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 Grey Templar wrote:

Since top/bottom is a meaningless distinction in space, a ship with top/bottom guns could also be said to have guns on its sides. its just a matter of perspective.

Anyway, when I envision a futuristic space warship. Assuming it doesn't just become a huge square or sphere with guns everywhere, I think a typical design might be something that looks vaguely like someone took two WW2 battleships and stuck them together at the keels.

So you'd have tubular hull with a roughly oval cross section. Each flat side of the ship would have ball turrets that could rotate to face straight up and to either side. The guns would have overlapping fields of fire to the sides and front of the ship, which would lead to the ship turning that side to the enemy. Combat to the top and bottom would be avoided as the guns on the far side could not contribute.

Thanks to how movement in space works, any ship can rapidly re-orientate its facing to bring its fields of fire to optimal orientation.

I actually think a realistic fighting spacecraft to be along the lines of a CubeSat with a .22, perhaps not literally, but along that theme.

The spacecraft turns itself to point its fixed weapon at the target, and is small enough to be deployed, potentially in multiples, with a single launch. A .22 precisely probably isn't adequate, but it doesn't exactly need to have a 5" gun to wreck another satellite.


The goal of this spacecraft is to deny the orbital theater to valuable enemy supporting assets, such as GPS and communications satellites, conventional/kinetic/nuclear strike vehicles, and rival power's kill-sats that are trying to kill your own communications and strike vehicles.


In terms of establishing the top level requirements of this satellite:
Its weapon probably should pass through the center of mass, to limit the effect of firing it on the ADCS. Probably smoothbore, small diameter, and high velocity.
The propulsion system must have at least enough delta-v capacity to equal that of the weapon, plus some more for orbital maneuvering or getting into GEO. Probably high-thrust low-Isp, since it needs to be fast.
Its ADCS needs to be able to maintain its own attitude despite impacts from rival kill-sats if it's still alive.
It needs to be able to track potential targets in a 360 degree sphere.

And after a dozen kills you've successfully littered LEO with so much debris you've denied everyone access to the orbital theater for any and all uses, including just passing through. Thus making the whole exercise rather pointless.

In a realistic scenario, anyway.

 Vulcan wrote:
And after a dozen kills you've successfully littered LEO with so much debris you've denied everyone access to the orbital theater for any and all uses, including just passing through. Thus making the whole exercise rather pointless.

In a realistic scenario, anyway.

A significant amount of debris is the consequence of any conflict in the space theater regardless of vehicle architecture. The only wait to avoid it is a agreement honored by all parties not to fight in space [which might not be honored anyway if you're losing].

Post-conflict orbital cleanup would definitely be a priority. Though a lot of low-orbit vehicles and their debris will naturally re-enter the atmosphere over the span of a few years due to atmospheric drag.

Now that we've established that as the most likely scenario in real life... can we go back to discussing warfare in science FICTION again?

 Vulcan wrote:
Now that we've established that as the most likely scenario in real life... can we go back to discussing warfare in science FICTION again?

Isn't that what we're doing? We seemed to be A: having the "X is harder sci fi than Y" debate and B: describing how a space combat vehicle would be optimally designed, given the operating conditions.

The goal of conducting combat in space is to deny the use of the orbital area to the enemy and secure it for your own use. You're not just ditzing around to find something to shoot at.
The things you want to use it for are maintaining your command and control network, operating strike vehicles, and deploying troops to the planet's surface.

It's important to consider how spacecraft move and meet each other. Meeting an opposing task group outside of the planetary sphere of influence is definitely a no go. It's not as simple as sortieing from a harbor, then turning around and coming back. Spacecraft travel on conic trajectories, ellipses and hyperbolas, and they don't stop moving. Your outbound fleet will have one opportunity for their outbound trajectory to cross the trajectory of the inbound fleet, and then they'll be in a big ellipse around the sun and are effectively removed from the fight for the remainder of the operation [This would be two Lambert transfers, with a burn after the fleet encounter to go from one to the other. It's possible that they could establish the interplanetary encounter close enough to come back quickly, but at that point why spend the delta-v for 3 major maneuvers when you could just stay inside the gravity well and save your fuel]. Further compounding the matter, ships approaching a planet from out-system will generally be catching up to the planet, and flying "backwards" to meet them in on the order of don't-bother-trying-it km/s [and you're definitely going to be out of the fight for a long time].

