Homing Laser

[Connor MacLeod]

The first thing I would ask is, how is the weapon depicted/portrayed/observed onscreen? for all we know its not like a "real" laser as we know it, and that greatly simplies explanations.

[Purple]

For all we know, it might just be a wire guided missile that for some reason does not tighten the wire ever but just leaves it curving behind. And than the wire for some reason glows visibly, possibly as a form of tracking the round.

[avatarxprime]

The first thing I would ask is, how is the weapon depicted/portrayed/observed onscreen? for all we know its not like a "real" laser as we know it, and that greatly simplies explanations.

There's no way it can be a real laser since lasers don't work that way. Anyway, in terms of depiction Ford Prefect nailed it with bringing up Zone of Enders. In case you haven't played the game, this is the homing laser, and here is the vector cannon, both beams can be directed with the first being a fire and forget and the second being continually emitted. For the homing laser, instead of blooming outwards and then tracking the target I would have it be fired directly at the target and then track the target's movements.

[Dwelf]

The Zone of enders game ones seem to be reasonably slow so maybe a missile might make sense. The thing that bothers me about having a missile for the effect is that we don't really see anything at the head of the beam. I was thinking of a slightly more extreme variant Eureka Seven The homing beams come in at 2 mins. I just can't see missiles replicating that effect without having to stack extra retarded onto them just to get the desired visuals.

[Darth Wong]

No matter what rationalizations you need to make it into a missile, it still works better than a winding force-fist tunnel that chokes the chicken at long range until it spooges on the target.

[Connor MacLeod]

It could be a projectile that carries photons in it or something. Or maybe it emits a laser pulse on impact. There's lots of ways to rationalize the "laser" part of it, especially since as time goes on the term "laser" tends to get used in other ways even in real life (nevermind sci fi) I mean fuck imaybe its a laser guided projectile (or laser propulsion, or whatever..)

[Ryan Thunder]

Any time I want any sort of energy weapon that doesn't behave itself i just rationalize it away as an exotic particle projector and then give it a colloquial name to go along with that so I can call it whatever I damned well please.

[StarSword]

You know, Star Wars has a version of a homing laser that actually would work, and doesn't require any technobabble. Commerce Guild spider tanks (AotC) have as one of their guns a laser turret that follows its target.

[Simon_Jester]

Um... you're remembering that there's a difference between a laser gun which is mounted in a turret that points the laser at the target, and a laser gun which fires a beam that curves in flight?

Either might be called a "homing" energy weapon, but it's not useful to compare the two types, since they're so different in effects- one can shoot around corners, the other can't, for instance.

[StarSword]

Oops.

Okay, chalk that one up to a brain fart.

[Swindle1984]

Has any sci-fi show EVER correctly portrayed lasers?

[avatarxprime]

The Zone of enders game ones seem to be reasonably slow so maybe a missile might make sense. The thing that bothers me about having a missile for the effect is that we don't really see anything at the head of the beam. I was thinking of a slightly more extreme variant Eureka Seven The homing beams come in at 2 mins. I just can't see missiles replicating that effect without having to stack extra retarded onto them just to get the desired visuals.

Yeah I know the ZOE ones are slow, they also have terrible range in the clips I picked. Connor wanted to get an idea of what I meant visually, and those do a good enough job I feel. I would certainly want them to be faster and longer ranged, but in terms of the visuals they look like what I want from a homing laser. I thought about posting the Eurkea Seven ones, but those are just too ridiculous looking with how much they bend around to track a target. The behavior of ZOE ones just feels more comfortable to me.

You know, Star Wars has a version of a homing laser that actually would work, and doesn't require any technobabble. Commerce Guild spider tanks (AotC) have as one of their guns a laser turret that follows its target.

Again, why bother with that when I can do a phased array laser that acts as both sensor and weapon all in one. Anything it tracks it can instantly turn up the juice and kill. Of course, as Simon_Jester again ended up pointing out, that's not exactly what I had in mind.

[StarSword]

The old Battlestar Galactica's hand pistols impressed me when I last saw it. (That was a long time ago though.)

It'd just flash and then cylons fall.

I'm assuming you're addressing Swindle1984 here, but feel free to correct me if I'm wrong.

I distinctly remember oBSG's "lasers" behaving like Star Wars blasters. For example, I recall the docking bay firefight in "Take the Celestra" as showing gunfire racing to and fro at decidedly sublight speeds. Clearly not lasers.

[StarSword]

So, in-universe, I guess we assume that early in the series, they were using pre-Caprica equipment that consisted of true energy weapons. Then (when Universal Hartland started doing the SFX out-of-universe), they switched to a particle-beam weapon manufactured on the fleet's factory ships. Maybe the second-gen "lasers" offered improved range or ammo capacity or something.

[Simon_Jester]

Again, why bother with that when I can do a phased array laser that acts as both sensor and weapon all in one. Anything it tracks it can instantly turn up the juice and kill. Of course, as Simon_Jester again ended up pointing out, that's not exactly what I had in mind.

Phased array lasers may be impractical to build, or impractical as a way of getting the kind of power we want out of the device.

For the real forms of lasers we've actually built and scaled up to the point where we can imagine weaponizing them, having the beam aimed by steerable "turret" optics makes a lot of sense.

