OTU Only: Stealth and Detection in the OTU

[atpollard]

Stealth in space does not exist in the OTU.

I hear this a great deal, usually stated as a simple fact.
I am not here to debate the real world thermodynamics ... I will yield the point for this discussion (although I think that there is an assumption of infinite resolution that would not hold up to a rigorous examination of wavelengths and apertures and pixel resolution and scanning times).

While I yield the point that there is no stealth in space in the Real Universe, I offer the following in challenge to the often made claim that there is no stealth in the OTU:

Starships can detect other ships at a range of approximately a half million miles (500 inches). Military vessels and scouts have detection ranges out to two million miles (2000 inches).
Ships which are maintaining complete silence cannot be detected at distances of greater than 100,000 miles; ships in orbit around a world and also maintaining complete silence cannot be detected at distances greater than 10,000 miles. Planetary masses and stars will completely conceal a ship from detection.

Ordinary or commercial starships can detect other ships out to a range of about one-half light-second; about 1,500 millimeters. Military and scout starships have detection ranges out to two light-seconds; 6,000 mm or 6 meters.
Ships which are maintaining complete silence cannot be detected at distances of greater than half detection range; ships in orbit around a world and also maintaining complete silence cannot be detected at distances greater than one-eighth detection range. Planetary masses and stars will completely conceal a ship from detection.

Getting a good sensor lock on a target requires two sensor tasks' the target must first be located using a sensor scan task, upon a getting a successful scan, the sensors must be locked onto the target using a sensor pinpoint task.
1. Locating the Target: Locate the desired target With the following task:
To locate an enemy unit with sensors'
Difficulty, Off=Computer Model Number; Def=Range (confrontation)
Referee' Use the most favorable sensor scan difficulty level from among the Unit's UCP. Use the number of squares from the sensing Unit to the target unit as a negative OM. Optionally, a character may use Sensor Op skill in place of the computer number.
Evaluate the results of this task as:
Extreme Failure: Scan failed.
Failure: Target located If Strong/Large
Success: Target located If it is Moderate/Medium or Strong/Large
Extreme Success: Target located

These basic core rules seem to imply that detection of ships is far from automatic and universal in the OTU. From the earliest rules, I would personally go so far as to assume that some level of stealth is innately assumed to be part of the package of Fusion Power Plants, Maneuver Drives and Liquid Hydrogen fuel. Beyond a certain range, the CT rules say that no detection is possible. Under a variety of conditions, the MegaTraveller rules make 'locating the target' statistically improbable to impossible ... the basic definition of 'stealth'.

I invite those more knowledgeable of the OTU to provide more than unsupported statements that there is no stealth in the Official/Original Traveller Universe.

I welcome anyone with insight from T5 to chime in on the latest thinking on the subject.

Based on the early rules, I am forced to reject the claim that there is no stealth in the OTU.
IMHO, limited stealth appears to be the default in the OTU.

 

[whulorigan]

[FONT=arial,helvetica]

Stealth in space does not exist in the OTU.

[/FONT]I hear this a great deal, usually stated as a simple fact.

I personally agree that that is too strong a statement. "[FONT=arial,helvetica]Stealth in space does not exist in the OTU" is different from saying that [/FONT][FONT=arial,helvetica]"Stealth in space cannot exist without some currently not-understood New Physics".[/FONT]

I am not here to debate the real world thermodynamics ... I will yield the point for this discussion (although I think that there is an assumption of infinite resolution that would not hold up to a rigorous examination of wavelengths and apertures and pixel resolution and scanning times).

While I yield the point that there is no stealth in space in the Real Universe, I offer the following in challenge to the often made claim that there is no stealth in the OTU:

These basic core rules seem to imply that detection of ships is far from automatic and universal in the OTU. From the earliest rules, I would personally go so far as to assume that some level of stealth is innately assumed to be part of the package of Fusion Power Plants, Maneuver Drives and Liquid Hydrogen fuel. Beyond a certain range, the CT rules say that no detection is possible. Under a variety of conditions, the MegaTraveller rules make 'locating the target' statistically improbable to impossible ... the basic definition of 'stealth'.

I invite those more knowledgeable of the OTU to provide more than unsupported statements that there is no stealth in the Official/Original Traveller Universe.

I welcome anyone with insight from T5 to chime in on the latest thinking on the subject.

Based on the early rules, I am forced to reject the claim that there is no stealth in the OTU.

IMHO, limited stealth appears to be the default in the OTU.

