heat shielding

[steuben]

I know the optimal way to shield craft aero braking is to tuck everything behind a heatshield. But how far out can I stick things before I'm outside of the shield's shadow? I figure that the further back from the shield the further they can stick out... but how far?

And I recall a post somewhen that said the shape of the nose affects that as well.

Anybody have any guidance?

[N_Molson]

Currently I'd say that KSP considers that anything in a "cylinder" beyond the heatshield is protected.

In reality, it depends on the spacecraft shape, indeed. Maybe those results about an ESA conducted experiment with a conical-shaped body can enlight you a bit :

 

Figure 8. Temperature distributions around the ESA ARD at an altitude of 85 km (x-y plane). (a) Translational temperature; (b) vibrational temperature.

[VektorWorlds]

36 minutes ago, N_Molson said:

Currently I'd say that KSP considers that anything in a "cylinder" beyond the heatshield is protected.

In reality, it depends on the spacecraft shape, indeed. Maybe those results about an ESA conducted experiment with a conical-shaped body can enlight you a bit :

 

Figure 8. Temperature distributions around the ESA ARD at an altitude of 85 km (x-y plane). (a) Translational temperature; (b) vibrational temperature.

Eh, I wouldn't say so.

 

I ran an experiment in KSP where I had two thermometers, one right next to the heat shield and another one some distance removed from it like this;

 

<1---2

With the < being the heat shield, the 1 being the first thermometer, and the 2 being the second one. I attached them with a structural element.

It turns out that 2 got significantly and measurably hotter during the early, intense stages of reentry.

They both became somewhat equal near the end, I would assume due to convection from the heat shield and probe core on the first thermometer.

[Foxster]

It's supposed to be a cylinder. But I have found that most craft will tend to wander about prograde during re-entry and that means the cylinder wanders about a bit too, producing an effective truncated cone. 

If you can maintain prograde tightly with air brakes at the back and plenty of reaction wheels then you are likely to maintain the cylinder. 

There is little or no tolerance outside the cylinder. I have had craft descending to Eve and had to be really careful to tuck things in tight.