Missiles in Megatraveller

[Carlobrand]

What would the effect of ablative armor in the missiles be? ...

Trivial. The ship's laser's supposed to be able to punch through ship armor, which starts at equivalent to a foot of steel. That's close to two inches of bonded superdense armor on a missile that's supposed to come in at 50 kg with fuel, warhead and guidance. It isn't carrying armor, and any conceivable ablative coat that would be as effective without impairing the missile would also be a dandy armor for a ship, even if it were only good for a few hits.

...I assume the missiles to take evasive moves while in movement to their target. If so, the probablility to be hit while pointing the arget is quite remote, so one hit is one miss for them. And remember odds are the arget is also evading at very high speeds...

First, at terminal stage there is no evading: the delay between the missile image reaching the sensor and the laser reaching the missile is measured in milliseconds, even at ranges of a few hundred kilometers. The missile dives in and "hopes" for the best because nothing short of an instant teleport device is going to save it if the laser is on target.

Second, you're looking at missiles closing at velocities in the tens of kilometers per second and suggesting that a lateral thrust of less than a meter per second is going to significantly alter its impact point. Maybe if it's a few hundred klicks out with several seconds yet before impact, but not if it's only a second from impact.

At 6G, a ship can displace itself 30 meters in a second. Assuming the missile is reasonably on target before it's killed and that it's killed one second out, the craft able to move out from under in that time are the boats and the smaller ships, roughly a thousand dTons and under. Given, say, five seconds, the ship can displace itself 750 meters - which is enough to save even a dreadnought.

... Ships lasers retain high probabilities of hit for hundreds of kilometers.

And that's my thought: the lasers are killing the missiles, or trying to, at ranges of hundreds of kilometers. If they can hit ships at light-second ranges, they can hit missiles at a thousandth of that range. If you wait till you're guaranteed to hit, he is too. (On the other hand, I would still expect better laser accuracy than we're getting.)

In any case, as MT is depicted (and as tables are shown), I'd expect most of orbital pinpoint fire to be conducted by beam weapons (lasers and energy weapons, PA may also help if there's no atmosphere and if you want their nuke-like effect), while the missiles only used for area fire (mostly against dispersed infantry, too numerous to be taken off by pinpoint fire), ...

Why? Missiles as portrayed in Striker are quite effective. They drop from orbit and then home in on a detected target, better than a laser-guided bomb since they have their own guidance and their own drives to pursue the target. Odds of a hit are quite a bit better than by indirect fire rules using orbital beam weapons. Only drawback is point defenses, and enough missiles will overwhelm that. Since MT draws heavily on Striker, I'd expect similar behavior.

...Those beams are quite lethal and precise in atmosphere, do not use ammo (if you're attacking a hostile planet cargo space would be at a premium), and are more difficult to stop by PD weapons, so I expect them (and fighters) to be the main ortillery weapons, instead of missiles.

Ship lasers and energy weapons in MT have a range attenuation of 5, which means they're full penetration to 500 meters in atmosphere, half pen from that point to 50,000 km. Effectively, they're half pen when fired from orbit at targets on the battlefield. MT did away with that armor face business that Striker had, so for example a TL13 beam laser fired from orbit, hitting a Zhodani Z-80 tank matches its penetration of 37 against an armor of 40 - it doesn't penetrate. Useful against thinner-skinned vehicles and troops, of course.

Pulse lasers and energy weapons have good punch and a decent danger space, but penetration declines quickly away from point of impact: half at 1.5 meters, quarter at 3, one eight at 4.5 and so forth. Outside of 3 meters, they won't penetrate TL14 combat armor. Outside of 4.5 meters, they won't penetrate the TL12 stuff. Something with an armor rating of 52 will withstand a fusion-15 fired from orbit.

Despite being straight-line weapons, orbital beam artillery must still use indirect fire rules. Someone has to spot for them. Indirect fire is a difficult task (11+ on 2D6 to hit the target zone) with a bonus for Forward Observer skill. I'm not sure what the role is for those in the area to be hit if you hit the right area. It's also "fateful": a mishap is guaranteed if the task fails. I am ambivalent about that rule. Not every miss in indirect fire results in a friendly fire incident.

