Speed of energy weapons in space

[Kagashi]

So, having a discussion with my buddy, we put up Robotech ships and mecha against Phase World ships and bots. The standard "power vs range" issue came up where Robotech ranges usually out range Phase World and Phase World usually can take a lot more damage and deal more damage than Robotech (minus Reflex/Syncho Cannons).

In the discussion of the scenario, we figured missile volleys would initiate the attack due to their 1000+ mile ranges, which usually out-range any other weapon system from either dimension. Then we looked at speeds...

Robotech Reflex Multi Warhead missiles fly "Mach 3" (which is a static 2010 mph in Palladium) and no indication that they fly faster in space. In a copy/paste coincidence, Rifts Nuclear Multi-Warhead missiles fly at the same speeds with the same range, making these missiles on both sides the longest range and fastest missiles in the scenario. (most examples of craft seem to fly 3 x faster in space than in atmosphere).

So if each fleet managed to detect each other at max range (1800 miles) and launched a massive volley, both volleys would take darn near an hour to reach the intended target. That is enough time to finish that episode of Dr. Who you started, grab a snack, and take a shower...then worry about defensive maneuvers/countermeasures.

Furthermore, once the volley arrived, most ships, even capitol ships, can OUTRUN the slow Mach 3 flying missiles. Some sub-light speeds are up to Mach 25 (granted in a straight line, but still...) Kittani Transformable Fighters fly in space at Mach 9. Unless you are going to hit these targets straight on, its going to be extremely easy for a target to simply put distance between themselves and the warhead. (Dog fighting, according to Phase World, happens at speeds under Mach 2, so the missiles would be better used at closer ranges...in an environment where dog fighting would occur).

For energy weapons, things are a little easier to hit with. Lasers can be assumed to move at the speed of light (some say slightly slower, but for sake of argument...SOL). So really at 186,000 miles per second, those strikes are going to be near instantaneous the moment the weapon is in range of the target (well within the end of the attack in which it was initiated).

But the question really is...what about other energy weapons like P Beams, Plasma Blasts, Disruptor Pulses and so on? Does anybody have any PB data on how fast these energy weapons travel? How about rail guns? Or Auto Cannons? Since it is a physical piece of metal flying through space...is it as slow as the fastest missile?

And lastly, a sub-question...should missiles receive the x3 faster in space treatment (or if its been established already, what is the source)?

[flatline]

Lasers: speed of light.

Particle beams: efficient particle beams should be close to the speed of light (say 0.9c or greater to be really worth while, but anything above 0.5c is probably good enough). Less efficient particle beams (aka "matter streams") would be much slower and would probably rely on dealing damage through some other mechanism than kinetic energy (say anti-matter or something).

Plasma weapons are physically impossible if they're actually shooting plasma.

Disruptors: no idea what these are.

Ion guns: sub-set of particle beams

--flatline

[Kagashi]

Lasers: speed of light.

Particle beams: efficient particle beams should be close to the speed of light (say 0.9c or greater to be really worth while, but anything above 0.5c is probably good enough). Less efficient particle beams (aka "matter streams") would be much slower and would probably rely on dealing damage through some other mechanism than kinetic energy (say anti-matter or something).

So really, instantaneous in terms of game mechanics (the beam will hit before the attack is even over), even at longest range of the weapon system.

Disruptors: no idea what these are.

Golgan Republic uses em...upon further reading they are just laser energy. So SOL.

Ion guns: sub-set of particle beams

--flatline

Plasma weapons are physically impossible if they're actually shooting plasma.

Regardless, they exist in Palladium games. Notably Naruni, but many other societies as well to include the Coalition and other lesser technologically advanced societies. Seems we should just lump all "energy" weapons into the instantaneous category.

[drewkitty ~..~]

In the AU:GG book it talks about the ranges of the ship-to-ship weapons, missiles being a part of the mix, that the range of missiles are half as long in an atmosphere. However, the ranges listed in the HU2MB are listed for use in atmo.

Then there are those missiles that used only in space which are listed for the same ranges as LRMs.

