GR translation: he’s already stopped believing in the rocket he saw

[Mike Jing]

P8.29-35   Pirate goes to the phone and rings up Stanmore after all.
Has to go through the usual long, long routine, but knows he’s already
stopped believing in the rocket he saw. God has plucked it for him,
out of its airless sky, like a steel banana. “Prentice here, did you
have anything like a pip from Holland a moment ago. Aha. Aha. Yes, we
saw it.” This could ruin a man’s taste for sunrises. He rings off.
“They lost it over the coast. They’re calling it premature
Brennschluss.”

What does it mean that he has "stopped believing in the rocket he saw"?