What ticks you off about scifi spaceship designs?

[Vanamonde]

I have a love/hate relationship with the TOS Enterprise for this reason.

Supposedly, Star Trek warp drive doesn't work through thrust. However, the impulse engines are supposed to work through thrust. Which is a problem, because they they weren't thrusting through the center of mass, either.

[adsii1970]

Supposedly, Star Trek warp drive doesn't work through thrust. However, the impulse engines are supposed to work through thrust. Which is a problem, because they they weren't thrusting through the center of mass, either.

This is a problem with nearly all the ships in the Star Trek universe, with the exception of the Defiant, Reliant, Klingon Bird of Prey, the Klingon Battlecruiser D7 (and variants), the Romulan Bird of Prey, and a handful of other craft. Each of the classifications of ships that I name are low profile for the most part and have thrust somewhere near the center of mass.

[Camacha]

Supposedly, Star Trek warp drive doesn't work through thrust. However, the impulse engines are supposed to work through thrust. Which is a problem, because they they weren't thrusting through the center of mass, either.

I will repeat my question: how do you know? How do you know how weight is distributed throughout a fictional vehicle?

[Newt]

I will repeat my question: how do you know? How do you know how weight is distributed throughout a fictional vehicle?

You really do not. You can guess about the centre of volume, but of mass, really who knows. On some of these large vehicles, it probably can shift dramatically, further complicating the issue.

Additionally, especially earlier on (i.e. ST:TOS) you really do not see the vehicle thrusting in the presence of objects to determine the direction it is heading in. You do not see matter comming from the engines. It is entierly possible that the centre of mass could match the centre of volume, and the impulse engines are simply vectored to go 'forward' through those centers.

The TNG technical manual discusses some of this, their engines are certainly vectorable, I will have to check up on their descriptions in greater detail.

[Fel]

The turret provides one more place for things to break down and another joint for the enemy to attack. Some guns might also have a lot of "Backend" behind the barrel that would make the turret very long and hard to manoevre (No aerodynamics, but there's still inertia), essentially making it a fixed-position gun in intense combat situations.

If the turret joint breaks down all you have is a fixed gun.

Since spaceships are suppose to be designed like battleships *cough*luxury cruise liners*cough*, and battleships have axes of rotation on their on-board weaponry. Why would we worry simply because it is in space now?

The TNG technical manual discusses some of this, their engines are certainly vectorable, I will have to check up on their descriptions in greater detail.

Wow... Paramount actually went and made something like that? Purely for sake of argument, I wonder if the nacelles are ever officially stated to be the impulse engines or if they're purely for warp.

Edited June 5, 2015 by Fel

[RainDreamer]

I think the reason space fighters doesn't use turrets is because it is added mass for a lightweight vehicle with low amount of dV available. Why adding all that motors and hull when in space your fighter can easily rotate with rcs and gyro at any direction to face threats? Beside, missiles would be the main damage dealer anyway, and that can be shot from anywhere.

[basic.syntax]

You really do not. You can guess about the centre of volume, but of mass, really who knows. On some of these large vehicles, it probably can shift dramatically, further complicating the issue.

Additionally, especially earlier on (i.e. ST:TOS) you really do not see the vehicle thrusting in the presence of objects to determine the direction it is heading in. You do not see matter comming from the engines. It is entierly possible that the centre of mass could match the centre of volume, and the impulse engines are simply vectored to go 'forward' through those centers.

The TNG technical manual discusses some of this, their engines are certainly vectorable, I will have to check up on their descriptions in greater detail.

Star Trek Impulse Engine "exhausts" are behind the centerline of the saucer. Fractionally above the thrust line, the warp nacelles. Significantly below the line, the secondary/engineering hull. To balance this, the warp nacelle coils would have to massively outmass the secondary/engineering hull. Unfortunately, the first official-looking ST: Tech Manual, published 1975, put some numbers on things, saying the nacelles weighed 18,000 metric tons each, and the entire ship: 190,000 MT. (The same total weight figure is also in The Making of Star Trek, published 1968.) [ 18x2 = 36, 190/36 = ratio of 1:5.3 ]

I now dislike all you people*, for drawing attention to things I happily ignored for years, making me read books, and think

* But not that much. "You'll thank us, later!"

