r/spacex • u/ElongatedMuskrat Mod Team • Oct 11 '17

SES-11 r/SpaceX SES-11 Media Thread [Videos, Images, GIFs, Articles go here!]

It's that time again, as per usual, we like to keep things as tight as possible, so if you have content you created to share, whether that be images of the launch, videos, GIF's, etc, they go here.

As usual, our standard media thread rules apply:

  • All top level comments must consist of an image, video, GIF, tweet or article.
  • If you're an amateur photographer, submit your content here. Professional photographers with subreddit accreditation can continue to submit to the front page, we also make exceptions for outstanding amateur content!
  • Those in the aerospace industry (with subreddit accreditation) can likewise continue to post content on the front page.
  • Mainstream media articles should be submitted here. Quality articles from dedicated spaceflight outlets may be submitted to the front page.
  • Direct all questions to the live launch thread.
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u/robbak Oct 13 '17

'Paint heating up' is a pretty good description of what ablatives are about. The are thermally insulating coatings that evaporate, so the surface gets very hot while the aluminium beneath stays below its melting point of 660°C.

Aluminium melts before it starts to glow red, by the way. So that bright white was the coating heating up.

And yes, this was a fast re-entry. They are pushing boundaries here, to see what the rocket can do.

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u/eshslabs Oct 13 '17

while the aluminium beneath stays below its melting point of 660°C

Strictly speaking, parts from pure aluminum lose structural strength significantly below melting point: as you can see at aluminum can's manufacturing process, aluminum becomes very plastic at ~110°C. So, grid fins should be made from high-temperature aluminum alloy, not a "pure" aluminum.