Are radiator panels useful for anything other than mining equipment?

[Dropbear67]

I know people put them on stations for aesthetics, but does anything really generate any heat on a station?

[OHara]

The only part likely to be on a space-station that generates enough heat to cause trouble is the ISRU, and that causes trouble only to itself when the core hot.

Other than that, RTGs and NERVA engines (for adjustments of orbit, maybe) generate noticeable heat, but not enough to have any effect in-game.  Mostly, that is because Kerbals are so tolerant of huge variations in temperature.

If you want radiators on the station, you can justify them by noticing (with alt-F12 to turn on extra thermal displays in right-click menus) that they keep the station much closer to a reasonable 300K living temperature.

[Krzysztof z Bagien]

I sometimes put radiator panels on spaceplanes, they somewhat help with reentry heat.

[Sky Vagrant]

If you are inside the orbit of Moho (close to the sun), your parts will start overheating. Found this out sending a probe to Moho. Only saw it when my orbit was below Moho, but I wasn’t watching my craft the whole trip.

[Snark]

On 4/29/2019 at 7:36 PM, Dropbear67 said:

I know people put them on stations for aesthetics, but does anything really generate any heat on a station?

In practice, not really.  Mining equipment (drills and ISRU) is pretty much the only thing where heat's a factor, in normal stock gameplay.

The solar-tracking ones help if you get really close to the sun, to cope with solar heating... but you need to be a lot closer to the sun than Moho before you need any radiators.  Since the stock game doesn't have anything closer than Moho, there usually isn't any reason to get that close to the sun, so it simply doesn't come up.

Once upon a time, the LV-N engine was such a heat generator that it would overheat and explode with prolonged use, unless you have radiators.  However, the heat output got nerfed many KSP versions ago, so that's no longer needed-- an LV-N can run pretty much forever with no overheating problems.  It'll get pretty warm, yes, but won't go boom.

That said... if you're running mods, the radiators may indeed serve a purpose.  Some solar-system mods add planets that are much closer to the sun than Moho, for example, or give some other reason to want to get close to the sun.  There may also be modded parts that have large heat output that would need radiators in order to cope.

[Daniel Prates]

That is an area where KSP needed some improvement. The real life ISS radiators are there for a reason (i.e., it will overheat without them!), and even the Apollo spacecraft had to keep slowly rolling on its roll axis to try and dissipate some of the heat off during the coast to the moon (I think they called it 'barbecue rolling'). As it turns out, space isn't "cold", not in the sense that being next to it could "cool" you. Actually, the absence of matter acts more like heat insulation of sorts since a spacecraft's heat can't "conduct" heat with the matterlessness of space. So if the craft is picking up heat, say because it is exposed to the sun for too much time, radiators are the only effective way to lose that heat. Otherwise heat will pile up and, given enough time, go above tolerable levels. 

In KSP you can cruise from Kerbin to Duna with no consequence (and ok, Kerbol is less powerful than our Sun), but in RL I have my doubts that would be possible. In innermost travels in the kerbol system, though, even KSP craft can be barbecued if close enough to Kerbol. Radiators mitigate that. But what I would like to see is craft slowly but surely picking up heat everywhere, except when actually very far from Kerbol (say, Jool?) or when constantly hiding from the sunrays (like a fast, low altitude orbit where the station or craft is shadow half of the time). Certainly around Kerbin's solar altitude, if exposure is constant, heat buildups should be a thing. Would be more realistic, and force you to mind heat management more closely.

Edited May 2, 2019 by Daniel Prates

[StrandedonEarth]

I had a rescue mission in a sub-Moho orbit that gave me a reason to get close enough to need radiators...

[Laie]

On 4/30/2019 at 1:01 PM, Krzysztof z Bagien said:

I sometimes put radiator panels on spaceplanes, they somewhat help with reentry heat.

Nah, they don't. Radiators are ineffective when flying fast through the atmosphere.

My use case was ascents, with a cockpit in front. At mach3+ in the 20-40km altitude band, skin temperature on the nose cone typically is 1800K and over. Slowly but surely, the heat seeps in and becomes part temperature. Most cockpits are only good for 1200-1500K part temp. If the skin stays hotter than that for too long, the cockpit will go poof. So if you put a cockpit in front, you have to climb decisively and get above 50km before the crew boils. Even then, it takes a while for skin temp to drop; as long as it's hotter than the inside, heat will seep in. I've had cockpits blow up long after the worst was over.

