Generally speaking, refers to an
epic adventure in space that focuses less on the technical details and more on good vs. evil and action. The mechanics of how things work ('hyperspace', 'the force') tend to be glossed over, as opposed to traditional "hard sci-fi", like
Poul Anderson's "Tau Zero", where realism is emphasized, generally leading to stories smaller in scope.
Not an absolute term - Star Wars is more space opera than Star Trek, which itself is more space operaish than
Deep Impact