Space-X Starship test this week

[klugesmith]

Space-X plans to test-fly their "Big Falcon Rocket" for the second time this Friday, after receiving the necessary government permits.

Here are some comments about one of the announced design changes since the April 2023 test:
improvement to the "flight termination system" required for range safety.
A typical report of the April event says: "An automated self-destruct command did not immediately destroy Starship. Instead, 40 seconds passed before the rocket finally exploded."

Personally I believe the ground-commanded destruct sequence failed completely.   The energetic materials were not placed to "blow rocket up" or, even less correctly, "detonate rocket".  They were placed to efficiently but reliably terminate thrust, and cut rocket into a few pieces that would slow down quickly and fall within the permitted impact area.  How could a firing event happen after 40 second delay?

I bet the rocket broke up and consequently exploded from structural loads, long after loss of control. (We were later told that an onboard fire on the Booster had broken connections to flight control computer.)    Speed, acceleration, and sideways and bending forces continued to increase as fuel mass decreased.  Posted videos show a sequence of two sudden outbursts of cloudy stuff.

Will now speculate that regulators gave Space-X a lot of grief, after the April flight, about the range safety failure.
Good thing the rocket didn't come down in one piece on Boca Chica town.
Maybe they turned up the design review by outsiders.  How about putting a button in the hands of a team that has done range safety at Cape Canaveral, Vandenberg, Wallops Island, etc for decades?  Not sharing any communication link or computer that's used for regular flight activity?

[rikkitikkitavi]

How would one "blow up " a rocket weighing a couple of thousand tons (metric) ?

Obviously mixing fuel and oxidiser would take care of that but it is not designed for that. But yes, traveling at Mach X (1-5 ) in the lower part of the atmoshere I would say that drag and non-aerodynamic shape (ie as you describe it cut in pieces) releases the fuel dispersing it rather quickly and probably the deflagration is limitied only by oxygen concentration.

Simply a vareity of a very large FAE but not detonating. Hydrogen would probably detonate upon igniton but either velocity is to slow at lower altitudes where O2 conc is higher or in such cases as the tragic Challenger in 1986 the altitude was so high that despite the hydrogen burning it is not a fast reaction. Some was probably not even burned.


But as you put it, the onboard fire or something that caused com failure eventually lead to the rocket disintegrating.

What is your opinion on this second flight, now a month later and we know how it went?