 

[Ulsyus]

Not every miss in indirect fire results in a friendly fire incident.

That depends on how close the friendlies are, and how big the area is that the battery puts its fire into.

Oh, plus the random (if you want) element of what the FO/spotter put into the firing process that contributed to it missing the target.

 

[McPerth]

At 6G, a ship can displace itself 30 meters in a second. Assuming the missile is reasonably on target before it's killed and that it's killed one second out, the craft able to move out from under in that time are the boats and the smaller ships, roughly a thousand dTons and under. Given, say, five seconds, the ship can displace itself 750 meters - which is enough to save even a dreadnought.

Where do you take from those 30 m/s?

After a full turn of acceleraton ,a 6G ship will go as fast as you told us for the missile, and they're likely to have been accelerating for more than one turn

Why? Missiles as portrayed in Striker are quite effective. They drop from orbit and then home in on a detected target, better than a laser-guided bomb since they have their own guidance and their own drives to pursue the target. Odds of a hit are quite a bit better than by indirect fire rules using orbital beam weapons. Only drawback is point defenses, and enough missiles will overwhelm that. Since MT draws heavily on Striker, I'd expect similar behavior.

As I said, one of the reasons is to sabe the missiles, as they are expensive and need cargo space to take the reloads to the combat, something that will be at premium when you're attacking a hostile planet. This same cargo space needed in your supply ships to bring missiles can be used to carry other supplies.

Ship lasers and energy weapons in MT have a range attenuation of 5, which means they're full penetration to 500 meters in atmosphere, half pen from that point to 50,000 km. Effectively, they're half pen when fired from orbit at targets on the battlefield. MT did away with that armor face business that Striker had, so for example a TL13 beam laser fired from orbit, hitting a Zhodani Z-80 tank matches its penetration of 37 against an armor of 40 - it doesn't penetrate. Useful against thinner-skinned vehicles and troops, of course.

Just a technicism here, close range does not count for attenuation (it begins at short range), so the full pen, with an attenuation of 5 is up to Distant range (5 km), and half pen is up to Far Orbit (500000 km). Of course, this doesn't void your argument too much (at most for ver thin atmospheres, once the modifiers given in RM page 23 are aplied, as full penetration will go up to 50 km), as ortillery is expected to be from farther than 5 km, as I said, just a technicism to make rules clear...

This said, ok, pen is halved. That means it achieves only zero penetration results against anything with armor over 35-40. As I expect those targets to be vehicles, with zero penetration damage they will receive "only" 10% hits as structural damage (that's among 50 hits for a Blaser-8 to 90 hits for a fusion turret)...

How many vehicles can sustain that?

Pulse lasers and energy weapons have good punch and a decent danger space, but penetration declines quickly away from point of impact: half at 1.5 meters, quarter at 3, one eight at 4.5 and so forth. Outside of 3 meters, they won't penetrate TL14 combat armor. Outside of 4.5 meters, they won't penetrate the TL12 stuff. Something with an armor rating of 52 will withstand a fusion-15 fired from orbit.

As said, they would be used for pinpoint fire, not for area fire.

Despite being straight-line weapons, orbital beam artillery must still use indirect fire rules. Someone has to spot for them. Indirect fire is a difficult task (11+ on 2D6 to hit the target zone) with a bonus for Forward Observer skill. I'm not sure what the role is for those in the area to be hit if you hit the right area. It's also "fateful": a mishap is guaranteed if the task fails. I am ambivalent about that rule. Not every miss in indirect fire results in a friendly fire incident.

While I agree that's what is in the rules, see that this means that a ship weapon has lower possibilities to hit a ground location (even if stationary, as it's treated as indirect fire) that a fast moving small craft in space, as in space the computer will have a big impact in accuracy, while in ortillery fire it will not...

About the mishap, as I understand last paragraph in PM page 73, it only means scattering, not friendly fire or weapon malfunction (and hence the modifier for FO skill)

 

[jec10]

Note that the Special Rules on MT RM pp91-92 cover the use of starship weapons as ortillery.

