I'm sure you know this, but you never say so which makes it a bit frustrating: what you refer to as "real science fiction" is commonly known as "hard science fiction" (http://en.wikipedia.org/wiki/Hard_science_fiction).
The "opposite", i.e. what you refer to as re-skinned fantasy, often falls into the "space opera" subgenre (http://en.wikipedia.org/wiki/Space_opera). For instance, "Star Wars" is often referred to as being space opera.
The "opposite", i.e. what you refer to as re-skinned fantasy, often falls into the "space opera" subgenre (http://en.wikipedia.org/wiki/Space_opera). For instance, "Star Wars" is often referred to as being space opera.