knowledge and applied critical thought.

>>9674150
>stealth is impossible

this friggin meme again

>implying reactionless thrusters don't exist

>>9672578
not really, the galaxy is basically a plane. We've got what, maybe 50 galaxies within our reach even if we left at light speed now. That's all we're gravitational bounds to

>>9674161

>>9674150
If you had to guess, what's the smallest feature you can see on the Moon without a telescope, just using your eyes (assuming 20/20 vision)?

>>9672672
The BFR can't manuveur around like OP says.

>>9672514
A very large scale version of the venture star should do what you are asking for.

>>9672514

>>9672672
Aerobraking is only effective for extremely low-energy destinations.

>>9674358
Real men use lithobraking.

>>9672517
No implausible shit in SW is a problem because THE FORCE DID IT!!!!!

>>9674450
Scientifically chuckling.

Anyway, I always liked pic related, though that long boom seems asking for trouble, if there may be reasons relating to radiation and heat and shit why t s unavoidable.

>>9674506
Forgive missing letters, keyboard is dying, I'll try and proof better. Also, pic related was a nice shuttle from LEO to lunar surface.

>>9674275
"20/20" vision means you can make out stuff on the eye chart 1 arc-minute across. At the Moon's distance, that's about 70 miles.
Actual resolution will depend on contrast, whether there are extended shadows, etc.

>>9672514
It is all magic hand-waving technology. They don't have t o explain shit.

>>9674506
Presumably, the engines were dangerously radioactive. Clarke liked dumbbell-shaped designs.

Here's what Discovery was SUPPOSED to look like. Reaction mass tanks and radiator fins. Kubrick removed them rather than having audiences asking "why does it have wings?"

>>9674540
Another concept that was dropped.
I think this was supposed to have Orion drive.
Kubrick killed that because the idea of the ship putt-putting along on a series of nuclear blasts was too reminiscent of "Dr Strangelove".

>>9674530
You mathed it out, but yeah, resolving anything with a Mark 1 eyeball is a bit of a task. Instruments can do the job much better, but even world class telescopes will have limited resolution for a given distance. An object in space will be detected fairly easily, but it will not be resolved. You'll know its approximate direction, but you'll have difficulty gauging distance and specific position. Trying to throw something at it on an intercept course will be difficult because of the great distances involved and the limits of precision.

>>9674546
Here's the Leonov from "2010".
In that case, the book came first and then it was turned into a movie.
The book Leonov had not rotating section.
Syd Mead, the visual designer for the movie, added that so there'd be something for the audience to look at during the scenes where we see the ships floating near each other.

The concept got swiped by Babylon 5.

>>9674558
And here is the Leonov as it (probably) was in the book -- pieced together from such descriptions as Clarke gave, plus input from an expert on Soviet engineering design practices.

The picture is a 3-D CGI model, by the same artist who did >>9672970

>>9674265
>produces massive butthurt reaction

>>9672514
>ctrl+f
>PhojectRho
>Zero Results.

Come on, /sci/, try to keep up.

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

"Atomic Rockets", the premier realistic spaceship design compendium.

Pretty much everything you would ever want to know about spaceships and space travel.

From "Atomic Rocket Engines", to "Zero-G toilets"

>>9672514
For combat, Battletech Dropships are hard to beat for realism, assuming fusion drives.
For trade, space ships will be trusses with engines and stuff docked to them.

>>9674275
Before reading the guy who googled, I would have said maybe ten miles. Not TOO far wrong.

>>9674540
Black fins also might have created problems for the FX guys, on a black bg, and might have confuse the audience as to why you could sometimes see them and sometimes not. When that happened with the Slab floating in space, it was OK since it was SUPPOSED to be mysterious.

>>9674546
That's also why he did not use a scene t the end, where the Star Child detonated all the orbital nuclear weapons at Earth.

They kept the idea of shots of the orbiting bombs earlier in the film, but there was no real way to know the models were built to be bombs, they just look like satellites...

>>9674540
>>9674546
>>9674564

Thanks, I'd not seen these.