If one looks at the issue from the RAW standpoint as the basis of discussion, then real-world considerations imply that there must be some type of basic (perhaps imperfect) stealth technology available in the OTU, that is available at (or retrofitable at) TL9+. It is just unstated and/or undefined in the OTU as to what that technology is or how it works. So I think your point is well considered.

The issue then becomes (for those interested in pursuing the nature of the technology in the OTU): "What would be necessary in order to obscure a signature"? It would likely require some type of modification to our current understanding of physics and/or some discovery related to it, but then that is part of what Science Fiction is by definition. FTL Drives and Gravitics are likewise impossible by any current understanding of physics, but yet they are clearly part of the Traveller RAW and the OTU.

As an issue tangentially related to the subject, the issue is often raised on the hard-science side of things that Traveller Ships would need large hull-radiators as well to dissipate the heat generated aboard a vessel fast enough to keep the crew and delicate technology from cooking inside the vessel. The way I handwave that is by suggesting that part of the operation of the Gravitic M-Drive is that just as it reacts against the gravitational gradient produced by the masses in a star system to produce thrust, it also "spreads out" the excess heat to those system bodies in proportion to the magnitude of their G-Fields.

Perhaps some advanced related/modified system could be employed in stealth technology as well (perhaps something that bleeds energy into Hyper/Sub/Jumpspace)? Since Jumpspace exists in Traveller, there must be spinoff physics (a "General Hypergravity Theory" ) associated with Jump-Physics.

 

[atpollard]

High Guard had some interesting items that cut both ways from an OTU perspective.

On one hand, they make a big deal of the Experimental/Artifact Black Globe Generator as a tool to achieve 'invisibility'. That could be interpreted as the only form of stealth available, but need not necessarily be interpreted that way. Since it could be used either way, I left it out.

However, it states explicitly that a black globe absorbs all energy ... both in and out. Think of the implications for the 'hot as the sun fusion drive' and 'ship covered with radiators' advocates. Your waste heat is being absorbed by the black globe constantly ... charging those capacitors ... threatening to overload the ship and explode. Even at a minimal 10% setting, 10% of all energy generated by that power plant will eventually end up as radiated heat absorbed by the Black Globe and charging the capacitors. It makes no difference whether you shoot or not, energy generated eventually becomes heat which eventually gets radiated, which gets absorbed by the globe.

Of course this is only an inescapable consequence if the PP is hotter than the sun and the ship is covered in radiators. If the PP operates at room temperature, then there is less waste heat. Either way, there will be some 'sufficiently advanced technology' ... only the location of the handwavium changes.

Personally, I like solid state heat pumps, thermoelectric generators, and insulated hulls. Outer hull is at 20 k (LH2 temperature) and inner hull is at room temperature, and working fluid carries away heat and thermoelectric generators convert heat to power and the whole system is generally inefficient so 1 dTon of LH2 only generates enough usable surplus power to provide 1 EP for 1 month. I prefer to start with all of the data as given and craft handwaves to fit the existing data as best as practical.

Of course, I prefer Proto-Traveller so I am more IMTU than OTU ... why waste all of those great rules for creating your own maps and worlds and trade routes.

 

[whulorigan]

However, it states explicitly that a black globe absorbs all energy ... both in and out. Think of the implications for the 'hot as the sun fusion drive' and 'ship covered with radiators' advocates. Your waste heat is being absorbed by the black globe constantly ... charging those capacitors ... threatening to overload the ship and explode. Even at a minimal 10% setting, 10% of all energy generated by that power plant will eventually end up as radiated heat absorbed by the Black Globe and charging the capacitors. It makes no difference whether you shoot or not, energy generated eventually becomes heat which eventually gets radiated, which gets absorbed by the globe.

BTW, T5 deals with this and has a write-up section on all of the types of Globes (Black/White/Silver/Stasis) at various TLs, as well as Options applicable to them.

 

[robject]

From a T5 angle:

Sensor actions are for target locks. A sensor already tells you "something's at such-and-such distance moving at this vector" without requiring a task roll, but it can't tell what that something is.

Certain technologies appear to be able to defeat target locks. I don't think they can mask general detections.

Some Black Globes can cancel part of their fields, so for example a ship with HEPlaR may accelerate with a Black Globe enabled except around the exhaust ports.

 

[whulorigan]

I prefer to start with all of the data as given and craft handwaves to fit the existing data as best as practical.

That is generally the way I like to approach it as well. An explanation based on the framework of what already exist in the milieu is preferable to one which introduces new concepts cut from whole cloth whose only purpose is to make an unworkable idea work.

