T4 Only: Some people say no stealth in space, a discussion.
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kilemall
SOC-14 5K
Right so in my case even if the throw is 11 or 12 you will be found out over time, it’s just will you slip past and be able to do your dirty deed in the time of exposure.
That is fine. It is logical to assume that military spacecraft in the future will have features to reduce their signature. A lot of the arguments about stealth in the real world are budgetary concerns of the B-2 vs B-52, which to be clear, there have been arguments about the effectiveness of strategic bombing in general. Speer wrote that the strategic bombing of Germany actually allowed him to make production more efficient, which contravenes the notion that it is effective. One can also use the submarine warfare argument, though ultimately we had miked the oceans to such a degree, and had optical satellites to see where all the Russian subs were (a big reason as to the payload capacity of the Shuttle). Game-wise it adds enough flavor, and suspense, and is realistic enough, to be there; give it a roll.
Taken to its (il)logical conclusion, it is therefore IMPOSSIBLE to miss ANY object (natural or artificial) within the entire Milky Way Galaxy when using a simple, ordinary, bog standard sensor scan.
Even a brown dwarf rogue planet (with "surface" temperatures well in excess of 300+ degrees Kelvin) wandering between star systems would be ... trivial ... to detect at a distance of light years away. You don't even need to roll anything ... it's just, automaticgic.
Why?
See quote above.
Your scale is wrong by multiple orders of magnitude.
A better analogy would be if someone standing on planet Terra switched on a flashlight and deliberately pointed it up at satellite Luna (~385,000 km away, or about ~1.3 light seconds distant).
Would a sensor on Luna be able to easily/trivially/automatically detect (and correctly identify) the light of that flashlight pointed up at Luna without error or difficulty of any kind? Basically, would the sensor suite be "so good" that you could flick the flashlight on/off and send a morse code message with the light of a handheld flashlight (from Terra to Luna) and have it be clearly/plainly visible and trivial to read by the sensor suite?
Pointed up from where? From Earth? Of course not - and a non-relevant argument because Earth is a huge thermal background environment with an immense EM-Spectrum background and atmospheric/thermal distortion and absorption/extinction as well. Not at all the same as the argument being made.
Pointed at Luna from deep space at Earth-Luna distance? A ship is not the size of a flashlight (your scale is wrong), nor does it emit at the same intensity. So point a 100 meter (or 1000 meter) diameter floodlight at Luna from Deep space at a nice round 300,000km range. Flick it on and off with morse code. Sensor is located on Lunar surface. Result?
If you know EXACTLY where to look.
The challenge gets VERY different when you DON'T know exactly where to look ... and therefore, have to search (or better yet, are continuously searching).
For example:
In this image of beach sand ... find the 1 sand grain that is a uniquely specific color because it is a speck of precious material (pick your gemstone of choice) rather than a variety of common silica. Take your time searching EACH GRAIN OF SAND in order to find "the right one" that you have been challenged to locate and extract from the background.
Take ALL THE TIME you need to sift through the sand to find whatever it is that you're looking for using yourhandseyessensors.
Then do the same thing again for the NEXT patch of beach sand.
And the NEXT patch ...
And the NEXT ...
(ad infinitum)
And the processing power and speed of the astrometrics and/or sensors/astrionics computer at the given TL is what?
LBB4 p41:
Hmmmm ...
So @ TL=12 it's possible to create a "man sized/shaped space craft" (which is what a vacc suit actually is) and actually "harden" it against hostile environments (see: Combat Environment Suit
But it's NOT POSSIBLE to do anything similar for something larger than man sized (such as a small craft/big craft/starship).
Um ...... that's akin to asserting that my air/raft can use gravitic thrust (no problem!
), but no spacecraft/starship can (don't be absurd!
).
It's an argument ... I guess ...
Not a very compelling one ... but it's an argument ...
Nonsense. And I am going to respond to this once and not engage it further. The above equivocates multiple different issues into a single response argument. The human armor is primarily being addressed for usage during play in its normal usage environment (esp. by PCs/NPCs), which is a world surface, NOT EVERY POSSIBLE ENVIRONMENT THAT EXISTS UNDER ALL POSSIBLE CIRCUMSTANCES AT ALL TIMES. It is expected that the GM will make common sense situational rulings as they arise. Yes the Combat Armor bleeds heat like a chameleon (to match its WORLD-SURROUNDINGS where there are similar immersive temperatures and temperature backgrounds and objects, and not much of an adjustment is required). Yes the Combat Armor can also be pressurized for use in vacuum like a Vacc-suit (like in Space).