I would take ALL the ranges stated as "In Atmo 'powered' Ranges" and double the ranges. However, doubling w/o touching the speed stats cause the longer ranged space optimized missiles have "crusing segments" built into their ranges. Examples being the names of the two biggest missile types "cruse missile" from the 3G books and "ballistic missiles" from AU:GG book. (I see them as equivalent classes of missiles, the names and SD/MD warheads being the only differences.)

Disruptors......(this name I used for magic enegry disruptor ship2ship weapons in the rifter artical I'm writing).....Magic weapons!...it depends, some are instantanius/faster then light, while others create effects that move at slower speeds, while other magics are carried by projectiles.

[Kagashi]

AU:GG certainly indicates there should be a range increase of the missiles (and likely auto cannons, rail guns, and other kinetic weapons). Now the question is, the missile ranges in both Rifts and Robotech for atmo? Rifts...I'd say yes, but Robotech is debatable.

Id think those speeds would double or triple as well.

[The Beast]

And lastly, a sub-question...should missiles receive the x3 faster in space treatment (or if its been established already, what is the source)?

Huh. This is something no one I've played with ever considered. My guess is that the speeds listed are for atmo, and therefore should get the multiplier. However, unless there is clear indication somewhere (I only have the 1st ed books) we'll never know unless PB clarifies it.

EDIT: After a quick check, the speeds listed in the Robotech book are the same as the ones in Invid Invasion.

[Tor]

I know this is something that will vary to planet to planet, atmospheres having different heights based on gravity, density, gas composition...

But since Earth (in various variations) is the most common 'main planet' amongst all the PB games...

Does anyone recall if, whether if be Phase World, Mutants in Orbit, HU or Robotech...

Where space begins? Like at what point you go from being 'in an atmosphere' to 'in space'?

This would be a major factor since many of the ships have variable weapons ranges, to know how low they have to come to be able to bombarb the surface of a planet.

MiO mentions that there is a 940 mile 'lower orbit' which some kill sats circle at. It apparently isn't geosynchrinous. I'm thinking that means the planet rotates faster than they can due to air resistance or something. The geosyncronous orbit is higher up, I assume the sats there go faster since no air resistance?

I'm not even sure if this lower orbit is atmosphere or space though... bleh. It's important to know since kill-sat weaponry also has variable range in atmosphere/space. It would let us know how far they can shoot, how hard they are to shoot down, etc.

[flatline]

The lower your orbit, the faster your orbital velocity must be.

Here's a handy graph (careful, it takes a moment to figure out how to read):
http://en.wikipedia.org/wiki/File:Compa ... orbits.svg

Here's another interesting image that gives you an idea how far the atmosphere extendes (the blue glow around the Earth):
http://upload.wikimedia.org/wikipedia/c ... itudes.jpg

Notice how far the Moon is from the Earth (look at the bottom).

--flatline

[Tor]

Those are some pretty awesome images... definitely prefer the 2nd to the first, easier to take in.

I guess the question is... when the change-over occurs in relation to the LEO/MEO/HEO heights above sea level...

https://en.wikipedia.org/wiki/Atmosphere_of_Earth mentions:

"Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km (75 mi)"

so I'm wondering if that might be used as a rough guideline as to when the range-multipliers of space guns take place.

Then again, it also says:

"The atmosphere has a mass of about 5.15×1018 kg,[2] three quarters of which is within about 11 km (6.8 mi; 36,000 ft) of the surface."

Realistically, the range-extension of weapons from atmosphere>space would probably happen gradually as the atmosphere thinned until it became non-existent. There would probably be some middle ground in the 11km>120km area, I'm just not sure how much.

https://en.wikipedia.org/wiki/Atmospher ... pal_layers breaks it down into

Exosphere: 700-10,000 km (440-6,200 miles)
Thermosphere: 80 to 700 km (50 to 440 miles)
Mesosphere: 50 to 80 km (31 to 50 miles)
Stratosphere: 12 to 50 km (7 to 31 miles)
Troposphere: 0 to 12 km (0 to 7 miles)

per above the Trop-osphere is where over 75% of the atmospheric mass is, even though it is the shortest and, the way sphere volume works, would take up the least amount of volume due to small surface area. I think once you begin climbing above 7 miles from sea level is when weapon ranges should start to increase.

