The best i could think of was "windfall" meaning an event that brings a sudden stroke of luck, equally unexpectedly.
J.R.R. Tolkien made up a word to fit that exact definition which he called "eucatastrophy", adding the latin prefix "eu", meaning good. He used it to define the epic, sudden and happy resolutions of hopeless situations in his stories.
a huge catastrophe
No, catastrophe is a noun.
The Apocalypse (revelation) is the last book in the Bible, and therefore its antonym is Genesis, which is the first book. The word apocalypse means "un-hidden, hence revealed," for which the antonym is mystery, which means " kept secret, not spoken." It depends on which type of apocalypse you are talking about, but if it is the one meaning "catastrophe," then some antonyms for it would be "benefit, blessing, favor, miracle, wonder, success."
The earthquake in China was a major catastrophe.
'Catastrophe' has four syllables.
Catastrophe Ballet was created in 1984.
Traces of Catastrophe was created in 1998.
The Catastrophe of Success was created in 1947.
U-Catastrophe was created in 2007.
Family Catastrophe was created in 1972.
Causing a Catastrophe was created in 2002.
Hijacking Catastrophe was created in 2004.