IGF::OT::IGF OATK SUPPORT FOR ARCUS PHASE A ARCUS IS AN X-RAY GRATING SPECTROSCOPY EXPLORER MISSION. THE ARCUS MISSION IS MANAGED BY NASA AMES RESEARCH CENTER (ARC), WITH THE PRINCIPAL INVESTIGATOR AT THE SMITHSONIAN ASTROPHYSICAL OBSERVATORY (SAO). ARCUS CONSISTS OF AN X-RAY TELESCOPE, PROVIDED BY SAO, INTEGRATED WITH A SPACECRAFT, PROVIDED BY ORBITAL-ATK (OATK). THE INTEGRATION AND ENVIRONMENTAL TESTING OF THE COMBINED SPACECRAFT AND TELESCOPE (I.E. OBSERVATORY) IS THE RESPONSIBILITY OF OATK. THE ARCUS MISSION INCLUDES THE DESIGN, PRODUCTION, TEST, INTEGRATION, LAUNCH, COMMISSIONING AND SCIENCE OPERATIONS OF THE OBSERVATORY, AS DESCRIBED IN THE SAO PROPOSAL TITLED: ARCUS- EXPLORING THE FORMATION AND EVOLUTION OF CLUSTERS, GALAXIES, AND STARS.