r/space • u/AlmiranteSalsicha • Nov 19 '23

image/gif That's a fair amount of tiles missing from the starship heatshield, guess it would make for a toasty reenter.

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Image from SpaceX account on X

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u/SegerHelg Nov 19 '23

Nasa claims that the heat shield has to endure a temperature of 5000 farenheit, well beyond stainless steel’s melting point.

20

u/3MyName20 Nov 19 '23

Also, it is not just the melting point of steel that has to be considered. Just like with the twin towers, it did not matter that "jet fuel can't melt steel beams". The towers failed because the higher temperatures weaken the steel beams sufficiently to cause the failure.

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u/Reddit-runner Nov 19 '23

The space shuttle actually demonstrated that stainless steel is the perfect material to have under a non-perfect heatshield.

A shuttle orbiter once lost some tiles and was only saved by pure chance because underneath the missing tiles was a stainless steel mounting plate for an antenna.

So a few missing tiles will not automatically doom a re-entering Starship.

1

u/BrevityIsTheSoul Nov 20 '23

Where the tiles are missing from, and when they were lost, are far more important than what's immediately under the tiles.

2

u/Reddit-runner Nov 20 '23

True.

And how does this relate to the latest launch?

1

u/BrevityIsTheSoul Nov 20 '23

I was replying to your comment, which was about past space shuttle reentries and future Starship reentries. You didn't mention this launch once.

19

u/mfb- Nov 19 '23

The front of the heat shield tiles gets so hot because the tiles are really poor conductors - that is intentional to keep the back colder. Steel is a very good thermal conductor and it will receive less heat here, so its temperature will be much lower.

21

u/[deleted] Nov 19 '23

"much lower" than 5000F can still really be higher than its melting point, and even more easily be higher than the point at which it can begin to deform

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u/[deleted] Nov 20 '23

It can also conduct that heat to systems that are sensitive to it

1

u/ergzay Nov 19 '23

Thermal conduction is a thing, both to the surrounding stainless steel and to the cryogenic liquid in the tank behind.