If one were to plot the black body radiation curve for the different temperatures each temperature has a peak emission which quickly drops off as you scan towards shorter wavelengths. https://www.physicsresourcebank.com/post/blackbody-radiation-spreadsheet-available-as-a-plaything. As you start from 0 degrees K you get very small values of W/m2, meaning it is very very hard to spot small and cold objects that are far away, there is just not much energy being relesed each second. With your shipboard sensors, you may be getting photons from that 1 m3 missile that has been sitting doggo for a month at a rate of one per hour. Just how long are you going to stare at each small patch of space looking for these threats? This is effectivly stealth in space. It CAN be detected with enough sensor area staring at that location for a few months, but an adventure class ship is not going to have the sensor m2 and time to make that detection.
T4 Only: Some people say no stealth in space, a discussion.
- Thread starter warwizard
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I think that’s the difference between the detect at x AU and practical detection- astronomy arrays do focus on objects for long periods of time, but that’s not a full sphere search done in tactically usable periods of time.
The Webb telescope is a 6.4 meter dish, so certainly portable enough to mount.
But such a dish for every EM wavelength is going to be quite a festival of deployed arrays. Very destroyable or at least painful to deploy or retract, like towed sonar arrays, and possibly be in the way of weapon arcs. And reflect any active sensors with larger returns.
But they might block at least some emissions so additional utility.
So you might have some dedicated guard ships doing the long range searches, and your actual tactical ready fleet nearby but in a stealthy deployment. And the point of long range detection is determining where deception efforts must be aimed.
So what does this look like in the third imperium? 1. With enough sensor m2 dedicated to doing nothing but constant survey of the full sky in multiple spectra, you can over time map all the medium large orbital objects in a solar system. Here at earth in 2024 we are still getting surprised by 100 m rocks that we do not detect until they were a few hours away from flying between the earth and the moon. So pop 9 TL 8 starport C? fails at this task. Perhaps if more funding was made available we would do a better job. So an analysis is needed to determine the threat level, and the government's likley response, eventually a sensor deployment and utilization program is developed, sensors deployed to detect the specific threats that are the most likley to be encountered, funding to operate these, and a response force ready to take action to divert the threats. That is for the NATURAL threats of a long period asteroid getting pertrubed and impacting your planet. What about the threat of sapient entieties that have intentions of removing your population from your planet? Detect jump entry into the oot cloud? Have all masses in the oot cloud that are able to precipate a ship out of jump pre surveyed so that a ship can be dispatched to the location? The deployed sensors and costs stagger the mind and destroy the budget. Here at Gliss Ten we maintain thousands of research class sensors that are primarially involved in monitoring the asteroid belt and long period oot cloud objects that enter the inner system. With all the mining activity in the belt the orbits of the asteroids are not very stable and we maintain watches so that none of the habitats are endangered by the mining activity.
2. Government scale military operations. Sensor drones, nuclear detonation grav focused active sensor pulses, grav focused nuclear detonation X-ray lazing arrays. All to find the enemy, fix the enemy, and destroy the enemy, and all done as far away from our actual ships as we can manage. Folding sensor arrays mess with your agility, we recommend owl head sensor mounts stressed to handle 2X the ship's agility in 3 axis. Every missile is a sensor drone, and the warheads are able to fire either as a sensor pulse or an attack pulse. The shot across the bow is 3 missiles at .2 LS detonating as sensor pulses each 120 degrees around your ship in the same plane as the system's orbital plane. (The .2 LS is the effective range of the grav foccussed X-ray lazing array.) I mean how obvious can we make it that you have been found and fixed? Oh and the sensor pulses at such short range can overload your passive sensors, and knock out your comms, best course of action is to cease maneuvering, turn on your transponder and running lights, and wait.
