Should sci fi ships use VLS?

[Graham Kennedy]

In the real world, missile launchers like these :



Have largely been supplanted by Vertical Launch Systems like these :



The big advantage is rate of fire - VLS can fire better than a missile a second.

But we very rarely see such systems in sci fi. Sci fi warships almost always launch their weapons through tubes/launchers.

Obviously the out of universe reason is that the major sci fi franchises like Trek and Star Wars predate the real world invention of VLS. But what might in-universe reasons be?

I ask because I've been looking at Coalition universe designs. Some early ones had VLS type launchers, then things reverted to the older style "missiles on rails" type launchers, then back to VLS, then to "torpedo tube" style launchers. I'm mulling over whether to try and make sense of it all, or redesign ships so they all have VLS, or what.

Any thoughts?

[Mikey]

Coalition stuff might be different, because the scale of the weapons generally increases to match the scale of the ships. In much other SF, though, the size of the ships greatly outpaces the size of the weapons. Either -tech means that the systems are ridiculously small for the apparent destructive ability (cf., proton torpedoes in SW, which can be mounted internally - with a magazine - in a one-man fighter) or the ships have become amazingly large compared to any naval conception we have, or both. What that all means is that the motivations that led to our development of VLS just don't exist.

Look at 'Trek: a typical UFP cruiser is pretty damned big compared to a torpedo-dependent (i.e., tactical, non-missile-carrier) submarine, say, a WWII Gato-class. However, a photon torpedo is, what? maybe 7 feet long, whereas the Mark 14 torpedos on that Gato-class were over 20 feet long. Even if photon torpedo launchers were as space-consuming as Mark-14 torp tubes (they aren't) and as many PT launchers were required to keep up the same rate of fire as torp tubes on the sub (they aren't) the 'Trek ship could have individual PT launchers from here to the latrine and still not miss the space.

Also, since most SF ordnance uses some arcane unexplained guidance a/o propulsion, there may be in IU reason for preferring a more direct launch angle than a VLS could provide.

[Coalition]

Modern cruisers also have little/no armor, while most SF ships have some armor. VLS would only have a thin hatch over the munitions, meaning any proximity hits have a chance of destroying the whole cluster.

So if they are used I'd see them as externally mounted boxes of missiles, fired early to avoid being mission-killed by enemy fire.

You also have cases where the missiles are prepped/assembled before launching. For example, Federation photon torpedoes might be stored empty, and only loaded with antimatter when prepped to fire. Photon torpedo VLS cells either need antimatter loading systems hooked to each cell, or you have a big box of boom attached to your ship. The nice part is that if they are pre-loaded, any failure in one storage system should hopefully be detected, and the missile can be launched on a beraings vector, with the bearings set up to be 'away from me'.

So VLS cell usage would be based on:
1) protection of shielding vs enemy fire (can enemy fire penetrate shields even before the shields drop, if so you don't want explosives on your hull)
2) munition assembly question (does the weapon need a delicate/complex system to prep the missiles before launch)
3) expected mission (will you be attacking as soon as you arrive, or will you accept potential weaknesses in your armor for a faster launch rate)

Plus other details that have to be considered and I can't think of right now.

[Graham Kennedy]

Coalition stuff might be different, because the scale of the weapons generally increases to match the scale of the ships. In much other SF, though, the size of the ships greatly outpaces the size of the weapons. Either -tech means that the systems are ridiculously small for the apparent destructive ability (cf., proton torpedoes in SW, which can be mounted internally - with a magazine - in a one-man fighter) or the ships have become amazingly large compared to any naval conception we have, or both. What that all means is that the motivations that led to our development of VLS just don't exist.

Look at 'Trek: a typical UFP cruiser is pretty damned big compared to a torpedo-dependent (i.e., tactical, non-missile-carrier) submarine, say, a WWII Gato-class. However, a photon torpedo is, what? maybe 7 feet long, whereas the Mark 14 torpedos on that Gato-class were over 20 feet long. Even if photon torpedo launchers were as space-consuming as Mark-14 torp tubes (they aren't) and as many PT launchers were required to keep up the same rate of fire as torp tubes on the sub (they aren't) the 'Trek ship could have individual PT launchers from here to the latrine and still not miss the space.

