Yes, that is where the planet is. But is that what you're really worried about? In space you're probably trying to go from a planet/station that's moving to another body which is also moving. So now you have to predict where your target is going to be in the future when you're arriving. For a planet close to a star, perhaps a red dwarf where the habitable zone is pretty close in, the period may be, say 1 month. If it takes 1 week to go from distant planet to inner planet, that close in planet is now 25% of the way around it's orbit! It can definitely be done- it's pretty much Newtonian physics. But then you have to calculate the distance between 2 planets at any/every time point players care about. I just won't do it. As an approximation, I use the average distance from a planet to the center of the orbit of the other planet... which just happens to be (for a circular orbit) the distance to the star. OK, it doesn't deal with the orbital dynamics but it makes rough calculations a lot easier. Plus the differences are relatively small for distant worlds because so much time is spent accellerating/ decellerating. Closer worlds like Earth and Mars actually have bigger percentage differences between closest and farthest distances.
System Tactics
- Thread starter Ulsyus
- Start date
Well, in Mongoose Traveller human scale damage is divided by 50 to compare it to ship scale damage (p. 151 in 1st edition). Bullets won't hurt a spaceship. I personally think 50 is too high a difference, and use 12x, meaning something doing 12d of damage to a person could do 1d to a ship. Anything less than 1d-1 is ignored, so minimum 8d damage to even have a chance of hurting a starship hull with a personal scale weapon. That works out to be roughly a 75mm shell. Fast moving debris of even modest size can do it, but I suspect most referees will only worry about it when they want to mess with their players. Otherwise the amount of debris from centuries old space battles would make space near planets uninhabitable. We are already having issues around Earth regarding debris.
The Oz
SOC-14 1K
I once calculated (using STRIKER values for armor, penetration, and energy value [demo points]) that an unarmored TRAVELLER ship could reach a max sublight speed of 0.167%c, which is about 500 km/sec or just under 14 hours of accel at 1-G. I was including a really big fudge factor, BTW.
Yes and no, consider the average speeds that combat takes place at. Couple that to the expanding cloud said debris is. At best there will be bits in a large elliptic solar orbit mostly outside of where most Traveller ships operate.
Now downstream of a recent combat will have a higher chance of incidence of encounter, but time shrinks that very low chance rapidly.
That occurred to me too. The question of how vessels make it through debris, clutter, and junk in their path may not be one they have to deal with constantly given how Big Space Is, but I've hand-waved this out of games for a long time.
...and there'll be plenty that's larger but not so large that they're a manoeuvre-worthy obstacle, or there may be a multitude of sand grains from that battle that was fought recently.
Could less-evasive manoeuvres to reduce the impact on a vessel be a simpler way of reducing damage vs avoiding this? It wouldn't be much of an issue with drives that don't require larges amounts of mass burned for thrust would it?
kilemall
SOC-14 5K
The CT Missile Supplement has a calculation for direct kinetic impact of the missile body increasing damage. So you could certainly reduce that damage potential by accelerating away from the incoming missile to the point there is no additional damage but not the actual warhead hits.
Of course accelerating to the point the missile runs out of fuel before impact would eliminate damage potential.
Silverhawk
SOC-12
I have parts of a game (don't know what happened to the parts that are missing) called Star Viking by Dwarfstar Games that had system cards with exactly that sort of set up. Box for main world, gas giants, asteroid belts even a space station on a couple as I recall. Always thought that it was a neat way to game fighting at the system level. Fleet elements could disengage and either leave or move to another part of the system.
BackworldTraveller
SOC-13
Where are your starships and how fast are they going.
The only time ships are going relatively slowly (and thus can have anything above spectacularly short engagements) is at the system's various usable bodies. Two fleets passing as one heads to the gas giant and the other returns are going so fast that traveller sensors don't see them for very long, let alone have time to engage effectively.
So that means all battles are going to happen near important system related stuff.
And even at 100D things are very spread out. Assuming a 10000km diameter planet, the 100D limit is over 6,000,000km long Those 150,000km sensors see just 2.5% of that. 50,000km sensors less than 1%. Ground based sensors need a range of 1,000,000km to see that far.