I agree with Carlobrand that the rules as written do not envisage the use of weapons on orbiting starships for pinpoint attacks. You have to use them as offboard artillery and hence your chances of getting a direct hit on a target are low unless you have a highly skilled forward observer with eyes on the target.

If you do get a direct hit then the 10% structural damage rule for zero penetrations against vehicles means an almost certain kill against most vehicles hit by starship weapons.

 

[McPerth]

Note that the Special Rules on MT RM pp91-92 cover the use of starship weapons as ortillery.

I guess you mean MTM (not RM), page 92...

If you do get a direct hit then the 10% structural damage rule for zero penetrations against vehicles means an almost certain kill against most vehicles hit by starship weapons.

See that this same zero penetration hit will do no damage to an individual with fully enclosed armor (as vacc suit, CA or BD).

So a near miss that reaches with pen 5 a tank with armor 40 and a man with TL 12 vacc suit (armor 6) is likely to destroy the tank while levaing the infantryman unhurt ...

 

[Carlobrand]

Where do you take from those 30 m/s?

After a full turn of acceleraton ,a 6G ship will go as fast as you told us for the missile, and they're likely to have been accelerating for more than one turn...

Postulated scenario was trying to get out from "under" a missile that had just been killed by your point defenses. You would not have a full turn to react under those circumstances. You would have only the time between the instant your point defense killed the missile and the instant the dead missile coasted the remaining distance to you. If you kill the missile while it's one second away - which could be tens of kilometers distant - then you'll only move 30 meters by the time it reaches the place you were when you shot it. If you kill it while it's farther away, then you can move farther and have a better chance of getting out from "under" the "falling" missile.

...As I said, one of the reasons is to sabe the missiles, as they are expensive and need cargo space to take the reloads to the combat, something that will be at premium when you're attacking a hostile planet. This same cargo space needed in your supply ships to bring missiles can be used to carry other supplies. ...

Maybe, but you presuppose that an attacker is not going to give adequate attention to his supply chain. Supplies are what win or lose wars. If the circumstances make the missile the more effective bombardment weapon, and the attacker forgoes the option because he hasn't invested enough in transport and defense of his supply line, then he merely weakens his ground offense. He may suffer needless casualties or lose the ground war because he tried to cut corners on his supply chain. Forgoing the missile option sounds more like something one is forced to do because something went wrong elsewhere than like a sound military decision.

...Just a technicism here, close range does not count for attenuation (it begins at short range), so the full pen, with an attenuation of 5 is up to Distant range (5 km),...

Whup, you're right, my bad.

...This said, ok, pen is halved. That means it achieves only zero penetration results against anything with armor over 35-40. As I expect those targets to be vehicles, with zero penetration damage they will receive "only" 10% hits as structural damage (that's among 50 hits for a Blaser-8 to 90 hits for a fusion turret)...

How many vehicles can sustain that?...

As I mentioned earlier, the zero-pen/structure damage rule is broken. While I'm perfectly willing to accept killing a tank because it got washed in enough hot plasma to cause a breakdown, I can also kill a tank by having a company of riflemen open up on it. Random chance means many will achieve exceptional hits, which have a minimum damage of 1 or more. Even without that, you can basically nick a heavily armored target to death with enough hits. I don't know what the solution is, but until I see one, I'm not ready to rest my hopes on zero-pen damage.

...As said, they would be used for pinpoint fire, not for area fire. ...

Yes, but missiles can be more effective in that role.

...While I agree that's what is in the rules, see that this means that a ship weapon has lower possibilities to hit a ground location (even if stationary, as it's treated as indirect fire) that a fast moving small craft in space, as in space the computer will have a big impact in accuracy, while in ortillery fire it will not...

Yup. Different challenge. Targeting a ship in space means using your mass sensor, EM sensors, neutrino sensors, and so forth to pinpoint a distant radiating mass sitting alone in vacuum. Targeting a vehicle on the ground means doing that against the backdrop of a planet's surface. Difficult to evaluate whether the rules are "right" or "wrong" on that score: one presumes the ground target will be using whatever means are at its disposal to evade orbital detection - camouflage netting, protective coloration, chill cans, whatever. However, a lot of these vehicles are using fusion plants, and while they're a lot smaller than a cruiser, they're also a whole lot closer. Still, the rules don't allow one to sit in orbit and pick off individual tanks by direct fire - and even if accurate, that would pretty much eliminate the ground combat picture, which might be unpopular play-wise.

