MarcusIII
Emperor Mongoose
Which of course is beyond broken. So active radar has a range of hundreds of light years? Passive sensors detect distant stars and planets.
Space Combat - Did I miss something?
- Thread starter Galen
- Start date
shirgall
Cosmic Mongoose
My interpretation of this has always been about detecting *enough* for a sensor lock that can provide actionable data (as in, apply a task chain DM) to the gunner.
MarcusIII
Emperor Mongoose
Passive by its nature doesn't provide enough for a sensor lock unless extremely close. But a passive sensor WILL detect a 4 watt radio transmitting out past Pluto's orbit. Or something the size of the space shuttle using its maneuvering rockets. Giving its bearing. Well that's 2000 A.D. TL. By TL 12 much further.
shirgall
Cosmic Mongoose
Sure, at TL7 that's the situation...
MarcusIII
Emperor Mongoose
correctSure, at TL7 that's the situation...
MarcusIII
Emperor Mongoose
Yes, at short range. We've had the tech since the late 50's with Sidewinder AA missilees
MarcusIII
Emperor Mongoose
Up to the point where range is uncertain. At that point you can't lock. A few thousand miles.
Limpin Legin
Emperor Mongoose
ChatGPT says light/EM waves can travel 0.6 billion km (there and back) in six minutes (one combat round). Of course, when dealing with tracking a relatively small, fast moving object, max distances would become a lot shorter to remain meaningful.
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"Sensor lock" really only has meaning in combat. Weapon ranges are all well within the sensor ones. Distant (300,000km, one light second) is stated in HG p.26 as the maximum practical distance at which attacks can be made.
There is no upper range limit on active radar and lidar... but you're only getting minimal detail on the target above Long Range. I'm not aware that minimal details prevents attacking; you resolve its basic outline. The range would be known, as would its motion. Knowing more about its shape or structure at Medium and Long range is handy, but doesn't affect your ability to burn it with a laser.
As far as using active radar on a distant star... yeah, there are practical reasons why that won't work.
In fact, there would be practical range limits on active radars, but it depends on the antenna size and reflected signal strength. You're probably okay to limit ship based radar/lidar to interplanetary distances, maybe about an AU or so. Bigger arrays - the sort of ones used for survey work - would do better. But keep in mind that passive thermal are good enough to give you bearing and aparrent motion. It's range that's the tricky part... but active sensors at least give you a cutoff. If there's no reflected signal within 16 minutes, it's either REALLY good at absorbing that wavelength, or further away than 1 AU. In most cases you'll have some idea of range from radar, but with rapidly increasing margins of error as distance gets greater.
There is no upper range limit on active radar and lidar... but you're only getting minimal detail on the target above Long Range. I'm not aware that minimal details prevents attacking; you resolve its basic outline. The range would be known, as would its motion. Knowing more about its shape or structure at Medium and Long range is handy, but doesn't affect your ability to burn it with a laser.
As far as using active radar on a distant star... yeah, there are practical reasons why that won't work.
In fact, there would be practical range limits on active radars, but it depends on the antenna size and reflected signal strength. You're probably okay to limit ship based radar/lidar to interplanetary distances, maybe about an AU or so. Bigger arrays - the sort of ones used for survey work - would do better. But keep in mind that passive thermal are good enough to give you bearing and aparrent motion. It's range that's the tricky part... but active sensors at least give you a cutoff. If there's no reflected signal within 16 minutes, it's either REALLY good at absorbing that wavelength, or further away than 1 AU. In most cases you'll have some idea of range from radar, but with rapidly increasing margins of error as distance gets greater.
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IMO, A consideration is that Thermal would pretty much see every ship in a system, and that the current range limits on sensors are there so that ships travelling through the system have some anonymity for game purposes.
This is a "This is how it works here." situation.
This is a "This is how it works here." situation.
Condottiere
Emperor Mongoose
When the drives are lit up, that will have a heat signature.
Ship components, like launch tubes.
Weapon systems that have power requirements.
The hull, at default twenty power points basic services, per hundred tonnes.
Ship components, like launch tubes.
Weapon systems that have power requirements.
The hull, at default twenty power points basic services, per hundred tonnes.
I can't find the links right now, but there are several articles around that discuss "There is no stealth in space" that discuss that even when the drives are not lit, ships can be seen thermally from anywhere in the system when looking at the background.
One particular article goes through all the ways it could be handled, and they make a pretty good case against it.
It is something I ignore.
Here it is
Detection - Atomic Rockets
Condottiere
Emperor Mongoose
In Traveller, the author(s)' intent is clear, that you can stealthify spacecraft.
I'd modify it by the actual amount of power output escapes the hull.
I'd modify it by the actual amount of power output escapes the hull.
Sigtrygg
Emperor Mongoose
How much waste heat does a gravitic drive produce?
Anything powered by electricity will generate waste heat.
Sigtrygg
Emperor Mongoose
And yet have neve described the mechanism by which it is possible.
If it doesn't get out of the hull in someway the ship melts eventually...
which is yet another way of plugging the gravitic heat sink concept
Condottiere
Emperor Mongoose
Well:
As such, thruster plates need not be exposed at all and can optionally be concealed behind bulkheads. This rather severely degrades performance but there are some ship designs that are willing to accept the trade-offs for added stealth. See the Sensors chapter on page 55 for more information about features that make a ship easier to detect, including the use of their manoeuvre drives.
Concealed manoeuvre drives are contained within ship bulkheads but must be within three metres of the accelerating surface of the ship. Concealed manoeuvre drives add 25% to the tonnage and cost of the drive. The additional tonnage comprises a system that contains and exhausts thruster plate ionisation out of specially designed ports, reducing their detectability to almost nil.
A stealth jump drive minimises the burst of radiation caused by the transition from jump space into real space. Normally, a ship that emerges into real space is automatically detected if it emerges within the minimum detail range of the sensor. However, detecting a ship equipped with a stealth drive emerging into real space requires a Formidable (14+) Electronics (sensors) check (1D rounds, INT or EDU) if it is within the ‘limited’ detail range of the sensors or automatically fails if outside the minimum detail range. Stealth jump requires two Advantages.
As such, thruster plates need not be exposed at all and can optionally be concealed behind bulkheads. This rather severely degrades performance but there are some ship designs that are willing to accept the trade-offs for added stealth. See the Sensors chapter on page 55 for more information about features that make a ship easier to detect, including the use of their manoeuvre drives.
Concealed manoeuvre drives are contained within ship bulkheads but must be within three metres of the accelerating surface of the ship. Concealed manoeuvre drives add 25% to the tonnage and cost of the drive. The additional tonnage comprises a system that contains and exhausts thruster plate ionisation out of specially designed ports, reducing their detectability to almost nil.
A stealth jump drive minimises the burst of radiation caused by the transition from jump space into real space. Normally, a ship that emerges into real space is automatically detected if it emerges within the minimum detail range of the sensor. However, detecting a ship equipped with a stealth drive emerging into real space requires a Formidable (14+) Electronics (sensors) check (1D rounds, INT or EDU) if it is within the ‘limited’ detail range of the sensors or automatically fails if outside the minimum detail range. Stealth jump requires two Advantages.
collins355
Emperor Mongoose
Yes, the problem (or, a problem) is we often unconsciously slip into treating Traveller thruster plates as if they are rockets (and hence treating them as great torches spewing out reaction mass).
But Traveller thruster plates are explicitly not that at all.
But Traveller thruster plates are explicitly not that at all.