Having said that, most astrogators use the same jump algorithms so they will yield the same "Best place to drop out of jump". As a result, a decent pirate/SDB can know that a fair percentage of incautious traffic from P will arrive at place X,Y(,Z) and thus be near enough to detect them. Cautious (or paranoid) astrogators will, of course then vary that and arrive somewhere else. Regulators will mandate where you arrive so customs will be on hand to inspect...and the randomness of it all means that, periodically, this arrival spot will be occupied, a few seconds later, by an unregulated incoming vessel trolling down (backwards as it is decelerating) from the gas giant! So the regulators then ban transits through the mandated arrivals area like they banned arrivals elsewhere.
Which comes to space tactics
You need to arrive in system away from standard arrivals areas, loose your bombardment missiles and leave/follow them in. Anyone that then sees that incoming will have to close with you to engage (they are then torn between engaging ships and missiles). Nuclear Dampers are pretty useless as the missiles kinetic energy is bad enough.
The only time ships are going relatively slowly (and thus can have anything above spectacularly short engagements) is at the system's various usable bodies. Two fleets passing as one heads to the gas giant and the other returns are going so fast that traveller sensors don't see them for very long, let alone have time to engage effectively.
So that means all battles are going to happen near important system related stuff.
And even at 100D things are very spread out. Assuming a 10000km diameter planet, the 100D limit is over 6,000,000km long Those 150,000km sensors see just 2.5% of that. 50,000km sensors less than 1%. Ground based sensors need a range of 1,000,000km to see that far.
Having said that, most astrogators use the same jump algorithms so they will yield the same "Best place to drop out of jump". As a result, a decent pirate/SDB can know that a fair percentage of incautious traffic from P will arrive at place X,Y(,Z) and thus be near enough to detect them. Cautious (or paranoid) astrogators will, of course then vary that and arrive somewhere else. Regulators will mandate where you arrive so customs will be on hand to inspect...and the randomness of it all means that, periodically, this arrival spot will be occupied, a few seconds later, by an unregulated incoming vessel trolling down (backwards as it is decelerating) from the gas giant! So the regulators then ban transits through the mandated arrivals area like they banned arrivals elsewhere.
Which comes to space tactics
You need to arrive in system away from standard arrivals areas, loose your bombardment missiles and leave/follow them in. Anyone that then sees that incoming will have to close with you to engage (they are then torn between engaging ships and missiles). Nuclear Dampers are pretty useless as the missiles kinetic energy is bad enough.
kilemall
SOC-14 5K
Two questions-
Not sure where you are getting the 6000000 km figure.
On bombardment, the kinetics are great but thicker atmospheres are going to limit what speed they can get to.
Traveller missiles historically show limited fuel too, if there is a 100D worth of detection those missiles would be vulnerable to counter missiles (due to spending most of that approach on the drift).
Also, if the fleet is coming in with similar vee of their missiles, they would be vulnerable and potentially devastated by missiles coming at them with that much greater closing speed.
Not sure where you are getting the 6000000 km figure.
On bombardment, the kinetics are great but thicker atmospheres are going to limit what speed they can get to.
Traveller missiles historically show limited fuel too, if there is a 100D worth of detection those missiles would be vulnerable to counter missiles (due to spending most of that approach on the drift).
Also, if the fleet is coming in with similar vee of their missiles, they would be vulnerable and potentially devastated by missiles coming at them with that much greater closing speed.
Spinward Flow
SOC-14 5K
You sure about that?
Program the missiles for multiple discrete burns at different times, in between inertial movement only, so as to "hide" the origin launch point.
After all, if acceleration IS NOT CONSTANT ... that makes the task of backtracking the course of an incoming object A LOT HARDER.
And I hate to be the one to point this out, but ... missiles will tend to have computers in them. Computers can be PROGRAMMED.
I know ... radical idea.
The other point to recognize is that with missiles, if an attacker is willing to accept a delay between launch and impact (and let's be honest, who WOULDN'T want to have such a delay?) then all kinds of shoot 'n' scoot orbital maneuvering to foil counterbattery retaliation becomes a very real possibility.
Functionally it winds up being somewhat analogous to AV-8 Harriers tossing bombs at ground targets (otherwise known as "bombardment").
If you're a counterbattery response firing BACK along the calculated path of the incoming projectile, you're going to MISS the launcher, because the launching platform HAS MOVED (in who knows what direction) already by the time the return fire arrives.
