This is an unplanned (written on request) addition to my post, 5 Essentials for Space Opera (http://www.holyworlds.org/blog/?p=561). So here I go, exploring the last frontier in space opera (for me, anyways).

Let me back up a bit to give definitions of space opera and hard SF. Hard SF isn't very dramatic or melodramatic in some cases. It's serious, and focuses more on the science than the characters or story. The laws of physics are absolute and can not be broken. Hard SF is quite popular in books and often is what give SF the adjective "atheistic." Many are. I haven't read any that aren't, but there are probably some out there.

Space opera, on the other hand, is the opposite. Space opera focuses on the grand scales of conflict, adventure, and personal conflict, or drama. Rules of physics are there to be broken, often literally. Space opera often has very little regard for current science.

I italicized the personal conflict or drama (And shall continue to do so) because it's what truly what drives space opera and puts a head and shoulders above the other genres. (Military SF, Golden Age, and steam/diesel-punk come close.) It's the characters.
Stories about aliens, rebellions, starships, and scruffy rogues aren't exactly relatable. Stories about inter-familial conflicts are. Aliens, rebellions, starships, and scruffy rouges just make them more interesting than your average soap opera or random neighbor down the street. We know how how personal problems feel. The nervousness, the indecision, the fear. That sickening, roiling feeling in the stomach. You know what I'm talking about.

I'm not sure how much more I can say, so I'll provide examples.

Star Wars: The Original Trilogy ~ Han, Leia, Chewbacca, Luke, R2-D2, and C-3PO are the driving charters in these three movies. Luke is the main character whose change and growth along the lines of the Hero's Journey is the main subject for the story. Han and Leia create the romantic sub-plot. Their fights, reconciliations, and acceptance draw viewers along for the movies. R2 and C-3PO add comic relief and aid in repairing damaged X-Wings. They add humor to what could otherwise be a grim affair.

Star Wars: The Prequel Trilogy ~ The driving characters are Obi-Wan Kenobi, Chancellor Palpatine, Padme Amidala, and Anakin Skywalker. Anakin and Padme are the two main driving characters; their forbidden romance brings about Anakin's fall to the Dark Side. Palpatine facilitates it and drives the entire Clone Wars with his schemes. Obi-Wan tries to keep Anakin on the good side, as well as a friend. Their interactions make what could be a standard pre-war conspiracy story in a galaxy far, far, away into a tense and emotionally rich story.

Star Trek: The Original Series ~ (Are you seeing a pattern?) The driving characters are, of course, Captain James Tiberius Kirk, Spock, Scotty, and Doc McCoy. Spock and McCoy are the most relatable since they're great friends and yet constantly argue with each other. Kirk adds some philosophy, and Scotty adds common sense.

Without unique characters who don't have conflicting personalities, space opera can quickly fall into unbearable melodrama.

This is an unplanned for addition to my post, 5 Essentials for Space Opera, written on request.