That does NOT mean that the GM is not to use his common sense and step in to make a situational ruling during play. Can you use the chameleon function as described in a space environment (without a temporary internal chill-can/removable heat sink to store the heat as it builds up)? No. Why? Because there is no background atmosphere envelope/terrain/environment with its own inherent relatively comparable temperature to "blend into" by adjustment. Vacuum has no "temperature" of its own (classically) by definition. It has no "thermals". What is your chameleon option going to "blend you into"? You are standing out against emissions from across the Universal environment from numerous varying sources of varying intensities and differing wavelengths (which are largely individual sources) against a 2.7 K microwave background. You are a resolvable heat source within a narrow-specified temperature range, that a chameleon "damper" can only adjust so many degrees one way or the other. Strong sources are either small and close by or immense and far away, and likely will have a "shape". So is that man-shaped heat source with backpack and rifle a 3000km long object that is very far away, 500 meters long at moderate range, or man-sized and close? What do you think? Have you ever looked at an object via military or civilian IR nightvision?
For Starships: Decreasing detection signature - certainly. But making them be able to sneak up stealthily or be largely undetectable because you have "stealth" to blend you into the background or remove your signature, not likely. If you want something like that, go gravitic damping, as I mentioned above. It's there. It's usable. It's feasible within the tech presuppositions of the setting. Why people want to argue this I don't understand. If you want the gritty no-stealth/difficult-stealth heat dissipation concerns in your game, sure - I get it. But if you don't, and you want the good detection damping and/or stealth options, and trivial heat dissipation concerns (or don't want to deal with them, but still want to engage the science and engineering implications of the SciFi at some level, then the above is the simple and easy in-Universe solution).
Spinward Flow
SOC-14 5K
Here is a NASA photo of the planet Uranus (plus moons) taken by the James Webb space telescope in the IR bands.
Here is the same photo ... again ... with a single modification.
I have edited in a white spot to the above image that was not in the original.
Challenge: Find the white spot (we'll call it a starship) that has been added to this IR image.
*IF* you find the white spot modification that I've added to this 985 × 1059 pixels image, edit the image again ... putting an obvious circle around the white dot and an arrow pointing at it to prove that you've found the "white hot" starship thermal dot in this IR image.
Easy enough, right?
And if you do take up this challenge, explain how you "found" your answer that you demonstrate.
This how I did it.
I put the arrow in with Preview after the fact.
I put the arrow in with Preview after the fact.
Code:
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.awt.*;
import java.io.File;
import java.io.IOException;
public class ImageDiff {
public static void main(String[] args) throws IOException {
if (args.length < 3) {
System.err.println("Usage: java ImageDiff <image1.png> <image2.png> <diff.png>");
System.exit(1);
}
BufferedImage img1 = ImageIO.read(new File(args[0]));
BufferedImage img2 = ImageIO.read(new File(args[1]));
if (img1.getWidth() != img2.getWidth() || img1.getHeight() != img2.getHeight()) {
System.err.println("Images must be the same size.");
System.exit(2);
}
int width = img1.getWidth();
int height = img1.getHeight();
BufferedImage output = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
// Copy original image
Graphics2D g2 = output.createGraphics();
g2.drawImage(img1, 0, 0, null);
g2.setColor(Color.RED);
g2.setStroke(new BasicStroke(1.5f, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
int radius = 6;
int diffPixels = 0;
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++) {
int rgb1 = img1.getRGB(x, y);
int rgb2 = img2.getRGB(x, y);
if (rgb1 != rgb2) {
g2.drawOval(x - radius / 2, y - radius / 2, radius, radius);
diffPixels++;
}
}
}
g2.dispose();
System.out.println("Different pixels: " + diffPixels);
ImageIO.write(output, "png", new File(args[2]));
System.out.println("Diff written to " + args[2]);
}
}
mike wightman
SOC-14 10K
I think I did it faster - I opened two browser windows so I could have both images to click between.
Within seconds I had spotted the different pixel.
Within seconds I had spotted the different pixel.
Spinward Flow
SOC-14 5K
Nice.
You wrote a program to do a pixel by pixel search and comparison.
Which is what I was expecting people to do for the "manual comparison" option.
Okay.
You found the "white hot" pixel.
Now characterize which type of starship it is (USP code will do).
Course, position, orbital trajectory and acceleration profile would be nice to know too.
Thanks! You guys made me go wiki-walking to find the name of the device used to find planets and comets and such by alternating two nearly-identical photographs so the differences stand out: it's a Blink Comparator (wiki). (I remembered the device but not its name.)
Clyde Tombaugh discovered Pluto in 1930 using one.
Edit to add: and @whartung knew the principle of it, as demonstrated, while I was typing.
Clyde Tombaugh discovered Pluto in 1930 using one.