In other words, deliberately launching from farther away and requiring a longer "coast" phase between launch and impact provides both the launching craft AND the missiles more opportunities to maneuver and "disassociate" their respective vectors from one another, giving an attacker a "standoff range advantage" beyond the sensor net detection radius of any defenders. If the missiles are "inertial coasting cold" after launch, they could potentially be incredibly difficult for a defensive network of sensors to detect, resolve and track (not impossible, just way more difficult to detect than 100+ tons of starship would be).
At that point, it becomes a question of saturation ... can you launch more missiles than the defenders can cope with?
You're then basically dealing with ORTILLERY strikes as a ground based defender.
Good luck with that.
Missiles with a reserve of maneuvering power (and deep magazines) enable standoff range massed bombardment tactics that low RoF weapons such as deeply buried planetary meson gun silos (or equivalent) are poorly equipped to deal with.
If you're a defender against such a heavy bombardment ... you want to fight in the shade ...
Well, it limits their velocity if there's any hope for terminal guidance. (Maybe that wasn't part of the plan though.) Also, if they're explosive rather than kinetic impactors, the warheads might cook off due to re-entry heat and fragment the missiles into pieces that are more susceptible to vaporization on re-entry.You sure about that?
Yes and no.
Yes, as the aircraft is not vulnerable to "counterbattery" fire after launch. No, because "counterbattery fire" isn't how you'd target the aircraft in the first place.
kilemall
SOC-14 5K
Our picture of system defense knowledge and maneuver is clearly different from one another.
You sure about that?
Program the missiles for multiple discrete burns at different times, in between inertial movement only, so as to "hide" the origin launch point.
After all, if acceleration IS NOT CONSTANT ... that makes the task of backtracking the course of an incoming object A LOT HARDER.
And I hate to be the one to point this out, but ... missiles will tend to have computers in them. Computers can be PROGRAMMED.
I know ... radical idea.
The other point to recognize is that with missiles, if an attacker is willing to accept a delay between launch and impact (and let's be honest, who WOULDN'T want to have such a delay?) then all kinds of shoot 'n' scoot orbital maneuvering to foil counterbattery retaliation becomes a very real possibility.
Functionally it winds up being somewhat analogous to AV-8 Harriers tossing bombs at ground targets (otherwise known as "bombardment").
If you're a counterbattery response firing BACK along the calculated path of the incoming projectile, you're going to MISS the launcher, because the launching platform HAS MOVED (in who knows what direction) already by the time the return fire arrives.
Using CT sensor ranges, military sensors are working at 600000 km. That is more than adequate for smaller planet 100D, but even in this case it is 60% of the distance- but nothing says the sensors are limited to the planet.
A placement of patrol craft/sensor stations out to say 500000 km would extend detection past the 100D. With as little as 4 in cardinal directions, you can get extended warning and with random movement more complicated to hit the gaps. A more prosperous planet will have enough to provide cover and of course a naval base/fleet would have patrol in depth far past 100D.
Then once any detection occurs, the detecting unit shares the data and suddenly every friendly in the area has 900000 km target solutions.
And of course civilian traffic can be picking them up with luck (probably bad for them), assuming a surprise strike and not locked down or running convoys.
With that, the concept of counterbattery fire is moot- the intruding fleet is directly detected and is free to maneuver all it likes, it’s a target. The scenario painted above is a picture of that fleet following their missile swarm in and splitting fire. They won’t be coming in on any vee level where missiles have a greater damage because they will be detected at range and setting themselves up to suffer kinetic level counterattacks themselves.
If a kinetic strike against known fixed orbital and planetary facilities is desirable, the more likely scenario is building vee prior to launch then after missiles are away either slow down to avoid direct detection or veer off to one side for a slowdown and another pass from a different direction.
Engaging the incoming missiles themselves is another matter. My view is during their boost phase they would be highly detectable with drive/reaction plumes. When they are coasting, presumably they might fit the doggo category by CT standards and thus detectable by 1/8 or 75000 km military. Pretty hard to ensure that tight a sensor net for less than military forces.
If you get detection at any reasonable range, I would say that antimissile fire could hit them especially given they are coasting and not maneuvering. That allows for multiple shots not just the last second PD shot.