Wasn't the rationale for VLS more about rate of fire than the relative size of the weapon to the ship? Defending against saturation missile attacks needs a lot of missiles in the air quickly, which arm launchers can't do.

Of course, at least in TNG, photon tubes seems more like shotguns or machine guns than our launchers.





And Trek ships at least certainly seem to hold off from firing at anything like their maximum rate on torpedoes, instead just taking the odd potshot during combat for some reason. So maybe this removes the need for a VLS type arrangement.

Here's another thought. The one thing VLS needs that launchers don't is a lot of surface deck space. But as you increase the size of your ship (assuming it stays roughly the same shape), your surface area : volume ratio drops. I was thinking about how I'd mount VLS type launchers on something like the Kororra class, and you just couldn't fit nearly as many torps in that way since once you've covered the surface of that hull section in VLS cells there's still a great big void behind all the VLS boxes that now can't be used for torpedo storage.

[IanKennedy]

I would have thought that one of the main reasons that they were able to switch from rail launchers to VLS systems was the improved manoeuvrability of the missiles themselves. The rail systems were required to point the weapon in the general direction that it needed to go in the first place, thus allowing it to change course minimally whilst in flight. VLS requires that the missile initially travels in an upwards direction before reorienting to face the target. This requires not only that the missile be able to quickly perform such manoeuvre but also have the computing power to control that process and in a cheap enough package that you're willing to blow that computer up with the missile. Either that or a nasty wire running from the ship to the missile during the initial period to provide control signals from the ship.

Torps in Star Trek as pretty smart with the ability to hunt out and search for their target, changing direction in all sorts of ways (STVI). Some of them have AI (Dreadnought).

[Graham Kennedy]

Yes, that is one of the stumbling blocks in being able to put a missile in a VLS; your missile needs to be able to change direction radically after launch. Some of the time they just use the control surfaces, but some are quite radical about it.

[Reliant121]

EVE online uses VLS in sci-fi extensively. Trailer below shows Caldari ships (Phoenix and Raven I believe) using them.

[Lt. Staplic]

It occurs to me that a VLS system isn't all that great for Space Combat. VLS works because I can launch straight up, then turn around using aerodynamics and boost toward my target which will be below my starting height.

In space you don't have aerodynamics, meaning any VLS style launch will have to require extensive reaction control systems and fuel for such systems on board. It also means that, unlike on earth based rockets, you will actually have to kill any velocity you give it to launch away from the ship, unless you are already launching at your target. Thus just to get it away from the ship and on it's heading you've burned up a decent amount of propellant.

What you probably want is some combination, you want the missiles to have some guidence, but I would think the best way to do it is to have the launch vector be at the target.

[Reliant121]

Unless the fuel and physics of changing course are trivial matters. If that is the case, fitting 10 tubes into the space of a single turret mechanism would be preferable.

[Coalition]

It occurs to me that a VLS system isn't all that great for Space Combat. VLS works because I can launch straight up, then turn around using aerodynamics and boost toward my target which will be below my starting height.

In space you don't have aerodynamics, meaning any VLS style launch will have to require extensive reaction control systems and fuel for such systems on board. It also means that, unlike on earth based rockets, you will actually have to kill any velocity you give it to launch away from the ship, unless you are already launching at your target. Thus just to get it away from the ship and on it's heading you've burned up a decent amount of propellant.

What you probably want is some combination, you want the missiles to have some guidence, but I would think the best way to do it is to have the launch vector be at the target.

So something like the missile cells from the aliens in Battleship? Where the entire missile array is turned towards the target?

[Lt. Staplic]

It occurs to me that a VLS system isn't all that great for Space Combat. VLS works because I can launch straight up, then turn around using aerodynamics and boost toward my target which will be below my starting height.

In space you don't have aerodynamics, meaning any VLS style launch will have to require extensive reaction control systems and fuel for such systems on board. It also means that, unlike on earth based rockets, you will actually have to kill any velocity you give it to launch away from the ship, unless you are already launching at your target. Thus just to get it away from the ship and on it's heading you've burned up a decent amount of propellant.

