A new musical group orbits Barcelona with a proposal that wouldn’t let you down. La Piccola Orchestra Gagarin lives up to its name in every way. It’s small because there are only three players, but it sounds like an original orchestra (with instruments tuned to that point). And “Gagarin” is a nod to history’s first cosmonaut launched into space, with whom they share the same uncertainty when they go up on stage, never rehearsed.