Heat Problem vs Stealth in Space

[MasterGwydion]

The solution is simple. Fusion+ makes Fusion reaction possible in briefcase size. In order for that to have happened, they must have overcome to whole heat generation issue. So without having to worry about heat anymore, ships can be very very stealthy in space.

https://wiki.travellerrpg.com/Fusion%2B

My guess is that Cold Fusion tech makes heat management technologies as common as a muffler on a car, but way more effective.

Just My 2Cr

 

[Sigtrygg]

Won't work, the waste heat comes from using all the electricity you are generating. If you re generating a couple of GW of power that is a lot of waste heat. even if your generation system is room temperature.

If you invoke magic technology stealth in space is possible, without magic technology it isn't.

 

[MasterGwydion]

Won't work, the waste heat comes from using all the electricity you are generating. If you re generating a couple of GW of power that is a lot of waste heat. even if your generation system is room temperature.

If you invoke magic technology stealth in space is possible, without magic technology it isn't.

If you consider Fusion+ which is OTU to be magic technology, then this discussion can not happen, as everything in the game would then be considered "magic technology" from Inertial dampers to jump drives.

So, please do not respond to this post further.

Thank you.

 

[Arkathan]

The use of direct conversion devices, generating electricity straight from heat, and room temperature superconducting materials the heat generation from fusion and conduction losses are greatly reduced.

 

[Sigtrygg]

I think you are misunderstanding me. Traveller has to have a magic heat sink technology it has just never hinted at what it is. Simply saying you can generate a few GW using fusion+ doesn't get rid of the waste heat generated by the 'use' of all that electricity.

As to handwaving generating electricity from waste heat and room temperature superconductors - you need a temperature gradient to generate electricity from the waste hear, so you need to cool something down, which generated more waste heat. You can only remove the waste heat by dumping it outside the ship either by sticking it a substance you dump into space or radiate it from radiators.

So what is needed is an explanation of where you dump the waste heat to, not how you can generate a few gigawatts of electricity at room temperature.

By the way I am using the term magic to represent anything that contravenes the physics we understand today, so yes the vast majority of Traveller tech once you get to TL8+ is magic.

 

[Condottiere]

Micro blackhole.

I suppose a large enough magnetic field could contain it.

 

[Arkathan]

I think you are misunderstanding me. Traveller has to have a magic heat sink technology it has just never hinted at what it is. Simply saying you can generate a few GW using fusion+ doesn't get rid of the waste heat generated by the 'use' of all that electricity.

As to handwaving generating electricity from waste heat and room temperature superconductors - you need a temperature gradient to generate electricity from the waste hear, so you need to cool something down, which generated more waste heat. You can only remove the waste heat by dumping it outside the ship either by sticking it a substance you dump into space or radiate it from radiators.

So what is needed is an explanation of where you dump the waste heat to, not how you can generate a few gigawatts of electricity at room temperature.

By the way I am using the term magic to represent anything that contravenes the physics we understand today, so yes the vast majority of Traveller tech once you get to TL8+ is magic.

Because saying what it is would be the same as trying to explain how a fireball spell works IRL.
The response would be similar to the doe in the headlights or flat out bored look of a small child sitting in on a quantum physics class.

 

[MasterGwydion]

Micro blackhole.

I suppose a large enough magnetic field could contain it.

No Romulan Warbirds! lol

 

[feld]

I tend to disregard any opinion on this topic as simple as "no stealth in space."

No one, not even the fine authors quoted on Atomic Rocket (of which I am one) which is where the "no stealth in space" finds is most cogent expression, have done a spectral study of a rocket plume (fission, fusion, or even chemical) vs. the relevant background radiation environments.

I've been working on doing a real signal to noise calculation of the above on and off for the last decade or more. It's non-trivial to do so. There are entire books on the phenomenology of rocket plumes...it's not trivial. Fission rocket plumes are in some ways easier. Fusion plumes are pretty complex plasma physics problems and are made more complex by the fact that you can trade Isp for a tailored radiation signature. Now, I'm a nuclear propulsion engineer, and not an astronomer...but it's still not trivial.

Yes stealth in space is going to be difficult but the question is, in my professional opinion, still an open one and depends strongly on the assumptions made about the way presently known technologies advance.

2300AD is actually a pretty good set of tech assumptions for stealth in space because the power level needed for seriously fast propulsion is really very low. Traveller...I dunno Traveller very well.

 

[MasterGwydion]

I tend to disregard any opinion on this topic as simple as "no stealth in space."

