Sensorlopes & Book 2 space combat

[Supplement Four]

In my recent discussion with Black Globe Gen, in the thread about Range Band movement, I began thinking about range and what it means in Bk 2 space combat.

You get one throw to attack, per weapon, each combat round.

And, really, the only negatives are a DM of -2 at 250,000 km or more, and a DM of -5 at 500,000 km or more.

Someone else, I forget who (not BGG), had a problem with the the single attack allowed over a period of over 15 minutes.

I've always chalked this up to the time delay given the distance, computing power, and all the data assimilation and interpretation that is required.

Of course, I know that the single roll is meant to be an abstract throw representing, probably, several attempts to hit the enemy over the 15 minutes of the combat round.

The thing that BGG said that got me thinking about this was his description of minis and playing out vector movement.

I know, looking at the rules, that movement and actual position in a space fight (unless some outside object is involved, like a planet, planetoid, derelict space ship, whatever) is usually not very important -- unless the space fight is happening next to the cusp of the -2DM or -5DM range mods.

Inside of 250,000 km, actual positions and plots of ships engaging each other is really rather moot (which is why the Range Band method in the GM's lined notebook paper works so well).

Doesn't is seem logical and rational that it's more dangerous to be closer to your enemy rather than farther away?

It does to me.

And then, I remembered my sensor rules.

And, a book 2 space combat rule change started to reveal itself to me...

 

[Supplement Four]

In my recent discussion with Black Globe Gen, in the thread about Range Band movement, I began thinking about range and what it means in Bk 2 space combat.

You get one throw to attack, per weapon, each combat round.

And, really, the only negatives are a DM of -2 at 250,000 km or more, and a DM of -5 at 500,000 km or more.

Someone else, I forget who (not BGG), had a problem with the the single attack allowed over a period of over 15 minutes.

I've always chalked this up to the time delay given the distance, computing power, and all the data assimilation and interpretation that is required.

Of course, I know that the single roll is meant to be an abstract throw representing, probably, several attempts to hit the enemy over the 15 minutes of the combat round.

The thing that BGG said that got me thinking about this was his description of minis and playing out vector movement.

I know, looking at the rules, that movement and actual position in a space fight (unless some outside object is involved, like a planet, planetoid, derelict space ship, whatever) is usually not very important -- unless the space fight is happening next to the cusp of the -2DM or -5DM range mods.

Inside of 250,000 km, actual positions and plots of ships engaging each other is really rather moot (which is why the Range Band method in the GM's lined notebook paper works so well).

Doesn't is seem logical and rational that it's more dangerous to be closer to your enemy rather than farther away?

It does to me.

And then, I remembered my sensor rules.

And, a book 2 space combat rule change started to reveal itself to me...

 

[Supplement Four]

Sensor Envelopes. Travellers call them "sensorlopes".

The ship's sensors have ranges akin to those in personal combat: Close / Short / Medium / Long / Very Long.

Each one of these range categories is a deep sphere, radiating from a point with the ship at its center when the sensors scan (or in slices of a cone when targeting). Each range category can be referred to as a "sensor envelope".

Because the detection time lag decreases the closer a target comes to the sensing vessel ... and because closer objects are easier to identify ... and because computation and interpretation occur more rapidly with better information gathered from closer objects ...

... a targeting solution can be achieved more quickly the closer the target is to the sensing vessel.

What does this mean in game terms?

CLOSE RANGE: ... is the same range band as the ship, and the ship can make a number of attacks, per weapon, equal to the ship's TL.

SHORT RANGE: ... is 1 RB away to a limit defined by the ship's computer model number (a model 3 computer would have a short range of 1-3 hexes). Enemies withing this sensorlope can be attacked 4 times per weapon.

MEDIUM RANGE: ... begins at the maximum limit of Short Range and extends to a number of RBs equal to the ship's power plant code (a ship with a model 1 computer and PPA would have a Medium sensorlope of 2-10 hexes). Enemies at Medium range can be attacked twice per round per weapon.

LONG RANGE: ... begins at the maximum limit of Medium Range and extends to the limit of the ship's sensor systems (as defined by the sensor's Class). A ship with Class I sensors and PPA would have a Long sensing range of 11-15 range bands. Enemies at Long Range can be attacked once per round per weapon.

