NASA's Goddard Space Flight Center/Conceptual Image LabPrimary StructureThe six-sided primary structure, also called the spacecraft bus, provides the structural support for the observatory. Partner(s): NASA's Goddard Space Flight CenterAttitude Control System (ACS)The ACS is a three-axis stabilized system that uses precision pointing to rotate the observatory to the right position for science. Partner(s): Honeywell Aerospace | Jena-Optronik GmbH | European Space Agency (ESA)PropulsionThe propulsion system will use hydrazine in its two types of thrusters to maneuver the observatory. Partner(s): European Space Agency (ESA) | ABSL SpaceCommand and Data Handling (C&DH)The C&DH system is responsible for monitoring the health and safety of the observatory. It will also store up to four terabytes of science data in its Science Data Recorder (SDR) for downlink to the ground when a ground station is in view.