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During launcher ascent, dynamic pressure evolution is described in this answer for the Saturn V. I suppose this is similar for most launchers.

Given the protections designed for reentry, I suppose dynamic pressure involved during reentry is more important than that during ascent.

What does this evolution look like during reentry? Does it look like the same bell shaped curve (which increases and decreases with almost the same slope)?

In case the answer varies with the spacecraft in consideration, this question can be narrowed to vehicles from the Apollo program or other manned ships.

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For capsule reentry, the Q profile is a bell-shaped curve, narrower than the ascent profile, slightly gentler in slope at the start and steeper at the end.

Here's what it looks like for a steep 40g ballistic (from Aerothermal Analysis of a Sample-Return Reentry Capsule; the dot-dash line is the dynamic pressure curve):

enter image description here

For a crewed capsule the dynamic pressure peak is not quite as narrow and sharp, but the overall shape would be similar; for a 'skip-entry' trajectory there may be multiple pressure peaks instead of a single one. Here's a plot from flight testing of the Orion capsule (blue simulated, red measured):

enter image description here

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Perhaps surprisingly, at least for an aerospace plane like the Shuttle, entry dynamic pressure is maximum once you go subsonic.

enter image description here

It doesn't get anywhere near the ~600 psf experienced during ascent.

source (p. 239)

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  • $\begingroup$ Russell Borogrove told me descent max Q can be 92 kilopascals. Perhaps your answer has the same info but it is hard to see. Pounds per square foot buried in a chart is a poor way to answer my question. $\endgroup$ – HopDavid Feb 21 at 21:20
  • $\begingroup$ My question was asked on April 5, 2017 and answered soon after. This question was asked on Nov. 7, 2018. So if you want to call questions duplicates it is this question that had already been answered. But I don't really see them as the same question. $\endgroup$ – HopDavid Feb 21 at 21:22

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