VERY LONG RANGE: ... is any range past the maximum limit of Long, up to the maximum tracking range (defined as 90 Range Bands in CT). Enemies at Very Long Range can be attacked once per round per weapon.

Range DMs (-2DM at 25 Range Bands and -5DM at 50 range bands) still apply to attempts to hit the target regardless of which sensor envelope the target resides.


==================

Thoughts on this?

 

[Supplement Four]

Sensor Envelopes. Travellers call them "sensorlopes".

The ship's sensors have ranges akin to those in personal combat: Close / Short / Medium / Long / Very Long.

Each one of these range categories is a deep sphere, radiating from a point with the ship at its center when the sensors scan (or in slices of a cone when targeting). Each range category can be referred to as a "sensor envelope".

Because the detection time lag decreases the closer a target comes to the sensing vessel ... and because closer objects are easier to identify ... and because computation and interpretation occur more rapidly with better information gathered from closer objects ...

... a targeting solution can be achieved more quickly the closer the target is to the sensing vessel.

What does this mean in game terms?

CLOSE RANGE: ... is the same range band as the ship, and the ship can make a number of attacks, per weapon, equal to the ship's TL.

SHORT RANGE: ... is 1 RB away to a limit defined by the ship's computer model number (a model 3 computer would have a short range of 1-3 hexes). Enemies withing this sensorlope can be attacked 4 times per weapon.

MEDIUM RANGE: ... begins at the maximum limit of Short Range and extends to a number of RBs equal to the ship's power plant code (a ship with a model 1 computer and PPA would have a Medium sensorlope of 2-10 hexes). Enemies at Medium range can be attacked twice per round per weapon.

LONG RANGE: ... begins at the maximum limit of Medium Range and extends to the limit of the ship's sensor systems (as defined by the sensor's Class). A ship with Class I sensors and PPA would have a Long sensing range of 11-15 range bands. Enemies at Long Range can be attacked once per round per weapon.

VERY LONG RANGE: ... is any range past the maximum limit of Long, up to the maximum tracking range (defined as 90 Range Bands in CT). Enemies at Very Long Range can be attacked once per round per weapon.

Range DMs (-2DM at 25 Range Bands and -5DM at 50 range bands) still apply to attempts to hit the target regardless of which sensor envelope the target resides.


==================

Thoughts on this?

 

[Supplement Four]

These rules do two things:

(1) Plotting movement is, all of a sudden, very important, a least in terms of range between combatants.

(2) The CT Sensor Rules become even more important to a space fight--if one combatant has better sensors than its enemy, it will have an advantage at certain ranges.


Remember that most vessels have Class I sensors. Those with the money to blow on very expensive Class II sensors have twice the Long Range limit of Class I's.

Class III and Class IV sensors are restricted to military vessels (and some scout vessels and such).

So, unless an enemy is a military vessel (and these rules will make your PC fear that customs patrol crusier even more than before), or some pirate has managed to canniblize some military hardware, MOST of the sensor packages used in a CT game will be Class I's (with an occassional Class II).

 

[Supplement Four]

These rules do two things:

(1) Plotting movement is, all of a sudden, very important, a least in terms of range between combatants.

(2) The CT Sensor Rules become even more important to a space fight--if one combatant has better sensors than its enemy, it will have an advantage at certain ranges.


Remember that most vessels have Class I sensors. Those with the money to blow on very expensive Class II sensors have twice the Long Range limit of Class I's.

Class III and Class IV sensors are restricted to military vessels (and some scout vessels and such).

So, unless an enemy is a military vessel (and these rules will make your PC fear that customs patrol crusier even more than before), or some pirate has managed to canniblize some military hardware, MOST of the sensor packages used in a CT game will be Class I's (with an occassional Class II).

 

[MaineCoon]

I was the one (or at least one of the people) who did not like the 1 attack per attack round idea, and while I do understand it is abstract, I still wasn't too keen on the idea. Although without it, ships may never have a chance to escape to 100D and jump out or run a blockade; if a ship can be destroyed in 15 minutes, then space travel becomes much more deadly and, potentially uninteresting (yet another intense combat where the ONLY option is to kill or be killed - almost the antithesis of Traveller's emphasis on picking your conflicts carefully).