Things like meson guns should be able to hit too especially given the Striker depiction of area detonations, depends on how closely the missiles fly to each other. Regular CT flight resolution could have distances of several thousand km between them, HG battery fire suggests a tight grouping to provide overwhelming/mutual support swamping the PD battery.
On the PD shot itself, I would tend to degrade the PD chances themselves if the PD firer is not the direct target itself. PD fire probability is predicated on knowing what target the missile is attacking and thus the limited area it must traverse to get there- general planetary PD is going to not know that. Mutual PD support should be highly limited too, something like 1000km.
OTOH sand should be MORE effective at higher velocity protection.
Finally, circling back to the atmo penetration question, meteors burn up in our atmosphere, not many survive to become meteorites. We can presume advanced materials such as iridium alloy and the like, and optimized reentry designs like the recent comet recovery probe, so there is probably a range of possible vee that could enhance damage, but it’s not at any speed.
Thin or below may will allow greater ranges.
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Spinward Flow
SOC-14 5K
Grains of sand to pebble sized, you are quite correct.
10-50kg sized onjects though (CT SS3 stipulates 50kg maximum for turret launched missiles) ... those tend to make it all the way down to the surface through a standard atmosphere.
kilemall
SOC-14 5K
The stuff that makes it through are either small pieces that ironically slow down enough because they are light, or very large meteors- neither profile fits high speed impact missiles.
Asteroid Fast Facts - NASA
Comet: A relatively small, at times active, object whose ices can vaporize in sunlight forming an atmosphere (coma) of dust and gas and, sometimes, a
www.nasa.gov
Highest speed recoverable vessel was the comet mission. It’s reentry speed would be easily achieved during accel of garden variety CT missiles-
Stardust (spacecraft) - Wikipedia
Even so, it made it to the surface by slowing down. We can assume better performance by Traveller missiles, but there are limits.
Not saying bombardment isn’t a thing, am saying it’s limited in potential deliverable kinetic energy by atmosphere.
Spinward Flow
SOC-14 5K
Atmospheric Drag IS A FACTOR ... but it's not a "don't even bother" type of thing (particularly with respect to weapons engineering).
BackworldTraveller
SOC-13
There seems to be a serious Mass Vs Volume thing here.
Missiles (per most version of Traveller) are 12 per dTon. (Volume). i.e. the same volume as 83kg of liquid hydrogen. Assuming 2/3rds of the volume is missile and 1/3rd packing, that would equate to the volume of the missile being the same volume as 50kg of liquid hydrogen. Liquid hydrogen has a density of .074. Almost everything explosive or metal is denser than that by a huge factor. That volume is 0.675m3 (with packaging, 1125m3). A tube of water that is size would mass 675kg! Including packaging it is 1125kg.
Given a 40kg warhead is that from a 152mm Gun Shell, a 50kg missile is way too light for that volume.
Missiles (or even sand barrels) aren't going to be something a single strong person can handle in 1G without mechanical help.
Missiles (per most version of Traveller) are 12 per dTon. (Volume). i.e. the same volume as 83kg of liquid hydrogen. Assuming 2/3rds of the volume is missile and 1/3rd packing, that would equate to the volume of the missile being the same volume as 50kg of liquid hydrogen. Liquid hydrogen has a density of .074. Almost everything explosive or metal is denser than that by a huge factor. That volume is 0.675m3 (with packaging, 1125m3). A tube of water that is size would mass 675kg! Including packaging it is 1125kg.
Given a 40kg warhead is that from a 152mm Gun Shell, a 50kg missile is way too light for that volume.
Missiles (or even sand barrels) aren't going to be something a single strong person can handle in 1G without mechanical help.
mike wightman
SOC-14 10K
A LBB2 missile is 50kg.
You can actually get twenty missiles per cargo ton.
kilemall
SOC-14 5K
We also know they are 15cm in diameter from Striker as opposed to 25cm plus much bigger bay missiles.
The missile supplement describes them as being on individual cases.
If nothing else the missile turret can be set for lower gravity to assist in lifting/handling.
kilemall
SOC-14 5K
Not saying it’s a not bother, am saying it’s diminishing returns at a certain point. What that point is is mostly a game preference choice not a modeling/ sim one.
RogerD
SOC-12
The real problem for ortillery is that the drag turns into heat which could destroy the missile. The problem for the planet is that the heat itself can cause a significant shock wave. The energy has to go somewhere.
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