Space Opera with a semi-hard-science edge.

Of course, the higher the TL something is, the less I feel constrained by the need to have a hard and fast explanation for it. The science becomes progressively less "hard" as the TL becomes progressively higher.

 

[atpollard]

From a T5 angle:

Sensor actions are for target locks. A sensor already tells you "something's at such-and-such distance moving at this vector" without requiring a task roll, but it can't tell what that something is.

Thank you, good information.

Just to keep everyone honest (and point anyone wanting to read more to a starting point) can you identify an exact page for this statement:

"A sensor already tells you "something's at such-and-such distance moving at this vector" without requiring a task roll, but it can't tell what that something is."

I just want to be clear what is 'explicit' and what is 'implied'.

[Although I owe you an apology, I recognize that finding an exact page in T5 is a bigger deal than in other versions ... with 700+ to choose from. ]

 

[SanDragon]

"Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the drug store, but that's just peanuts to space."

Douglas Adams

I propose you're hiding in a vast vastness that is just too much to sift through!

Inverse-square law seems to apply in that the farther an object is from the observer, the more volume you have to scan just to see what's there. And that's just a two-dimensional field at a specific distance.

Add that third dimension, depth, and all the 4th in the world could make it seem near impossible.

That's why.. sensors and computers to enhance that Mark I eyeball!



If you're still confused, please see my representative, Magnus von Thornwood.

 

[aramis]

Note that field densities fall off as 1/distance^(dimensions-1). A 2 dimensional wave drops off linearly. A 3 dimensional one as the square of the distance, a 4 dimensional one as the cube of the distance, etc.

 

[mike wightman]

Read this:

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

Now remember that in CT what you are actually doing when 'sensing a ship' is being able to get a weapon lock and firing resolution on them.

Note this addendum to the sensor rules in CT:

Tracking: Once a vessel has been detected, it can be tracked by anyone up to
three light-seconds (about 9,000 mm, or 9 meters).

Lasers are at -2 to hit at ranges beyond 2500mm/0.83 light seconds and -5 to hit at ranges beyond 5000mm/1.67 light seconds.

In Mayday you don't have any sensor rules at all, you can see everything on the map at all times suffering a -1 to hit per light second/hex.

The HG rules in Mayday give HG short range as being within 5 light seconds/hexes, long range beyond 5 light seconds/hexes, and out of range at 15 light seconds/hexes.

These are the ranges for establishing a firing solution, actually knowing something is out there would be much further.

 

[maksimsmelchak]

For all practical purposes, the Ancients in Traveller can do ANYTHING... They are a precursor race with effectively unlimited capabilities...

Yaskodrei certainly has steal in space (...or anywhere else including pocket universes) if he/she/it wants it...

Shalom,
Maksim-Smelchak.

 

[kilemall]

I go with the thermogenic absorption/reuse enough to power life support direction more then the gravitic dissapation direction as I am all about the reaction drives, but either in conjunction with the L-Hyd tanks works for me on IR.

Firing the mains however is a major active transmission on the same level as an all-bands mayday.

I stick with the CT rules on this mostly because I don't want to map out the 300+ ships that would be driving around an A/B starport. Most of the autoalerting kicks in when something appears to be on an intercept and/or match course/vee.

You can read my expanded sandcaster thread for my view on countermeasures.

I've got rules and a matrix actually for all this as I want powered down ships to be able to sneak around, and a bit of active/passive play.

The lock-on for both sensor reading AND actual weapons use requires the Target program. Active sensor use makes lock-on and sensor work a higher chance of success, but of course makes the active user that much easier to spot.

There is also a sort of communications/protocol aspect as there is no seeming difference between an active 'scan' and a weapons lock- to avoid situations sometimes only passive target locks are used, and they can also be an element of surprise.

I'm using skill rolls, I won't bore you with the full IMTU version so this will be a simple Auto-68AC version with appropriate skills applied so on initial detection-

Active vs.
Auto Active
8+ Passive
A+ Stealth

Passive vs.
6+ Active
A+ Passive
C+ Stealth

Stealth vs.
8+ Active
C+ Passive
None Stealth

Opposed rolls not possible for detection, I may change my mind.

Once detected, +2 for lock on, computer model +/- and HG ship size modifiers if you like, opposed rolls possible, sandcaster countermeasures if appropriate. Opposed rolls can only be done if the opposing ship has detected the locking ship.

Active lock on is auto detection in all sensor modes, passive/stealth lock or all forms of detection is not.