I do like these ideas for the most part, but I'm still too new to Traveller space combat; I think damage reductions might be necessary to compensate for increased attacks in close range combat. This gives more incentive to close range, especially before attacking, not JUST for easier locks or to trap your target.

I would give close range a constant number as well - say, 8 or 10. Resolve a laser return fire after each laser shot, if the target can do so.

Finally, surprise attacks - a target who is attacked unexpectedly at close range loses 2 attacks, at short range 1 attack, and loses no attacks at medium range or further.

A small ship could get in close, undetected, go active and open up, doing significant damage.


Regarding timeframes, T20 has an advanced vehicle/spacecraft system where it uses a hex map, and each hex is represented by another hex map. The larger, strategic plot, and the smaller tactical plot. Each is a hex-shaped box of hexes, 13 hexes along an edge. On the strategic plot a ship may move and attack only once per 20 tactical rounds, but get bonus +5 to-hit OR +5 damage dice when attacking ships on a tactical plot. Each hex is 15,000 KM on the strategic plot, with a 20 minute rounds, and 750 KM on the tactical and 1 minute per round. Its a much more in-depth system including the various types of actions various crew members may take each round and the skill rolls required to do them. Includes sensor operators focusing sensors on a target to give gunners better locks. Very tactical... but I dont like hex maps. Im still of the opinion that 2 objects in space is a 2D equation. Someone argued in favor of standard book 2 ruler/protractor combat, that a few degrees makes a difference, so how you maneuver matters... With a spaceship's computers and sensors to help, you shouldn't have a problem flying directly at or directly away from your target.

T20 also has a reasonable sensor system, but I like yours better. (PDF! PDF!

 

[MaineCoon]

I was the one (or at least one of the people) who did not like the 1 attack per attack round idea, and while I do understand it is abstract, I still wasn't too keen on the idea. Although without it, ships may never have a chance to escape to 100D and jump out or run a blockade; if a ship can be destroyed in 15 minutes, then space travel becomes much more deadly and, potentially uninteresting (yet another intense combat where the ONLY option is to kill or be killed - almost the antithesis of Traveller's emphasis on picking your conflicts carefully).


I do like these ideas for the most part, but I'm still too new to Traveller space combat; I think damage reductions might be necessary to compensate for increased attacks in close range combat. This gives more incentive to close range, especially before attacking, not JUST for easier locks or to trap your target.

I would give close range a constant number as well - say, 8 or 10. Resolve a laser return fire after each laser shot, if the target can do so.

Finally, surprise attacks - a target who is attacked unexpectedly at close range loses 2 attacks, at short range 1 attack, and loses no attacks at medium range or further.

A small ship could get in close, undetected, go active and open up, doing significant damage.


Regarding timeframes, T20 has an advanced vehicle/spacecraft system where it uses a hex map, and each hex is represented by another hex map. The larger, strategic plot, and the smaller tactical plot. Each is a hex-shaped box of hexes, 13 hexes along an edge. On the strategic plot a ship may move and attack only once per 20 tactical rounds, but get bonus +5 to-hit OR +5 damage dice when attacking ships on a tactical plot. Each hex is 15,000 KM on the strategic plot, with a 20 minute rounds, and 750 KM on the tactical and 1 minute per round. Its a much more in-depth system including the various types of actions various crew members may take each round and the skill rolls required to do them. Includes sensor operators focusing sensors on a target to give gunners better locks. Very tactical... but I dont like hex maps. Im still of the opinion that 2 objects in space is a 2D equation. Someone argued in favor of standard book 2 ruler/protractor combat, that a few degrees makes a difference, so how you maneuver matters... With a spaceship's computers and sensors to help, you shouldn't have a problem flying directly at or directly away from your target.

T20 also has a reasonable sensor system, but I like yours better. (PDF! PDF!

 

[cheepicus]

I don't have much experience with Traveller combat, but I thought I'd give my thoughts.