>>9672672
>BFS
I wonder if the military will ever get their own version of this. Maybe something along the lines of the DC-3. There were so many military variants of that aircraft, and they remained in widespread use for decades. https://en.wikipedia.org/wiki/Douglas_C-47_Skytrain

>>9672973
FTL miiiiiiiiiiiiiiiight be possible, in fact, there's a weird astronomy professor who thinks he has it cracked. He's probably a nut but i like following his work. He's presenting at the AIAA in july so we'll see how that goes

He's on facebook at SWarpDynamics

The "I can't remember if it had a name" ship from the short-lived series "Quark." The ship and crew roved around the galaxy collecting the bags of garbage dropped off by other ships who were busy having better adventures. Front view. The Internet is distressingly bereft of higher resolution images

>>9674699
Side view.

Crew included Ficus the plant man who taught alien women to pollinate, Gee/Jean with a randomly variable gender, and Otto Bob Palindrome.

>>9674540
Wouldn't you want radiator fins to be white so they absorb less light?

>>9674711
Maybe less of an issue where Discovery was going. But black-body radiation works everywhere.

They're not totally realistic but I really like Iron Sky's ship designs

>>9674720

>>9674722

>>9674726

>>9674711
Radiator fins are to get RID of heat.
No thermal cycle can turn 100% of the input heat into useful energy. The remainder has to be dumped somewhere and radiation is the only way to do that in a vacuum.

Black absorbs energy which falls on it -- but it's also best at emitting it. You just try to keep the radiators edge on to the Sun whenever possible.

This design is mainly radiator. It spins to generate centrifugal gravity for the crew and also to improve heat transfer in the radial tubing in the "parasol".
The reactor is at the bottom of the "handle" and the ion drive at mid-point, next to the landing craft.

>>9672523
thrust vectoring

>>9674738
If black is a better heat emitter, why does the ISS have white radiator panels?

>>9674155
Pitch me your idea for a successful stealth space ship.
>>9674275
How is this relevant to the creation of a function stealth system on a space ship? To clarify simply being in the sector of space people arent looking isnt valid.

>>9674491
Serious tho, that went from an esoteric almost religious concept to being on the tips of everybody's tongues overnight for no apparent reason.

>>9674275
Tycho crater.

>>9672571
If it's a spaceship that never enters the atmosphere it's probably gonna change it's course at some point, rather than listlessly drift thru space forever. Also what about maneuvering around space junk

>>9674759
I thought about that, then Googled for an answer.
They don't look very white in the image.

>>9674598
The jump ship concept is also very good. Dropships are interplanetary at most. Jumpships never land and often never enter more than solar orbits. Usually they stay at the solar zenith or nadar node and wait for the next jump.

>>9674759
Heat conductivity is important.

>>9674776
You can go any direction you like. Spacecraft have tiny reaction control thrusters which can re-orient them. Without air, doesn't matter if you fly "sideways". Then you use the main engines to change your vector.

Arthur C Clarke did a story about that once. Space cruiser trying to locate a spacesuited man hiding on Phobos. Ships are long cigar shapes with a huge moment-of-inertia. Takes 15 or 20 minutes to roll 90 degrees. Normally doesn't matter. Maneuvers are planned long in advance. But the man could walk around Phobos (and stay out of the ship's line-of-sight) much faster than the cruiser could circumnavigate the tiny moonlet.

>>9674767
Skin temperature, cabin temperature, radiator temperature and reactor temperature can all be different, the reactor might be 9000K but that doesn't mean a 9000K blackbody spectrum on the radiator.

Exhaust plumes cool very fast and do not persist. Redshift analysis is also imprecise. Realistic detection methods give first order of magnitude measurements. They don't give exact answers.

>>9672689
Once the spin is started, there's nothing to stop it, is there?

Possible brsinlet question, but forgive me I'm a few drinks in

>>9674790
Fair point, but wouldn't it be easier to match an orbital speed and thrust upward a few thousand feet to meet the dock rather than have to orbit again to match the height the 2nd time around? I think if we've mastered traveling across the galaxy we can have the luxury of thrusting the final manuever in any direction

>>9674777
They are clearly white, you just picked a bad image

https://www.nasa.gov/mission_pages/station/structure/elements/radiators.html

They use Z-93 white paint (https://www.nasa.gov/pdf/473486main_iss_atcs_overview.pdf page 15)

study exploring various paints and materials here https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19990021250.pdf

Are there any good forums that discusses existing military space? Things like military satellites, X-37b, signal jamming, even the US "Space Force" concept that is being pushed.

>>9674759
If they're heat dispersion fins, maybe they treated the white side to the sun and black side to space?