You could use active detection AND passive lock-on, the opposing ship could make an opposing lock-on roll if they have detected the active ship.

Using weapons, drives or communications is considered going active, in most cases might as well use active sensors once that threshold is crossed.

 

[robject]

can you identify an exact page for this statement:

I just want to be clear what is 'explicit' and what is 'implied'.

No apology required - I will look it up. What I remember them ACTUALLY saying, by the way, is that sensors will flash an alert. I might be wrong with the heading and vector bit (even so, I figure it can be implied).

 

[BlackBat242]

As an alternative to the automatic "radiate lots of always-detectable heat in all directions always" that some seem to insist on, what is wrong with hull insulation, heat pumps/hull&drive-cooling systems, and using the lasers/other energy weapon to discharge the excess energy (heat converted to electricity) in the opposite direction from whatever you are trying to hide from?

As long as you aren't in a dust cloud, there will be nothing to scatter the energy in the beam, and thus the beam won't be detectable from any appreciable distance unless it later bounces off an object or hits a dust cloud.

 

[aramis]

As an alternative to the automatic "radiate lots of always-detectable heat in all directions always" that some seem to insist on, what is wrong with hull insulation, heat pumps/hull&drive-cooling systems, and using the lasers/other energy weapon to discharge the excess energy (heat converted to electricity) in the opposite direction from whatever you are trying to hide from?

As long as you aren't in a dust cloud, there will be nothing to scatter the energy in the beam, and thus the beam won't be detectable from any appreciable distance unless it later bounces off an object or hits a dust cloud.

You very quickly get to magic melt-resistant radiators.

 

[whulorigan]

PREFACE: Note that the issue of waste heat build-up and effective stealth are directly related - its just that for a stealth system you have much more heat to dissipate than just maintaining a comfortable on-board environment. Simple environmental heat radiators must maintain the internal temperature at about ~ 290 K. A stealth system must cool the surface of the ship to down to around ~ 3 K. That is an additional ~ 285 K of heat that you need to remove and/or deal with.

As an alternative to the automatic "radiate lots of always-detectable heat in all directions always" that some seem to insist on, what is wrong with . . .

hull insulation,

Then you are holding all of the heat inside the ship ^*, which will build up and cook the crew and internal systems (that is what insulation does - it holds in heat). That is why the Space Shuttle always has its cargo bay doors open while it is in orbit (even when it is not deploying/unloading payload) - its heat radiators are mounted on the internal surface of the doors. The heat from the internal environment (crew bodies and operating equipment, and fuel cell waste heat) are enough to raise the internal temperature dangerously high over time unless dealt with.

* (which you still cannot do, BTW, because all things [even insulators] will radiate heat away until they reach thermal equilibrium with their surroundings - it is just a matter of how quickly)
​

heat pumps/hull&drive-cooling systems, and

A heat pump (like a water pump) pumps something from one location to another location. Where are you pumping the heat to? You are either pumping it around the ship (and effectively accomplishing nothing while slowly building up heat generated by the heat pump unit itself), or you are pumping it out of the ship (which is what a heat radiator does and what causes you to have a visible heat signature against the backdrop of space). An Air-Conditioner is a heat pump - the way you get a nice cool living environment in your house is by having one side of the A/C projecting outside the house where the hot air is being vented. A/C does not work well if you sit the unit in the middle of your living room, with one side blowing cold air and the other side blowing hot air.

using the lasers/other energy weapon to discharge the excess energy (heat converted to electricity) in the opposite direction from whatever you are trying to hide from?

The equipment that generates the laser beam will itself generate additional heat due to its operation, requiring more heat-dissipating laser fire, which generates more heat, which will require more laser fire, etc. . . .


Basically, for stealth (after accounting for power-plant and equipment heat over and above the ambient temperature of the living environment) you need to get ~ 500 K + of heat off the ship entirely in such a way that the system venting the heat does not show up to an enemy as a pinpoint heat source.

The only way I can see to do that is if you are venting the heat into some "otherspace" or using some other form of super-science ultra-tech (such as using the gravitational interaction of M-Drive technology in some way that it distributes the heat to other bodies w/o identifying the origin of that heat-increase as a point-location in space). Which is fine, BTW, (it is SciFi after all) as long as you are aware of it and are prepared to deal with any unintended consequences or ramifications of the method you invent.

