Passive IR detection ranges TL 7

[sideranautae]

This gives you a baseline from where you can set Passive sensor detection ranges for various TL's. Just pick a % increase for each subsequent TL above 7.

This example is based on off the shelf, commercial electronics today of perhaps $2,000 vs. a ship of ~3,000 tons running with only lowest level of life support (cabin temps of around freezing) and no other systems.

Detection range of ~38,800,000 kilometers (129 light seconds.)

R = 13.4 * sqrt(A) * T2

A = spacecraft projected area (m2 ) (figuring a cylindrical shape)
R = detection range (km)
T = surface temperature (kelvin)

Military grade sensors would of course be MUCH more sensitive...

If I get a chance I'll work up a simple dual value table (civvie & Mil) with ship size categories.

 

[sideranautae]

The figures in the OP are for a ship that is "running dark" and shutdown. For a ship that is running "hot" with PP going, reactor coolant being put out and the hull used as a huge radiator (necessary if you don't want to melt your ship while using a fusion PP), you are looking at detection ranges in multiple AU range.

 

[Matt Wilson]

Detection but not identification? Can you tell the "cold" ship isn't an uncatalogued asteroid at that range, or is it merely a blip?

I would assume that anything running hot would be obvious as some sort of ship even if you can't make out details.

 

[phavoc]

Detection but not identification? Can you tell the "cold" ship isn't an uncatalogued asteroid at that range, or is it merely a blip?

I would assume that anything running hot would be obvious as some sort of ship even if you can't make out details.

AFAIK all you get is the blob on your sensor, it's temperature, speed and heading. You still have to go out and check it out. Easy enough to fake, since it's just heat.

 

[sideranautae]

Detection but not identification? Can you tell the "cold" ship isn't an uncatalogued asteroid at that range, or is it merely a blip?

Temperature

 

[sideranautae]

AFAIK all you get is the blob on your sensor, it's temperature, speed and heading. You still have to go out and check it out. Easy enough to fake, since it's just heat.

Fake as what? At freezing (32 degrees) and moving, it is a ship.

 

[Infojunky]

My real question is "What is your pixel size at what range?" (Hint, inverse square plays a big part of this as well.... Especially with thermographs...)

 

[sideranautae]

My real question is "What is your pixel size at what range?" (Hint, inverse square plays a big part of this as well.... Especially with thermographs...)

That depends on target size, range, equipment magnification, pixel size, etc. The same variables as image size in visual EM range band.

Ships would use 2 systems.

1) fast scanner to detect.

2) System set up with parallax for general range & hi-mag for detail = ID.

 

[phavoc]

AFAIK all you get is the blob on your sensor, it's temperature, speed and heading. You still have to go out and check it out. Easy enough to fake, since it's just heat.

Fake as what? At freezing (32 degrees) and moving, it is a ship.

Fake as in I drop a few dozen drones off and let them spoof your IR. You see "ships" but if you can't resolve what the "ship" really is, it's not going to be all that useful to a commander. Look back to WW2 and how the Axis and Allies would use subterfuge and faking to throw off the enemy. Painting giant canvases to make whole factories disappear or move, dummy tanks, using tinfoil to obfuscate radar, painting fake bows and wave lines on ships. Faking out the enemy goes back to the beginning of warfare. Until you can resolve exactly what you've detected, it's not helpful.

 

[sideranautae]

AFAIK all you get is the blob on your sensor, it's temperature, speed and heading. You still have to go out and check it out. Easy enough to fake, since it's just heat.

Fake as what? At freezing (32 degrees) and moving, it is a ship.

Fake as in I drop a few dozen drones off and let them spoof your IR. You see "ships" but if you can't resolve what the "ship" really is, it's not going to be all that useful to a commander.

Sorry, doesn't work like that physics wise. A decoy needs to emit a similar amount of radiation and heat as the ship that launches them. That translates to every decoy having a power source comparable in size to a full ship, including the cross sectional radiation area. Total heat energy is different than absolute temperature too. Take another look at the formula in the OP of this thread.

