Scale, the Battle Experience and the D-limit

[kilemall]

The railgun thread brought a lot of people out of the woodwork who clearly feel that sensor, heat handling, targeting and/or power/attenuation issues favors the MgT 1000s of kms approach to ranges rather then CT/Plus LS+ type ranges.

Independent of what one can support/live with, at the end of the day the issue of scale our ships move to is dependent on the battle experience we want to provide.

CT/Mayday/BL type movement highlights the inertial movement and fight, but ultimately has more of a wargamer/mini fighting scale rather then character drama.

MgT fighting is more on the RPG scale in terms of time and character interaction with the various abstract movement/ranges.

Both approaches have merit, both ignore how greatly power generation and weapon/sensor ranges would increase across TLs, and all are ultimately game choices for the sort of entertainment one wants.

The one aspect I wanted to highlight by branching off into a separate thread is the battlespace/sensor issue.

CT had the sensor and engagement limits IMO defined by the 100D limit- maximum sensor detection still allowed for some margin for ships traveling from planets to that limit or vice versa.

Mayday and BL were not tied to those limits per se, but something like them and certainly a degraded to-hit/accurate fire solution/attenuation issue baked in.

MgT on the other hand has everything down to 1000s of kms and at a time scale that is at least personally playable, rather then assuming our characters are blazing away for 1000 seconds.

This is fine, except the CT-derived rules regarding the 100D limit are still in play.

With the meaningful engagement/detection range at 50,000km+ (I'm assuming MgT2E is largely like 1E this way), all anyone has at ranges exceeding that is an IR and visual dot, possibly IFF transponders with all the hanky-panky that may bring.

That is a LOT of territory to cover, even with increases to 8-10 Gs, asuming one interprets that 50,000km+ extreme range to light seconds to cover 100D distances.

If it's more like 100,000 km maximum detection range, any ship that wants to remain safely anonymous can just avoid any obvious watering hole places. Piracy is more possible, but has just as much targeting/interception problems as navies without inside intel/help.

That's a lot of ships passing in the fog without seeing each other.

If one assumes something like light second or even AU detection of IR traces, it still involves a whole lot of travel not on the Mongoose player time scale.

So here is the crux of my thread- if you want to play at Mongoose-type scales for player drama and/or weapon reality concerns with actual distances or at least abstracted to 100D limits, you need to consider either

• tripling the G-accel,
• increasing the sensor ranges to generate encounters (possibly a LOT of sensor drones),
• have a fierce IFF regimen (anything that doesn't have a transponder sending is automatically a pirate),
• and/or reduce the D-limit to 10D.

Of the above, I would tend to go with the 10D limit- that would reduce the battlespace down to where the 50,000 km+ detection range makes sense, 150,000 km or less in most cases, and the movement-to-player action phasing stays in the same scale throughout encounters.


Bottom line, the entire action biome has to be considered and scaled correctly for the intended entertainment effect whenever one aspect of a system is changed.

 

[mike wightman]

I was watching the Expanse s1e4 space battle:

enemy ships spotted a long way out, as they get closer they are told that they had 1 minute to alter course or they would be fired upon

the engagement range is entered and the black ships open fire with torpedoes and the Donnager returns fire with her own torps

it takes a couple of minutes for the torpedoes to close and everyone is twiddling their thumbs, and then the Donnager PDW take care of them

in that couple of minutes the enemy ships continue to close to direct fire missile range - again the PDW mean this is little threat

the Donnager readies rail guns and the black ships open fire with their own rail guns, surprising the Donnager as such small ships don't have rail guns.

by now the Donnager has splashed five of the six incoming ships - the remaining ship can now launch boarding pods

This is what I want for Traveller ship combat - not cinematic Star Wars fighter dogfight male cow solid excrement.

I quite happily mix scales for rpg ship combat - tens of minutes for the sensor scans and sub hunt close to weapon lock range maneuver phase. Once in weapon lock range 15 second turns do me just fine - the trick is to realise that combat in Traveller normally takes place around choke points at slow relative velocities or deliberate fleet engagements at slow relative velocities - a high V pass is mutually assured destruction.

Mayday or LBB2 vector movement still works if you reduce the weapon ranges and time scale and hence hex size/mm scale.

Reduce weapon ranges in line with real world physics for TL7-9 with slight improvements, and then make allowances for higher TLs increasing the velocity of railguns until they are replaced with plasma then fusion railguns.

