CT Only: The Littlest Starship

[kilemall]

Why would the fact that being invisible in space is impossible make those tonnage ranges a particular function? Not saying it ain't so, I am just curious as to why. (I don't play much if any fleet actions in my game.

The idea would likely be that stealth is easier to do with much smaller craft due to less IR/EM/mass 'emissions' therefore possible to stealth them whereas it would be prohibitively expensive or impossible to do to the larger ships.


IMTU I have multiple EM bands that have to be stealthed for, costs 10% of the total ship for each (-1) detection/lockon per band, start getting into usable -3/-4 to cover everything and you start costing 4-5x the original craft. Then, any repair of damage to said ship to regain stealth requires the same multiplier expenditure, plus of course maintenance.



So, other then highly notable one-offs, the vast majority of stealth craft are small craft.

 

[mike wightman]

Repeat after me - there is no such thing as stealth in space.

Without magic... (eg magic heat sinks, black globes)

read this again:

http://www.projectrho.com/public_html/rocket/spacewardetect.php

 

[Proneutron]

The idea would likely be that stealth is easier to do with much smaller craft due to less IR/EM/mass 'emissions' therefore possible to stealth them

Um, no. It isn't possible to stealth them. If you are running a Fusion PP you are visible across the entire system. Unless LOS is blocked by a large object. :coffeesip:

 

[AnotherDilbert]

Repeat after me - there is no such thing as stealth in space.

Quite, just as there is no such thing as stealth against radar. Oh, wait...


You have to radiate waste heat, you do not have to radiate equally in all directions, just as with current radar stealth craft.

 

[Proneutron]

You have to radiate waste heat, you do not have to radiate equally in all directions,

Unless all those who want to detect you are in a fairly static, narrow area, it doesn't matter. Even if the part of your ship facing the "enemy" is only at room temp you'll be spotted DAYS away using mil passive IR sensors.

 

[mike wightman]

Also the radiated heat will be reflected, scattered and absorbed/re-radiated by the gas and dust molecules in the 'empty space' your directional radiator is radiating in...

 

[AnotherDilbert]

Unless all those who want to detect you are in a fairly static, narrow area, it doesn't matter.

Everything interesting is basically in the ecliptic, so radiate away from the ecliptic. Some systems may have massive sensor systems many AUs away, looking up and down on the ecliptic, some systems may not...

Even if the part of your ship facing the "enemy" is only at room temp you'll be spotted DAYS away using mil passive IR sensors.

It wouldn't be much of a stealth system if you radiate at 300 K.

If you can detect every minor heat signature "days away" you will also detect every loose bolt or space junk closer to the sensor. Once you get a few thousand (or hundreds of thousands) false detections, the sensor will reject unlikely detections, giving the stealth systems something to work with.



Tech isn't perfect, sensors most certainly are not. The more sensitive you make them, the more false detections you get. The more false detections, the larger chance of rejecting a true detection as false since a system generating thousands of false detections would be unusable.

 

[AnotherDilbert]

Tech isn't perfect, sensors most certainly are not.

Neither are stealth systems, of course. They don't make you invisible, just more difficult to detect.

 

[Proneutron]

Everything interesting is basically in the ecliptic, so radiate away from the ecliptic. Some systems may have massive sensor systems many AUs away, looking up and down on the ecliptic, some systems may not...

They only need a probe about 2 meters in diameter. A decent sized world will have MANY all over the place.

It wouldn't be much of a stealth system if you radiate at 300 K.

Right, and it isn't as stealth in space doesn't exist.

If you can detect every minor heat signature "days away" you will also detect every loose bolt or space junk closer to the sensor.

That one is funny. Space junk and bolts will be the same temp as background. Unlike a ship with a nuke PP.

 

[AnotherDilbert]

Space junk and bolts will be the same temp as background. Unlike a ship with a nuke PP.

So chill the surface presented to the enemy to the same temp as a loose bolt in sunlight. Objects in sunlight will not be 4 K.

 

[mike wightman]

The surface of your ship pointed towards the target is much larger than a bolt - and you still have the problem that you have even more waste heat to deal with since you are now actively cooling one aspect of your ship.

Space is not empty, whatever direction you radiate the heat away in it will heat up gas and dust and leave a detectable signature for TL9+ sensors...

 

[AnotherDilbert]

The surface of your ship pointed towards the target is much larger than a bolt - ...

But much farther away, making the detectable angle very small.

... and you still have the problem that you have even more waste heat to deal with since you are now actively cooling one aspect of your ship.

Agreed, obviously.

Space is not empty, whatever direction you radiate the heat away in it will heat up gas and dust and leave a detectable signature for TL9+ sensors...

Space plasma isn't very cold or still, at least close to planets. Sunlight will heat it and the solar wind will perturb it.

If we are moving (as we always are in space) no single point in space will absorb all that much heat.


The same can be said of current radar stealth, radio waves reflected by the stealth plane will be re-reflected by any other object nearby and can be measured and used to detect the stealth plane, yet there seems to be practical problems making that not trivial.


