All US boosters (I assume other nations as well) have flight termination systems. The goal is to try and stop an out of control booster (Big vehicle, full of explosives/fuel/oxidizer) from causing MORE harm.

When the CRS-16 mission booster (Core B1050) clearly was spinning out of control on landing, why did they not use the FTS to blow it, instead of letting it try to land.

That is actually was pointed somewhere safe (would divert if all was going well to land, by design) and that it actually landed softly on the water, is sort of immaterial.

Why did the flight safety officer not terminate the flight?


1 Answer 1


The Block 5 Falcons uses a new system called AFT (Autonomous Flight Termination) that is run by the booster, not the flight safety officer any longer.

Additionally you can hear them call out during launch that the flight termination system is safed on the way up, before the booster tries to land.

The theory is the booster is basically empty at that point and there is no need to terminate it.

So the system is turned off, and there isn't a person in the loop anymore to terminate it, and the booster computer knew it was going in a safe direction.

In an article reporting on the post mission briefing, Hans Koenigsmannis reported saying:

The booster is equipped with an autonomous flight safety system, but that was disabled as planned prior to when the booster started to spin up. Koenigsmann said the flight termination system is turned off when the booster no longer poses a threat to the public.

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    $\begingroup$ A more fleshed out answer should probably include info about instaneous impact points and how the AFTS goal is to destroy the vehicle before the IIP crosses defined lines that would allow it to threaten civilians. AFTS is safed on return when the IIP can no longer exit the range safety box. Link for more info - I may try and revisit later if I have time: itea.org/wp-content/uploads/2018/05/Burke.pdf $\endgroup$
    – Saiboogu
    Dec 6, 2018 at 15:20

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