> And the problems haven’t been completely ironed out: the first launch attempt of Starship’s flight test 13 was aborted automatically by the vehicle’s flight software at T-0 (right before liftoff) this past July when several Raptor 3 engines failed to start

And several engines failed to relight on the booster for flight 13. I believe ice in feed lines is viewed as the most likely cause.

I'm pretty sure that the heat exchanger is going to end up being one part they have to put back in. Pushing CO2 and H2O (both ices at prop temp) into the tanks just seems so ill-advised to me. The amounts of contamination are small, but there are just so many different ways that can go wrong.