# Tag Info

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The Space Shuttle used liquid hydrogen, contained in the external tank along with liquid oxygen. While the Falcon rockets do use liquid oxygen, they do not use liquid hydrogen. Keeping the liquid hydrogen cool was the primary driver for the foam. The Orbiter was mounted alongside and below the the top of the external tank. The Falcon payload is mounted at ...

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The problem is not the foam breaking off per se, but the fact that the orbiter was below the fuel tank and got hit by the falling foam. The Dragon capsule is on top of the stack, it can't be hit by a piece of foam that comes off the booster.

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Do all chemically-fueled rockets need foam insulation? Not all, but some do. Generally the small subset of ones that utilize hydrogen fuel. The hydrogen-fueled Delta IV uses essentially the same insulating foam as shuttle did. Photo from clickorlando.com The hydrogen-fueled SLS uses a similar foam. Photo credit NASA This question Insulation on rockets--...

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The critical pressure ratio for a de Laval nozzle is $$\left(\frac{P_0}{P_{atm}}\right)_{crit} = \left(\frac{\gamma+1}{2}\right)^{{\gamma}/({\gamma-1})}$$ Where $P_0$ = stagnation pressure in chamber $P_{atm}$ = atmospheric (back) pressure $\gamma$ = ratio of specific heats for the gas $(P_0 / P_{atm})$ must exceed this critical value in order for a de ...

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I don't have a source sorry, but I suspect the reason for having insulation is to prevent formation of liquid oxygen on the out side of hydrogen tanks. Hydrogen is so cold that it can cause the Oxygen (and Nitrogen) in the the air to condense. Liquid Oxygen just dribbling onto the launch pad and rocket would be a bad thing. Steel burns in liquid oxygen. ...

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The Space shuttle used Cryogenic fuels for it's main engines, including liquid hydrogen and liquid oxygen...That required the insulation. Falcon rockets used RP1 fuel (highly refined kerosene), though they use LOX tanks, they require no insulation

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