IXPE Mission System and Development Status

IXPE, an international collaboration, will conduct x-ray imaging polarimetry for multiple categories of cosmic x-ray sources such as neutron stars, stellar-mass black holes, supernova remnants and active galactic nuclei. The Observatory uses a single science operational mode capturing the x-ray data from the targets. This paper summarizes the IXPE Mission System: Observatory, Launch Segment and Ground System. The IXPE Observatory consists of spacecraft and payload modules built up in parallel to form the Observatory during system integration and test. The payload includes three x-ray telescopes each consisting of a polarization-sensitive, gas pixel x-ray detector, paired with its corresponding grazing incidence mirror module assembly (MMA), x-ray optics set. A deployable boom provides the correct separation (focal length) between the detector units (DU) and MMAs. These payload elements are supported by the IXPE spacecraft which is derived from the BCP-small spacecraft architecture. IXPE is launched to a circular LEO orbit at an altitude of 600 km and an inclination of -0.2 degrees by a Falcon 9 launch vehicle. The ground system consists of three major elements: the ground stations for data receipt and command upload to the Observatory; the Mission Operations Center (MOC) at University of Colorado Laboratory for Atmospheric and Space Physics (CU/LASP); and Science Operations Center (SOC) at NASA Marshall Space Flight Center (MSFC). This paper summarizes the IXPE mission science objectives, updates the Observatory implementation concept including the payload and spacecraft elements, covers the launch segment, ground system and summarizes the mission status since last year's conference including COVID impacts.