Exploration of Kerbol and heat management near it

[lajoswinkler]

So I've sent a shielded probe down to Kerbol. 1.8 km apoapsis. As it was approaching, some things overheated and exploded. The game crashes somewhere around 2 million kilometres, but that's probably because I use some mods. Maybe not, though. It behaves as if I lost free RAM even if I lower the textures significantly.

The question is - how to manage all the heat Kerbol is pounding the probe with? I've requested this mod recently, but nobody replied.

My approach so far is to use a large shield and NFE radiators looking towards the space behind.

(In addition to this topic - I've heard some people managed to perform (partial? total?) aerobraking above (how much?) this star. How is that even possible with such enormous radiative heat coming out? It's not even realistic if it's in the corona because corona is a tiny fragment of one pascal. Couple billion of particles per cubic centimeter. That's a very strong vacuum. The only aerobraking I could expect is in the lower chromosphere. There is no benefit from unrealistic solar atmosphere in KSP.)

I'm all for Kerbol being a monster you can not approach, FYI.

[tychodin]

i've successfully gotten to within half the moho orbital distance before running out of fuel, and i definitely noticed the incidental heating at periapsis. if your game crashed, you probably had the heating gauges on? those have a memory leak in the current version.

there are several heat management mods out there, though, and a heat-shield is really only effective for reentry, as once it ablates, it no longer shields.

[Streetwind]

You probably crashed because of the memory leak associated with overheating parts. Contrary to popular belief, it's not the little heat gauges that can be turned off by pressing F10, but rather the red glow effect that hot parts get laid over them. That can be disabled in the game options I believe (though I forget what it's called).

As for how to... I must admit I've never tried it in 1.0, but my first impulse would be to install the largest heat shield available at the very front and instruct my probe or pilot to always point the craft radial-in... meaning the heatshield always faces the sun and the craft itself always remains in the shadow. The ablator on the heatshield should be consumed over time, negating some of the intense heat influx. I would try to insulate the rest of the craft from the heatshield... using stock parts, I dunno, perhaps another, smaller heatshield? I know those are among the parts that conduct the least in stock KSP. Or perhaps mount the heatshield on something with a really tiny bulkhead cross-section, like an I-beam or cubic octagonal strut. I would have to test to see what works best. The craft itself, I'd try to have something with a large thermal mass on it so it can soak for a while without endangering fragile components if some head leaks through the kludged-together "insulation".

Mod parts? I'd install Nertea's Heat Control and use two insulator parts back to back between the heatshield and the craft. Perhaps active radiators on the inside of the heatshield, if they can surface-attach to it, in order to help mitigate the heat buildup.

Finally, I wouldn't go quite as low as 1.8 km... Don't you explode way before getting that close anyway? I'd try to just slip inside the "in space low" regime long enough to do science.

[Archgeek]

I'd go with a huge heat shield sans ablator or a custom shade made of structural panels (or wings...does the game model albedo?) on one end of the ship to take the heat, under a big fuel tank to soak up the heat, bearing a bunch of fins or panels (carefully kept in the shadow of the shade) to purge the heat, and the other end of the ship with all the sensitive probe core and battery like parts connected to the assembly via a docking port, as those make weirdly good insulators. 'Might have some upward facing panels on the sensitive end as well, just to help keep it cool.

Dang it, now I'm tempted to build a sundiver this weekend and see how much a few different designs can take.

[lajoswinkler]

Yeah, I use Heat Control and NFE.

I want to know how to disable those heat indicators so that they never pop up. It annoys me having to do it all the time at the launch.

- - - Updated - - -

I'll try this next time.

Streetwind, Kerbol used to allow some 1.5 km. I don't suppose that will be possible now, but I want to come as close as possible.

[Miravlix]

I think the Sun has a magic zone, where it explodes anything.

http://forum.kerbalspaceprogram.com/threads/39440-Lowest-kerbol-orbit?p=505596&viewfull=1#post505596

[Streetwind]

Ah yes, that's what I meant. I thought it was higher than that, though. Guess I misremembered!

[NathanKell]

Miravlix, that's from 2013. It's quite hilariously out of date....

[mythbusters844]

For the heat overlays crashing your game, you can use HeatWarning. It disables the stock heat gauges AND the part heat overlays and has a bunch of other features too.

[Gargamel]

Miravlix, that's from 2013. It's quite hilariously out of date....

But wouldn't it still be pertinent if the code handling that is still there? I would expect such a "bug" or effect even would be very very low on their priority list. Without seeing anything else to the contrary, but first reaction would be the behavior would be the same.

[Feradose]

Stock parts actually handle this really well, if you build a custom heatshield out of wings/structural panels and hide behind it, it will be safe for a while. You will need lots of radiators and a way of protecting the smaller parts.

I have a big question that might aid this, lets say we have two fuel tanks at each end of craft and only the one near the heatshield is full of fuel. It is getting warmer, if we transfer fuel from the warm tank to tank with radiators, will the other tank get hotter and cool the fuel, so we can repeat the cycle?

[*Aqua*]

No. Fuel doesn't have its own temperature in the game.

