Reentry Heating (For Science!)

[Vl3d]

Wow, KSP2 reentry heating is no joke! I just killed Valentina trying to get back from orbit without a heat shield, like in KSP1. Big no-no!  Love it!

Edited December 22, 2023 by Vl3d

[LameLefty]

24 minutes ago, Vl3d said:

Wow, KSP2 reentry heating is no joke! I just killed Valentina trying to get back from orbit without a heat shield, like in KSP1. Big no-no!  Love it!

I killed Jeb on a suborbital hop, like the early Mercury-Redstone flight - only about 7G's, too, so not even THAT hardcore. RIP.

https://imgur.com/a/lNfWqcR

 

[Kerb24]

Val nearly died when her capsule parachute failed following a botched re-entry. However, apparently any kerbal can repack ripped chutes.

[Scarecrow71]

I tried the "engine as your heat shield" trick from KSP1, and lost Tim C. Kerman on his initial voyage into the dark recesses of LKO.  RIP, Tim; we barely knew ye.

[boolybooly]

that caught me out with Bob but I reran the mission and found the flying cylinder trick works, if you get down to 35km region you can tilt a cylindrical rocket to give lift i.e. fly retrograde and then try to get the navball pointer on the brown bit, pointing the nose down so the forward engine end lifts up and gives lift, thereby avoid plunging into the inferno of thick atmosphere at high speed and gradually lose speed to friction by skipping along at high altitude, Bob lives and he brought home the science

 

[Superfluous J]

I got a hint that "re-entry" heating was worse than KSP1 when my parachute almost exploded on the way up on my suborbital hop. So I bought heat shields with that flight's science and Bill is very happy I did.

Not only did it protect him from re-entry heating on the way down, it also bore the brunt of the 400-ish-m/s plunge into the water due to a parachute malfunction (not my fault!) that he somehow survived.

[JeanRenaud]

5 hours ago, Vl3d said:

Wow, KSP2 reentry heating is no joke! I just killed Valentina trying to get back from orbit without a heat shield, like in KSP1. Big no-no!  Love it!

I did too. I killed two Kerbals. Why does KSP1 tolerates no-shield Low orbit, and KSP2 does not, is interesting.

The other question: Since this is an issue now, why does they do not put the heat shield in the first objects we must "research" before going to orbit ? We have plenty of options of research and we probably can build something able to launch to other planets, without having unlocked the heat shield... that seems like a death trap considering the "experience" people got in KSP1.

I noticed in KSP1 the specs of max temperature for MK1 is "850K inside / 2200K skin", and in KSP2 it is "850K" without giving skin/interior differentiation, could it be for this reason ?  Kerbin atmosphere cannot be suddenly thicker...

And why does the command pod explodes if there was no plasma trail ? Maybe just because the reentry effects are not yet perfect ?

Edited December 20, 2023 by JeanRenaud

[BComFly]

4 hours ago, JeanRenaud said:

I noticed in KSP1 the specs of max temperature for MK1 is "850K inside / 2200K skin", and in KSP2 it is "850K" without giving skin/interior differentiation, could it be for this reason ?  Kerbin atmosphere cannot be suddenly thicker...

I think you got the point. They unified the internal/external temperature, but it doesn't seem they adjust the max temp accordingly. The re-entry environment became very harsh as a result. My SSTO has its wing (mid-size) melted at 60 km and 2.1 km/s at Kerbin, at which it is definitely a safe situation in KSP1. As of now, SSTO is merely implausible because of re-entry heating. The only way to reduce temperature during re-entry at this moment is to use ablator, which wings just doesn’t have.

[Alpha_star]

1 hour ago, BComFly said:

I think you got the point. They unified the internal/external temperature, but it doesn't seem they adjust the max temp accordingly. The re-entry environment became very harsh as a result. My SSTO has its wing (mid-size) melted at 60 km and 2.1 km/s at Kerbin, at which it is definitely a safe situation in KSP1. As of now, SSTO is merely implausible because of re-entry heating. The only way to reduce temperature during re-entry at this moment is to use ablator, which wings just doesn’t have.

Hey! Would start your “KCP equivalent campaign” soon? I have always been a great fan of your channel so it would be great if you deliver more content to your fans.

Talking about re-entry, they are of course geting harder. However, just like in RSS, you can always have a shallower trajectory and use more body-lift. That’s how I deal with reentrys on Earth.

再次催更

Edited December 20, 2023 by Alpha_star

[The Aziz]

Peoples, the very note on the changelog post

"A Note on Heat

It's important to keep in mind that the Part Heat system in KSP2 is different than KSP1, so do not expect parity in this area. Tuning the numbers for the heat system will be a long-term project, so feedback is appreciated!"

It's not supposed to be the same as KSP1 (why would it be lol), neither it is a final product.

[Vl3d]

I think it's great that we can't re-enter without a heat shield. That's exactly the way it should be - unprotected parts should be very fragile to heating and aero-forces.

That being said, I think the re-entry heating visuals are fugly. But I just look away.

[Superfluous J]

I discovered that decouplers are GREAT heat shields. I've not tried it yet, but I think you could return from Mun with a flipped-over decoupler, so when it decouples the fuel tank the decoupler stays attached to your pod.

[Vl3d]

9 minutes ago, Superfluous J said:

I discovered that decouplers are GREAT heat shields. I've not tried it yet, but I think you could return from Mun with a flipped-over decoupler, so when it decouples the fuel tank the decoupler stays attached to your pod.

File a bug report please.