Limit lasers to PDW due to heat until x-ray lasers are a thing at higher TLs. PA and then meson beams are your spinal and bay weapons of choice at TLs 11+

missiles and torpedoes remain a threat at all TLs, even with the advent of repiulsors

 

[Silverhawk]

I was watching the Expanse s1e4 space battle:

enemy ships spotted a long way out, as they get closer they are told that they had 1 minute to alter course or they would be fired upon

the engagement range is entered and the black ships open fire with torpedoes and the Donnager returns fire

it takes a couple of minutes for the torpedoes to close and the Donnager PDW take care of them

in that couple of minutes the enemy ships continue to close to direct fire missile range - again the PDW mean this is little threat

the Donnager readies rail guns and the black ships open fire with their own rail guns, surprising the Donnager as such small ships don't have rail guns.

by now the Donnager has splashed five of the six incoming ships - the remaining ship can now launch boarding pods

This is what I want for Traveller ship combat - not cinematic Star Wars fighter dogfight male cow solid excrement.

I quite happily mix scales for rpg ship combat - tens of minutes for the sensor scans and sub hunt close to weapon lock range maneuver phase. Once in weapon lock range 15 second turns do me just fine - the trick is to realise that combat in Traveller normally takes place around choke points at slow relative velocities or deliberate fleet engagements at slow relative velocities - a high V pass is mutually assured destruction.

Mayday or LBB2 vector movement still works if you reduce the weapon ranges and time scale and hence hex size/mm scale.

Reduce weapon ranges in line with real world physics for TL7-9 with slight improvements, and then make allowances for higher TLs increasing the velocity of railguns until they are replaced with plasma then fusion railguns.

Limit lasers to PDW due to heat until x-ray lasers are a thing at higher TLs. PA and then meson beams are your spinal and bay weapons of choice at TLs 11+

missiles and torpedoes remain a threat at all TLs, even with the advent of repulsors

Absolutely agree with you on this. The idea of long turn time for space combat always seemed odd. Doesn't seem like any of the recent fiction I read recently has had that type of timeframe. It is more like the six minutes of terror that leaves you going, "What the <BLANK> just happened and how did we survive"

 

[kilemall]

I'm not suggesting one is 'better' then the other, I am saying that to get that time scale you want, either the 100D limit needs to go to 10D, the ships need to be faster, and/or you need to accept a different sort of game with the two scales Mike mentions, Sub Hunt then relatively fast resolution at shorter ranges.

And when people talk about 'what should be' they don't seem to talk much about either the character action scale or it's effects on what sort of game is delivered.

 

[infojunky]

And when people talk about 'what should be' they don't seem to talk much about either the character action scale or it's effects on what sort of game is delivered.

Actually that is how I got to the 1000km increment, the question was How to give the Players the most things to play with. It also gives a reference point, in that I use the Geosynchronous orbital point where the High Port sits as the center of the map stationary point. Or some significant rock in a asteroid belt setup. Then I can add in bunches of orbit debris and the like.

Then there are all the silly Sancaster and cargo dumping tricks, that players can come up with as well. One of the reasons I use very simple Sensor rules is to give the players lots of room for Ideas and tricks. I much rather centering on a PC and his skill than the ship m3000 uber eyeball.

 

[mike wightman]

My rule for rpg starship combat - every player has to be involved, not just the only one who understands vector movement.
Pilot - makes piloting rolls obviously
Navigator - sensor scans
Computer operator - ECM, program selection
Engineer - extra power from engines, damage control
Any character with Vacc suit/Mechanic/Electronic/JoT - damage control

 

[Brandon C]

My rule for rpg starship combat - every player has to be involved, not just the only one who understands vector movement.
Pilot - makes piloting rolls obviously
Navigator - sensor scans
Computer operator - ECM, program selection
Engineer - extra power from engines, damage control
Any character with Vacc suit/Mechanic/Electronic/JoT - damage control

The player running the ship commander must resist the urge to micromanage. His job is to make decisions affecting the entire ship (not just gunnery, engineering, etc) and to give orders that are not complex but are clear in the desired result (allowing each crew position to do their job as they best see fit, given their orders). A micromanaging PC commander will get hated by other players quickly.

 

[whartung]

The Expanse combat was essentially long range missile combat combined with "point blank" direct fire combat. Missile combat was at "long range" (thus the "minutes to impact") -- imagine surface vessels flinging cruise missiles at each other.

The rail gun combat was Wooden Ships range. Pull up close and let fly broadsides when the ships are within swearing distance and ROF seems to dominate the battle space. Only thing missing was grappling hooks and men with knife in their teeth. Essentially ships seem to be equipped with cruise missiles and .50 cal machine guns, and nothing of note, apparently, in between.