>>9674799
You despin the same method you used to spin. 2001's Discovery had an internal centrifuge. Not shown was a probable counterweight or RCS to counter spin up or down.

>>9674818
get ready for 2 digit iq members

>>9674767
If FTL then Picard maneuver because you arrive before your light.

For piracy do it the Somali way. Target an unarmed cargo ship, commedeer and demand randsom. There is no way Star Patrol can protect all cargo ships. Electronics can be hacked or bypassed and replaced.

>>9674823
According to google they have a special paint on them that's white in the visible spectrum and black in the infrared spectrum.

Dude, the last three replies were all me. I’m so totally high bro haha.

>>9674776
Get children of a dead earth. Your minimum needs for full control is two gimbaled engines on the end. You can get away with one engine if you don't need roll control.

Generally you can have fewer, larger, higher thrust and ISP efficient engines rather than having a bunch of shitty micro engines everywhere that have garbage efficiency and just waste your reaction mass.

>>9674588
your post has the least amount of thought in the entire thread. That website lacks rigor outside of basic equations.

It's just gotta be the Apollo Lunar Module - just a beautiful piece of machinery that is also extremely strong and functional. You cannot beat it.

>>9674809
Wouldn't "orbit again". If you're closing in on the ISS you've already matched the "horizontal" velocity very well.
Orbital mechanics in a gravity well is tricky. Sometimes you have to do counter-intuitive things.
But once you get within a hundred meters or so, things become familiar again. The RCS thrusters can move you an any direction. They're just not practical for major delta-vee.

>>9674833
Discovery had no counterweight. In "2010", the centrifuge had run down in the years since Bowman abandoned the ship and the whole thing tumbled end-over-end as the angular momentum was shared.

Actually, that makes no sense. What was the orientation of the carousel? The shaft had to be parallel to the ship's long axis; Otherwise it'd be visible in >>9674506's image, through the control deck's window or in the pod bay.
It would leave the ship turning like a barbeque spit, not tumbling. But that would have lacked drama and made Curnow's job too easy. :)

The spin rate was also ridiculous in the movie. Discovery had a huge moment of inertia and would have turned quite slowly if it really was end-over-end. I asked Arthur about that once. He admitted I was right and he hadn't thought to check while writing "2010".
Furthermore, the movie hadn't made a profit (according to MGM's devious "Hollywood accounting") so there was no point asking them to reshoot the scene.

>>9675469
the presence or absence of a counterweight on the Discovery would be pretty subtle and with a proper counterweight and 0 net angular momentum it wouldn't have any effect on discovery's rotation. Without a counterweight Discovery would experience gyroscopic precession while maneuvering, which is a little annoying but it is something that can be predicted and compensated for. In the end it doesn't really matter because lots of things could cause end-over-end rotation, the obvious being a propellent leak, decompression, or stuck thruster. Heck even gravitational perturbations from Jupiter's(or Saturn's depending on book/movie) moons could eventually do it.

If Discovery was in LEO it might stablize into a "vertical" orientation due to the uneven gravitational attraction at each end. It is fiction and there are lots of real world stuff that could go wrong in a derelict spacecraft with no computer or crew to manage attitude.

>I asked Arthur about that once
You're quoting someone else?

>>9675502
No, that was me. I met him a few times and still have his letter re the tumble. It's in shaky handwriting on the back of his standard "Thank you, but I no longer travel or make appearances at conventions" form letter. He was suffering neurological problems.

Your suggestions are ingenious (except for the ones about perturbations from nearby moons.) However, the book specifically states that the tumble was caused by the carousel running down -- and ceased when it was restarted.

In early SF (including Clarke's own books) ships were turned by reaction wheels. Thrusters used fuel and their effect was permanent. Reality turned out differently. Hubble and Kepler use reaction wheels (and are in deep s*** when one fails) but they're the exception. Telescopes need fine control and they need it continuously. When you go weeks between corrections, thrusters have proven to be the way to go.

Consider the countermass Discovery would need. It would be much smaller than the centrifuge itself, so would have to turn at VERY high speed and be reasonably massive -- something designers hate!

Leonov had no countermass -- though I admitted earlier that its rotating section was a movie add-on, for visual interest and to avoid having to fake weightlessness any oftener than necessary.