2. Government scale military operations. Sensor drones, nuclear detonation grav focused active sensor pulses, grav focused nuclear detonation X-ray lazing arrays. All to find the enemy, fix the enemy, and destroy the enemy, and all done as far away from our actual ships as we can manage. Folding sensor arrays mess with your agility, we recommend owl head sensor mounts stressed to handle 2X the ship's agility in 3 axis. Every missile is a sensor drone, and the warheads are able to fire either as a sensor pulse or an attack pulse. The shot across the bow is 3 missiles at .2 LS detonating as sensor pulses each 120 degrees around your ship in the same plane as the system's orbital plane. (The .2 LS is the effective range of the grav foccussed X-ray lazing array.) I mean how obvious can we make it that you have been found and fixed? Oh and the sensor pulses at such short range can overload your passive sensors, and knock out your comms, best course of action is to cease maneuvering, turn on your transponder and running lights, and wait.
Front license plates and headlights' parabolic reflectors suggest it can't.
Try waving a laser pointer at the front of a parked car some evening (safety and prudence would suggest that you only do this if the car is parked and unoccupied, of course) and see where the red dot shows up and where it doesn't.
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Something to keep in mind, that I haven't seen mentioned but admit I haven't read the whole thread, is the time it takes to scan the sky. Nominally there's no stealth in space. You're going to radiate something that someone can detect. The real question is how they're going to detect you.
A Type-S could probably be detected across the solar system by the JWST or Hubble in terms of sensitivity. The caveat being if they knew where to look. Both telescopes have a field of view of about 0.25deg², the celestial sphere has a "surface area" of 41,253deg². Even if you assume a Far Future sensor in a Hubble sized telescope could take quality exposures at 1/60th of a second, it would take 45 minutes to scan the whole sky.
There's also a question of angular resolution. For Hubble it's about 0.05 arcseconds. At that resolution a 100m ship 1 light second away would just resolve to a discernible point. A Star Destroyer at 1600m in length would be discernible at about 22 light seconds (if my small angle formula math is correct). Any further away from the telescope and those objects won't resolve to a point. Their heat signature might be a ship 23 light seconds away or a star dozens of light years away.
Most civilians ships' sensors might only have a couple 30cm telescopes with a few wide angle (fish eye) optical cameras. With great seeing a 30cm telescope could have an angular resolution of 0.5 arcseconds. It could only resolve about a 1000m ship at 1 light second. The wide angle sensors would only be useful for seeing really big stuff far away or ships really close.
While ships can't really hide in space, detecting distant ships and getting actionable intelligence from that detection would be a lot of work for the sensor technicians. They'd need to not only check and recheck parallax of possible detections but run spectral analysis to see if the emission curves suggest a ship or natural phenomenon.
A Type-S could probably be detected across the solar system by the JWST or Hubble in terms of sensitivity. The caveat being if they knew where to look. Both telescopes have a field of view of about 0.25deg², the celestial sphere has a "surface area" of 41,253deg². Even if you assume a Far Future sensor in a Hubble sized telescope could take quality exposures at 1/60th of a second, it would take 45 minutes to scan the whole sky.
There's also a question of angular resolution. For Hubble it's about 0.05 arcseconds. At that resolution a 100m ship 1 light second away would just resolve to a discernible point. A Star Destroyer at 1600m in length would be discernible at about 22 light seconds (if my small angle formula math is correct). Any further away from the telescope and those objects won't resolve to a point. Their heat signature might be a ship 23 light seconds away or a star dozens of light years away.
Most civilians ships' sensors might only have a couple 30cm telescopes with a few wide angle (fish eye) optical cameras. With great seeing a 30cm telescope could have an angular resolution of 0.5 arcseconds. It could only resolve about a 1000m ship at 1 light second. The wide angle sensors would only be useful for seeing really big stuff far away or ships really close.
While ships can't really hide in space, detecting distant ships and getting actionable intelligence from that detection would be a lot of work for the sensor technicians. They'd need to not only check and recheck parallax of possible detections but run spectral analysis to see if the emission curves suggest a ship or natural phenomenon.
