Haha, thanks OP, Im often told Im a bit of a Space Cadet myself ^_^
Agree with most ppl up here, that used in profiles, its similar to laid-back, chill, masculine, and other non-descriptors that may turn out to be queens with attitude
However, the way I hear most ppl use it (not gay ppl, bt in general) does not have anything to do with attitude.. it simply means "practical, sober, sensible, realistic and pragmatic"http://dictionary.reference.com/browse/down-to-earth
In which case, I understand why you prefer a space cadet... they can be crative and fanciful and spontaneous more so than a down-to-earth person 3. Down to earth
Someone basic, attached to day by day issues, ruled by the common sense. Not a dreamer or idealistic, not into the creative field or the Arts. Usually connoted with one either without studies or a especial knowledge or intellectual skill. In some context you may use it to express ones singular act, but not the person them self.
"I'm quite down to earth: eating, drinking, fucking and sleeping are my life".
"She's too down to earth you may need to do a drawing, so she may understand."
"Lincoln used to plant his own garden."
"This book is really down to earth; any child can read it."