...So a near miss that reaches with pen 5 a tank with armor 40 and a man with TL 12 vacc suit (armor 6) is likely to destroy the tank while levaing the infantryman unhurt ...

Yup. Broken. Exceptional hit rule still gives you some hope of hurting the man in the vacc suit, but a pen 5 result is anything from a rifle shot to standing too close to an HE round. Maybe the rifle shot won't do more than leave a nasty bruise through armor, but I'm under the impression that being suddenly accelerated away from the point of an explosion can be quite hard on a person even when he's heavily armored.

 

[McPerth]

Postulated scenario was trying to get out from "under" a missile that had just been killed by your point defenses. You would not have a full turn to react under those circumstances. You would have only the time between the instant your point defense killed the missile and the instant the dead missile coasted the remaining distance to you. If you kill the missile while it's one second away - which could be tens of kilometers distant - then you'll only move 30 meters by the time it reaches the place you were when you shot it. If you kill it while it's farther away, then you can move farther and have a better chance of getting out from "under" the "falling" missile.

I see I didn't explain myself as well as I thought. I was refering to the ship's built up speed (as I expect it to have been accelerating for several turns before engaging).

Unless the missile comes from directly ahead (in which case the targer would be smaller, BTW), the ship will move quite more in one second that the 30 m you said, and it will be evading, so this movment will not be in straight line.

Maybe, but you presuppose that an attacker is not going to give adequate attention to his supply chain. Supplies are what win or lose wars. If the circumstances make the missile the more effective bombardment weapon, and the attacker forgoes the option because he hasn't invested enough in transport and defense of his supply line, then he merely weakens his ground offense. He may suffer needless casualties or lose the ground war because he tried to cut corners on his supply chain. Forgoing the missile option sounds more like something one is forced to do because something went wrong elsewhere than like a sound military decision.

As much attention as the atacker has put to supply, things will sure go stretched, as the needs are enormous. To refill a single 100 dton bay, you need about 10 dt (according to MT:RM, page 74), so, to fill a cruiser you can need a full shipload of supplies, and you must carry them separately fron the ones you'd use for anti-ship role, as I guess they are quite different warheads.

Also, if your bomber ships are loaded with ortillery missiles, those are what they would have to use against any ships that might appear to defend the planet (be them hidden SDBs or ships coming from jump). Quite akin whan the Japanese fleet in Midway had its planes loaded with HE bombs (ready to bomb the atoll), instead AP ones, when they located the US fleet, having to decide among sending them with inadequate ordnance or losing precios time by rearming them.

Whup, you're right, my bad.

Quite common an error, don't be ashamed. And, after all, it didn't affect the rightess of your reasoning .

As I mentioned earlier, the zero-pen/structure damage rule is broken. While I'm perfectly willing to accept killing a tank because it got washed in enough hot plasma to cause a breakdown, I can also kill a tank by having a company of riflemen open up on it. Random chance means many will achieve exceptional hits, which have a minimum damage of 1 or more. Even without that, you can basically nick a heavily armored target to death with enough hits. I don't know what the solution is, but until I see one, I'm not ready to rest my hopes on zero-pen damage.

Yup. Broken. Exceptional hit rule still gives you some hope of hurting the man in the vacc suit, but a pen 5 result is anything from a rifle shot to standing too close to an HE round. Maybe the rifle shot won't do more than leave a nasty bruise through armor, but I'm under the impression that being suddenly accelerated away from the point of an explosion can be quite hard on a person even when he's heavily armored.

I agree this rule is somewhat broken, probably having been thought to represent the (mostly blunt) damage you talk about, but having a bad application to this case.

Yes, but missiles can be more effective in that role.

I dont see them to be so much more effective, and, given its Pprice and the problems told above (supply/warheads), less efficient than energy weapons, that can effectively fire for free and kept ready for anything that appears.