>>9675447
Good design, yes! "Strong", no. It was essentially a tin foil cockleshell and the astronauts had to be careful not to accidentally damage it.

>>9675524
Two counter-rotating habitats could also work, aside from the complexity and efficiency of scale disadvantages. In regards to reaction wheels, they work, but over long periods of time you can get angular momentum buildup and end up with your wheel running at maximum speed just to hold a steady attitude.

That's great that you had corrispondence with Clarke. He's got lots of interesting books, I like the one where they intercept an Earth-threatening asteroid and the popular hairstyle is a shaved head so people can wear their brain-scanning VR headsets.

>>9675534
Counter-rotating habitats would work -- but can you imagine the pain it would be to go between them?
You need a little cabin that can spin and de-spin (like when Dr Floyd arrives at the orbiting hotel) AND doesn't lose any air when it couples and de-couples from each wheel.

>>9672582
>Constant deceleration
>Video clip shows it's some nasty gees after flip.
What they should experence is ~1g when engines on. Then 0g when engines off. Then delicate carousel when flip. Then ~1g when engines on.
Fuck off with your gay movie. Watch 2001

>>9675575
?
Why would you deliberately accelerate slower than you are capable of unless there is some sort of other reason?

Just makes the whole trip take longer

Also anyone talking about "accelerate constantly at 1g+" has been watching too much sci-fi

>>9675556
Discovery has internal centrifuges, there are no rotating seals because the space beween the outside of the centrifuge and the inside of the non-rotating hull can be pressurizzed. For two counter-rotating internal centrifuges you either have two of those cylindrical interior spaces or put them next to each other. You'd need to go to the center, non rotating part of the ship to enter the other centrifuge.

It isn't like the centrifuges need to spin very fast if you're only going for moon gravity at Discovery's size. Plus if you run on the track you can exceed earth's gravity during your excercise.

As for depressurization and airlock location. You put an airlock at the entry-exit to the centrifuge area and on the rotating centrifuges themselves. You'd also want to plan for how you're getting an astronaut or repair drone to the interior of the pressurized hull (outside the centrifuge.)

I drew a picture, talking about the yellow volume. It could be wasted space or you could partially fill it with supplies.

My brain just anyeurism'd wondering why Discovery had a crew of 2 but had 3 pods. Turns out the crew is 5, but the other 3 were in cryosleep.

>>9675595
>accelerate slower than you are capable
Space ships are capable, humans not so much.
>unless there is some sort of other reason
Simulation of natural human habitat. Too much or too little gravity for too long ain't good for ya.

>Also anyone talking about "accelerate constantly at 1g+" has been watching too much sci-fi
Anything past Venus or Mars that is crewed is too much sci-fi. Humans are redundand and the weakest part. Should be easier to create AI or upload consciousness than sending a living human to Enceladus. Unless you can freeze them, but then - why even bother?

>>9675648
>we should never send humans anywhere because it is inefficent
you have the dumbs, the human cargo is the most important part of the ship because AI and drones simply aren't versitile when you try to do more than just take pictures from 100,000km away.

>upload consciousness
thanks for telling everyone you're a brainlet.

https://mars.nasa.gov/msl/mission/instruments/

for example here is the science package on Curiosity. Pretty good huh? It actually is pretty good, but what does it do? Take pictures, sense temperature and radiation and the big one is do some drilling and analysis on surface rocks. Look under more than a few inches of dirt? Good fucking luck.

>>9675665
>we should never send humans anywhere because it is inefficent
Now who said that? Oh, it was you.
While I am saying that by the time you'll be able to send humans safely to Enceladus, a terminator will be already there and another one fucking you up the ass for being such a straw man creating cunt.

Also this guy thinks brain is a magic box that can't be copied because magic.

>>9675595
Two reasons not to pull 1 gee continuously. I'm talking real life, not The Expanse.

1) You attain very high velocities at mid-point (which is the whole idea) and then have to lose it again. Earth-to-Jupiter turns over at 2800 km/sec. Even with a "perfect" fusion engine (deuterium-tritium, no losses, not even neutrinos) over 20% of your initial mass is fuel.
2) Space isn't quite empty. A pebble is immensely destructive if you run into it at such speeds. Of course you use radar and swerve if it's in your path. But it takes a few seconds to "sidestep" the width of your ship and in those seconds you move thousands or tens of thousands of km. Confident you can spot every small obstacle at those distances? (Easier after turnover. Anything you're going to hit runs into the exhaust plume first.)

