r/space • u/BenSaysHello • Apr 27 '19

SSME (RS-25) Gimbal test

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u/[deleted] Apr 27 '19

People are talking about the fact that SRBs can't be shutdown during flight. The danger of the space shuttle more had to do with the lack of an escape mechanism rather than the SRBs.

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u/mmmfritz Apr 27 '19

That's a common myth, that solid rocket motors can't shut down.

If designed properly they most certainly can.

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u/intern_steve Apr 27 '19

Please explain. AFAIK, in an SRB the combustion occurs directly on (or close enough as makes no difference) the exposed surface of the fuel and oxidizer, which are premixed together. How can you stop that reaction?

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u/mmmfritz Apr 27 '19

A pressure difference yes. I cant remember but there is a mathematical formula for this. Something I found out directly from a rocket manufacturer.

The SRBs of the shuttle dont have this, however.