A few things come to mind, but I'm pretty sure it's not what you're looking for.
The opening theme song of SilverHawks comes to mind for me because I remember Bluegrass' electric guitar.
And for rock bands in outer space, of course, there's also Josie and the Pussycats in Outer Space. (Which is actually getting released to DVD soon in a complete series set, by the way.)
There's also The Partridge Family 2200 A.D.
Maybe it's possible you're thinking of an episode of one of those shows?
Or were these bear-like creatures the main characters?
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"You can do anything you want to do if you put your mind to it."- MacGyver
"Thunder...Thunder....Thunder...ThunderCats...HOOOO!!!!!!"- Lion-O