STENNIS SPACE CENTER, Miss., Oct. 11, 2017 (GLOBE NEWSWIRE) — Aerojet Rocketdyne, a subsidiary of Aerojet Rocketdyne Holdings, Inc. (NYSE:AJRD), announces the four RS-25 engines slated to fly on Exploration Mission-1 (EM-1), the maiden flight of NASA’s Space Launch System (SLS), are ready for integration with the rocket’s core stage.