The IXPE Mission Scenario Test #3 (MST-3) was completed successfully on 8/26/21. This test included Mission Operations Center (MOC) at Colorado University/LASP, the IXPE Observatory, Science Operations Center (SOC) at MSFC, and Italian Instrument team all supporting this important series of tests. MST-3 verified operational procedures and performed Instrument Commissioning steps successfully. In addition, the MOC simulated download of contact telemetry files at 32kbps and 2Mbps. All test objectives were met ahead of schedule and no new Test Anomaly Reports (TARs) were recorded. The CU/LASP operations team produced the operation procedures and then successfully executed the Instrument commissioning plan from the MOC!
The IXPE Project personnel from the MSFC Astrophysics Branch/ST12 (Brian Ramsey, Stephen Bongiorno) traveled to Ball Aerospace and Technologies and conducted the final inspection of the three integrated Mirror Module Assemblies (MMAs) and their thermal shields (two per MMA). The inspections conducted 8/12-14/21, resulted in replacement of one thermal shield and confirmed the MMAs are ready for flight. The Astrophysics Branch prepared for the inspection by utilizing the EV74 (Allen) developed IXPE Observatory Mockup. The mockup was instrumental for defining access for thermal shield removal/installation and viewing angles for MMA inspection. ST12 conducted a detailed visual and photographic inspection of the MMA mirror shell alignment, doubler bond joints, shell bond joints, and rear comb condition. No discrepancies were identified. Detailed inspection of the thermal shields identified one previous discrepancy had not worsened, and one new discrepancy, a small tear in the thermal shield film. The shield with the film tear was replaced with a spare shield. All others were re-installed for flight. Brian Ramsey supported the installation of thermal shield center disk Multi-Layer Insulation (MLI) on the replacement shield and confirmed the final installation for flight.
Martin Weisskopf (ST12), IXPE PI, reports that the science portion of IXPE is well on its way to launch readiness, with most hurdles (e.g., ground calibration) accomplished. HQ has been provided the final updates to the Level-1 requirements. The outstanding efforts from the over 100 IXPE scientists —including target selection; theoretical modeling; development of advanced data analysis techniques (both for the standard moments analysis with weighting and for optimally weighted neural-network analysis); ground calibrations of the flight detector units (DUs), of the flight mirror module assemblies (MMAs), and of the spare telescope (DU + MMA); and progress in preparing the Science Operations Center (SOC) is applauded.