When the enemy ships first become available to shoot at, they'll be flying freely on their inbound trajectory, waiting to start their orbital insertion burn. During this period of time, they don't really care which way their guns are pointing relative to their engines, and neither do the defenders. Eventually, the enemy ships will pass by the planet on their entry hyperbola, and conduct an insertion burn to enter low orbit. They'll be pointing any direction they want for most of this time, but will point backwards while they slow down. The nature of their engines is relevant here; a high thrust low Isp engine could make a short burn at high mass cost, while a low thrust high Isp would save on fuel mass but force them to take a long spiral trajectory into low orbit. Here's a compelling reason for a turret, since the inbound ships have to maintain a given orientation which may not coincide with the direction their guns are mounted. Once they're in low orbit, you have two or more clusters of ships "chasing" each other around the planet. The spacecraft once again no longer really care which way their engines are facing, since they're not using them, and from this point on they just keep pulling shots off at each other until one side is dead. If they can't hit each other, they make a short burn to put them on an more eccentric orbit that will lead to them orbiting faster or slower, and start shooting when the window again presents itself. You don't necessarily have to re-assume the circularized orbit, though you can. Turrets would be nice to have if you do this a lot, but you probably don't have to.

With respect to having guns on the top and the bottom of your spacecraft [or on both flanks], you don't really need to. You can roll the spacecraft about the engine axis to bring the guns into firing arc. If all your burns are short burns, you don't even need to have turrets, and can fix them in orientation for maximum simplicity. It may also not be worth the mass penalties of having turrets.


Sizing is the other question. Sizing is effectively driven by your payload and propulsion system [your guns and your engines]. Mass growth of fuel required is exponential with increasing mass of not-fuel parts of your spacecraft [this is the Rocket Equation]. Armoring mass penalties also increase rather drastically with spacecraft size. Ergo, you want your vehicle to be the minimum mass possible to support the envisioned operations. High Isp low thrust engines are good choices, since they use their mass reserve more efficiently but don't have the thrust for quick impulsive maneuvers. Dual operation mode engines may be an option, with the awareness that it will need fuel reserves scaled for both operation modes.

Since they have not been mentioned, my ideas and vision of space combat have been influenced heavily by two SF series. The first is the Honor Harrington series by David Weber (debuted in 1993). The second and possibly the real inspiration for the Star Wars style broadside is Gunbuster (Aim for the Top) which debuted in 1988 (just ignore the super awesome giant robot).

 Inquisitor Lord Katherine wrote:

 Vulcan wrote:
Now that we've established that as the most likely scenario in real life... can we go back to discussing warfare in science FICTION again?

Isn't that what we're doing? We seemed to be A: having the "X is harder sci fi than Y" debate and B: describing how a space combat vehicle would be optimally designed, given the operating conditions.

The goal of conducting combat in space is to deny the use of the orbital area to the enemy and secure it for your own use. You're not just ditzing around to find something to shoot at.
The things you want to use it for are maintaining your command and control network, operating strike vehicles, and deploying troops to the planet's surface.

It's important to consider how spacecraft move and meet each other. Meeting an opposing task group outside of the planetary sphere of influence is definitely a no go. It's not as simple as sortieing from a harbor, then turning around and coming back. Spacecraft travel on conic trajectories, ellipses and hyperbolas, and they don't stop moving. Your outbound fleet will have one opportunity for their outbound trajectory to cross the trajectory of the inbound fleet, and then they'll be in a big ellipse around the sun and are effectively removed from the fight for the remainder of the operation [This would be two Lambert transfers, with a burn after the fleet encounter to go from one to the other. It's possible that they could establish the interplanetary encounter close enough to come back quickly, but at that point why spend the delta-v for 3 major maneuvers when you could just stay inside the gravity well and save your fuel]. Further compounding the matter, ships approaching a planet from out-system will generally be catching up to the planet, and flying "backwards" to meet them in on the order of don't-bother-trying-it km/s [and you're definitely going to be out of the fight for a long time].