Having 9ish attacks at close range is a big incease in deadliness. I can't tell right now if it's good or bad; getting close to a ship with a lot of firepower certainly seems like a bad idea, and it would make sense that closing to close range is scary.

Also I sort of wonder why maneuver class of a ship doesn't play any role in avoiding getting hurt. There are the evasion programs, but these tend to reward the ships with big computers; if I'm reading it right, a huge ship with a big computer but maneuver-1 is likely harder to hit than a maneuver-6 fighter. I understand that you can't really dodge a laser, but certainly higher maneuver class should help you be in the wrong place at the right time. (Am I missing something about the way Evade works?)

Since you've strictly increased the firepower of all ships, maybe you could take some of it away with a rule like this:

Evasive Action
Whatever maneuver Gs a ship doesn't put towards accel. in the maneuver turn can be used as a defensive DM (up to the limit of the Pilot's skill) applying until the player's next turn. This only applies if the firing ship is within the evading ship's SHORT or CLOSE sensor bands (er, sensorlope ). At this range basic sensors can detect lock-ons, power surges, and other signals that indicate imminent fire (including simply getting a visual of the turret!), such that a sudden jerk on the controls can help avoid the attack.

 

[cheepicus]

I don't have much experience with Traveller combat, but I thought I'd give my thoughts.

Having 9ish attacks at close range is a big incease in deadliness. I can't tell right now if it's good or bad; getting close to a ship with a lot of firepower certainly seems like a bad idea, and it would make sense that closing to close range is scary.

Also I sort of wonder why maneuver class of a ship doesn't play any role in avoiding getting hurt. There are the evasion programs, but these tend to reward the ships with big computers; if I'm reading it right, a huge ship with a big computer but maneuver-1 is likely harder to hit than a maneuver-6 fighter. I understand that you can't really dodge a laser, but certainly higher maneuver class should help you be in the wrong place at the right time. (Am I missing something about the way Evade works?)

Since you've strictly increased the firepower of all ships, maybe you could take some of it away with a rule like this:

Evasive Action
Whatever maneuver Gs a ship doesn't put towards accel. in the maneuver turn can be used as a defensive DM (up to the limit of the Pilot's skill) applying until the player's next turn. This only applies if the firing ship is within the evading ship's SHORT or CLOSE sensor bands (er, sensorlope ). At this range basic sensors can detect lock-ons, power surges, and other signals that indicate imminent fire (including simply getting a visual of the turret!), such that a sudden jerk on the controls can help avoid the attack.

 

[Supplement Four]

Originally posted by Genjuro:
Having 9ish attacks at close range is a big incease in deadliness.

Yep ... but, the only time a ship will get a butt-load of attacks is when the enemy vessel is in the same hex (within 10,000 km).

Then, it will get a number of attacks, per weapon, equal to its TL.


Let's look at an everyday TL 13 Type A Free Trader. Computer Model 1. Power Plant A. Class I sensor suite.

This ship is a 200 toner, and it's got 2 hardpoints. Let's say that both hard points are filled with turrets sporting dual lasers.

Given regular Book 2 combat, this ship will get 4 attacks per round -- all the time -- no matter what.

Under what I'm proposing (using the sensor ranges from my sensor rules), this ship would get:

Same Hex: 13 x 4 = 52 attacks (vs. 4 standard)

@ 1 Hex: 4 x 4 = 16 attacks (vs. 4 standard)

@ 2-10 Hexes: 2 x 4 = 8 attacks (vs. 4 standard)

@ 11+ Hexes: 1 x 4 = 4 attacks (vs. 4 standard)


Basically, what this will do is have combatants jockeying for position on the battlefield. They'll want to get as close as possible without giving their enemy bonus shots.

With the Free Trader here, you'll want to stay betwee 110,000 km and 250,000 km to combat him. Any closer, and you'll give him double attacks. Any farther than 25 Range Bands, and you'll get a -2DM to hit him.

See ... all of a sudden, plotting and movement is very important.


NOTE: You'll be obliterated if you get in the same hex with your enemy ... and that kinda makes sense to me. You've got a weapon that can shoot out to almost a million km. If you're only at 3000 km, then the dang thing should tear you up over a 15 minute period.


