Ionospheric Monitoring and Specification Utilizing Data from the Defense Meteorological Satellite Program

Abstract : Activities this year have been largely devoted to the adaptation of the ground software to accommodate the very low levels of solar activity, to continued examination of the robustness of the procedures to recover for single event upsets, and to the analysis and post-mortem associated with a malfunction of the ion drift meter on the F17 spacecraft. The low levels of solar activity have led to a significantly contracted ionosphere that resides predominantly below the satellite altitude. Such a condition leads to the dominance of H+ in regions where O+ might be expected to be the major ion. This condition has required the re-programming of some of the logic associated with ground software processing for the retarding potential analyzer (RPA) and the ion drift meter. Extensive analysis of the F17 drift meter data, and the physical configuration of the sensor, has been undertaken following a malfunction that rendered the instrument inoperable. During this reporting period, various failure modes were investigated and compared with the temporal history of the instrument performance. The most likely failure mode has been identified and a detailed analysis has been provided to AFRL.