Stock ICBM RVs?

[SunlitZelkova]

I want to build an R-7 replica, but the last time I tried to build an ICBM, the reentry vehicle, which used a fairing with a probe core inside, burned up. Do I need to use nose cone parts? Does launching ICBMs require a very delicate trajectory to prevent the RV from burning up?

[king of nowhere]

that depends on a lot of factor.

assuming you play in the stock game, there should be no problem with reentry from orbit with most normal parts. unless there was some heat sensitive part outside of your fairing. fairings have pretty good thermal resistance, in general, so I assume you made some building mistake? can you post a picture?

[FleshJeb]

Which part is failing? (F3 screen).

If the fairing is the root part of your RV, it won't shield what's inside. This is a long-standing bug with all drag-occlusion parts.

If it's the fairing, they have really bad radiative properties (60% ? emissivity, close to 0 heat transfer to attached parts). They can handle a quick shock heating due to the high temperature limit, but they barely dump any energy overboard, and have no ability to spread it into attached parts.

You can try a steeper re-entry, or at least make sure it gets into the coolest part of the atmosphere (25km-10km) as soon as possible.

For flatter atmo-dives, I like the Small Nose Cone and the NCS Adapter (95% emissivity and high heat transfer to attached parts). I've got a fuel tanker that can survive aerobraking down to 28km from Minmus orbit.

What I would try is:

• Small Nose Cone
• NCS Adapter (empty)
• Service Bay with all the fragile parts.
• 2-4 small elevons attached to either the nose cone or the NCS, and offset behind the Service Bay.

Elevons are also fantastic radiators. The whole thing will glow white, but it should live.

[SunlitZelkova]

11 hours ago, king of nowhere said:

that depends on a lot of factor.

assuming you play in the stock game, there should be no problem with reentry from orbit with most normal parts. unless there was some heat sensitive part outside of your fairing. fairings have pretty good thermal resistance, in general, so I assume you made some building mistake? can you post a picture?

I actually deleted the craft file, but this is roughly what it looked like.

I used a very steep reentry and almost made it through, but at the last moment the fairing exploded. The probe core inside did survive, but that just wasn't as satisfying.

1 hour ago, FleshJeb said:

Which part is failing? (F3 screen).

If the fairing is the root part of your RV, it won't shield what's inside. This is a long-standing bug with all drag-occlusion parts.

If it's the fairing, they have really bad radiative properties (60% ? emissivity, close to 0 heat transfer to attached parts). They can handle a quick shock heating due to the high temperature limit, but they barely dump any energy overboard, and have no ability to spread it into attached parts.

You can try a steeper re-entry, or at least make sure it gets into the coolest part of the atmosphere (25km-10km) as soon as possible.

For flatter atmo-dives, I like the Small Nose Cone and the NCS Adapter (95% emissivity and high heat transfer to attached parts). I've got a fuel tanker that can survive aerobraking down to 28km from Minmus orbit.

What I would try is:

• Small Nose Cone
• NCS Adapter (empty)
• Service Bay with all the fragile parts.
• 2-4 small elevons attached to either the nose cone or the NCS, and offset behind the Service Bay.

Elevons are also fantastic radiators. The whole thing will glow white, but it should live.

The probe core is the root part. My reentry angle was very steep (close to vertical) by accident. As mentioned above, it almost made it through, but exploded right before passing below 25km.

In any case however, thanks for the design tips!

[FleshJeb]

12 minutes ago, SunlitZelkova said:

it almost made it through, but exploded right before passing below 25km.

I wish blunt-bodies actually worked the way they do in real life.

Having a little bit more surface area  for the fairing to radiate heat with might do the trick. Maybe a one-tick high vertical section just above the base. (Provided they're actually calc'd the way I think they are.)

If you end up experimenting with this some more, please ping me--I find KSP's aero and thermal systems endlessly fascinating.

[Akagi]

Try adding a heat shield clipped into the bottom of the RV.