No one, not even the fine authors quoted on Atomic Rocket (of which I am one) which is where the "no stealth in space" finds is most cogent expression, have done a spectral study of a rocket plume (fission, fusion, or even chemical) vs. the relevant background radiation environments.

I've been working on doing a real signal to noise calculation of the above on and off for the last decade or more. It's non-trivial to do so. There are entire books on the phenomenology of rocket plumes...it's not trivial. Fission rocket plumes are in some ways easier. Fusion plumes are pretty complex plasma physics problems and are made more complex by the fact that you can trade Isp for a tailored radiation signature. Now, I'm a nuclear propulsion engineer, and not an astronomer...but it's still not trivial.

Yes stealth in space is going to be difficult but the question is, in my professional opinion, still an open one and depends strongly on the assumptions made about the way presently known technologies advance.

2300AD is actually a pretty good set of tech assumptions for stealth in space because the power level needed for seriously fast propulsion is really very low. Traveller...I dunno Traveller very well.

Agreed. It gets even more complicated when you realize that M-Drive are gravity drives and only produces gravimetric thrust and is therefore undetectable without a densitometer to detect the drive pulling on the local gravity wells. (by undetectable, I mean simply not producing any form of thermal thrust or reaction type energy plume.)

 

[Geir]

I know better than to wade into a stealth in space discussion, but I must be off my meds today, so here goes:

Somebody (was it me?) once said we can detect a lit fart off Uranus. (yes, groan away). That might be true, but there is this massive trade-off between detection of something faint (I will only partially avoid a pun on 'faint' relating to the earlier pun) and with detecting it across a broad range of sky. It takes days or longer to scan the sky with any decent resolution. That's why most transient events are missed and why - even though we detect a of them lot - asteroids the size (admittedly colder) of multi-thousand ton starships get missed until they explode over a large Russian city.

So here's the rub: Detection is hard. Tracking is easy. Once you know where that point of light (thermal, gamma ray, whatever) is located and have a good reading on its vector, you can track it because it sticks out like a sore... thumb. Now, like fighters dropping flares today, I'm sure there will be countermeasures to blind or confuse tracking sensors, but that's not really covered - except in an abstract way - who's to say that a stealth hull doesn't include a bunch of tiny heat emitting decoys? Or 'gravimetric heat displacement fields'.

And now I'll shut up about stealth in space and try to find my pills.

 

[MasterGwydion]

I know better than to wade into a stealth in space discussion, but I must be off my meds today, so here goes:

Somebody (was it me?) once said we can detect a lit fart off Uranus. (yes, groan away). That might be true, but there is this massive trade-off between detection of something faint (I will only partially avoid a pun on 'faint' relating to the earlier pun) and with detecting it across a broad range of sky. It takes days or longer to scan the sky with any decent resolution. That's why most transient events are missed and why - even though we detect a of them lot - asteroids the size (admittedly colder) of multi-thousand ton starships get missed until they explode over a large Russian city.

So here's the rub: Detection is hard. Tracking is easy. Once you know where that point of light (thermal, gamma ray, whatever) is located and have a good reading on its vector, you can track it because it sticks out like a sore... thumb. Now, like fighters dropping flares today, I'm sure there will be countermeasures to blind or confuse tracking sensors, but that's not really covered - except in an abstract way - who's to say that a stealth hull doesn't include a bunch of tiny heat emitting decoys? Or 'gravimetric heat displacement fields'.

And now I'll shut up about stealth in space and try to find my pills.

Well said.

 

[Sigtrygg]

CT ship fusion reactors range from 0.25 GW to 10 TW according to published designs.

Let's assume you have a perfect insulation hull so the outside is the temperature of space and the inside is 300 K.

Switch on the reactor. Transmit all that electricity around the ship, how long before you cook the crew and electronics due to waste heat?

Let's even assume that a lot of the power is taken by the maneuver drive, you still have all the electricity running around the ship (and no room temperature superconductors at Imperial TLs according to the corpus of Traveller). You have to remove the waste heat.

There are several ways to do this:

an on board heat sink that will soon get full

heat sink/coolant that is dumped overboard

radiate the heat away (there is a reason for those massive radiators on the ISS and they only have to deal with a few kW, it's also the reason the space shuttle had to open its cargo bay doors to act as radiators)

use a magic heat sink technology that is consistent with existing Traveller tech paradigms (I favour a gravitic heat sink, although the Imperial level of technology should allow the production of black holes but they have their own issues, mostly mass but this is Traveller so only volume counts).