So ... Combat won't take place (and typically doesn't in standard Book 2 combat) in the same hex as your enemy vessel ... and probably won't take place real close to the vessel either (within a few hexes of Short Range).

Combat takes place at medium range and long range.

 

[Supplement Four]

Originally posted by Genjuro:
Having 9ish attacks at close range is a big incease in deadliness.

Yep ... but, the only time a ship will get a butt-load of attacks is when the enemy vessel is in the same hex (within 10,000 km).

Then, it will get a number of attacks, per weapon, equal to its TL.


Let's look at an everyday TL 13 Type A Free Trader. Computer Model 1. Power Plant A. Class I sensor suite.

This ship is a 200 toner, and it's got 2 hardpoints. Let's say that both hard points are filled with turrets sporting dual lasers.

Given regular Book 2 combat, this ship will get 4 attacks per round -- all the time -- no matter what.

Under what I'm proposing (using the sensor ranges from my sensor rules), this ship would get:

Same Hex: 13 x 4 = 52 attacks (vs. 4 standard)

@ 1 Hex: 4 x 4 = 16 attacks (vs. 4 standard)

@ 2-10 Hexes: 2 x 4 = 8 attacks (vs. 4 standard)

@ 11+ Hexes: 1 x 4 = 4 attacks (vs. 4 standard)


Basically, what this will do is have combatants jockeying for position on the battlefield. They'll want to get as close as possible without giving their enemy bonus shots.

With the Free Trader here, you'll want to stay betwee 110,000 km and 250,000 km to combat him. Any closer, and you'll give him double attacks. Any farther than 25 Range Bands, and you'll get a -2DM to hit him.

See ... all of a sudden, plotting and movement is very important.


NOTE: You'll be obliterated if you get in the same hex with your enemy ... and that kinda makes sense to me. You've got a weapon that can shoot out to almost a million km. If you're only at 3000 km, then the dang thing should tear you up over a 15 minute period.


So ... Combat won't take place (and typically doesn't in standard Book 2 combat) in the same hex as your enemy vessel ... and probably won't take place real close to the vessel either (within a few hexes of Short Range).

Combat takes place at medium range and long range.

 

[Supplement Four]

What about something like this?

Close Range - Number of attacks equal to TL.

Short Range - Double number of attacks.

Medium Range - Only 1 attack per weapon, but made with a +2DM.

Long Range and beyond - 1 attack per weapon.


What we end up doing here is keeping the uber kill zone when in the fight happens in the same hex; Doubling attacks at short range ...

... but only giving a +2DM and no bonus at the main two combat ranges.

How about that?

 

[Supplement Four]

What about something like this?

Close Range - Number of attacks equal to TL.

Short Range - Double number of attacks.

Medium Range - Only 1 attack per weapon, but made with a +2DM.

Long Range and beyond - 1 attack per weapon.


What we end up doing here is keeping the uber kill zone when in the fight happens in the same hex; Doubling attacks at short range ...

... but only giving a +2DM and no bonus at the main two combat ranges.

How about that?

 

[Supplement Four]

Remember that starship combat will hardly ever take place at Close or Short range.

It almost always takes place at Medium and Long range, and this sometimes stretches to Very Long range.

So, if we keep the bonus at Medium and Long range lite, then we won't be tweaking Book 2 combat much ... and we still make it dangerous to approach a ship.


I'm thinking some pirate vessels could use this as a tactic--play possum as a derelict ship, and as the PC's apporoach and beging to dock, the pirate ship lights up with laser fire.

 

[Supplement Four]

Remember that starship combat will hardly ever take place at Close or Short range.

It almost always takes place at Medium and Long range, and this sometimes stretches to Very Long range.

So, if we keep the bonus at Medium and Long range lite, then we won't be tweaking Book 2 combat much ... and we still make it dangerous to approach a ship.


I'm thinking some pirate vessels could use this as a tactic--play possum as a derelict ship, and as the PC's apporoach and beging to dock, the pirate ship lights up with laser fire.

 

[MaineCoon]

Originally posted by Genjuro:
I understand that you can't really dodge a laser

Normally, you can't, being a lightspeed weapon and all, but when ships are at fighting at ranges of a lightsecond, it almost becomes a projectile weapon. You are aiming at a target that could be moving hundreds of kilometers/second, and is maybe showing you a profile that is roughly 2000 sq meters in size (not really taht big - about 45mx45m).