I tried radiators in the hope that they would at least help a little once I was out of the worst. I mean, when the cockpit skin starts to cool down, there ought to be leeway for the radiators to work, don't you think? But no such luck. I paid really close attention and the radiators had no noticeable effect for as long as I was in atmosphere. At 70km, they'd suddenly spring into action, but not before.

A pre-cooler just behind the cockpit was more effective, at least in the sense that one could see an effect when looking at the numbers. Not effective enough to make a difference, though.

(The simple cop-out is to use anything but a cockpit for a nosecone. But I wanted a cockpit there, dangit, and spent a lot of time trying to make it work.)

[Krzysztof z Bagien]

On 5/5/2019 at 12:04 AM, Laie said:

Nah, they don't. Radiators are ineffective when flying fast through the atmosphere.

It's not like radiators can be used instead of a proper heatshield or something, but they help a little. Their effect is noticeable (meaning things explode slightly later  and sometimes they don't explode at all), but in most cases it doesn't really make a difference.

[Aeroboi]

3 hours ago, Krzysztof z Bagien said:

It's not like radiators can be used instead of a proper heatshield or something, but they help a little. Their effect is noticeable (meaning things explode slightly later  and sometimes they don't explode at all), but in most cases it doesn't really make a difference.

That depends, in fact the radiators will completely shield everything behind them. Using only Oscar-B or the 0.625m MH fuel tanks a large heatshield will engulve all the tanks and protect everything as long as the heatshield is facing the wind. Like a proper space plane it would have either fins or enough reaction wheels to stay in the proper orientation. Since it has 2500k resistance it would be more heat resistant then a regular 2400k space plane which most are. So you'd be better of. Practically, it's kind of pointless  

Edited May 7, 2019 by Aeroboi

[Daniel Prates]

3 hours ago, Aeroboi said:

That depends, in fact the radiators will completely shield everything behind them. Using only Oscar-B or the 0.625m MH fuel tanks a large heatshield will engulve all the tanks and protect everything as long as the heatshield is facing the wind. Like a proper space plane it would have either fins or enough reaction wheels to stay in the proper orientation. Since it has 2500k resistance it would be more heat resistant then a regular 2400k space plane which most are. So you'd be better of. Practically, it's kind of pointless  

And besides that would be a little gamey, dont you think? I mean, in RL the radiators couldt be used like that. As a matter of fact I read above people talking about using radiators during reentry..... in any serious scenario they would simply be OBLITERATED WITH EXTREME PREJUDICE if used like that.

 

My humble opinion: radiators work better - thay is to say, they make more sense - in modded games. Near Futute Elecrtical for instance. In vanilla games they really only make sense with converters, and very low in Kerbol's orbit. I mean, waaaay too low. If you ask me, we should need them even when coasting to the Mün.

Edited May 7, 2019 by Daniel Prates

[Aeroboi]

26 minutes ago, Daniel Prates said:

And besides that would be a little gamey, dont you think? I mean, in RL the radiators couldt be used like that. As a matter of fact I read above people talking about using radiators during reentry..... in any serious scenario they would simply be OBLITERATED WITH EXTREME PREJUDICE if used like that.

 

My humble opinion: radiators work better - thay is to say, they make more sense - in modded games. Near Futute Elecrtical for instance. In vanilla games they really only make sense with converters, and very low in Kerbol's orbit. I mean, waaaay too low. If you ask me, we should need them even when coasting to the Mün.

Yes, thin metal plates and pipes are not very rigid. Often a aluminum or copper alloy is used which is also not strong to begin with, and, not that heat resistant either, so 2500K heat resistant makes no sense. Because of this the radiators are very light, so why does it have these attributes?

Anyway, the suggestion I made was gamey intended. Logical or not it is fun and people could try.

[Daniel Prates]

23 minutes ago, Aeroboi said:

Anyway, the suggestion I made was gamey intended. Logical or not it is fun and people could try

Oh you're right there. KSP can be fun in many different ways. If something works, its worth trying, goofy or not. Thats one of KSP's merits, being fun for people looking for either suave or hardcore entertainment. And TBH the game can only be taken as a more RL experience when heavily modded.

Edited May 7, 2019 by Daniel Prates

[Krzysztof z Bagien]

On 5/5/2019 at 12:04 AM, Laie said:

Radiators are ineffective when flying fast through the atmosphere.

I did some testing, and radiators are actually working in atmosphere and it is noticable. I deorbited a command pod from 500km on a steep trajectory with radiators turned off and then with radiators on -  and it overheated and exploded several kilometer closer to the ground with radiators active.