Solve that conundrum and you can have stealth without having to resort to elven (Romulan) cloaks...

 

[MasterGwydion]

CT ship fusion reactors range from 0.25 GW to 10 TW according to published designs.

Let's assume you have a perfect insulation hull so the outside is the temperature of space and the inside is 300 K.

Switch on the reactor. Transmit all that electricity around the ship, how long before you cook the crew and electronics due to waste heat?

Let's even assume that a lot of the power is taken by the maneuver drive, you still have all the electricity running around the ship (and no room temperature superconductors at Imperial TLs according to the corpus of Traveller). You have to remove the waste heat.

There are several ways to do this:

an on board heat sink that will soon get full

heat sink/coolant that is dumped overboard

radiate the heat away (there is a reason for those massive radiators on the ISS and they only have to deal with a few kW, it's also the reason the space shuttle had to open its cargo bay doors to act as radiators)

use a magic heat sink technology that is consistent with existing Traveller tech paradigms (I favour a gravitic heat sink, although the Imperial level of technology should allow the production of black holes but they have their own issues, mostly mass but this is Traveller so only volume counts).

Solve that conundrum and you can have stealth without having to resort to elven (Romulan) cloaks...

I am not sure that without room temperature superconductors you could even have a Starship along the lines of Traveller. I always figured that they figured that out when they figured out Fusion+ or even a TL or so before. Cold Fusion has to be harder to do than room temperature superconductors, not to mention trying to build a Jump Drive without room temperature superconductors. I'm pretty sure you'd melt the ship every time you powered it up. Just My 2 cents.

 

[Condottiere]

It occurs to me that spacecraft might work on energy efficiency.

 

[Sigtrygg]

Room temperature superconductors are beyond the TL15 Imperial standard - they are listed as one of the areas of research conducted by Imperial Research stations.

Even with 'energy efficiency' the heat generated on board by shifting all that energy arounds has to go somewhere that is not the ship. There is only so much heat you can remove by dumping hydrogen plasma out of the back of the ship (which neatly explains the glowing strips and 'exhaust plume' you see in so many Traveller ship illustrations).

There are only three potential tech paradigms in Traveller that could be handwaved as a solution:

1 - a jump space heat sink - this would need to be separate from the jump drive since 100t+ spacecraft have the heat issue but no jump drive.

2 - gravitics tech can be used as a heat sink

3 - damper technology of some sort

 

[Condottiere]

We have nuclear dampers, and heat, I believe, is a very active atom.

 

[Sigtrygg]

You believe/understand wrong.

'Heat' can be thought of as the movement energy of atoms and molecules. Nuclear dampers operate on the quarks within the nucleus of the atom or at least they are said to be able to increase or decrease the strong nuclear force.

Which gets me thinking - an endothermic process stores heat so you could use damper tech to move the 'heat' to the nucleons...

 

[MasterGwydion]

Room temperature superconductors are beyond the TL15 Imperial standard - they are listed as one of the areas of research conducted by Imperial Research stations.

Even with 'energy efficiency' the heat generated on board by shifting all that energy arounds has to go somewhere that is not the ship. There is only so much heat you can remove by dumping hydrogen plasma out of the back of the ship (which neatly explains the glowing strips and 'exhaust plume' you see in so many Traveller ship illustrations).

There are only three potential tech paradigms in Traveller that could be handwaved as a solution:

1 - a jump space heat sink - this would need to be separate from the jump drive since 100t+ spacecraft have the heat issue but no jump drive.

2 - gravitics tech can be used as a heat sink

3 - damper technology of some sort

What is the source for that bit on Room Temperature superconductors not being available even at TL-15? I want to check it out. Please?

 

[Sigtrygg]

Check out the Library Data in research Station Gamma concerning Imperial Research Stations, it's repeated in CT LD A-M.

Imperial research may delve into many areas. Some examples include black hole
research, both large-scale and mini-black hole investigation, instantaneous transmitter
development (so far proving impossible), advanced gravity manipulation,
genetic manipulation, anti-matter containment, weaponry research, disintegrator
beams, black globe development, deep planetary core soundings, nova prevention
(and prediction), psychohistory, mass population behavior prediction, psionics,
stable superheavy elements, deep radar analysis, long-range detection systems,
robotics, artificial intelligence, stasis and time travel, so-called magic, cryptography,
bionics, personal shields, x-ray lasers, and high temperature superconductors

Note I am being generous here since a high temperature superconductor is still way bellow room temperature...
and I agree that a room temperature superconductor is a much more 'realistically' possible breakthrough than fusion+