One example:

To get a lock on the target, and where it will be when you fire, you need to be fairly certain of the range, velocity, acceleration, and have a pinpoint lock on it it's last known location.

Using an example distance of 300,000 kilometers (30 range bands; only a -2 DM), or 1 light second, that means the information is already 1 second out of date. If you fire, the shot will arrive 1 second later. The ship will have travelled for 2 seconds from the location you saw it at. Standard tracking software should do a pretty decent job of estimating where a target will be, and if it isnt making any attempt to alter course/velocity/acceleration, even a simple computer program could predict the location of the target in 1 seconds time even using 1 second old information, given several seconds of prior tracking info.

At that range, if a 3G ship is altering it's velocity randomly, rather than coasting or maintaining even acceleration, it could be anywhere from 0 to 60 meters* away from where you predict it will be, which is enough to miss it by. And that's if its not even trying to dodge, just randomly altering acceleration. A ship may not.

(* 120 meters if it manages to full accelerate away)

 

[MaineCoon]

Originally posted by Genjuro:
I understand that you can't really dodge a laser

Normally, you can't, being a lightspeed weapon and all, but when ships are at fighting at ranges of a lightsecond, it almost becomes a projectile weapon. You are aiming at a target that could be moving hundreds of kilometers/second, and is maybe showing you a profile that is roughly 2000 sq meters in size (not really taht big - about 45mx45m).

One example:

To get a lock on the target, and where it will be when you fire, you need to be fairly certain of the range, velocity, acceleration, and have a pinpoint lock on it it's last known location.

Using an example distance of 300,000 kilometers (30 range bands; only a -2 DM), or 1 light second, that means the information is already 1 second out of date. If you fire, the shot will arrive 1 second later. The ship will have travelled for 2 seconds from the location you saw it at. Standard tracking software should do a pretty decent job of estimating where a target will be, and if it isnt making any attempt to alter course/velocity/acceleration, even a simple computer program could predict the location of the target in 1 seconds time even using 1 second old information, given several seconds of prior tracking info.

At that range, if a 3G ship is altering it's velocity randomly, rather than coasting or maintaining even acceleration, it could be anywhere from 0 to 60 meters* away from where you predict it will be, which is enough to miss it by. And that's if its not even trying to dodge, just randomly altering acceleration. A ship may not.

(* 120 meters if it manages to full accelerate away)

 

[Cymew]

Originally posted by WJP:
What about something like this?

Close Range - Number of attacks equal to TL.

Short Range - Double number of attacks.

Medium Range - Only 1 attack per weapon, but made with a +2DM.

Long Range and beyond - 1 attack per weapon.


What we end up doing here is keeping the uber kill zone when in the fight happens in the same hex; Doubling attacks at short range ...

... but only giving a +2DM and no bonus at the main two combat ranges.

How about that?

Considering all starships have TL over ten, you will get an awful lot of attacks at close range. Sure, it makes sense if you suppose the weapon punches Megawatts of energy millions of kilometers, but is it still possible to board a ship?

Can you in these rules cripple a ship and then close for boarding? I'm not familiar enough with Traveller starship combat (any version) to know. But, it has to be a known tactic that still ought to work, right?

 

[Cymew]

Originally posted by WJP:
What about something like this?

Close Range - Number of attacks equal to TL.

Short Range - Double number of attacks.

Medium Range - Only 1 attack per weapon, but made with a +2DM.

Long Range and beyond - 1 attack per weapon.


What we end up doing here is keeping the uber kill zone when in the fight happens in the same hex; Doubling attacks at short range ...

... but only giving a +2DM and no bonus at the main two combat ranges.

How about that?

Considering all starships have TL over ten, you will get an awful lot of attacks at close range. Sure, it makes sense if you suppose the weapon punches Megawatts of energy millions of kilometers, but is it still possible to board a ship?

Can you in these rules cripple a ship and then close for boarding? I'm not familiar enough with Traveller starship combat (any version) to know. But, it has to be a known tactic that still ought to work, right?