Originally Posted by RichardC10
So they removed a single-point failure (unlock failure) by moving it to earlier in the flight, but consequently added a new single-point failure of incorrect unlock actuation (at high speed).
It's interesting the feathering system is to provide "care-free reentry". The design goal was to eliminate "risky" active control and requirement for precise AOA during reentry. Rutan conceptually modeled it on the self-stabilizing badminton shuttlecock.
However -- to my knowledge there has been only one reentry fatality related to flight control -- the Mike Adams X-15 flight on 15 Nov 1967:
https://en.wikipedia.org/wiki/X-15_Flight_3-65-97
Although not widely reported at the time, Scott Carpenter's Mercury mission was a near fatality due to reentry control problems:
Mercury Astronaut Scott Carpenter and the Controversy Surrounding Aurora 7 | Popular Science
However those are the only two. In retrospect it seems odd to make "care free" reentry such a fundamental design priority. Reentry is critical but it's just one phase. Flight control is always critical, whether inside or outside the atmosphere, or at reentry interface. SS1/SS2 have cold-jet RCS to provide active attitude control above the atmosphere, so it's not like the feather system eliminates that.
Furthermore VG's ultimate goal is using follow-on vehicles for point-to-point suborbital transport. However that requires nearly the same engines, velocity and thermal protection as orbital flight. It is unclear if the feathering system would work at orbital reentry speeds or whether VG has even done preliminary testing on this. If the experience gained on SS2 can't be used on that, it's a technological dead end.
There is an obvious attraction to passively safe systems. Engineers learn early that "complexity breeds failure". But as we see from this incident, even passively safe systems introduce their own complexity and tradeoffs.