SpaceX has long had a very different idea about FOD than most other rocket companies, famously Merlin engine qualification testing contains ingesting stainless steel nuts.
What size nuts do they pass through their engine? Every engine before it goes to space has to have a nut passed through the system? Like a 12mm "go into space" grade nut or a little itty bitty nut like I might find holding down a heat sink assembly in a 1998 vintage motherboard?
I'm off to the googles to find videos...
Here's an account of just one such incident:
"Boisjoly wrote a memo in July 1985 to his superiors concerning the faulty design of the solid rocket boosters that, if left unaddressed, could lead to a catastrophic event during launch of a Space Shuttle. Such a catastrophic event occurred six months later resulting in the Space Shuttle Challenger disaster."
Robustness and anti-fragility may not be so critical for an expendable vehicle that operates once for something like 12 minutes, but seems a key attribute for a refuel-able and reusable spacecraft?
You can make all sorts of rules about what's not allowed to happen, but often those things happen.
I'm just ... astonished if they've got a little practice room somewhere in their factory where they give each of their new rockets a nut to process... "Okay kid here's your graduation test!". A "we need screens to cope with big things and filters to deal with small things" is probably smart for any anything that's going to be reused.
A nut's probably in some ways easier to deal with than a blob of wd40 (in your lox tank).
That's what their McGreggor test site in Texas is for. It's a long, boring, two hour drive from anywhere or anything.
Anti-fragility means more than robustness, it means that the system is getting stronger with each adverse event, and it is not a realistic goal that ingestion of a nut should make the engine better/stronger etc.
It is all "just" about robustness, resilience.
But Anti-Fragility as you define it definitely should be a goal for their overall organization and system of building and operating the fleet.
Each issue or incident should feedback into the engineering of new units and updating of existing units so that they are improved, stronger, less likely to create issues, more able to handle issues, etc. on each iteration. This actually seems to be the case at SpaceX, including this incident.
Or, am I missing something?
Thinking about that, an important feature of that antifragility is not to risk human lives during the process if that risk can be avoided. Even though space exploration is inherently risky, any actual fatality is a huge setback.
Edit: I will say that what actually is a test commonly done (also in industry in general) is doing a “roll test”. They put the stages on these massive rollers and slowly turn them… listening for any “clinks”. Pretty funny seeing it done.
> Part of the Merlin’s qualification testing involves feeding a stainless steel nut into the fuel and oxidizer lines while the engine is running—a test that would destroy most engines but leaves the Merlin running basically unhindered.
They're not running it through the engine, they're verifying that the filter is installed and functional so it doesn't get to the engine.
Maybe it's more of a type certification/ crash test thing. Test one to failure and assume it works