If you're going to park that close to the opponent, why not hold the missiles and just pump them in straight at short range, like a big RPG. Treat the ship as a large, armored drone carrier able to better withstand PD fire before launching the missiles in to the face of the opponent. Also, the ranges expressed in the Expanse make kinetic "deadfall" payloads perhaps interesting as well. Bring the attack ship in and go "bowling for dollars", peeling off at the last second while leaving large, iron bowling ball in your wake. "mv^2" for the win.

Of course there's not much to really suggest that the drives in the Expanse were anything like what we have in Traveller. Perhaps they have some power, but not necessarily duration.

Is the goal here to redo combat in Traveller? Many seem to reject the "science" as posited by the game.

 

[mike wightman]

Probably because at that short range range a rail gun generates a higher projectile velocity than a missile can achieve...
The Expanse weapons systems appear to be:
torpedoes at long range
direct fire missiles
rail guns
PDW

 

[Brandon C]

Of course there's not much to really suggest that the drives in the Expanse were anything like what we have in Traveller. Perhaps they have some power, but not necessarily duration..

The Epstein drives appear to be similar to TNE's HePlaR drives, but with better thrust, fuel efficiency and more destructive exhaust (other drives are clearly used in the atmospheres of Earth and Venus).

The big difference is that Epstein drives aren't coupled with grav compensation. If a ship accelerates at 10 g, everyone onboard feels that 10g for the duration of the burn. Also, the drives aren't vectored. Direction is changed using compressed gas thrusters located at multiple points on the ships.

 

[Xerxeskingofking]

The railgun thread brought a lot of people out of the woodwork who clearly feel that sensor, heat handling, targeting and/or power/attenuation issues favors the MgT 1000s of kms approach to ranges rather then CT/Plus LS+ type ranges.

Independent of what one can support/live with, at the end of the day the issue of scale our ships move to is dependent on the battle experience we want to provide.

CT/Mayday/BL type movement highlights the inertial movement and fight, but ultimately has more of a wargamer/mini fighting scale rather then character drama.

MgT fighting is more on the RPG scale in terms of time and character interaction with the various abstract movement/ranges.

Both approaches have merit, both ignore how greatly power generation and weapon/sensor ranges would increase across TLs, and all are ultimately game choices for the sort of entertainment one wants.

The one aspect I wanted to highlight by branching off into a separate thread is the battlespace/sensor issue.

CT had the sensor and engagement limits IMO defined by the 100D limit- maximum sensor detection still allowed for some margin for ships traveling from planets to that limit or vice versa.

Mayday and BL were not tied to those limits per se, but something like them and certainly a degraded to-hit/accurate fire solution/attenuation issue baked in.

MgT on the other hand has everything down to 1000s of kms and at a time scale that is at least personally playable, rather then assuming our characters are blazing away for 1000 seconds.

This is fine, except the CT-derived rules regarding the 100D limit are still in play.

With the meaningful engagement/detection range at 50,000km+ (I'm assuming MgT2E is largely like 1E this way), all anyone has at ranges exceeding that is an IR and visual dot, possibly IFF transponders with all the hanky-panky that may bring.

That is a LOT of territory to cover, even with increases to 8-10 Gs, asuming one interprets that 50,000km+ extreme range to light seconds to cover 100D distances.

If it's more like 100,000 km maximum detection range, any ship that wants to remain safely anonymous can just avoid any obvious watering hole places. Piracy is more possible, but has just as much targeting/interception problems as navies without inside intel/help.

That's a lot of ships passing in the fog without seeing each other.

If one assumes something like light second or even AU detection of IR traces, it still involves a whole lot of travel not on the Mongoose player time scale.

So here is the crux of my thread- if you want to play at Mongoose-type scales for player drama and/or weapon reality concerns with actual distances or at least abstracted to 100D limits, you need to consider either

• tripling the G-accel,
• increasing the sensor ranges to generate encounters (possibly a LOT of sensor drones),
• have a fierce IFF regimen (anything that doesn't have a transponder sending is automatically a pirate),
• and/or reduce the D-limit to 10D.

Of the above, I would tend to go with the 10D limit- that would reduce the battlespace down to where the 50,000 km+ detection range makes sense, 150,000 km or less in most cases, and the movement-to-player action phasing stays in the same scale throughout encounters.