One method explicitly detailed in T5 (primarily as an optional subsystem for Black Globe heat build-up) is to have an "ejectable" heat sink. Heat is transferred to the heat sink linked to the Globe, and is ejected when the heat sink is at capacity, and is then replaced with another heat-sink module. Of course, as far as stealth is concerned, that will not help since even if you render the ship as cold as the 3 K background, the ejected heat sink will show up as a hot-spot moving along a linear vector after "magically" appearing out of nowhere from a start-point, which anyone observing will easily be able to infer as the location of the ship.

 

[robject]

I was somewhat wrong, in that sensors' maximum range is truly a maximum operating range (however, Deep Space ranged sensors aren't expensive).

Sense Only As Really Necessary. The Sensor Process is a sequence of steps dealing with the unknown. If the system is totally unknown to the characters, then using the Sensor Process is entirely appropriate. If the system is familiar, then Sensors come into play only when problems or unusual readings occur.

[...]

Sensor output is provided in three distinct stages, each revealing more information.

Alert

When there is something of possible interest, the Referee conveys to the players an Alert:
"Your [sensor] sees something about here [location]."

Detection

Using the Sensor Task, the characters try to resolve what gave the alert (or they can ignore it). Success in the Sensor Task provides information about the alert.

Tracking

Once a sensor detects an object, it can track that object until some event causes the signal to be lost (it moves out of range; it is hidden by a world; it deliberately jams or hides its signal).

A Sensor cannot operate beyond its stated Range.

 

[atpollard]

First a brief observation:
When I claim that 1 dTon of LH2 fuel and a PP-A and a MD-A in a 100 dTon Scout will allow 2 G acceleration for up to two weeks (as claimed in CT:HG), I am not challenging the law of Conservation of Momentum. So any arguments or calculations or references that you present that 'prove' that the propellant mass fraction of a scout ship is too low does not refute the fact that in the OFFICIAL TRAVELLER UNIVERSE, 1 ton of hydrogen will allow a scout ship to accelerate for 2 weeks at 2G.

Ultimately, we are forced to accept that in the OTU, the MD and Conservation of Momentum do not function like they do on an Apollo Rocket. That is just a fact of the OTU.

In exactly the same manner, when I claim that Stealth exists in the OTU, I am not launching an assault on the Law of Thermodynamics. It is a simple statement of fact based on rules that appear to state that Stealth is possible in the OTU. I offer the following to bracket the earliest set of rules and the most recent set of rules, but examples can be found scattered between them:

Ships which are maintaining complete silence cannot be detected at distances of greater than 100,000 miles; ships in orbit around a world and also maintaining complete silence cannot be detected at distances greater than 10,000 miles. Planetary masses and stars will completely conceal a ship from detection.

[quote='T5 Sensors (p353)]
Once a sensor detects an object, it can track that object until some event causes the signal to be lost (it moves out of range; it is hidden by a world; it deliberately jams or hides its signal). [/quote]

How can one interpret "maintaining complete silence" in CT Book 2 except that Stealth in Space is possible in the OTU?

How can one interpret "deliberately hides its signal" in T5 except that Stealth is possible in the OTU?

To continue to argue that there is no stealth in the OTU and ships can 'see' everything within a parsec is pointless unless you can provide something from the actual game that at least suggests that is the case, because the sensor and detection rules seem to clearly indicate a different reality for the OTU.

Now IYTU, you are free to change whatever you want. I personally miss conservation of momentum. However, strong claims about how things are in the OTU require some support from within the game.

I suggest, absent any evidence from the rules that sensors are all-seeing, that the real question is not IF there is stealth in the OTU, but HOW it might be done.

 

[atpollard]

You very quickly get to magic melt-resistant radiators.

Does that conclusion come from the EP generation of the PP or the assumed energy in fusing hydrogen?

 

[robject]

when I claim that Stealth exists in the OTU, I am not launching an assault on the Law of Thermodynamics. It is a simple statement of fact based on rules that appear to state that Stealth is possible in the OTU.

[...]

I suggest, absent any evidence from the rules that sensors are all-seeing, that the real question is not IF there is stealth in the OTU, but HOW it might be done.

1. Traveller has "naval warfare" style space combat (ref: design notes from Battle Rider). Thus we have "sub hunts".

2. TRAVELLER has Stealth in space. Not just the OTU, but any setting which defaults to the core rules.

3. "HOW is stealth possible?" is not the question that people ask. They ask "HOW can we avoid fantasy?" (ref: Wil's note about "magic melt-resistant radiators". He didn't ask how it was possible: he already knew that it was only possible via fantasy.)

4. You can't avoid fantasy.