[adsii1970]

This has been a pretty fun thread to read... we are all discussing the realistic portrayal of spaceflight and space warfare as portrayed in movies... kinda makes me feel like one of the Thermians out of Galaxy Quest learning that the "historical documents from earth" they received from space were actually a television show...

That makes me think of waste disposal in space...

I wonder why there haven't been any fiction feature a field of...well, you know what it is...on an interplanetary orbit due to long term interplanetary travel.

In Star Wars: Empire Strikes Back, we learn that Imperial Star Destroyers dump all waste before going into hyperspace. I imagine this would reduce the overall mass of the vessel but do not see how it would be significant enough to curb the energy needs of such a large vessel accelerating to FTL travel. There were a few episodes of Enterprise and Voyager where waste recycling were discussed; water waste purified and reprocessed so that it can be reused. Solid waste was also broken down into common substances and recycled as well.

Supposedly, Star Trek warp drive doesn't work through thrust. However, the impulse engines are supposed to work through thrust. Which is a problem, because they they weren't thrusting through the center of mass, either.

The warp engines, based on Star Trek canon, works by creating an envelope around the ship, then folding space around that envelope. It is the same theory behind space travel in the original movie, Dune, but just from a different perspective. In the Star Wars canon and Babylon 5 canon, they talk about hyperspace - a plane where space itself is condensed and folded because of gravity. Not sure how it works yet, but let's just say that "they've gone plaid..."

About the most realistic portrayal of FLT, in my opinion, is both the original and SyFy remake of Battlestar Galactica. In both episodes, Galactica could achieve FTL travel but only in short bursts as it was rough on the superstructure and it was costly in fuel, indicating the Galactica used raw thrust to achieve the speed rather than folding space.

Star Trek Impulse Engine "exhausts" are behind the centerline of the saucer. Fractionally above the thrust line, the warp nacelles. Significantly below the line, the secondary/engineering hull. To balance this, the warp nacelle coils would have to massively outmass the secondary/engineering hull. Unfortunately, the first official-looking ST: Tech Manual, published 1975, put some numbers on things, saying the nacelles weighed 18,000 metric tons each, and the entire ship: 190,000 MT. (The same total weight figure is also in The Making of Star Trek, published 1968.) [ 18x2 = 36, 190/36 = ratio of 1:5.3 ]

I now dislike all you people*, for drawing attention to things I happily ignored for years, making me read books, and think

* But not that much. "You'll thank us, later!"

I'm glad I am not the only one that collects Star Trek "manuals", memorabilia, as well as the novels. I still choose to ignore the physics and just enjoy the good storyline. Now want to talk about a ship that violates physics - we can harp on almost every ship in the Star Wars universe... Don't get me wrong, I do love science fiction and science fantasy, the category where Star Wars belongs.

As it stands right now, I have all the components needed to make (yes, I do sew) a uniform from ST:TWoK, which in my opinion were the best uniforms of Star Trek; the only one that came close was the uniforms used on Voyager and the Next Generation movies.

[pincushionman]

…In Star Wars: Empire Strikes Back, we learn that Imperial Star Destroyers dump all waste before going into hyperspace. I imagine this would reduce the overall mass of the vessel but do not see how it would be significant enough to curb the energy needs of such a large vessel accelerating to FTL travel…

That particular line was never about reducing mass for dV requirements; the implication was "the Empire does what it damn well pleases, and doesn't give a rat's behind for the messes it leaves in everybody's backyards." Essentially another character-development line establishing how the Empire is a bunch of bastards.

[Camacha]

Dumping waste is a very 19^th century centred view on things. Even now we are evolving towards a society where waste does not exist. Everything is a resource and waste collection can actually be profitable based purely on the values of the materials gathered.