[avatarxprime]

Again, why bother with that when I can do a phased array laser that acts as both sensor and weapon all in one. Anything it tracks it can instantly turn up the juice and kill. Of course, as Simon_Jester again ended up pointing out, that's not exactly what I had in mind.

Phased array lasers may be impractical to build, or impractical as a way of getting the kind of power we want out of the device.

For the real forms of lasers we've actually built and scaled up to the point where we can imagine weaponizing them, having the beam aimed by steerable "turret" optics makes a lot of sense.

Yeah but this is for a vastly more advanced then we are space-farring civilization, not "the near future." If DARPA can be playing around with creating 100kW phased array lasers now, I can have a future civilization that has developed far more powerful versions.

[Simon_Jester]

Okay, but I wouldn't sneer at non-phased array lasers either, if I were you. It's a valid concept and there are logical reasons to expect other forms of lasers to work as well or better than phased array designs for high power applications.

[Darth Wong]

If a laser is to be used as a weapon to track fast-moving or very distant targets, one must also take into account its moment of inertia about its rotational axis. A weapon with a large moment of inertia is basically "heavy", and therefore much more difficult to precisely and quickly aim at a target (you can get precise aiming or you can get quick aiming, but you can't have both at once if the object has a large moment of inertia).

Of course, if you can redirect the beam at the muzzle with some kind of low-mass device, that would greatly help. If you're talking about a large weapon system which must be rotated in its entirety, then you're going to have a lot of problems aiming it precisely at distant objects unless those objects travel along very predictable flight paths.

[avatarxprime]

Okay, but I wouldn't sneer at non-phased array lasers either, if I were you. It's a valid concept and there are logical reasons to expect other forms of lasers to work as well or better than phased array designs for high power applications.

No one is "sneering" at any kind of laser. I personally like the flexibility and additional side benefits that large-scale phased optics array represent. I'm sure something like a FEL will likely out power a phased array setup for an equal sized device, but not by such a margin as to count against all the other benefits the phased array would provide. Besides, the entire discussion is largely off-topic since I started this thread to discuss trying to replicate a homing laser.

If a laser is to be used as a weapon to track fast-moving or very distant targets, one must also take into account its moment of inertia about its rotational axis. A weapon with a large moment of inertia is basically "heavy", and therefore much more difficult to precisely and quickly aim at a target (you can get precise aiming or you can get quick aiming, but you can't have both at once if the object has a large moment of inertia).

Of course, if you can redirect the beam at the muzzle with some kind of low-mass device, that would greatly help. If you're talking about a large weapon system which must be rotated in its entirety, then you're going to have a lot of problems aiming it precisely at distant objects unless those objects travel along very predictable flight paths.

Wouldn't this then funnel back to what Sea Skimmer was talking about earlier with the design for the ABL, massive laser with quick moving beam guide to direct the beam at targets?

[Simon_Jester]

If a laser is to be used as a weapon to track fast-moving or very distant targets, one must also take into account its moment of inertia about its rotational axis. A weapon with a large moment of inertia is basically "heavy", and therefore much more difficult to precisely and quickly aim at a target (you can get precise aiming or you can get quick aiming, but you can't have both at once if the object has a large moment of inertia).

Of course, if you can redirect the beam at the muzzle with some kind of low-mass device, that would greatly help. If you're talking about a large weapon system which must be rotated in its entirety, then you're going to have a lot of problems aiming it precisely at distant objects unless those objects travel along very predictable flight paths.

So far, the only working laser cannon I know of use a large fixed machine to generate the beam, and a steerable set of turret optics that can redirect at the muzzle. The turret optics are relatively low-mass.

Nor are lasers the only kind of 'energy weapon' that makes this possible. With a charged particle beam you can do fine-adjustment redirection at the muzzle using a set of dipole magnets; you don't even need moving parts.

[Starglider]

A sufficiently large number of fast homing projectiles will look like a beam from a distance. In Stargate SG-1 and Atlantis, the huge swarms of drones they use to blow up large ships do look like curving beams (albeit slow ones) in the wide shots. Even restricted to hard sci-fi technology you could salvo millions of antimatter powered thimble-sized hyper-accelerating smart missiles, which probably would look like a curving glowing beam from any significant distance. It would be an effective way to overwhelm some kinds of point defence - although for that you'd probably want the 'beam' to diverge into a 'cloud' for the close approach to the target.

[StarSword]

Here's an absolutely bizarre version of a homing laser (the OP type): the link gun from Unreal Tournament 2004.


(Sorry about the huge image. Couldn't find one smaller and I don't have the demo anymore.)

Not only is it a bendy-beam laser IIRC, it hurts enemies and heals friends.

[Batman]

Were, exactly, does it bend? It fires slightly off-axis, that is all.

[StarSword]

It doesn't bend in the image, no, but that's a stationary target. If I remember gameplay (and it's been a few years, I'll admit), if you target other players it bends to follow them.

[Connor MacLeod]

what he means is: "does it come from the barrel off axis, but stay essentially straight from gun to target, or does it actually curve in the air or bend in any obvious way like a projectile or reflected beam would?