CHANTILLY, Va.–(BUSINESS WIRE)– #ArtemisII–Amentum (NYSE: AMTM) delivered advanced end-to-end ground systems engineering for a key Artemis II launch rehearsal at the Kennedy Space Center on December 20. The Countdown Demonstration Test (CDDT) simulated launch day operations for the integrated Orion spacecraft and Space Launch System (SLS). During the Artemis II mission, Orion will carry four astronauts on an approximately 10-day journey around the Moon and back. It will be propelled by the SLS, the most