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take 45 minutes to scan the whole sky." We covered the exposure time issue for Hubble esque sensors trying to detect cold and small objects at light minute and longer ranges: When relying on blackbody radiation for detection of very cold and very small objects at long distances the exposure time to collect enough photons to get a spike above background can run into several months of observation time. In fact that is why we are putting the instruments at L3 or L5 points is to shorten the time needed for generating the needed observation time, they no longer need to change to a different observation target while Earth is blocking the first target.I put a link to a spreadsheet that if given the degrees K of the target, it tells you the W/m2, and the point is that really cold objects do not put out many Watts per square meter, and if the object is really small like a 1 m3 missile there is not even 1 m2 facing the sensor. We are not talking about a candle on mars, we are talking about a piece of metal that somebody touched a month ago that has been sitting in the in the shade of an asteroid for the past month. It is not the ships that are your highest priority sensor target, it is the oppsition forces's sensor drones and missiles (think 1 m3 missiles not 14 m3 missiles). There is a lot more effort made to get these objects to be as stealthy as possible, placed into tacital situations that reduce thier likleyhood of ever being detected. It is the missile you did not see comming that shoots you down. I was tracking a black fly on my computer monitor, when it was on the white areas it was instantly detected, but when it walked over the starfield sections it dissappeared, and I had to start scanning for a hole in the starfield pattern. Fixing the fly's position was an order of magnitude harder due to the tactical positioning of the fly.
take 45 minutes to scan the whole sky." We covered the exposure time issue for Hubble esque sensors trying to detect cold and small objects at light minute and longer ranges: When relying on blackbody radiation for detection of very cold and very small objects at long distances the exposure time to collect enough photons to get a spike above background can run into several months of observation time. In fact that is why we are putting the instruments at L3 or L5 points is to shorten the time needed for generating the needed observation time, they no longer need to change to a different observation target while Earth is blocking the first target.I put a link to a spreadsheet that if given the degrees K of the target, it tells you the W/m2, and the point is that really cold objects do not put out many Watts per square meter, and if the object is really small like a 1 m3 missile there is not even 1 m2 facing the sensor. We are not talking about a candle on mars, we are talking about a piece of metal that somebody touched a month ago that has been sitting in the in the shade of an asteroid for the past month. It is not the ships that are your highest priority sensor target, it is the oppsition forces's sensor drones and missiles (think 1 m3 missiles not 14 m3 missiles). There is a lot more effort made to get these objects to be as stealthy as possible, placed into tacital situations that reduce thier likleyhood of ever being detected. It is the missile you did not see comming that shoots you down. I was tracking a black fly on my computer monitor, when it was on the white areas it was instantly detected, but when it walked over the starfield sections it dissappeared, and I had to start scanning for a hole in the starfield pattern. Fixing the fly's position was an order of magnitude harder due to the tactical positioning of the fly.
Spinward Flow
SOC-14 1K
This is the basic flaw of the LBB2 detection ranges (0.5 light seconds for civilian, 2 light seconds for military, 3 light seconds for tracking of anything previously detected). It's an overly simplistic system ... and the radical simplification used creates non-sense edge cases.
Under LBB2, a 20 ton Launch with A/A drives has the exact same sensor signature as a 5000 ton craft with Z/Z drives.
Why?
Because there are no conditionals for "size" of sensor targets or consideration of what Striker would later define as a modifier for detections ... sensor signature.
And under LBB2, sensor detections and tracking are a boolean (Y/N) result. There's no "continuum of possibilities" or any kind of "contest" involved to make determinations. Either you "know" (with total information) or you don't.
For tabletop wargaming (which is what LBB2 was meant for), that's "good enough" for quick and dirty gameplay on a map.
For space simulation of what it must be like to live aboard a spacecraft ... it's woefully inadequate, to the point of being laughable.
Of course, signature reduction (stealth) wasn't exactly as well known to be "a thing" in aerospace engineering during 1977. It was only later that things like "stealth fighters" became a reality (for the public) to know about, along with the realization that signature modification of craft IS POSSIBLE.
Remember, it's not about having "an invisibility cloak" ... it's about being able to reduce the range at which sensor systems can detect and track your craft. If you can "degrade" a sensor system's detection and tracking capabilities "enough" you can operate closer to a sensor system without being detected (or tracked) by that sensor system ... effectively "shrinking" the radius at which that sensor can usefully find your own craft ... and sometimes, all you need is to be able to "get closer than expected" in order to have an overwhelming first strike advantage (that decides the engagement).