When the enemy ships first become available to shoot at, they'll be flying freely on their inbound trajectory, waiting to start their orbital insertion burn. During this period of time, they don't really care which way their guns are pointing relative to their engines, and neither do the defenders. Eventually, the enemy ships will pass by the planet on their entry hyperbola, and conduct an insertion burn to enter low orbit. They'll be pointing any direction they want for most of this time, but will point backwards while they slow down. The nature of their engines is relevant here; a high thrust low Isp engine could make a short burn at high mass cost, while a low thrust high Isp would save on fuel mass but force them to take a long spiral trajectory into low orbit. Here's a compelling reason for a turret, since the inbound ships have to maintain a given orientation which may not coincide with the direction their guns are mounted. Once they're in low orbit, you have two or more clusters of ships "chasing" each other around the planet. The spacecraft once again no longer really care which way their engines are facing, since they're not using them, and from this point on they just keep pulling shots off at each other until one side is dead. If they can't hit each other, they make a short burn to put them on an more eccentric orbit that will lead to them orbiting faster or slower, and start shooting when the window again presents itself. You don't necessarily have to re-assume the circularized orbit, though you can. Turrets would be nice to have if you do this a lot, but you probably don't have to.

With respect to having guns on the top and the bottom of your spacecraft [or on both flanks], you don't really need to. You can roll the spacecraft about the engine axis to bring the guns into firing arc. If all your burns are short burns, you don't even need to have turrets, and can fix them in orientation for maximum simplicity. It may also not be worth the mass penalties of having turrets.


Sizing is the other question. Sizing is effectively driven by your payload and propulsion system [your guns and your engines]. Mass growth of fuel required is exponential with increasing mass of not-fuel parts of your spacecraft [this is the Rocket Equation]. Armoring mass penalties also increase rather drastically with spacecraft size. Ergo, you want your vehicle to be the minimum mass possible to support the envisioned operations. High Isp low thrust engines are good choices, since they use their mass reserve more efficiently but don't have the thrust for quick impulsive maneuvers. Dual operation mode engines may be an option, with the awareness that it will need fuel reserves scaled for both operation modes.

All right, you win, I'm out.

 Lord of Deeds wrote:
Since they have not been mentioned, my ideas and vision of space combat have been influenced heavily by two SF series. The first is the Honor Harrington series by David Weber (debuted in 1993). The second and possibly the real inspiration for the Star Wars style broadside is Gunbuster (Aim for the Top) which debuted in 1988 (just ignore the super awesome giant robot).

Note that David Weber engineered the science of his setting (impeller wedges) to create broadsides so he could do Hornblower IN SPAAACE!. After a few books, the miraculous engineering developments of the protagonists and antagonists got away from that idea, and delivered the huge swarms of "off-axis" missiles that dominate combat in the latter half of the series.

So, why do so many sci-fi series want to do the 18th century with lasers and rocket motors? For the romance of it, I think. the "Age of Sail" was when you could feasibly have a single ship out in the middle of nowhere on their own, able to fight, trade, conquer on their own authority with no interference from high command. That translates pretty well to the feeling of being a hundred light years from Earth with no FTL radio. Once you've got the setting, the next step can be to emulate the technology, society and tactics too - Weber's Star Kingdom of Manticore is a right-of-centre corporate state cosplaying as 18th-century England with less slavery and racism, the Alexis Carew series goes one further by having the protagonist come from a somewhat backwards colony so the author can include a "woman in a man's wordl" theme without it looking too odd, and twists the physics even more so they can have human-loaded single-shot (laser-) cannon broadsides.

Star Trek was "Wagon Train to the Stars", but with a hint of age of sail flavour when it came to Kirk's authority and responsibilities as captain. WW2 did intrude on occasion (the episode with the Romulans was a WW2 "hunt the submarine" plot).

The counter-examples are Battlestar Galactica, Buck Rogers and Star Wars. They're all a more "modern" military style, which is the other place that SF settings crib from; if it's not the Napoleonic wars, it's the Second World War.

 AndrewGPaul wrote:

 Lord of Deeds wrote:
Since they have not been mentioned, my ideas and vision of space combat have been influenced heavily by two SF series. The first is the Honor Harrington series by David Weber (debuted in 1993). The second and possibly the real inspiration for the Star Wars style broadside is Gunbuster (Aim for the Top) which debuted in 1988 (just ignore the super awesome giant robot).

Note that David Weber engineered the science of his setting (impeller wedges) to create broadsides so he could do Hornblower IN SPAAACE!. After a few books, the miraculous engineering developments of the protagonists and antagonists got away from that idea, and delivered the huge swarms of "off-axis" missiles that dominate combat in the latter half of the series.

So, why do so many sci-fi series want to do the 18th century with lasers and rocket motors? For the romance of it, I think. the "Age of Sail" was when you could feasibly have a single ship out in the middle of nowhere on their own, able to fight, trade, conquer on their own authority with no interference from high command. That translates pretty well to the feeling of being a hundred light years from Earth with no FTL radio. Once you've got the setting, the next step can be to emulate the technology, society and tactics too - Weber's Star Kingdom of Manticore is a right-of-centre corporate state cosplaying as 18th-century England with less slavery and racism, the Alexis Carew series goes one further by having the protagonist come from a somewhat backwards colony so the author can include a "woman in a man's wordl" theme without it looking too odd, and twists the physics even more so they can have human-loaded single-shot (laser-) cannon broadsides.

