BCS Discussion (Fall 2022) (<HG79)
- Thread starter robject
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Not just any emissions, but a bright point-source significantly above background, with nothing to hide or attenuate it between you and the source. In hard science fiction, an operating fusion torch drive on a spacecraft at Alpha Centauri would be clearly detectable from Earth (though 4.3 years out of date) with modern-day detection equipment.
But Traveller isn't strictly hard science fiction, of course. That's why the gravitics heat dissipation sink idea works as a hand-wave to get us to low-detectability.
The question is how to reduce them.
- You could transfer the heat to an internal sink which would eventually need to be ejected (and then become an observable heat-source afterward - this is actually an option for Black Globe heat dissipation methods in T5.10).
- You could vent it directionally (and handwave away the fact that the mechanism that produces the directional emission will generate its own additional heat), as long as you know in advance in what direction your adversary is located, and as long as the native system does not have a spherically distributed set of detection grid stations in place surrounding the defended part of the system to detect directional emissions (with SDBs or Monitors on standby). Directional dissipation might work for a time, depending on how it was implemented.
Yes, correct. I agree with you concerning Active Sensors. I am specifically referring to Passive Sensors detecting native emissions from a target.
True. And this at least presents one of the interesting tactical and strategic situations that will arise. When a ship or fleet jumps into system, they will be immediately aware of other native ships in the system (though their positions and activities may be several hours out of date - but a good strategist will be able to make good assumptions about their current whereabouts and readiness status). But the native vessels already in the system will not be aware of the incoming ship/fleet for a number of minutes to hours, depending on how far away they are, because it will take time for the native vessels to receive the first emissions of the incoming ship(s) after jump emergence.
This implies that in-jumping units should have a tactical advantage (i.e. initiative, several rounds of free and unobserved maneuver, etc ) as compared to the native units. This should probably be an element in any BCS Combat Rules system.
But it's a fixed modifier.
All well and good if you just want to line the ships up across from each other and let fly.
The singular point about stealth, in a TACTICAL scenario is how it relates to maneuver.
WIth stealth you have control over range and relative position. ("Flying out of the sun", "sneaking up behind").
If those factors don't matter, then stealth doesn't buy you anything.
Strategically, stealth is Mostly Pointless, since any real strategic response is a week (in-system) to two weeks away.
You can walk up and ding the door and have your way, and leave before reinforcements arrive.
And, especially with the historic traveller game systems, the turn lengths are so long, there's not even much benefit to tactical surprise (being caught with "shields down", being caught unable to launch fighters, can't get the gunners to the turrets in time, etc.).
Historically space combat is seeing the sails on the horizon and just waiting for them to get into cannon range.
"Lieutenant, that General Quarters drill was unacceptable -- it took 32 minutes. We only have a small window of 30 minutes to prepare for surprise attacks and get the crews geared and to their stations!!"
"General Quarters! This is not a drill! Make sure you finish your sandwiches and bus your tables before rallying to post! and NO RUNNING!"
So, you know, "urgency" is relative.
Sensor lock mechanics are how "Stealth" is typically managed. We KNOW the ship is there, we know SOMETHING is there. As they get closer, we know more and more about what they are. The lock mechanics can take into account "evasive maneuver", ship size, ECM, ECCM. In TNE you can use detonated missiles to "hide behind" and break locks. All with "knowing" the ships are there, without stealth.
Your point are noted. But look at the scope of the game as described, and a simple comparative modifier is in line with the theme.
Also note that Sensors/Stealth are all relative, which more scenario based than platform based in terms of their Military effectiveness. Meaning warships have beefier electronics to process the single they receive as compared to civilian craft.
RogerD
SOC-12
Don‘t neglect the effects of active countermeasures either. Blanket the sky with emissions deliberately amped up to hide the stuff you don‘t want to see. Turn those on and off and move to confuse the incoming ships. Make the fleet look bigger than it is. Send decoys to mask what your fleet is really doing. Get your fighters or missiles in close by covering them with jamming. There are lots of tactical options for a clever admiral to use.
Yes, this is really what the computer is for in LBB2/5, but it should be a first class concept. We have this in BBB2, fortunately. It just needs to be carried into the BCS.
I guess I like my space combat to be more like The Hunt For Red October or the battle of Midway than the battle of Jutland.
Yes, this is really what the computer is for in LBB2/5, but it should be a first class concept. We have this in BBB2, fortunately. It just needs to be carried into the BCS.
I guess I like my space combat to be more like The Hunt For Red October or the battle of Midway than the battle of Jutland.
mike wightman
SOC-14 10K
Considering that the fusion reactors on capital ships can be on the order of terawatts, you are not going to hide. Nor can you emulate a terawatt reactor with decoys without putting a terawatt reactor in each decoy.
Without a magical technology there is no stealth in space. I have been proposing a gravitic heat sink for years.
And another thing to consider, within a certain range a laser or particle beam weapon cannot possibly miss.
Without a magical technology there is no stealth in space. I have been proposing a gravitic heat sink for years.
And another thing to consider, within a certain range a laser or particle beam weapon cannot possibly miss.
RogerD
SOC-12
If I stipulate that, it still leaves room for stealth in a smaller ship or missile, especially with larger ships to help cover for them.
Would it be useful to think in terms of astronomical apparent magnitude? Above a threshold based on output and distance, I agree detection would be relatively simple, but the higher the relative magnitude, the harder it is. The Webb telescope can see a magnitude 35 object, but that is with a long exposure looking in the right direction. Technology is higher in the Imperium of course.
ATLAS looks in all directions once per day with a limit of about 19.5. Binoculars can see +9.5 so thats a lower bound.