>>9675607
That's my view of Discovery as well. Everything within a pressurized shell. We know the bridge and the pod bay are pressurized (the latter when the doors are closed.)

I was thinking more of the set-up Poul Anderson used in "Starfarers". Two counter-rotating toroids. I've drawn this, based on descriptions.
Coil is ion-thruster. Boom at far end is magnetic shield against interstellar dust. Aft wheel holds the technobabble (though he tried valiantly to make it seem plausible) almost-as-fast-as-light drive.
You can see that going between wheels (say, to inspect the machinery) would be a major operation. That issue never comes up in the book.

>>9675729
>le golden BB of kinetic energy
It just vaporizes into a little plasma explosion onto whatever it hits.
If you use a little bit of planning and a small amount of armor mass you either get a small amount of pitting or just a few small holes to patch. Neither of which are mission ending for any well engineered spacecraft that has damage control proceedures. This is one of the reasons that you keep your internal airlocks closed so only affected sections are temporarily depressurized and crew members know to put on internals or leave the affected area.

>>9675826
At 2800 km/sec a 1" inch cube of steel carries 5.03e11 joules.
That's 120 TONS of TNT!

>It just vaporizes into a little plasma explosion onto whatever it hits.
>If you use a little bit of planning and a small amount of armor mass you either get a small amount of pitting or just a few small holes to patch.

Right.

>>9674768
>no apparent reason.

Welcome to the Star Wars Universe. Have some midichlorians!

t. George Lucas, Poet Laureate of the Universe

>>9674777
Huh. I always assumed those were solar panels. Shows what I know.

>>9675749
rotating seals and connections are a pain. They certainly aren't impossible. In your example I'd have a structural cylider through the center which is continous and airlocks before and after each rotating ring.

It means a 360 degree cutout in the hull, but if you have a thicker spine and internal structure on the spine then it just means a two ring seals both forward and aft of each centrifuge crew connection. As well as another set of ring seals for each fluid duct between the spine and centrifuge. Maintence is guaranteed to be fucking annoying and probably involves stopping the centrifuge and then disassembly of the spine's skin on the inside of the rotating seal, then removal and replacement of the seal as you access the connections between the centrifuge and spine. Sounds like you'd want to minimize the piping and electrical connections in and out of the ring.

The other way is you have a rotating elbow connection on the center of the spine that rotates with the habitat. So that's another set of rotating seals inside the spine, but you avoid a much larger rotating seal if it was the outside of the spine. know what, I'll go for that and label it in blue. So now we have 2 big rotating seals connecting the exterior of the spine to the interior of the centrifuge and lots of smaller rotating seals around the center of the spine that are your power/water/air umbilicals. The smaller rotating seals can't be too small because that is the only solid structure that connects the ship before and after the centrifuges. For this reason I encourage some kind of external truss and cabling exerior to the rotating rings to give stiffness.

>>9675447
It was an amazing little craft, combining just enough structural strength with minimal mass.

NB4 some troll starts posting about "foil."

>>9675469
>Actually, that makes no sense. What was the orientation of the carousel?

Hard to say, but given the size and the location of the pod bay, there seems no room for the carousel, but if there was it would have to have an axis parallel to the "spine."

>>9675469
>I asked Arthur about that once.

No shit? That's pretty ool.

>>9675524
>In early SF (including Clarke's own books) ships were turned by reaction wheels.

Certainly you see that n a lot of Hainlein's stuff. "Clutching" or "unclutching" the gyro/flywheel comes up repeatedly as the Rolling Stone maneuvers, for example.

>>9675826
At 2800 km/sec a 1" inch cube of steel carries 5.03e11 joules.
That's 120 TONS of TNT!

>It just vaporizes into a little plasma explosion onto whatever it hits.
>If you use a little bit of planning and a small amount of armor mass you either get a small amount of pitting or just a few small holes to patch.

WW2 battleships carried up to 14" thick armor.
A quarter (bomb) to a third (torpedo) of a ton of chemical explosives opened them up like tin cans. 120 tons would snap any warship ever built like a matchstick.

added external truss/cables. You could have some connectiosn to the centrifuges, they would be rolling/sliding connections and are vacuum, don't need sealing. Just to add stiffness to the entire spacecraft so it can maneuver and accellerate while reducing the stresses at the centrifuge connections.

