Most of the year, the Pacific Northwest Ballet Orchestra is heard but not seen. Musicians play down in the orchestra pit while glamorous dancers use the stage above. But for tonight’s Celebrate Seattle program, PNB’s contribution to the World’s Fair 50th-anniversary bash, the musicians will emerge for a program focused on outer space. PNB music director Emil de Cou was previously the music director for NASA (!), and he’ll be leading the PNBO through “sci-fi favorites and celestially-themed classics”—meaning Silvestre’s Back to the Future, Holst’s Saturn and Jupiter movements from The Planets, plus bits of Beethoven’s Ninth and Stravinsky’s Firebird. In addition, PNB dancers will perform parts of Apollo and the Circus Polka. And there are even visiting astro-celebrities! These include astronaut Cady Coleman, Nichelle Nichols (Uhura on the old Star Trek), and NASA’s Bobak Ferdowsi (the guy with the Mohawk we saw during the recent Curiosity rover landing on Mars). Videos will also document the space-age fervor that informed our Century 21-themed World’s Fair. SANDRA KURTZ

Sun., Sept. 16, 6 p.m., 2012