[BComFly]

15 hours ago, Vl3d said:

unprotected parts should be very fragile to heating and aero-forces

I agree, we need an option to lay heat tiles on wings and other parts. Otherwise, we can't even recover a space shuttle at current state. 

[PicoSpace]

On 12/19/2023 at 3:56 PM, Vl3d said:

Wow, KSP2 reentry heating is no joke! I just killed Valentina trying to get back from orbit without a heat shield, like in KSP1. Big no-no!  Love it!

I’m down 8? Kerbals now, only two died on impact, the rest… well they didn’t make it.

overhangs are brutal!

[tstein]

On 12/20/2023 at 7:30 AM, Vl3d said:

I think it's great that we can't re-enter without a heat shield. That's exactly the way it should be - unprotected parts should be very fragile to heating and aero-forces.

That being said, I think the re-entry heating visuals are fugly. But I just look away.

More or less, because not all parts  can be behind a heat shield (wings?)  unless we  add a modifier to all parts  (tick here to add thermal protection for X% mass increase)

[kdaviper]

On 12/19/2023 at 3:56 PM, Vl3d said:

Wow, KSP2 reentry heating is no joke! I just killed Valentina trying to get back from orbit without a heat shield, like in KSP1. Big no-no!  Love it!

One of the first things I noticed was that the mk1 capsule has a flat bottom. 

Is it lighter than the mk1 in ksp1?

[Aeolica]

My SSTO with 900t payload successfully survived the reentry heat.

The returner weighs approximately 850t

[Tallenn]

I'm loving the re-entry heating do far, but curious about the parachutes. They sometimes seem to just break off, and other times work flawlessly. Bug, or am I doing something wrong?

[Timbo]

14 hours ago, BComFly said:

I agree, we need an option to lay heat tiles on wings and other parts. Otherwise, we can't even recover a space shuttle at current state. 

YES to heat tiles or some form of radial  heat shield!  I'm currently finalizing a SpaceX Starship clone and after the update, it cannot survive re-entry because the only heat shields available are designed for capsules    

Edited December 21, 2023 by Timbo

[tstein]

Just now, Timbo said:

YES to heat tiles or some form of radial  heat shield!  I'm currently finalizing a SpaceX Starship clone and after the update, it cannot survive re-entry because the only heat shields available are designed for capsules    

https://imgur.com/a/wYYz9d0

https://imgur.com/a/7dgISMx

I would prefer we just add a slider on each  aerodynamic part  names Ablative  protection. that  icnreases protection at mass cost.  Better than adding extra pieces that will be anoying to lay and will just  tax the physics system. Just embed the armor in the parts where they make sense

[Timbo]

1 minute ago, tstein said:

I would prefer we just add a slider on each  aerodynamic part  names Ablative  protection. that  icnreases protection at mass cost.  Better than adding extra pieces that will be anoying to lay and will just  tax the physics system. Just embed the armor in the parts where they make sense

Good idea, and keeps the part count down.  But for realism I feel like you need to add a heat shield, not just adjust every part's characteristics.  Also, it's not just aerodynamic parts that need protection. In my case, the engine overheats and blows up on reentry, even when it's off.  For space shuttle type vehicles, a "procedural" shield that covers the entire underbelly or the whole stack would be ideal

[Wheehaw Kerman]

On 12/20/2023 at 5:30 AM, Vl3d said:

I think it's great that we can't re-enter without a heat shield. That's exactly the way it should be - unprotected parts should be very fragile to heating and aero-forces.

That being said, I think the re-entry heating visuals are fugly. But I just look away.

Last night I had Jeb do a Münshot, and the re-entry came in over Kerbin’s night side.  The way the heat shield lit up was gorgeous - it gave a real sense of intense heat far outside of normal experience.  The trail, not so much, but wow, that glow…

[shdwlrd]

Don't know if you were playing KSP1 at the time 1.0 released. But in the early days of the release, reentry heating was very brutal. You needed shielding for any part that was exposed to the air stream or it would explode. It was changed because noone wanted to learn/try new reentry profiles to minimize the heat buildup.

I'm glad that the devs went this route. Reentry it just as tricky as any other part of flying rockets.

[Scarecrow71]

So I was playing this morning, and I ended up testing a typical Mun return with an aerobrake capture.  From Mun orbit to a return with a Pe of ~45km, aerobraking until my Ap was low enough to just land.  I started with the heat setting at 100%.  I'll state that this is a typical return trajectory from Mun in KSP1, and this works without anything bad happening.  The results:

1. 100% heat:  Capsule exploded
2. 90% heat:  Capsule exploded
3. 80% heat:  Capsule exploded
4. 70% heat:  Capsule exploded
5. 60% heat:  Capsule exploded...but started to take longer than it did before
6. 50% heat:  Capsule exploded
7. 40% heat:  Capsule exploded
8. 30% heat:  Capsule nearly exploded, but it survived
9. 20% heat:  Capsule survived

The heating system is way overpowered and needs to be tweaked by the devs.  I get that we are supposed to have to deal with heat upon re-entry, but this is way worse than what it is in KSP1.  By the time I hit 20%, I simply decided to shut the heat effect off.  If I have to turn it all the way down for it to work the way it should, why have it at all?  We waited 10 months for this?

27 minutes ago, shdwlrd said:

I'm glad that the devs went this route. Reentry it just as tricky as any other part of flying rockets.

I am not glad the devs went this brutal.  Re-entry should be hard, but when you consider you are supposed to go sub-orbital before you even get heat shields AND you know that the capsule will overheat and explode even with a heat shield?  If you really want new players to walk away from the game, this is a great first step to getting that to happen.