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The one reason to go from external match sticks to internal ignition using hypergolic fuels is to be able to relight in flight after an engine shutdown.
by petschge 8y ago
The one reason to go from external match sticks to internal ignition using hypergolic fuels is to be able to relight in flight after an engine shutdown.
- bunderbunder 8y agoYep. Which seems like a fairly unnecessary requirement for an expendable first stage. I'm no rocket engineer, but my guess would be that, if you're shutting down an engine at that stage in the flight, your only realistic options are going to be redirecting fuel to the remaining engines for a longer burn, or cutting all engines and activating the launch escape system. I can't imagine there's any practical reason to plan on shutting down and re-igniting engines during the first stage of a launch, and I also can't imagine trying to decide whether an engine is safe to re-light during the few seconds you'll have between when you executed the emergency shutdown and when it's time to jettison the first stage entirely.