>>9675665
>AI and drones simply aren't versitile

Apologize!

>>9675931
A one inch cube of steel is not a pebble. Maybe you get lucky and your whipple shield turns the entire thing into a diffuse plasma before it reaches the hull, maybe you get lucky and it passes through an unimportant part of your ship and you patch the holes afterward. Maybe it makes a ragged hole 8ft wide and rips open an entire section and you just seal it off for the remainder of the mission. Maybe it splits your ship in half and or disables critical systems. You can't be invincible to everything, sometimes the bear gets you.

>>9675910
I exempt >>9675524
from the label of "troll" for mentioning foil, but really, man, don't give them ammo that way.

The 'tards look at the mylar-and-friends thermal control skin, and claim it is tinfoil, and pretend not to know (or really don't know) anything about the actual structure of the craft. Which you already know, of course, I'm just venting.

Yeah, everything was as lightweight as they could make it, which made it a relatively fragile craft -- but they managed to get the mass down to where they could land, and then take off again, while still making the ship JUST strong enough to do so. That's impressive, and does not deserve to be denigrated as a "tinfoil" ship...

>>9675960
The LEM was honeycomb aluminum(alloyed) panels. Kinda like a metal cardboard. It is also a two stage, one stage for descent/landing, the other for ascent. Each stage is technically a single state to orbit.

>>9675926
In "Space Cadet" they devote a couple of paragraphs to spinning and de-spinning the PRS Randolph.

>>9675905
Certainly not impossible. You've summarized the alternatives neatly. As an engineer, I'd still prefer to avoid all of them if I could.
In the movie version of "The Martian" I recall the opening between the spin and non-spin sections was quite large. You could look (and step) through easily.

>>9675910
I said it was a good design. Enough strength for it's mission and not a newton more. I just protested the adjective "strong".

>>9675982
>The LEM was honeycomb aluminum(alloyed) panels.
Partially, yes. And also other things. The important point here is that it was not "made of" the mylar-et-al that wrapped the descent stage.

Which, again, you already know. But a subset of retards do not.

>>9675983
>I just protested the adjective "strong".

Absolutely fair. I just protested your use of "tinfoil." (I'm not the guy who posted the "strong" post you refer to, from his word choice I suspect he's a troll ironically overstating to set up a "moon hoax" derail attempt.

BTW, It saddens me that we're anonymous here. Don't know who you are, but you seem an old-school sci-fi fan. It would be fun to talk in real life. But some things were not meant to be.

Grok on that for awhile.

>>9675951
Whipple shields are for orbiting stations and ships on Hohmann trajectories between planets.
At over a 1000 km/sec, it would punch through without a thought. Even if it was vaporized, the KE would still be there and no more than inches across when it hit the pressure hull.
It'd go through any imaginable armor thickness and heat the internal atmosphere to a few hundred thousand degrees. A ship would burst like a water-filled tin can hit with a 22 caliber bullet.

I'm not saying it's impossible to have fast interplanetary transit. You'd likely get away with it most of the time. Space IS pretty empty. I'd have to calculate the odds and compare them to, say, jetliners swallowing birds.
Imagine you're the director of TriPlanet Spacelines. Would you advertise, "Fast, comfortable flights to all worlds as far as Saturn and only one-in-a-thousand chance of dying on a given flight!" Elon Musk can't guarantee even those odds but his potential customers aren't flying to visit grandmom or a theme park.

But someone asked "why would you not go as fast as possible?" and that is the #2 reason.
#1 is mass-ratio and the insane amounts of energy you need.

>>9676000
Oh, yeah.
Have all the Heinlein juveniles in original hardcover and Astounding continuous back into the '40s.

Might as well post another spacecraft. 99.99% efficient atomic-electric converter powering an ion-drive which allows a sea-level take-off. Works in air and produces more than 1 gee.
Curving arc at bottom of image is rival chemically-powered rocket, turning back after technical problems.

>9672679

This game blew my mind

>>9676034
Really sucks that the ISS has been destroyed by a cubic inch of iron that seem to fill the whole of interplanetary space, or has ISS not blown up because the iron cubes bounced off ISS at low velocities?

>>9674168

>We've got what, maybe 50 galaxies within our reach even if we left at light speed now. That's all we're gravitational bounds to

It will take roughly 150 billion years for other galaxy groups to be cut off from us by the expansion of space.