Yup. Different challenge. Targeting a ship in space means using your mass sensor, EM sensors, neutrino sensors, and so forth to pinpoint a distant radiating mass sitting alone in vacuum. Targeting a vehicle on the ground means doing that against the backdrop of a planet's surface. Difficult to evaluate whether the rules are "right" or "wrong" on that score: one presumes the ground target will be using whatever means are at its disposal to evade orbital detection - camouflage netting, protective coloration, chill cans, whatever. However, a lot of these vehicles are using fusion plants, and while they're a lot smaller than a cruiser, they're also a whole lot closer. Still, the rules don't allow one to sit in orbit and pick off individual tanks by direct fire - and even if accurate, that would pretty much eliminate the ground combat picture, which might be unpopular play-wise.

Or more likely a weapons glitch due to different combat systems/paradigms. Aquin AH Air Force, where it was easier to kill a tank than an airplane with a fighter's 20 mm gun...

Sensors are quite acurate at high TLs in MT, and my guess is they can easily detect any fusion using vehicle (most neutrinos detect them on he 10-1000 kW range). As for targeting, using low power lasers as markers and just adjusting the power when on target should make them quite acurate at those distances (we're talking about times under 0.001 seconds) against effectively stationary (at the speeds they are used to fight) targets.

 

[Carlobrand]

I see I didn't explaim myself as well as I thought. I was refering toe ship¡s built up speed (as I expect it to have been accelerating for several turns before engaging).

Unless the missile comes from directly ahead (in which case the targer would be smaller, BTW), the ship will move quite more in one second that the 30 m you said, and it wil lbe evading, so this movment will not be in straight line. ...

MT fails to capture the missile movement paradigm you describe because it hauls the High Guard abstract rules system into the MT space combat system. Thus, when you fire a missile, you roll to hit same as you would a beam weapon. There's no consideration of the target's movement with respect to the firing vehicle.

One could adopt the same vector movement system for MT by treating the missiles as little ships, but this is only practical when there are very few ships and very few missile volleys to keep track of. The result, no surprise, is very different from High Guard. The player using missiles either uses them tactically to keep the opponent at long range, forcing the opponent to keep turning away and outrunning missiles, or he has to very carefully plan his missile launches for those opportunities where the opponent has stumbled in too close to make a successful run for it. However, were I to apply a movement system, I would not also apply the High Guard hit rules to missiles; that's double-penalizing them for the target's agility.

Now, on the one hand, the Book 2 model for missile intercepts says that a missile that successfully reaches its target will hit unless killed or diverted by ECM. On the other, Book 2 gives even a basic Model-1 a 7+ to destroy an inbound warhead with ECM, assuming it has ECM running. Easiest way to model that is to assume the High Guard missile to-hit roll already includes ECM, with the warring computer levels representing better ECM verses ECCM, and then just eliminate the agility bonus (since I think that's already captured in that trying-to-outrun-the-missile business, and since once it's on top of you it can pretty well mirror whatever evasive maneuvers you try). Of course, you could just lift the Book 2 missile rules in, but you need to find some way to capture the business of there being up to a hundred missiles in a given volley.

...As much attention as the atacker has put to supply, things will go sur stretched, as the needs are enormous. ...

Of course they will, but one does not deliberately tie one's hand behind one's back. A large fraction of the staff and resources of any military organization is devoted to making sure the combat forces have the resources they need to do their job. Things never go to plan when the action starts, but that doesn't mean you forgo an effective weapon from the start. The job of supply is to provide the supplies, and if they are doing so poorly that you will plan to completely forgo a weapons option before the shooting even starts, then there's a serious problem in the organization.

As it happens, missiles aren't very useful in naval combat once the dampers arrive on scene: between armor and nuclear dampers, they do little or no damage. MT big ships lumber, but they tend to be pretty heavily armored, and a high-level damper on anything bigger than a destroyer is pretty much standard. Other things being equal, a TL15 factor 9 damper basically stops all nukes, and a TL14 factor 6 stops 5 in 6 factor 9 missile volleys. An armor rating of 82 stops all non-nuke missiles and almost 60% of nukes, leaving the rest to hit weapons and fuel only, and a rather low armor rating of 55 means you only take weapon and fuel hits from nonnukes - which only means you rotate out and get patched up while someone else mans the siege line. Means, among other things, that the high tech "bomber ships" aren't vulnerable to the traditional missile SDB; you go after the big ships with small spinal mount warboats more akin to battleriders than the old SDBs, and they conversely go after you with spinal mounts unless they want you to keep coming back. With its space combat role diminished, the missile from about TL13 forward has become most effective as a surface bombardment weapon.