Bottom line, the entire action biome has to be considered and scaled correctly for the intended entertainment effect whenever one aspect of a system is changed.

see, I would go with a version of option 2: accept that one single ship did not have the sensor range to properly cover a earth sized planets d100 sphere. form their, their are possibilities for interesting RPG scenarios.

first off, it raises the possibility of "sneaking up" on a planet, which could be part of any number of adventure plans.

second, it greatly increases the importance of sensor pickets for naval operations, which means that any available sensor platform (like the players ship) could get dragooned into assisting plug holes in the coverage, or to help "create" such a hole.


third, the reduced sensor coverage increases the potential for piracy, as it raises chance that the players and the pirate are the only two ships in clear sensor range of each other. I've never been a fan of the star trek/star wars "able to read the airlock warning labels at 3 light years" sensors anyway.


personally, I think the reduction of sensor ranges is good for the game, even if its "realistic".

 

[Brandon C]

The Expanse weapons systems appear to be:
torpedoes at long range
direct fire missiles
rail guns
PDW

The battle between the Martian frigate and stealth ship in S2E2 is the closest we've gotten to a dogfight, which wasn't close (more cat and mouse with the frigate using the space station for cover). The battle was too close for missiles but not for the rail gun on the stealth ship or both vessels PDWs. The stealth ship was trying to line up a shot with its rail gun while frigate was trying to rake the opponent with multiple PDWs.

Worth noting that warships in The Expanse are effectively unarmored against the weapons available.

 

[Xerxeskingofking]

Absolutely agree with you on this. The idea of long turn time for space combat always seemed odd. Doesn't seem like any of the recent fiction I read recently has had that type of timeframe. It is more like the six minutes of terror that leaves you going, "What the <BLANK> just happened and how did we survive"

just to pick up on this, the only example I can think of is the Honourverse, where missile engagements routinely take several minutes form launch to impact (although the story often compresses the apparent time somewhat)

 

[infojunky]

Sensors is one of those areas that don't get a lot of respect in Traveller. All to often they are treated as a Magic Panopticon where all is visible, then arguments devolve from there.

Let's now take a look sensors in the real world, Commercial aircraft/Marine depend on two systems, for Long range detection Transponders are the core. Short range is a combination of both radar and visible light sensors (Often the mark 1 Eyeball) for collision avoidance. Now Military craft are different and not. Most non-combat craft look a lot like commercial craft, with Specialist craft carrying longer range sensors, while similar sized combatants carry sensors with ranges that are in line with their engagement ranges for their carried weaponry. Note maritime combatants differ here as their long range sensors are generally limited to the horizon.

With all that Sensors are limited by the environment they are operating in. And the state of the ships and other objects they are trying to detect. Looking at the basic rules in Book 2 Commercial ships have a Open space range of 150,000km and military ships 600,000 km. Then taking in the Silent running and orbital rules one has the basis for a simple set of sensor rules.

In terms of my current house system Sensor short range is 18 hexes, i.e. the range where a ship can be specifically identified without help from the targets Transponder. In Skill terms it is a Sensors roll with DMs of Comparative Computer, skill level and Edu.

 

[Xerxeskingofking]

Sensors is one of those areas that don't get a lot of respect in Traveller. All to often they are treated as a Magic Panopticon where all is visible, then arguments devolve from there.

In terms of my current house system Sensor short range is 18 hexes, i.e. the range where a ship can be specifically identified without help from the targets Transponder. In Skill terms it is a Sensors roll with DMs of Comparative Computer, skill level and Edu.

see, depending on what you consider the requirements to "identify" a ship at, that range in MgT rules could be as short as 1,250Km (Short range, where the major sensors are at full capability), 25,000Km (Long range, where visual and thermal scanners are able to pick up more than "minimal" details), or somewhere over 50,000Km (Distant range, were visual sensors are still able to determine "basic outline", which would at least be enough to say that the ships class matched its transponder).


I agree that some people treat sensors like star trek/star wars, as magic oracles able to read a scribbled out line of writing, in a closed book, inside a lead lined building, on the other side of a planet, form a range of several parsecs. the trouble is that those two settings are the major sci-fi franchises that the majority of people know, so inevitably, they affect Traveller as they are a major "go-to" for reference.

 

[Mako]

Shortening the sensor ranges does seem like an easy fix, and perhaps has a lot of the benefits listed in this posting, but it also seems to me to be a bit short-sighted, especially for star-faring races that can use FTL travel, and/or even advanced, sub-light speeds.

The moon is about 350,000 - 400,000 kms. from the Earth, and I suspect we can/could detect spacecraft orbiting around it now, and/or back in the day, at those ranges, so 50,000 kms. for a search sensor's range, even using 1960s - 1980s tech, would probably be a bit low, in terms of actual performance.

