Source? It would be solid water ice, mostly surrounded by shuttle wing structure, in a low-g reentry. Not an "ice & volatiles & etc." meteor in a high-g situation.

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poulpy123 7 days ago | parent [-]

the sources are the pressure and temperature conditions at reentry and the water phase diagram

	▲	bell-cot 7 days ago \| parent [-]
		Ablative heat shields work very reliably, even though their material has no substantial liquid phase between solid and vapor. The function of the ice would be to act as an ersatz ablative heat shield. Also a famous ex-NASA engineer analyzed a similar situation (water + protein) - https://what-if.xkcd.com/28/ - and noted no possibility of explosion, except in the case of a hypersonic tumble. A hypersonic tumble would shred the shuttle orbiter anyway, due to the extreme aerodynamic forces.