>>9676080
Because the ISS just crawls along.
And the odds are pretty low.
It has, however, been hit by stuff which pitted the surface and crazed windows and which would have completely demolished it at the velocities "fast" interplanetary ships would use.

The Earth averages one hit by something 2.5 meters in radius every 128 years. Roughly speaking, doubling the diameter increases the interval fourfold. The log-plot looks pretty straight right up to dinosaur killing sizes.
2.5 meters is 2500 cm. I’d expect Earth to be hit by someone 1 centimeter in radius about every 11 minutes. Of course, the ISS is very small compared to Earth, but you can’t dodge the bullet indefinitely.

The odds are worse for a “fast” interplanetary ship. At the speeds they travel, everything else might as well be stationary. So a ship would run into everything within a cylinder with the diameter of its frontal cross-sectional area and as long as the distance between planets. Matter is continually entering and leaving that cylinder, of course, but that evens out.

>>9676080
Because the ISS just crawls along.
And the odds are pretty low.
It has, however, been hit by stuff which pitted the surface and crazed windows and which would have completely demolished it at the velocities "fast" interplanetary ships would use.

The Earth averages one hit by something 2.5 meters in radius every 128 years. Roughly speaking, doubling the diameter increases the interval fourfold. The log-plot looks pretty straight right up to dinosaur killing sizes.
2.5 meters is 2500 cm. I’d expect Earth to be hit by something 1 centimeter in radius about every 11 minutes. Of course, the ISS is very small compared to Earth, but you can’t dodge the bullet indefinitely.

The odds are worse for a “fast” interplanetary ship. At the speeds they travel, everything else might as well be stationary. So a ship would run into everything within a cylinder with the diameter of its frontal cross-sectional area and as long as the distance between planets. Matter is continually entering and leaving that cylinder, of course, but that evens out.

>>9672517
star wars covers it maneuvering details in a lot of the earlier EU, the big ships hover with oversized repulsor lifts (Space magic thats a mix between magnetic levitation and acoustic) and the turning in space is justified with inertial dampeners so that the crew isn't turned into silly puddy. UNSC ships don't make a damn bit of sense in atmosphere, mass effect has its answer in the name with its mystical Element zero physics bending technology

>>9674869
Any ship could do this so it isnt unique to a stealth system.
>>9674795
Yes but the initial measurement still tells you something artificial is there and in conjunction with other factors will give you a good idea of what you are looking for. Stealth in the modern military sense (and indeed in the show) is a total defeat of enemy detection capability such that they dont know you are there.

>>9676080
The ISS just crawls along. However, it’s been struck by stuff which pitted the skin and the windows and would have demolished it at one or two thousand km/sec. Furthermore,
>http://articles.chicagotribune.com/1997-05-29/news/9705290201_1_earth-planet-snowballs
says we’re pelted by multi-ton mini-comets multiple times daily.
Even leaving the “snowballs” out, I compute the Earth is hit by rock or stone an inch across every 17 hours. That’s extrapolated from junk which actually makes it through the atomosphere.
Of course, the Earth is large and the ISS is minuscule.

The odds are worse for a “fast” interplanetary ship. At the speeds they travel, everything else might as well be stationary. So a ship would run into everything within a cylinder with the diameter of its frontal cross-sectional area and as long as the distance between planets. Matter is continually entering and leaving that cylinder, of course, but that evens out.

>>9676220
The earth is larger than your theoretical spaceship and orbital velocities are already high enough. The point is the risk of a catastrophic impact is astronomically low and an Apollo 13 style collision is much more likely.

So design your spacecraft to survive an Apollo 13+ collision and stop worrying about the one in a trillion chance that no amount of armor or redundancy (aside detection and avoidance) would have prevented. The big stuff you either detect and avoid or you're simply screwed. The small stuff that is actually common can be armored against and can be repaired or managed.

>>9676238
You still don't understand the energy really high velocity objects carry.
You keep making the same objections.
And you won't (or can't) do the math, so there's no point trying to convince you.

