Sorry for the possibly dumb question, but I don't know much about rocket technology.
As I gather, the main problem in the recently failed Elon Musk's Starship launch was that the Starship "capsule" couldn't separate from the booster and that forced the control center to activate the self-destruct sequence.
Now, what perplexes me is that I would assume (in my technical ignorance of the subject) that a basic function such as firing the pyrotechnics to separate two stages should be one of the most reliable part of the design, especially at this stage of Starship development and after decades of space missions in which multistage/multi-part space vehicles were employed.
In other words, with so many things that could go wrong, is it really so likely that the failure was that of separating two stages? When I heard that, my engineering gut feeling was "it smells of sloppy design or sloppy implementation". I would have assumed that something bad could indeed happen, but just immediately after the separation, not that the separation wasn't going to happen.
Is it really that the reason for the mission failure, or was a journalistic simplification? Did the Starship team disclosed the actual causes of the failure (to their current knowledge)? Did I miss something? Is my "gut feeling" completely wrong due to my ignorance in the field and "separation failure" is indeed a reasonably likely failure in a new rocket design?
Moreover, can independent experts say something on the actual reliability and sensibleness of the design from this failure and the data Musk's company has released until now about the project?
Some of the comments seemed to imply that my assumption of the failure being caused by a failed separation was not warranted. However I have heard and read Italian news reports that mentioned that as apparently one of the causes.
Here is an excerpt from "Il Sole 24ore", maybe the most authoritative economics newspaper of Italy (emphasis mine):
Nel primo test in volo, la nave Starship della SpaceX non si è separata dal lanciatore e non tutti i motori del razzo Super Heavy si sono si sono accesi correttamente, ma secondo l’azienda di Elon Musk il test è stato comunque un successo. «Il successo deriva da ciò che apprendiamo e il test di oggi - scrive la SpaceX in un tweet - ci aiuterà a migliorare l’affidabilità di Starship». «Congratulazioni alla squadra di SpaceX per l’eccitante lancio di prova di Starship! Abbiamo imparato molto per il prossimo lancio di prova, che avverrà tra qualche mese», è stato il commento su Twitter di Elon Musk, amministratore delegato di SpaceX, dopo il lancio della Starship.
La Starship è stata fatta esplodere in volo per motivi di sicurezza, perché la mancata separazione dal primo stadio del lanciatore la rendeva altamente instabile. Subito dopo il lancio, la navetta ha cominciato a ruotare in modo disordinato e i tecnici della SpaceX hanno deciso di distruggere la navetta perché il suo rientro a Terra sarebbe avvenuto in modo incontrollato.
This is my translation:
In its first flight test, the SpaceX ship Starship didn't separate from the launcher and not all engines of the SuperHeavy rocket ignited correctly, but according to Elon Musk's company [...]
Starship has been made explode during flight for safety reasons, because the failed separation from the first stage of the launcher made it highly unstable. Right after the launch, the ship has begun spinning in a chaotic way and SpaceX technicians decided to destroy the ship because its reenter on Earth would otherwise have happened in an uncontrolled manner.
That's why I also mentioned "journalistic simplification" as a possible source of my doubts.