What you probably want is some combination, you want the missiles to have some guidance, but I would think the best way to do it is to have the launch vector be at the target.

So something like the missile cells from the aliens in Battleship? Where the entire missile array is turned towards the target?

I would have to look that up again, I'm not sure if I ever saw that movie.

I was more thinking multiples of 6 tubes pointing in the +-x, +-y, and +-z directions on your ship. A combination then of ship maneuvers can line up a target fairly close (within 10-15 degrees) of one set of tubes, maneuvering on the missile itself can then correct the final vector. This ensures that at most ~mv^2 sin((pi/12)) energy is lost in the missile correction.

The more maneuverable your ship is the more you could focus your tubes in a single direction and bank on being able to line up with your target that way. The less maneuverable the more directions you would have to cover in order to ensure you can line up a shot.

[Mikey]

'Course, then you have to make space for three times the number of tubes that you actually want.

[Coalition]

So something like the missile cells from the aliens in Battleship? Where the entire missile array is turned towards the target?

I would have to look that up again, I'm not sure if I ever saw that movie.

I was more thinking multiples of 6 tubes pointing in the +-x, +-y, and +-z directions on your ship. A combination then of ship maneuvers can line up a target fairly close (within 10-15 degrees) of one set of tubes, maneuvering on the missile itself can then correct the final vector. This ensures that at most ~mv^2 sin((pi/12)) energy is lost in the missile correction.

The more maneuverable your ship is the more you could focus your tubes in a single direction and bank on being able to line up with your target that way. The less maneuverable the more directions you would have to cover in order to ensure you can line up a shot.

Here is a clip showing one of the alien ships, about the 1:09 mark you can see the small turreted cells being deployed:
https://www.youtube.com/watch?v=PktGR2t-yX4

(Not true VLS, more like small expendable projectiles being fired like an artillery or howitzer shell.)

[Lt. Staplic]

Here is a clip showing one of the alien ships, about the 1:09 mark you can see the small turreted cells being deployed:
https://www.youtube.com/watch?v=PktGR2t-yX4

(Not true VLS, more like small expendable projectiles being fired like an artillery or howitzer shell.)

Something like that could certainly have the desired effect. With 2-3 sets of those around a ship to ensure full 360* coverage you would have a relatively localized firing system as well as a small angle between your launch and target vectors.

'Course, then you have to make space for three times the number of tubes that you actually want.

This is true. Really I guess what it comes down to is which design method is going to work better for a given infrastructure:

"VLS": No ship maneuvering needed to get a missile on target. Launch equipment is localized to a series of missile tubes in one part of the ship. Launch multiple missiles at the same time. Difficult/Impossible to Reload. Either need fixed ordinance or additional machinery to deliver a payload before launch. Relatively Large amount of propellant will be needed in the missile to ensure proper targeting. Quicker from point of contact to missile launch, but slower from point of launch to impact comparatively.

Tubes: Easier to utilize variable yield missiles. Easy to reload have rapid-fire launching. Lower amounts of Delta-v will be needed by the missile to find the target. Requires higher maneuverability by the ship to line up missile launches. Large numbers of tubes spread around the ship along different vectors OR a willingness to have missile "blind spots". Slower from point of contact to missile launch, but faster from point of launch to impact comparatively.

Both systems seem to work well for larger ships: They can support larger numbers of "VLS" launchers/arrays around the ship in the same way they can easily house multiple tubes along multiple vectors.

For smaller ships I would say that a Tube system has an advantage. With the scaling of Surface Area to Volume, the smaller the ship the more difficult it is to find a large enough area to house the "VLS" array, and the fewer launchers you could have in it. While the same holds true for the Tubes, the smaller ship could be designed to capitalize on maneuverability, and focus it's tubes along 1-2 axes.

It would also appear that something like point defense system on an enemy craft would promote the use of tubes since time from launch to impact is smaller giving the enemy less time to take out your missile on approach.

[McAvoy]

Keep in mind Stargate SG-1 ships (human built like Prometheus and Daedalus) had VLS. In fact there is a really cool part where the Daedalus spammed a Wraith ship with missiles. Didn't work though.