>>9675595
>Why would you deliberately accelerate slower than you are capable of unless there is some sort of other reason?


https://ocw.mit.edu/courses/aeronautics-and-astronautics/16-323-principles-of-optimal-control-spring-2008/lecture-notes/lec10.pdf

>>9676238
What do you mean by Apollo 13 style collision? Apollo 13 didn't hit anything remarkable that I can remember

>>9676500
Apollow wasn't actually struck by anything but a short circuit in the oxygen tank stirrer caused an explosion on the service module leading to a complete loss of all three oxygen tanks, meaning no power and no thrust. Crew survived only because the LEM was also a complete spacecraft.

Apollo 13 is valid as a real world example of a major failure of a spacecraft's systems. The cause is less important, more that there was an explosion on board.

>>9676053
This thread needs more Colliers/Disney/Von Braun rockets.

Also. spaceship fans need this coffee table book.

>>9672718
You guys are retarded. The problem is POWER. If you have a high specific impulse engine with a lot of thrust, you need a lot of power from somewhere, either your fuel itself or lots of electricity. This is why ion engines have such low thrust.

>>9676238
>Apollo 13+ collision

Wat?

>>9672517
>muh anti-gravity generator

In sci-fi design, for example, the engines are always biggest in the back but does that really matter? If an engine generated say 5G worth of accelerating thrust, could you vent it in any direction to move that way or would you need specific nozzle sizes for specific impulses?

>>9675575
In that particular video they are doing an emergency flip and high G burn to change course, it's not a normal maneuver.

>>9676838
Nothing matters because TV/movie engines are like the six-guns in old Westerns. They can thrust/shoot forever without refueling/reloading.
The engines emit a blue-white glow and that's it.
Rockets? Reaction mass? WTF?
Does that luminescent panel look like an exhaust nozzle to you?

>>9676816
See "The Tranquility Alternative" by Allen Steele.
Alternate history where vonBraun got the funding he wanted and they built ships like these. And the orbiting space wheel and the lunar base.
All for fear that the Commies would do it first and dominate the Earth.

>>9677076

>>9677076
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>>9677076
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>>9677076
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>>9677076
....

>>9677076
Can't recall where I got these, but try https://paul-lloyd.deviantart.com/gallery/
for some fantastic retro-SF modeling.

>>9675432
>your post has the least amount of thought in the entire thread.

It wasn't a difficult mental task to talk about projectrho, that is assured, i'm frankly suprised that it wasn't brought up earlier.

>That website lacks rigor outside of basic equations.

Oh, my bad... what website for realistic star-ship design do you read?

>>9677076
I have a couple of these in plastic.
Google "Glencoe Models Von Braun"

This one was built by Disney technicians for the TV show.
Mine is smaller, has cement stains all over, and the parts fit poorly. My fault, not Glencoe's.
I was never good with plastic.

>>9677110
Not the guy sarcastic/critical of you & Project Rho.
You might try https://www.centauri-dreams.org/

>>9675203
That's sincerely some bad-ass paint. Well done, paint scientists.

Get on my level.

The ships in Avatar and Sunshine both seemed pretty realistic

>>9672514
The one that "went" to the moon in 1969.

>>9672514
if you have basically magic stuff like force fields and such then the shape won't really matter since the magic force field bubbles will be your real hull.
And even if you need weapons that can only shoot outwards and a definitive direction of travel, then you'll basically have something like in Ian M. Banks' Culture:
Basically a fatish cone with let's say 5 weapon blisters in a ring at the base and 3 near the top, so that if needed all 8 can fire forward and 5 to any side and backwards at any time. Plus the shape provides some basic survivability in high-abrasive fluid enviroments like atmospheres, even in case of complete field failure.

But if you don't have access to fancy sci-fi magic then you'll most likely have to use something like the ISV venture star from Avatar . You'd still need HUGE improvements in lots of areas, mostly material science for things like perfect mirrors, carbon nanotubes, gamma ray redirection, incredible heat raditaion, multi GW lasers... and all of that super light...
But it's still within known science and could be done with super advanced metamaterials and let's say a century more of research.

Well okay.. this sort of design still might not actually work simply because of the required amount of fuel.
But you could do it with a Bussard-ramjet which does seem to be the most realistic way to travel long interstellar distances.
All you need is a working fusion reactor plus a BIGASS collector and bam, you got interstellar flight

>>9679063
One that can fuse "light" hydrogen at a decent rate.
And a scoop whose drag doesn't overwhelm the thrust of the engines -- at least not until you want to slow and then you use it as a braking loop.

Nice picture though.