[lajoswinkler]

Seems that NFE radiators "see" Kerbol only, nothing else.

Heat shield does loose its ablating layer. I haven't experienced any reentry even at 400 km.

The problem is that the heat shield itself is radiating heat so no matter how good the insulator cap is, components will eventually heat up and explode.

A sungrazing vessel actually requires a solar reflector part, and as far as I know, such mod does not exist.

Can you imagine all the new field of KSP exploration on sungrazing planet(s)? Remember that sweet awesome planet called Ablate from Kragathea's Planet Factory?

I wish if I knew how to make mods. I have tons of ideas, but can't turn them into anything useful.

Edited June 13, 2015 by lajoswinkler

[Whovian]

For the heat overlays crashing your game, you can use HeatWarning. It disables the stock heat gauges AND the part heat overlays and has a bunch of other features too.

If you just want the gauges disabled without any other things, there are two plugins (1 2) to do that.

[carlorizzante]

http://images.akamai.steamusercontent.com/ugc/26241203488291383/C4B83B6D5DA63CB1C5062C4842ECFC90522980D2/

Quick question. How could I get the same info panel you show in your picture, with so much data about temperatures and flux things?

[WOODY01]

Here is some notes from my first low orbit mission around Kerbol.

The probe was designed without any non stock heat management.

http://forum.kerbalspaceprogram.com/threads/125067-Kerbol-Probe

[lajoswinkler]

http://images.akamai.steamusercontent.com/ugc/26241203488291383/C4B83B6D5DA63CB1C5062C4842ECFC90522980D2/

Quick question. How could I get the same info panel you show in your picture, with so much data about temperatures and flux things?

alt+F12, then go to physics/thermal and check the appropriate option.

Here is some notes from my first low orbit mission around Kerbol.

The probe was designed without any non stock heat management.

http://forum.kerbalspaceprogram.com/threads/125067-Kerbol-Probe

Yes, surprising - the shield gives way and then the probe core and some other parts survive for a while.

[SkyRender]

It's all about being smart with your heat management.

Here's the Solar Flare, which went down close to 800,000,000m from the sun. It has some very important design decisions made with it. First of all, it has two 3.25m heatshields on top of each other, no Ablator on either. Second, the probe core is in the middle of the craft, then the science instruments above that, then the battery and solar panels. This was intentional: the items are placed in order of greatest heat resistance and least mission value towards the sun. It was holding stable at around 1300 degrees on the top heatshield, 1150 degrees on the solar panels and less than that on everything else at 900,000,000m or so from the sun. It could easily have made an even closer sundive (~680m/s dV left in it), but I decided that proof of concept was more important than showboating.

[Captain Sierra]

Mine is still in transit (I'm not time warping for sake of not missing my Duna window) but I'm using a 2.5m flat adapter (because heat shields don't let you surface attach to them) with two heat pipes pushing the heat into a large 1.25m battery which is cooled by 4 small universal radiators (these are all Near Future parts BTW). The idea is the battery can serve as a heatsink with a lot of active cooling on it, while the adapter is the initial blocking plate, but has its heat pulled off of it into the heatsink.

[lajoswinkler]

SkyRender, I've came way closer with my probe, but it still isn't close enough for me.

[Shrike99]

Hmm, turns outs Kerbol does indeed have an atmosphere if you dive close enough, this probe survived until the 1250m mark, then hit some sort of barrier

I should point out that i only had reentry heating set to 100%, not the 120% i usually play with.

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I should also make note of the fact that this is not very much of the original probe, nor have i yet repeated the test.

This is because i believe that craft handle thermal radiation better if you don't time warp, so i ran this mission in real time from about the 250 million km mark, on a highly eccentric orbit, so that it would spend as little time at its 100km Periapsis as possible, and it took about 5 hours.

Edited June 14, 2015 by Shrike99

[lajoswinkler]

The limit you've encountered was there basically ever since Kerbol became an actual body. It's like Jool's "surface" at some -250 m.

Maybe I'm having enormous problems because:

1) 120% heating settings

2) DRE

3) HeatControl

4) timewarping

I'm still waiting for the proof there's actual atmosphere (i.e. drag, pressure, plasma forming on vessel) around Kerbol.

[magnemoe]

One idea, it looks like decoplers and docking ports works as insulators. noticed that LV-N tugs and 1x2 core stages heats up but the payload does not, this can be useful for protecting sensitive parts

Did an test run, one major problem was that parts blowing up also destroying other parts. it also looks like radial connected parts are not protected well has to stuff them inside an service bay.

[Captain Sierra]

I'm running into an issue where my craft spontaneously heats up to ~700k upon passing 100x time warp. Its making this damn near impossible. What sucks is I know for a fact this is a quirk of the stock game. Vessel heat gets the handwavium treatment when exceeding 100x time warp. I'm gonna have to look at some alternate methods and test some things with time warp.

[lajoswinkler]

Similar thing happens with cooling. After some mark (100x, perhaps), heated stuff like previously run LV-N abruptly cools down to the thermal equilibrium. Heat simply doesn't work well with timewarping, and to reach Kerbol at normal time... that would last for a "while".