Edit to add: and @whartung knew the principle of it, as demonstrated, while I was typing.
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When it gets in close enough to Earth to be a remote threat, maybe I'll point some binoculars at it to see what fuzzy shape it is. Until then, let it drift with the comets and other cold, dead rocks.Now characterize which type of starship it is (USP code will do).
My view is that you can massive reduce an IR signature in most directions by cooling your hull and pumping the heat into radiators that emit across a fairly narrow angle. The obvious downside being that if you guess the wrong direction to point your emitters you'll be spotted extremely trivially.
But I also note that Traveler has never worried too much about spaceships' waste heat issues, so I assume it's been somehow largely solved, and thus stealth is just more and better heat control gear and I don't worry about just how it works any more than I worry about just how a jump drive works.
But I also note that Traveler has never worried too much about spaceships' waste heat issues, so I assume it's been somehow largely solved, and thus stealth is just more and better heat control gear and I don't worry about just how it works any more than I worry about just how a jump drive works.
Condottiere
SOC-14 5K
Collected, then discarded.
If someone had to have a scientific theory of where the heat goes, use an extra dimension it is shunted to, such as in string theory: https://www.space.com/more-universe-dimensions-for-string-theory.html There is already an extra dimension with jumpspace. This is rehashing something like with Hans years ago on the board. Little dimensional coils.
Condottiere
SOC-14 5K
If heat is information, quantum entanglement could teleport it away.
Spinward Flow
SOC-14 5K
A (temporary) alternative would be something akin to doing active chemistry/chemical refining ... except that instead of doing exothermic stuff, you do something endothermic.
Say ... ammonia decomposition ...
Neither nitrogen nor hydrogen should be "difficult to obtain" from wilderness refueling (either water ocean or gas giant skimming) and a reversible ammonia process could potentially be incorporated into the engineering design of a starship as a limited "heat battery" reserve for dumping waste heat (concentrated by heat pumps) into for short durations.
It doesn't have to be this EXACT chemical reaction, mind you ... I'm just using ammonia decomposition as a convenient example of an endothermic reaction that can be used to "drain" waste heat from an enclosed system (such as a spacecraft/starship), rather than necessarily radiate it away into space (in all directions).
A (temporary) alternative would be something akin to doing active chemistry/chemical refining ... except that instead of doing exothermic stuff, you do something endothermic.
Say ... ammonia decomposition ...
Neither nitrogen nor hydrogen should be "difficult to obtain" from wilderness refueling (either water ocean or gas giant skimming) and a reversible ammonia process could potentially be incorporated into the engineering design of a starship as a limited "heat battery" reserve for dumping waste heat (concentrated by heat pumps) into for short durations.
It doesn't have to be this EXACT chemical reaction, mind you ... I'm just using ammonia decomposition as a convenient example of an endothermic reaction that can be used to "drain" waste heat from an enclosed system (such as a spacecraft/starship), rather than necessarily radiate it away into space (in all directions).
Workable on a temporary basis. But you will eventually need to radiate/cool the heat sink or eject it (which will allow it to radiate freely, of course). - BTW, this is one option for heat dissipation with Black Globes in T5, but you have to eject it thru a controlled opening in the field when saturated, or the interior of the globe will begin to heat up, or the heat sink will melt and superheat the ship, and then heat the globe interior.
So you could look to T5 rules for heat sinks for this option.
Melting ice, then heating water is a pretty good heat sink, too.A (temporary) alternative would be something akin to doing active chemistry/chemical refining ... except that instead of doing exothermic stuff, you do something endothermic.
Say ... ammonia decomposition ...
Neither nitrogen nor hydrogen should be "difficult to obtain" from wilderness refueling (either water ocean or gas giant skimming) and a reversible ammonia process could potentially be incorporated into the engineering design of a starship as a limited "heat battery" reserve for dumping waste heat (concentrated by heat pumps) into for short durations.
It doesn't have to be this EXACT chemical reaction, mind you ... I'm just using ammonia decomposition as a convenient example of an endothermic reaction that can be used to "drain" waste heat from an enclosed system (such as a spacecraft/starship), rather than necessarily radiate it away into space (in all directions).
Spinward Flow
SOC-14 5K
If all you need is "a few hours" to slip past a sensor net ... temporary will get the job done (adequately).
But that is the question. Do you have the technology to create a heat sink efficient enough not simply to store excess heat to keep the ship from superheating/melting due to its own internal heat production for several hours (i.e. heat dissipation/radiation problem), but to cool it down far below the 300K level to a background-level where it will not be quickly detected against the universal background? Those are two different regimes. The ability to do the first for several hours does not necessarily imply the ability to do the second for the same amount of time.
