While the fate of a multigenerational interstellar population cannot be predicted with anything approaching certainty, the many dangers presented by the instantaneously lethal environment of space, plus the interpersonal pressures and conflicts that might result in social breakdown, make it doubtful that a successful transit to another star system with all the successive onboard generations remaining safe, healthy, and happy across time, is a realistic possibility. It is far more likely that the crew would suffer one or another kind of irremediable catastrophe en route than that everyone aboard would survive, and that the final, arriving generation would get there intact. But if that is true, then the question arises whether it would be morally justifiable to launch such an expedition to begin with, given its immense costs, high probability of failure, and lack of any benefit accruing to the sponsors back on Earth who had paid for it all.