CAPE CANAVERAL, Fla.—Attention asteroid aficionados: NASA is set to launch a series of spacecraft to visit and even bash some of the solar system’s most enticing space rocks. The robotic trailblazer named Lucy is up first, blasting off this weekend on a 12-year cruise to swarms of asteroids out near Jupiter—unexplored time capsules from the dawn of the solar system. And yes, there will be diamonds in the sky with Lucy, on one of its science instruments, as well as lyrics from other Beatles’ songs. NASA is targeting the predawn hours of Saturday for liftoff. Barely a month later, an impactor spacecraft named Dart will give chase to a double-asteroid closer to home. The mission will end with Dart ramming the main asteroid’s moonlet to change its orbit, a test that could one day save Earth from an incoming rock. Next summer, a spacecraft will launch to a rare metal …