I haven't done the maths, so I can only say maybe the region of slightly higher temp plasma will be trivial to detect, maybe it won't. Maybe far future stealth tech can reduce the likelihood of detection, not by removing the heat but redistributing it.

Either way you are saying waste heat stealth is difficult, not impossible.

 

[Proneutron]

So chill the surface presented to the enemy to the same temp as a loose bolt in sunlight. Objects in sunlight will not be 4 K.

Unheated object in sunlight WILL be noticeably colder than your ship. (about 200 Kelvin) Also, in comparison to ship speeds, standing still. Realize that detectors in any defended system will be all around you. 'nuff said.

All I can say is read all the factual arguments at Atomic rockets that have already falsified any argument you have or will make.

 

[AnotherDilbert]

Unheated object in sunlight WILL be noticeably colder than your ship. (about 200 Kelvin)

So chill the ship in some directions.

Realize that detectors in any defended system will be all around you. 'nuff said.

Maybe in HiPop or Base systems, but in all other tens of thousands of systems the Imperium isn't very interested in (because only a few percent of the Imperial pop lives there)?

Sensors are not free nor perfect. Having lots of them means constantly maintaining and replacing them.

All I can say is read all the factual arguments at Atomic rockets that have already falsified any argument you have or will make.

I haven't read all of it, but most of it considers current technology and chemical rockets.

I agree that hiding a chemical rocket with current tech would be impossible, but that is not what we are discussing in the Traveller context.

Only the discussion of waste heat management is applicable to Traveller. Directing the waste heat is discussed as possible, and the counter argument is basically that sensors are everywhere (in the Sol system since it is industrialised and HiPop). Low tech or low pop systems in the far future are not discussed as far as I have seen.


Even accepting that sensors are near perfect with near infinite range, but with limited view angles, and limited directions from the craft for detection, it becomes a practical problem of maintaining many sensors in tens of thousands of systems for centuries on end without fail rather than a discussion of physical impossibility.


You could just as well argue that current aircraft stealth is impossible since they have to reflect radar pulses in some directions and radars will be all around the aircraft since radars are cheap and "Realize that detectors in any defended system will be all around you. 'nuff said."

 

[Proneutron]

I haven't read all of it, but most of it considers current technology and chemical rockets.

Current DETECTION tech. And heat (source is irrelevant). Detection tech will improve. Thermodynamics will remain the same. THUS, since I can detect a fusion powered ship with off the shelf tech from the year 2000 from Walmart unfailingly. Your ship is COMPLETELY and IRREVOCABLY hosed using TL 12 detection gear. Meaning detected very quickly.

 

[AnotherDilbert]

Current DETECTION tech. And heat (source is irrelevant). Detection tech will improve. Thermodynamics will remain the same.

And obfuscation tech will obviously never improve? You realise that IR-shielded spacecraft already exist (for entirely different reasons) [see the projectrho page already referenced]?

THUS, since I can detect a fusion powered ship with off the shelf tech from the year 2000 from Walmart unfailingly. Your ship is COMPLETELY and IRREVOCABLY hosed using TL 12 detection gear. Meaning detected very quickly.

If the sensor is in the right place, looking in the right direction, perhaps. If you don't have infinite amounts of sensors that is not a guarantee.

How many sensors does the Imperium have in Zhodani systems? Sensors that are easily detectable, since stealth is impossible, right?

 

[whartung]

Everything interesting is basically in the ecliptic, so radiate away from the ecliptic. Some systems may have massive sensor systems many AUs away, looking up and down on the ecliptic, some systems may not...

Why would some systems have this and others not?

The real question is what's the base line sensor grid for commercial and civilian traffic control.

Not every system, perhaps, will have military grade sensors (unless there's simply not enough difference to matter). But every system (at least C starport and above I would think) would have traffic control systems up to some imperial standard.

 

[Proneutron]

Not every system, perhaps, will have military grade sensors (unless there's simply not enough difference to matter).

At TL 7, Walmart civilian equip will let you see out to Mars. At TL 12 civilian equipment will cover the entire solar system with basically no cost. Earth's CURRENT scanning for asteroids in the IR band would spot a ship out to the asteroid belt. The scanning is in all directions out from Earth.

 

[AnotherDilbert]

Why would some systems have this and others not?

How about:
Leander/Spin E695244-5 Lo { -3 }

A few hundred people at TL-5 with nothing much of a starport.

How much resources will they plow down in a high-tech military sensor network?

 

[Proneutron]

How about:
Leander/Spin E695244-5 Lo { -3 }

A few hundred people at TL-5 with nothing much of a starport.

How much resources will they plow down in a high-tech military sensor network?

They would be almost incapable of mounting sensors that would "see" past their local moon if any. Based JUST on that raw UWP. But, Trav world gen is weird. IMO. Where did those people come from? They aren't native. They aren't colonists (too few people). Who the heck are they? What are they doing there and why? Answer those questions then re-ask your question.