A bigger, better Harrier

[locarno24]

The ship works fine in the right context. I found that in practice the Barbette doled out a lot more damage than 4Dx3 would suggest. It has +4 from software and the accurate trait. With a +3 gunner like my group had*, the crit's made it devastating against small ships. Even an average hit damage wise on say an Empress Marava, is likely to be in the 35-50 damage range (the weapon is high yield). On a 80HP ship, that's 44-62% damage before you add the crits.

*My former group already had a ship when starting the campaign. They ended up using that ship, plus a few they captured, to do all the pirating, and used the Harrier as the Drinaxian cavalry riding in to save the day. They got both loot AND a positive reputation... and I learned one of my players knew the plot ahead of time.

The first major bit of work done to the Harrier last time we played it was replacing the remains of the missile rack with an accurate triple beam laser - partly for point defence and partly for called shots that don't blow the target to rapidly expanding fragments.

 

[locarno24]

By measuring how long it takes laser light to bounce back — about 2.5 seconds on average — researchers can calculate the distance between Earth laser stations and Moon reflectors down to less than a few millimeters. This is about the thickness of an orange peel.

Laser Beams Reflected Between Earth and Moon Boost Science - NASA

Dozens of times over the last decade NASA scientists have launched laser beams at a reflector the size of a paperback novel about 240,000 miles (385,000

www.nasa.gov

That is over 384,000km, way beyond that range of most Traveller space combat. 2.5 seconds in a 6-minute combat round is nothing. That is 144 times every round. There and back for active sensors. Half of that for lightspeed weapons fire and passive sensors.

"Dozens of times over the last decade NASA scientists have launched laser beams at a reflector the size of a paperback novel about 240,000 miles (385,000 kilometers) away from Earth."

We can accurately target something the size of a paperback novel at 385,000km currently and hit it. I am going to guess that targeting the M-drive on a 100-ton ship should be much easier, even if it is moving independently, considering it is several thousand times the size.

Lets slightly clarify: they're not firing a beam that hits the reflector as a targeted point. By the time the beam they're using reaches the Moon's surface it's about six and a half kilometres across. That's the same issue with laser-fire in space combat. Hitting a starship at 25,000 km with a laser that (given the same beam width) is about 300 metres across is easy. Hitting a point on a starship with a tight-focus beam maybe a metre across (given the ability to hit one turret out of an adjacent pair) and holding the laser on that point (give or take) for a long enough proportion of the 6-minute combat round to impart enough energy to do damage whilst it tries to accelerate, roll and generally shimmy about to STOP you doing that is quite another.

 

[locarno24]

The math came out to something like less than a thousandth of a second and a movement of less than a meter at 1,000km or something like that. Might have been 10,000km. I do not recall off the top of My head.

At the edge of medium range (10,000km), you're 0.03 light seconds from the target, so you're looking at a 0.03s old image and your speed of light shot takes 0.03s to arrive, meaning about 0.65m unobservable evasion per G of acceleration. On a big, fat freighter it means nothing but stopping you holding your fire on a single spot easily but obviously something like a TL15 Navy Heavy Fighter can easily generate half-a-dozen metres of evasion (thrust 9) which is significantly more than its centreline-to-edge width.

 

[MasterGwydion]

Lets slightly clarify: they're not firing a beam that hits the reflector as a targeted point. By the time the beam they're using reaches the Moon's surface it's about six and a half kilometres across. That's the same issue with laser-fire in space combat. Hitting a starship at 25,000 km with a laser that (given the same beam width) is about 300 metres across is easy. Hitting a point on a starship with a tight-focus beam maybe a metre across (given the ability to hit one turret out of an adjacent pair) and holding the laser on that point (give or take) for a long enough proportion of the 6-minute combat round to impart enough energy to do damage whilst it tries to accelerate, roll and generally shimmy about to STOP you doing that is quite another.

So, you are saying that lasers in Traveller do not actually work the way they say in the books since We haven't figured out how to focus them at range yet? I am pretty sure that if you make that the standard, We won't have a game left to play that isn't an historical game. No Jump Drives. No M-Drives. No artificial gravity. No fusion power. No arcologies. No anagathics. etc...

 

[Sigtrygg]

Yes, Traveller laser performance is totally space magic.

It doesn't have to be. it is possible to do the real world calculations for fictional laser parameters (input energy, efficiency) in order to rate them for damage at various ranges - beam area, diffusion.

The combat range would likely be in the thousands of km at the energy input of Traveller lasers. Not a lot else would really have to change.

 

[MasterGwydion]

Yes, Traveller laser performance is totally space magic.

It doesn't have to be. it is possible to do the real world calculations for fictional laser parameters (input energy, efficiency) in order to rate them for damage at various ranges - beam area, diffusion.