Star Trek was "Wagon Train to the Stars", but with a hint of age of sail flavour when it came to Kirk's authority and responsibilities as captain. WW2 did intrude on occasion (the episode with the Romulans was a WW2 "hunt the submarine" plot).

The counter-examples are Battlestar Galactica, Buck Rogers and Star Wars. They're all a more "modern" military style, which is the other place that SF settings crib from; if it's not the Napoleonic wars, it's the Second World War.

It's also easy to comprehend. Most people know how a [sea] ship moves, and a ship can move fairly freely. [that is to say, it's attitude is pretty easy to define without math]

Most people would require a class, or multiple, to understand orbital mechanics. And fundamentally, describing how [space] ships move is pretty much irrelevant to the story.

Drager wrote:
Real naval ships.

All Scifi space warfare are more or less originated from oceanic naval warfare throughout history.
- Leiji Matsumoto's space operas (since Space Battleship Yamato, Captain Harlock and more) favors 'near past' (heavily WW2, Himself was born in 1938 and his father was a Zero Fighter pilot but not sure if he survived the war). all space warships designs are Dreadnough based, (with or without underside mainguns).
- 40K universe appears to be inspired by Broadside-based naval combat. and Imperial Ships (including Chaos defectors) are pretty much Pre-Dreadnough in design., with FTL and space aviation mixes
I'm not sure about Star Wars or Star Trek though.


Automatically Appended Next Post:

 Peregrine wrote:
BFG is real-world sailing ships in space, so BFG copies the real-life broadside weapons of those ships.

I'd rather say, BFG is a fleet of Pre Dreadnoughs in space. much of Imperial warships are designed that way. (Broadsides and turrets), I might think of Tsushima in space.



Automatically Appended Next Post:

 Slowroll wrote:
Starblazers/Space Battleship Yamato had port and starboard guns in the 70's. I can't think of anything earlier.

Ain't that Space Yamato supposed to be Dreadnough with a giant supergun (Wave Motion Gun) mounted on bow?




Space Yamato did indeed have lateral mounted weapons, but these are missile launchers and not mainguns. the ship's design (courtesy of Leiji Matsumoto) is quite flawed. particularly with no underside turrets. yet it did an uncanny ability to fight in the deep space.

Lack of keel turrets is probably not a problem for a spacecraft. It can roll about its axis to bring its one set of turrets to bear.

Aye. It does become a problem if you’ve got enemies on both sides though.

 Grey Templar wrote:
Aye. It does become a problem if you’ve got enemies on both sides though.

If that happens then you've already lost as you've been thoroughly outmanoeuvred. Those ships will be able to both bring their full firepower against yours whilst you will be splitting yours between them.

 Inquisitor Lord Katherine wrote:
Lack of keel turrets is probably not a problem for a spacecraft. It can roll about its axis to bring its one set of turrets to bear.

But your ship has to be agile enough to flip just in time to shoot



(This one is a rebooted Space Battleship Yamato (the 2199) series, the original ones didn't say that Space Yamato is an agile space dreadnough, only said it was the first spaceship that can warp, AKA the first FTL ship, the combat agility of this ship is quite poor).

 Lone Cat wrote:

 Inquisitor Lord Katherine wrote:
Lack of keel turrets is probably not a problem for a spacecraft. It can roll about its axis to bring its one set of turrets to bear.

But your ship has to be agile enough to flip just in time to shoot.

Any spacecraft which cannot rotate cannot manoeuvre. Just stick a big reaction wheel in there at the very least.

 Lone Cat wrote:

 Inquisitor Lord Katherine wrote:
Lack of keel turrets is probably not a problem for a spacecraft. It can roll about its axis to bring its one set of turrets to bear.

But your ship has to be agile enough to flip just in time to shoot

Spacecraft can roll pretty easily.

More relevantly, can an opposing vehicle exploit your limited arc? Almost certainly not.


There's an argument for your guns not being tied to your engine axis, because you may need to point your engines one way for a burn and your guns another; but the spacecraft doesn't care which way it's rolled about it's engine-axis, so it can always roll to keep it's guns in arc.