This counts even stronger in space, where every gram up there is a gram of launch weight saved. The only reason to start dumping is having some sort of excessive power source available that removes energy and economic limits on launching things. If it is almost free, hauling stuff up is not an issue any more, though you still throw away resources. Plus that almost free energy also means taking mass cheaply with you, so little sense in dumping (unless you are trying to do something fancy, like outrunning or overtaking).

[basic.syntax]

That particular line was never about reducing mass for dV requirements; the implication was "the Empire does what it damn well pleases, and doesn't give a rat's behind for the messes it leaves in everybody's backyards." Essentially another character-development line establishing how the Empire is a bunch of bastards.

This, so much

Per science-fantasy, Star Wars doesn't want us to think about how stuff might work, just enjoy that it does. Sometimes you need an R2 unit to sort out problems, other times a swift kick does the job.

On BSG's FTL, I don't think it was explained. Something had to "spin up." (Moving parts were shown in a final season episode, and also in the prequel pilot, Blood and Chrome.) The effect looked like a space warp / instantaneous relocation, probably at a high fuel cost. Then they had regular engines that burned Tylium, shown burning away most of the time. In a few episodes I think the big ships did some coasting, but perhaps they always kept the fires running on low, in case of trouble. I listened to a bunch of Ronald Moore episode commentaries. Fuel was important to him; that worked well in stories, because you could always be running out of it

[lajoswinkler]

I've heard that Kubrick and Clarke fought over that, Clarke insisted that the Discovery needed a huge radiator while Kubrick didn't want it for aesthetic reasons.

That was Kubrick's huge mistake and one of the rare things that this movie crapped up.

Radiators can be formed so that in no way they resemble wings or any aerodynamic function.

[megatiger78]

not enough buttons.

[Vanamonde]

I will repeat my question: how do you know? How do you know how weight is distributed throughout a fictional vehicle?

By looking at it.

The cylindrical secondary hull is way the heck below the impulse engines. Unless it's a hollow balloon, it's going to drag the center of mass far below that engine mount. It's not just it's unknown mass, but it's known physical location that's the problem.

[adsii1970]

That particular line was never about reducing mass for dV requirements; the implication was "the Empire does what it damn well pleases, and doesn't give a rat's behind for the messes it leaves in everybody's backyards." Essentially another character-development line establishing how the Empire is a bunch of bastards.

Since it is a movie, we have no idea what the real story line actually was and while your perception may be valid, I do feel that there was something else at work. To simply assume that Star Destroyers jumped garbage simply because they could do it and to show their ultimate badness can be considered a leap of faith. One could argue that the reason they did this was to keep the craft more stable - after all, who would want a hold full of garbage that could not be secured shifting around while in hyperspace? It would have to require computer monitoring and nearly constant adjustment to keep the ship stable.

Besides, the Millennium Falcon could not have escaped had the Star Destroyer not dumped its garbage load.

[Fel]

I think the reason space fighters doesn't use turrets is because it is added mass for a lightweight vehicle with low amount of dV available. Why adding all that motors and hull when in space your fighter can easily rotate with rcs and gyro at any direction to face threats? Beside, missiles would be the main damage dealer anyway, and that can be shot from anywhere.

Rotating the ship with RCS would significantly expend more RCS to do so QUICKLY. Usually we use RCS as a quick burst and then wait for an eternity before releasing another burst to stop the rotation. KSP's reaction wheels provide significantly more force than possible and cannot exist as such in reality.

Now, using reaction wheels, or rcs, or whatever on the free moving turret part requires significantly less RCS / "reserve angular momentum" than moving the whole ship at the same angular velocity.

Also, do note in "single engine" design you have zero ability to perform maneuvers while aiming at the same time. Even with missiles you can evade or even shoot down the targets; a simple turret can provide a large amount of defense.

I mean, that list did bring up a very bad argument in that if two ships are pursuing each other you should just rotate around; but if you're in pursuit that means you are expending dV trying to out maneuver / outrace your pursuer... not that you're just drifting through space. The time required to cut engines and rotate the ship can easily open you up to attack. You're going the same speed, but what matters is the relative speed which was 0m/s and now is rapidly increasing.

