Scotland has no need for a manned space program -- they've already got Mogwai. The Glasgow postrock quintet's earliest recordings embodied the violent beauty of a rocket launch with their cathartic instrumental dynamics, tensely building, then exploding. Rock Action, from 2001, saw the band's guitar-fueled boosters become less essential, the established chaos tempered by subtle, nearly orchestral instrumentation; tighter, more melodic arrangements; and (gasp!) vocals. Now, the band's fourth studio album, Happy Songs for Happy People, offers a blissful expansiveness that suggests the good ship Mogwai is gliding in glorious orbit. That's certainly the case on "Boring Machines Disturbs Sleep," which drifts on the kind of ethereal, guitar-and-keyboard drones and anesthetized murmurs Spiritualized's Jason Pierce would kill for. Same with "Kids Will Be Skeletons," a puffy cloud of a number that swells majestically but swirls in on itself rather than burst in one of frontman Stuart Braithwaite's trademark six-string detonations. "Golden Porsche" rests on a bed of heartrending strings and meandering percussion, and "I Know You Are but What Am I?" sets a simple piano melody and chimes against electronic twinkles and thwonks. Throughout, Braithwaite seems mostly content to relinquish the controls to his bandmates, particularly multi-instrumentalist Barry Burns, whose symphonic inclinations have had a profound effect on the outfit. Still, the group hasn't entirely erased the sonic power only a big guitar riff can provide, as evidenced by the lofty, eight-minute "Ratts of the Capital" (which out-epics Sigur Ros) and the sublime closer, "Stop Coming to My House." Where Mogwai goes next is anyone's guess. For now, floating in space is a heavenly thing.