One 100dT bay represents a hundred missiles on the battlefield. If they're nukes, odds are fair one will get through to do the job, probably several. Not a place one wants to be. If they're not, then it only takes one of them to kill a tank to make the cost-benefit ratio worth it, and odds are good the volley will kill several tanks after point defenses. Against a lower tech opponent, they can be particularly devastating. If the same volley is fusion guns, then the odds are ... what the heck are the actual odds of getting hit if you're in the middle of a barrage? I can find the rules for figuring out if the barrage is on target, but where are the rules for being in the middle of a barrage? Do they do that the same as Striker?

...I agree this rule is somewhat broken, probably having been thought to represent the (mostly blunt) damage you talk about, but having a bad application to this case. ...

My suspicion is they didn't want unkillable opponents on the playing field. They wanted to emulate the situation of the tank being taken out because of attrition to the armor or a damaged tread or a lucky shot to a weak point. They just didn't think through the extreme cases.

...
Sensors are quite aurate at high TLs in MT, and my guess is they can easily detect any fusion using vehicle (most neutrinos detect them on he 10-1000 kW range). As for targeting, using low power lasers as markers and just adjusting the poswer when on target should make them quite acurate at those distances (we're talking about times under 0.001 seconds) against effectively stationary (at the speeds they are used to fight) targets.

Actually, I agree with you, but that's not the universe MT paints. By the game's own rules, you ought to be able to use the neutrino sensor to lock onto a tank. It is a difficult roll, but you get a wicked good computer bonus. Knowing the location of one tank pretty much gives you an idea of where the rest of the company is, at least enough to put down a barrage and kill a lot of them, and with several ships in orbit you've got a very good shot at spotting several tanks and getting a vague idea of their disposition. Ought to be able to pretty much sweep a front in a few hours. Game doesn't seem to think that way though.

 

[HG_B]

Postulated scenario was trying to get out from "under" a missile that had just been killed by your point defenses. You would not have a full turn to react under those circumstances. You would have only the time between the instant your point defense killed the missile and the instant the dead missile coasted the remaining distance to you.

Based on what ship lasers do to armored ships hulls, a missile that is hit it pretty much vaporized.

 

[Carlobrand]

Based on what ship lasers do to armored ships hulls, a missile that is hit it pretty much vaporized.

On what do you base that? We have a good idea of how much energy is going into the laser, but we don't know the diameter of the beam or its precise effect on striking the missile. Much of the energy may go through and out the other side. We can hope, I think with reasonable cause, that the missile dies explosively, but that's still mass impacting at speeds of tens of kilometers per second. My earlier question hasn't really been addressed: what happens when things not designed as a penetrator - in this case missile fragments - smack into a bonded superdense hull that's as strong as a foot thickness of steel? Will the hypervelocity fragments deliver the energy as damage or is most of that going to be spent making harmless pancakes of the missile fragments? I suspect the latter, but I'm not certain.

This is made worse by the OP's applying the MT Player's Handbook vehicle combat rules instead of the Referee Manual space combat rules. Under the vehicle combat damage rules, those hypervelocity fragments - even if they lack the power to penetrate - will do a bit of superstructure damage. Enough shattered missile fragments slam into you, and the ship is out of action due to superstructure damage.

 

[HG_B]

On what do you base that?

The sentence I wrote gives more than enough data to extrapolate what would happen to a sheet metal thick hull of a missile when hit by a ship's laser turret.

 

[Carlobrand]

The sentence I wrote gives more than enough data to extrapolate what would happen to a sheet metal thick hull of a missile when hit by a ship's laser turret.

And my response gives more than enough information to explain my incredulity. World of difference between a through-and-through and vaporizing 50 kg of assorted components.