Discussion Main / StealthInSpace

I wouldn't call it biased. It's based around physics - a powered spacecraft more or less will emit some form of IR radiation, and that radiation can be picked up by sufficiently powerful sensors. That doesn't make it useful information (see my post below on telescope resolution), but they would likely still pick up the presence of an IR-emitting source out there.

Perfect stealth in space might be impossible, but you don't need perfect stealth, you just need to be discreet enough that any sensor sensitive enough to pick up your ship will be overwhelmed by false positives. I don't think the page reflects that.

The argument detailed on the page disregards basic astronomical realities - it takes a huge amount of time for astronomers to find and categorize objects in space, exponentially more so if they are relatively dim. Just doing a sky survey that can theoretically see a ship is in no way equal to actually targeting that ship. The computational requirements to do meaningful difference analysis between different sky surveys, especially at the sensitivities implied, are mind-bendingly ridiculous.

"Perfect stealth in space might be impossible, but you don't need perfect stealth, you just need to be discreet enough that any sensor sensitive enough to pick up your ship will be overwhelmed by false positives. I don't think the page reflects that. "

There isn't even perfect stealth on earth. But in fact it is desirable that space stealth be inperfect. It will help arrange the advantages and disadvantages of a Standard Sci Fi Scuffle in an interesting manner.

Not to mention the time required to scan the sky with an infrared telescope in search of said spaceships against the background of space. With current technology, that would take days at best, and even then any spaceship would look a lot like a dead rock, with few clues as to its real nature. This page, like most things that come out of project rho, is just flat out wrong.

There, I said it.

It's more that RHO's page on "stealth in space" tends to under-estimate some of the practical difficulties in detection.

Project RHO/Atomic Rockets is a large factor for my rather wordy input on the 'Hardness of Science Fiction' discuss page. Specifically because that site purports to be 'scientific' when at most they look at raw physics, see whether something is possible by current physics and then declare that because it is possible or impossible by current physics, it therefore either MUST happen or CANNOT happen. The Atomic Rockets Detection in Space Warfare page, for instance, doesn't take into account civilian traffic. So while it points out, to it's credit, that 'detection is not a weapons lock', it fails to point out that the 'weapons lock' range is still a lot longer than the 'actually knowing whether or not the ship you can now fire at is actually an enemy warship or simply a civilian transport' range.

Essentially it goes 'it's possible to tell at a certain range that there's something there, therefore there's no Stealth in space', whilst ignoring that the objective of Stealth is not Invisibility, but simply masking who and what you really are by making us of the myriad things you could be.

Space isn't cold or warm. There's no such thing as measuring the temperature of a vacuum. However, you would still gradually radiate some of your heat away, and realistically, that would make you stick out like a sore thumb against the background of of space. You don't lose all of your heat instantly, but you have to lose some of it - otherwise you'll fry.

That's true, although merely detecting heat doesn't necessarily provide you with any useful information, other than that something is out there. In real life, telescopes (IR and optical) don't have arbitrary resolution, so all you see beyond a certain distance is a dot. That doesn't help you much, particularly if the enemy uses counter-measures (like a drone that basically blasts off a whole bunch of heat to deliberately draw the eye of enemy ships looking for IR).

For example, using 750nm infrared light and a 500-meter wide telescope (which is probably unrealistic for your average sci-fi starship, although not for relatively "fixed" locations like asteroid bases and orbital facilities), an approaching 100-meter wide starship at a range of 50 million kilometers produces a picture with a resolution of . . . one pixel.

I find the whole situation with detection a pretty fascinating and overlooked subject in sci-fi. A lot of sci-fi basically has ships with "sensors" that have arbitrary resolution and light-gathering abilities.