Beside, missiles would be the main damage dealer anyway, and that can be shot from anywhere.

I'm 50/50 with this. Missiles are going to be the main damage dealer, but the openings for a highly maneuverable "scout ship" that packs heavy weapons are there. Even if your "heavy weapon" is nothing more than a javelin hurtled at close range (you don't need a GUN in space, you just need to be going at a high relativistic velocity), overwhelming defenses and delivering a strike is sound military tactics.

There's crop dusters and fighter craft... the list posted basically assumed that all "real spacecraft" are the types that NASA has designed; but lacking any reason for space warfare we've never seen exactly what we're capable of given the need to fight. Technology is often a reaction to a necessity rather than an anticipation of the necessity.

Really, the way I see it, maneuverability will be extremely important, be it in "smart" missiles (basically drones) that are able to track and evade enemy counter fire or in training humans to work with systems and provide the "missing link" to do so.

Edited June 5, 2015 by Fel

[Camacha]

One could argue that the reason they did this was to keep the craft more stable

Did you forget the fancy trash compactor? Super stable.

[Newt]

Also, do note in "single engine" design you have zero ability to perform maneuvers while aiming at the same time. Even with missiles you can evade or even shoot down the targets; a simple turret can provide a large amount of defense.

Have you forgotten about vanes and gimbals, not to mention the ability to shift centre of mass? Single engine craft are steerable.

Really, the way I see it, maneuverability will be extremely important, be it in "smart" missiles (basically drones) that are able to track and evade enemy counter fire or in training humans to work with systems and provide the "missing link" to do so.

I agree with this. Frankly, Star Wars style fighters seem, silly. By sticking a human in the craft, you limit acceleration (or add some sort of science fiction accelaration compensation system, which equals mass and power drain), add life support, and quite importantly make the vehicle less a candidate for suicide attacks. By using smart missile/drone auxilary craft, it seems that there are many more options. And often, the entire point might be to ram as fast as you can into the target capital ship's reactor, radiator, or what have you, not to shoot at the little things gaurding it.

And the Star Trek The Next Generation Technical Manual does indeed comment about vectoring the main impulse engine, though only really during seperated flight (when the saucer is freeflying). the saucer engines are seldom used during joined flight, as suggested by the representation as being generally dark.

[CelticCossack51]

Interesting. Well, it's time for me to go in my space pill that has not so aerodynamic fins as landing legs and probably does not have enough fuel to reach orbit and beyond.

[adsii1970]

Did you forget the fancy trash compactor? Super stable.

The trash compactor was in the Death Star... yeah, a realistic space station. No rotation yet it has GRAVITY...

[Randox]

I'm not sure I would want an accurate portrayal on screen. I quite like the balance Babylon 5 hit, particularly with human ships, between acknowledging that physics do apply to the movie universe, but also making the fight scenes visually interesting.

By far the most accurate portrayal of space combat I have come across so far are in the Halo books. There is one fight in particular between Captain Keys in a Destroyer engaging I think a couple of Covenant ships, and I can't remember which book it is (I think it's "The Fall of Reach"). The use of orbital mechanics, long range weaponry, and maneuvering thrusters is detailed in this fight, and I think it's a pretty good stab at what a real space fight could look like, at least for a ship using a mass driver and missiles. It's a relatively slow pace, long ranges, and orbital mechanics that a lot of people don't intuitively understand and which would be very clunky to try and explain as part of a movie.

It's certainly not a perfect portrayal, but some thought did go into it, and the author is working within limits by what had already been portrayed in the first game and so on.

As far as the ships go through, it's the engines and the way they fly. Don't thrust when you aren't accelerating, don't arrange engines in a way that couldn't possibly push without rotating the ship, don't do everything with the engines at the back (they aren't brakes), and don't fly like your in an atmosphere.

Edited June 6, 2015 by Randox