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From the Apollo Experience Report: Thermal Protection System, there is a diagram that shows the surface temperatures of the Command Module at various points (image was obtained from this answer). It shows about 1500 °F (816 °C).

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From Apollo Infrared Acquisition and Tracking System on Google Books, on page 26, there is a graph showing the temperature of the leeward side. Here it shows the temperature around 1250 °F (676 °C).

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However, in the Apollo Command Module recovery photographs, only one half of the CM still has Mylar on the surface. This is the Apollo 13 CM.

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My initial thought was that the spacecraft re-entered at a non zero angle of attack as that was how they controlled lift. But Mylar and Aluminum have melting points of 250 °C and 660 °C, respectively. How is it that the Mylar and the Aluminum handles survived re-entry?

Question: What was the leeward surface temperature of the Apollo Command Module during re-entry? And how did the Mylar and Aluminum survive?

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  • $\begingroup$ The outer film was Kapton. Mylar was used to protect the surface during manufacturing, but was removed before flight. $\endgroup$
    – DrSheldon
    Commented Sep 27, 2020 at 7:05
  • $\begingroup$ The Mylar/Kapton distinction is explained in this answer and is based on the Apollo Experience Report cited above. $\endgroup$
    – DrSheldon
    Commented Sep 27, 2020 at 7:30
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    $\begingroup$ Added text "leeward side" to the first image. $\endgroup$
    – Uwe
    Commented Sep 27, 2020 at 12:16
  • $\begingroup$ @DrSheldon I suppose the same question could apply. Kapton is stable up to 400 °C. What was the leeward side temperature and how did the Kapton and Aluminum parts survive? $\endgroup$
    – Star Man
    Commented Sep 27, 2020 at 14:53
  • $\begingroup$ Note that just because the temperature on the outside reaches 676°C, that doesn't mean the Aluminium gets the same temperature. In fact, it would take some time to reach equilibrium with the outside temp. I wasn't able to find a good source for convective heat transfer of aluminium in this regime, though. $\endgroup$
    – Polygnome
    Commented Sep 27, 2020 at 20:05

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