Would be cool if we could get some rules regarding these intermediary heights off earth and how much extra range the different weapon types get as the atmosphere thins. Since missiles/lasers/plasma/particle beams and similar sometimes function with different multipliers to their atmospheric base range, to get a consistent treatment for the types would be pretty cool.

Also an interesting thing about this: LRMs can fire up into the exosphere, and LEO satellites (lower than 2000km altitude) would often be in their range. The CS might plausibly be shooting down some of the low-hanging killer-stat fruit from MiO based on this.

[Lukterran]

The problem you are having is that Palladium Books wasn't attempting to be super accurate with all those stats and numbers. It was just trying to give a simplified number for being able to conduct combat for something that I doubt that staff truely put a lot of time and thought toward combat in space vs. earths atmosphere.

Not only would missiles go faster in space. They would continue to increase in speed until their fuel supply was depleted. Space missiles would require special manuevering thrusters to stay on target as well. (If they are smart warheads).

I am not sure about railgun speeds. I am sure that in the future tech worlds like Phase World etc... the speeds would be faster. However, the rail gun that the Navy developed today fires projectile rounds at hypersonic velocities of approximately 2.4 kilometres per second (8,600 km/h) or about 5,300 mph. (That is in earth atmosphere, it woud be faster in space).

Plasma weapons would probably travel the slowest firing high-energy ionized gases.

Particle Beams, Ion Guns and Laser weapons would be at or jus under the Speed of Light.

I am assuming disrupters are just another energy type weapon. So speeds would be about the same.

Regardless of all that non-sense. I would probably just use the KISS rule. And assume that missiles and other weapons travel fast enough for them to be applicable in combat terms and perhaps give more time to manuever or do other actions when engaging in combat at extreme ranges.

[kb001]

The problem you are having is that Palladium Books wasn't attempting to be super accurate with all those stats and numbers. It was just trying to give a simplified number for being able to conduct combat for something that I doubt that staff truely put a lot of time and thought toward combat in space vs. earths atmosphere.

Not only would missiles go faster in space. They would continue to increase in speed until their fuel supply was depleted. Space missiles would require special manuevering thrusters to stay on target as well. (If they are smart warheads).

I am not sure about railgun speeds. I am sure that in the future tech worlds like Phase World etc... the speeds would be faster. However, the rail gun that the Navy developed today fires projectile rounds at hypersonic velocities of approximately 2.4 kilometres per second (8,600 km/h) or about 5,300 mph. (That is in earth atmosphere, it woud be faster in space).

Plasma weapons would probably travel the slowest firing high-energy ionized gases.

Particle Beams, Ion Guns and Laser weapons would be at or jus under the Speed of Light.

I am assuming disrupters are just another energy type weapon. So speeds would be about the same.

Regardless of all that non-sense. I would probably just use the KISS rule. And assume that missiles and other weapons travel fast enough for them to be applicable in combat terms and perhaps give more time to manuever or do other actions when engaging in combat at extreme ranges.

KISS rule would most likely be the best bet. However, you could calculate the delta V or terminal velocity after the rocket motors had expended all their fuel, as w/o atmo. then the projectiles inertia will keep building up until it has burned out all its fuel which I would say for single stage motor, 2min would be about it, and if its a cruise missile that's air breathing then it is not going to fly in space at all. Yet most solid fuel missiles flying at mach. 3.5 w/ long range like bombac or nike, or USSR S400 or patriot fly only 40-150mile w/ some specs. Anyways flying at around 1Km per sec.w/ 15-25 sec ramp up maybe more, leaves less then 2min burn time, plus the type of fuel, nozzle size and shape, launch platform and other variables affect terminal velocity. I would guess 10-12Km/s as average and maybe as high as 30-40km/s for multi-stage and such. One pt that another person made is that once the missiles juice is gone all you need to do is side step it. even w/ vector thrusting mini nozzles to change course you need to over come some of the projectiles already established velocity. You can't just fart to the left and expect the missile to go totally to the right b/c in space you have to resistance and that left fart would only make the missile face right while still travelling on it original course.

[ShadowLogan]

Disruptors: no idea what these are.

In Robotech, they are basically a particle beam type weapon that can create holes inside force fields. The hole is such that you can drive a vehicle through by passing the forcefield, at least in regard to the area the hole is influencing on the force field.