Anyone know how far we can detect, and/or track spacecraft around Mars, and/or our other probes sent to fly by, and/or orbit other planets/moons, and asteroids currently?

I think using the latter as a decent baseline, along with perhaps some of the other stats, might help to come up with some reasonable levels of sensor performance.

I'd hate to see the same issue crop up with sensors, that did with computers from the olde, CT days.

Of course, I guess if you do want to use shortened sensor ranges anyway, you can just assume the ships have developed some type of basic stealth to minimize, and/or to defeat them.

 

[Xerxeskingofking]

Shortening the sensor ranges does seem like an easy fix, and perhaps has a lot of the benefits listed in this posting, but it also seems to me to be a bit short-sighted, especially for star-faring races that can use FTL travel, and/or even advanced, sub-light speeds.

The moon is about 350,000 - 400,000 kms. from the Earth, and I suspect we can/could detect spacecraft orbiting around it now, and/or back in the day, at those ranges, so 50,000 kms. for a search sensor's range, even using 1960s - 1980s tech, would probably be a bit low, in terms of actual performance.

Anyone know how far we can detect, and/or track spacecraft around Mars, and/or our other probes sent to fly by, and/or orbit other planets/moons, and asteroids currently?

I think using the latter as a decent baseline, along with perhaps some of the other stats, might help to come up with some reasonable levels of sensor performance.

I'd hate to see the same issue crop up with sensors, that did with computers from the olde, CT days.

Of course, I guess if you do want to use shortened sensor ranges anyway, you can just assume the ships have developed some type of basic stealth to minimize, and/or to defeat them.

Mostly because we can track their transmissions, and we rely on the probes onboard nav systems to tell us where they are.

for direct observations, it's a bit tricker, as we are tracking a item with a known speed and path (so we know exactly where to look), plus we don't really have an equivalent system to compare it to.

 

[Brandon C]

Would it be useful to have detection and weapons lock be distinctly different? IE., just because you have detected a ship and it has moved into weapons range doesn't mean you automatically get to shoot at it.

 

[kilemall]

Would it be useful to have detection and weapons lock be distinctly different? IE., just because you have detected a ship and it has moved into weapons range doesn't mean you automatically get to shoot at it.

This is what I am toying with. Detection easy, lock on can be hard.

With a twist that a lock on is required to get other info like ship type, size, EM, gravitic data, etc. as all the exotic sensors require a calibration of precise distance.

Passive lockon more difficult, active easier, and scientific ships simply trying to scan may use active sensors and look exactly like an active lockon.

 

[pendragonman]

snip...
The moon is about 350,000 - 400,000 kms. from the Earth, and I suspect we can/could detect spacecraft orbiting around it now, and/or back in the day, at those ranges, so 50,000 kms. for a search sensor's range, even using 1960s - 1980s tech, would probably be a bit low, in terms of actual performance.

Anyone know how far we can detect, and/or track spacecraft around Mars, and/or our other probes sent to fly by, and/or orbit other planets/moons, and asteroids currently?

I don't think of it as a matter of detection, but of speed of detection. Even if the sensor operator has mad skills and notices every blip as soon as it shows up on the screen, there is the transmission time of the sensor wave to reach the target and return.

Just reaching Lunar orbit the round trip is several seconds in length. That distance fits into one space combat round pretty easily. But what about around the nearer gas giant? On average, it takes 30+ minutes at the speed of light for a signal to reach Jupiter and the same back again. So while the detection once the information reaches the sensor op might be instantaneous, that information is about an hour old once you get it. Not sufficient for targeting.

The idea of shortening the sensor ranges is really about weapons locks. After all, detecting someone around Jupiter (who is not trying to hide in the sensor shadow of Jupiter at least) is not a problem, but I wouldn't want to send a missile barrage in on hours old info.

My method is to allow detection at even the Kuiper Belt, but that information is very old. Shooting ranges. i.e. target locks, are more like up to a half light minute of distance for long range on direct fire weapons, and missile ranges are more about how far out can the missile make course corrections before all fuel is expended and it becomes a ballistic ally targeted dumb bomb. Therefore larger missiles with more than one burn tank can get course corrections further along to correct for target movement after launch, but the corrections are going to be perhaps several minutes old and at the mercy of your predict program's efficiency. (which, come to think of it, is very Honorverse, especially if you think antimissile missiles are more of the sidewinder size, and making the single stage a cruise missile, and 2 or three stage missiles ICBM sized).

Of course, if you have FTL comms/FTL sensors in your TU, then all of this is unnecessary.