The combat range would likely be in the thousands of km at the energy input of Traveller lasers. Not a lot else would really have to change.

I just figured that they figured out how to focus lasers to meet the parameters set forth in the books. Out of those two things, laser characteristics and targeting, targeting would seem to be the easier of the two to accomplish.

 

[Condottiere]

There's a reason that in the Honorverse, all tactical combat decisions are made and carried out by computer programmes.

If we're still in the loop, it gets delayed.

 

[Sigtrygg]

I just figured that they figured out how to focus lasers to meet the parameters set forth in the books. Out of those two things, laser characteristics and targeting, targeting would seem to be the easier of the two to accomplish.

Diffusion is the issue, not focus. They used magic laser focussing.

 

[Sigtrygg]

There's a reason that in the Honorverse, all tactical combat decisions are made and carried out by computer programmes.

If we're still in the loop, it gets delayed.

The computer tales your reaction time into account.

I don't think in Traveller ship combat there is a guy sitting in a ball turret looking out the window and seeing the incoming fighters, swinging the ball turret and lining up crosshairs to lead the fighter... the only thing that they get right is the computer says fire now and you fire now (the computer has already taken your reaction time into account).

 

[MasterGwydion]

Diffusion is the issue, not focus. They used magic laser focussing.

Doesn't more focused mean less diffuse? A laser that has a 1mm cross-section at 100m is more focused than a laser with a cross-section of 5mm at 100m. Doesn't saying that something is less diffuse means that that something is more focused?

 

[Condottiere]

I suspect, in Traveller, prediction and fire control programmes have to be specified.

Otherwise, the Gunner skill becomes irrelevant.

 

[Sigtrygg]

Doesn't more focused mean less diffuse? A laser that has a 1mm cross-section at 100m is more focused than a laser with a cross-section of 5mm at 100m. Doesn't saying that something is less diffuse means that that something is more focused?

The diffusion is caused by diffraction, there is a limit to how focused a beam can be. Diffraction dues to the laser waves/photons interfereing with each other leads to spread or diffusion, which means your 1cm² beam is going to spread regardless of how focused it is when it comes out of the emitter/mirror.

 

[MasterGwydion]

The diffusion is caused by diffraction, there is a limit to how focused a beam can be. Diffraction dues to the laser waves/photons interfereing with each other leads to spread or diffusion, which means your 1cm² beam is going to spread regardless of how focused it is when it comes out of the emitter/mirror.

Does this mean that it is impossible to emit them perfectly in-sync and parallel? Even at advanced TLs? So that they don't interfere with one another.

 

[Sigtrygg]

Yup, waves interfere with each other, its what waves do

(I should caveat all this with the real world limitation being more likely the actual laser machinery itself, but assuming a perfect beam emitted from your laser array the beam will undergo diffraction which causes beam spread/diffusion)

 

[Geir]

Lasers are all about mirror size and wavelength and the resultant diffraction.
See:

Beam Weapons - Atomic Rockets

www.projectrho.com

The 'Dull Equations" section.

For best range, you need a short wavelength and a big mirror (or is that a short skirt and a long jacket? I get confused)

 

[MasterGwydion]

What if the light was tuned using gravity instead of a mirror? We know that gravitic lensing is a thing when observing distant energy sources. Couldn't you have a controlled version of this to make a laser? Would you still have the same issue?

 

[collins355]

Yes, TNE went through all this. You need to introduce magictech to explain how Traveller lasers can be useful as weapons at the ranges Traveller has traditionally had them operating. In TNE that magictech was called gravitatic focusing. See pages 123 onwards of TNE/FF&S.

 

[MasterGwydion]

Yes, TNE went through all this. You need to introduce magictech to explain how Traveller lasers can be useful as weapons at the ranges Traveller has traditionally had them operating. In TNE that magictech was called gravitatic focusing. See pages 123 onwards of TNE/FF&S.
View attachment 4883

Not sure that I would consider gravitic focusing as "magictech", since gravitational lensing is a real thing. Unless airplanes, cars, elevators, hydroelectric dams, etc are magictech as well... Not like, well, jumpspace, which has no basis in reality.

 

[collins355]

Not sure that I would consider gravitic focusing as "magictech", since gravitational lensing is a real thing. Unless airplanes, cars, elevators, hydroelectric dams, etc are magictech as well... Not like, well, jumpspace, which has no basis in reality.

We had long debates about this on TML and sister lists.

Suffice to say, some people (including real physicists who were on the mailing list) consider this magictech and others do not. I'm perfectly willing to suspend disbelief for this technology so we can have the laser ranges we're used to in Traveller (after all, we have jump drives and contra grav as you correctly point out).

 

[Condottiere]

Refined magnetic bottle focussing.