posted 10-18-2023 07:36 AM               

If you look at the Buran, you can see that there are black and white tiles in an irregular pattern at the base of the wings (in the area where the wings emerge from the fuselage), as seen here:

Where one would have expected white tiles, there are also occasional black ones. However, the patterns on the left and right are different. I have a guess though, but I would like to know if one of our the fellows here is a real expert and can answer my question as to why black ones got "lost" among the white tiles.

posted 10-18-2023 03:42 PM               

quote:

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Originally posted by Rocket Chris:
...there are black and white tiles in an irregular pattern at the base of the wings

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The U.S. space shuttle Columbia was notable in its appearance because its wing chines were entirely covered in black tile. But when Columbia was first delivered by Rockwell to NASA, its chines were white. NASA had the extra black tiles added because, by all accounts I could find, they weren't sure of the heating effects in that region during reentry.

Later orbiters, beginning with Challenger, forewent the black tiles for white thermal insulation blankets as both a weight saving measure and because it was found that the reentry heating at the chines did not require the greater protection afforded by the black tiles.

Buran didn't fly until 1988, giving the Soviet Union time to see not only Columbia launch and return from multiple missions, but Challenger, Discovery and Atlantis, too. The Soviet engineers would have seen NASA forgo the black chines on the later orbiters but still fly Columbia as originally configured.

It is only a guess, but maybe the staggered pattern was a bit of hedging one's bet, so to speak, on the part of the Soviets seeing NASA fly both configurations and not having the benefit of the AFRSI insulation.

posted 10-18-2023 11:44 PM               

I was not aware of this expression but you are right.

At first I also thought that it was related to a thermal analysis, or that some white tiles were missing before completion and they were quickly replaced with black ones in order to keep the target date.

What is also noticeable is that there are also some black tiles on the RCS near the nose cone.

Jim, do you have more information about what exactly the thermal analysis was intended?

And once again I appreciate this forum... just competent and helpful people here! Thank you!!!

posted 10-20-2023 12:36 PM               

quote:

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Originally posted by Rocket Chris
Jim, do you have more information about what exactly the thermal analysis was intended?

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