I'm shocked, SHOCKED that they didn't manage to cover this in 8 (small) pages of rules.
Spinward Flow
SOC-14 1K
Your reminder that "wargames are not simulations" sticker goes HERE.
Brilliant Lances is T3 or T4 build/game ?
BL is TNE, but I think they're referring to FF&S 2, which apparently has some kind of sensor component that I don't think is in FF&S 1.
Yes, there are, but I don't think the "rules" for them on in FF&S, whereas (as I understand it) FF&S2 has some rules or support for sensors and impact of design choices on that.
mike wightman
SOC-14 10K
Star Cruiser, TNE crb, Brilliant Lances, Battle Rider all have sensor rules that pre-date T4
This is a great discussion about stealth in space. I love the science. I really only have one issue: they know this. Anything we can think up, they've already been dealing with for thousands of years. As of 1100, the Vilani have been in space for something like 10,000 years. The Terrans have had something like 3500 years to advance on the tech we're currently using. They've been dealing with stealth and counter-stealth using tech millenia past what we can imagine. Lying cold in wait might be a useful strategy if you're hanging out somewhere that you know someone's going to be coming to and the place lacks the ability - or interest - to spot you as you set up and warn others that you showed up there a few days ago and are just sitting there. Otherwise, not so much; space is huge. You might manage directional stealth, but combatants know to send out drones and probes and fighters to ensure they have as complete as possible a picture of the volume of space around their ship from every possible direction, and those power plants are little neutrino stars. I really don't see stealth being practical except against civilian shipping traveling well off the beaten path.
My view is more abstraction in terms of each shop in a fleet has assigned search sectors, so beyond a certain point only a critical snake eyes failure could prevent detection and it will probably be caught on the next sensor sweep.
So stealth practical only for small craft and spec ops/smuggling with limited numbers of detecting ships/stations.
mike wightman
SOC-14 10K
In a fleet how many escort class vessels do you have? Then there are smallcraft equipped with sensor packages.
As many as necessary.
See, that's the key point. The planners know the limitations, one way or another. They know the threat model, even if we don't, and, as a general rule, like to balance their doctrine and designs around that threat model.
As is said, no plan survives first contact, but they have been doing this for 100's to a thousand years. Tech has changed, but space, the mission, the terrain, not so much.
If a lone ship with a few small craft is a viable, then they'll do that. If a lone ship tends to do poorly in combat, then they'll do a combined arms/sensor design of some kind. It may be they just launch a 10,000 dt ship that carries 10 scout ships that immediately fan out on entry to get an eye on the nearby space and pick out any lurking intruders.
Why do that? Because they found its necessary, and thus developed a doctrine, "all large ships carries intrinsic scouting and sensor capabilities".
All we have to go on is the mechanics manifested in the game systems we've been provided, and somehow try to figure out what the doctrine might be. But, that's very hard as we have no economy to protect, or missions to achieve. It's all pretty much done in, ahem, a vacuum.
Spinward Flow
SOC-14 1K
Have you SEEN our Defense Budget Outlays?
I'm sorry, @whartung but you seem to have confused these too concepts for each other to the point of thinking they are both equivalent and interchangeable:
- As many as are necessary.
- As many as we can afford.
Guess how often that happens to be the case in practice.
And we aren't even talking about "mission creep" yet ...
Point being, color me skeptical that your "as many as necessary" is the valid/correct answer to the question posed (in good faith) by @mike wightman.
I'm going to edit this quote
ever so slightly to make it about land and sea warfare instead of space warfare. See if you can spot the differences in underlying assumptions that result.As is said, no plan survives first contact, but they have been doing this for 100's to a thousand years. Tech has changed, but the land, the mission, the terrain, not so much.
As is said, no plan survives first contact, but they have been doing this for 100's to a thousand years. Tech has changed, but the sea, the mission, the terrain, not so much.
Anyone who tells you "the tech has changed, but that won't make any difference" is ... missing a few Tricks Of The Trade™ (to put it politely).