Condottiere
SOC-14 5K
The thing about silent running is that you can shut down non essential equipment, turn down the oven, possibly switch over temporarily to the backup batteries.
mike wightman
SOC-14 10K
Small ships are still putting out gigawatts, that is going to be easily detectable. There is no stealth in space without magical technology.
mike wightman
SOC-14 10K
And cook or freeze your crew.
Condottiere
SOC-14 5K
That would depend on whether you consider life support non essential.
All well and good.
Simply, if you're just going to line ships up and roll dice, you may as well be playing Risk.
There's nothing wrong with Risk, but just know that's what you're getting.
A fundamental concept in regards to High Guard is that Fleet design is the paramount factor towards success. And that's all well and good as well, but the point there is that fleet design overrides execution of the combat.
That means there there are few decisions during combat that are of interest. Specifically, I should say there are few interesting decisions to be made during combat. A player can "decide" to not fight at all and watch that Rampart fighter slowly pick the Tigress apart. But that's not, outside the hyperbole of the scenario, realistic play. Players "won't do that".
What they'll do is make the same decisions as any other informed player. It's fair to assume that once the fleets are revealed, the decision making is pretty much done and all that remains is the rolling of the dice to iron out the details.
And if thats the game you want, Risk with a few more modifiers, then hallelujah and away you go. It's just helpful to be forthright that that is, indeed, the end goal.
mike wightman
SOC-14 10K
The formations from Double Star are one way to make a line of battle a bit more interesting. Tactical movement and ship facing is another.
RogerD
SOC-12
I wanted to test this, so I looked up some equations and did some math using the ideas of luminosity, bolemetric magnitude and apparent magnitude.
A Book 5 minimum size power plant puts out 1EP which is 250MW per Striker. If you assume that all 250MW are waste heat and so are emitted from the ship, this ship has a bolometric absolute magnitude of 50.2. At 1 light second, this would be an apparent magnitude of +5.2. That's naked eye visible in dark skies. At a terawatt (4000 EP) of waste heat, you would have an absolute magnitude +41.2 - about the same as Venus from the surface of Earth.
I'm not sure what kind of apparent magnitude limit is useful for passive detection. It's a logarithmic scale, and beyond a point you (currently) need a long exposure which is searching a very limited surface area at a time. A starship wants to scan in all directions as often as possible. Certainly if you can see it with the naked eye, a camera should be able to do the same thing, but there will be limits somewhere.
The idea that the entire output of a power plant is waste heat should be examined. A quick search shows that modern fission nuclear power plants could approach 45% efficiency and higher techs should achieve higher efficiencies - so roughly half the power generated should be used, not wasted. We'd have to guess at what the efficiency of a fusion plant is and what the efficiencies are of the transmission systems and the equipment being powered, but in any case, not all of it ultimately becomes waste heat.
The huge powerplants a dreadnought uses typically are mainly there to power the weaponry and drives - if either is not used, the heat signature should be much less. Power plants can be offline or running in an idle state.
We can quantify life support power using The Belter's Handbook - basic power requires 0.05 tons of fuel per week per 100 tons of ship. That would be 0.2 tons out of the 1 ton normally allocated for 4 weeks of operations per ton of power plant. That works out to be about 50MW per 100 tons of ship. (Seems high to me, but ok.) LBB2 tells us we don't even need that - we can run for 1D days on batteries - we could use batteries to run even more silently for at least a day.
There is also no reason to believe that waste heat would be emitted as a point source - if a ship could emit it directionally it would be harder to detect in the directions it isn't emitting (but easier to detect in the other directions).
mike wightman
SOC-14 10K
If you have a directional heat exhaust you need a way to move the waste heat to that exhaust, which generates yet more waste heat.
The great unknown is the efficiency of the M-drive, the energy removed from the ship by the M-drive output. Striker actually gives us the efficiency of most ship weapons.
The great unknown is the efficiency of the M-drive, the energy removed from the ship by the M-drive output. Striker actually gives us the efficiency of most ship weapons.
RogerD
SOC-12
Sure, it takes energy to pump heat, but whether that is done directionally or not shouldn't matter much. The fusion power plant already has to deal with not just radiating the heat in all directions.
Earlier in the thread, the parameter of 240m as a critical length for a dreadnought was mentioned. If you take that as a diameter, to radiate 1 TW of waste heat gives you a surface temperature of 16464K. 250MW would be 2070K. I think it's safe to say we're not dealing with those levels of waste heat in Traveller.
mike wightman
SOC-14 10K
The only reference to radiators I have found to date is in the AHL Supplement.
RogerD
SOC-12
Thanks for the reference! I looked it up, and it says: "The fins [...] are used to radiate excess heat from the power plant when it is in overload or high capacity function." - from that we could take it to mean that in normal operation, you would not need to do that. You could also take it to mean that all ships need this and it is included in the power plant tonnage.
Probably have beat this to death by now, sorry about that all - I stand by the idea that BCS needs to have sensor and stealth ratings though. YMMV.
If T5 is any indicator, then sensors and stealth have roles.Thanks for the reference! I looked it up, and it says: "The fins [...] are used to radiate excess heat from the power plant when it is in overload or high capacity function." - from that we could take it to mean that in normal operation, you would not need to do that. You could also take it to mean that all ships need this and it is included in the power plant tonnage.
Probably have beat this to death by now, sorry about that all - I stand by the idea that BCS needs to have sensor and stealth ratings though. YMMV.
mike wightman
SOC-14 10K
The battles described in his stories are filled with EMP, comm/datacaster EW, ECM, ECCM and a variety of sensors across different TLs.
The sensor game could be an important phase in the battle...
The sensor game could be an important phase in the battle...