 

[phavoc]

Cross section is easy to do via sting up a Web or something similar. A fusion reactor should easily be able to pump out energy to replicate a larger vessel. It's always been easy to scale up like that. The difference is the real ship is trying to hide it's emissions and the decoy isn't.

 

[sideranautae]

Cross section is easy to do via sting up a Web or something similar. A fusion reactor should easily be able to pump out energy to replicate a larger vessel. It's always been easy to scale up like that. The difference is the real ship is trying to hide it's emissions and the decoy isn't.

No. The physics is more complex than that. Start with study of black body radiation. There is a sci-fi writers advice (not sure the exact name) website that has a tutorial on this subject. But, you are right about the ship still radiating. Also all that the decoys would do is make the ship easier to find as they are now clustered next to the ship trying to hide. 8)

 

[phavoc]

Raytheon may have already solved the IR spoofing:

http://beforeitsnews.com/science-and-technology/2012/01/raytheon-has-quantum-dot-system-that-mimics-the-radiation-profile-of-a-satellite-as-an-anti-missile-decoy-1670401.html

According to Raytheon's method, to replicate a fake Hubble, it would take .08mg of "quantum dot" material. I found this looking for the site you mentioned. From their article:

A quantum dot cloud may be able to simulate the radiation signature of a protected asset (e.g., satellite) by reproducing an accurate infrared spectrum that would have a general profile as the radiation emission profile of the protected asset.

Sounds pretty interesting.

 

[sideranautae]

Raytheon may have already solved the IR spoofing:

http://beforeitsnews.com/science-and-technology/2012/01/raytheon-has-quantum-dot-system-that-mimics-the-radiation-profile-of-a-satellite-as-an-anti-missile-decoy-1670401.html

According to Raytheon's method, to replicate a fake Hubble, it would take .08mg of "quantum dot" material. I found this looking for the site you mentioned. From their article:

A quantum dot cloud may be able to simulate the radiation signature of a protected asset (e.g., satellite) by reproducing an accurate infrared spectrum that would have a general profile as the radiation emission profile of the protected asset.

Sounds pretty interesting.

Yes. Neat system. Works well against sensors being used in orbit and from ground versus low orbit vehicles. (detection from a known direction VERY close at hand for a VERY limited time thus, not much computation occurring from aggressor) Remember, the Dots have to be then powered by the craft. More EM emissions. Useless in deep space for hiding a spacecraft.

 

[BlindBleu]

*Throwing out a Clue*
Current Modern Day Counter Sensor operations/devices basically "interfere/interact" with the way the sensor processes the signal.
Agreed modern day IR counter sensor operations are not quite as sophisticated as the ones for RF band/range of today.
But give military its due, they will find ways/methods not yet conceived of by us low tech nearantwits<g>

 

[sideranautae]

But give military its due, they will find ways/methods not yet conceived of by us low tech nearantwits<g>

???

 

[BlindBleu]

But give military its due, they will find ways/methods not yet conceived of by us low tech nearantwits<g>

???

Neandertals+twits my crude attempt at a work using both Neandertwit....my bad a spelling.

 

[sideranautae]

But give military its due, they will find ways/methods not yet conceived of by us low tech nearantwits<g>

???

Neandertals+twits my crude attempt at a work using both Neandertwit....my bad a spelling.

Not that. I was wondering if you think that the Army will REALLY figure out how to cancel the laws of thermodynamics...

 

[Matt Wilson]

Whatever fits YTU, man. If Traveller can have samurai lions, there's probably room for spaceship stealth.

 

[sideranautae]

Whatever fits YTU, man. If Traveller can have samurai lions, there's probably room for spaceship stealth.

Absolutely. Just make sue that you it works across the boards with the broken physical law being consistent. In this case, perpetual motion machines become reality too. 8)