I read about suicide before I wrote this, I put those notes in the bottom. So let's assume these are the most capable people humanity has chosen, free from what their society considers mental illnesses. The story made it seem like they made their decision after this cold calculated kind of conversation in which everyone was still quite friendly towards each other. Whereas in reality people commit suicide mostly because of social reasons, if you don't take into account psychiatric conditions. Or people commit suicide in situations where they don't see any other option that would free them from the immediate mental pain they are feeling at that moment, which is usually basically the same as being loathed by most people in your tribe or otherwise strongly pressured to do it. Using present-day abstract rationalist terms, they would have had seen no other way that some of their terminal values could be fulfilled, otherwise they would have chosen any other option. But that's of course if the mental experience of suicide is similar to what it's in our current world, where it has been made intentionally quite viscerally terrifying by laws and norms. People trying it have to defy their basic instincts like falling from a tall place, doing harm to their own bodies or otherwise expect an uncertain and a painful fate. It's not as viscerally terrifying in the story because they can blow up their star from so faraway, but the procedure seems quite complex including several steps although it's not described very presicely. So here's my opinion: someone in that process still has to think that they are sacrificing their lives, and so that it could happen the way it happened in the story, they would have had to manipulate their social dynamics much more that was seen here. And almost everyone involved in that manipulation would have had to think it was the best course of action, otherwise they could have easily sabotaged it. And the end result of that manipulation would have to be that the final person doing the last bit of the procedure sees no other escape but to destroy the star. Anyway, I could personally easily see some alternative options in almost any part of that procedure.

Umm. And here's the background research I did. I checked from /r/suicidewatch and they have a guide that says that the main three factors of suicide are the feeling of being a burden, "profound loneliness and isolation" and desensitization to death and violence. A study about a meta-analysis of 3275 suicides concluded that about 87% of suicides have a history of psychiatric disorders. "Suicide risk management: a manual for health professionals" said that factors that protect from suicide are things like a positive self-esteem and self-efficacy, effective interpersonal skills, effective problem-solving skills, adaptive coping, good frustration and distress tolerance, strong sense of purpose or meaning etc. Risk factors for suicide are being divorced, unemploeyd, having conflictual interpersonal relationships, having low achievement, social isolation, poor interpersonal relationships, domestic violence, sexual abuse and having a good plan and access to suicide methods, and several other things. So I think that manual confirms what the guide in /r/suicidewatch said. Most of the risk factors in that manual are related to psychiatric disorders. But most of the others are social factors, like being low status or really lonely and despised, and otherwise being perceived as being a bad member of your tribe. And having a plan and a method. I don't know how people have been motivated to jump on grenades, become kamikaze fighters or suicide bombers and I don't exactly how I could get that information. I don't really want to find out, actually.