The Time, Dependence Of The Power Production Capability Of Navstar Global Positioning System Satellites

Analysis of the performance of NAVSTAR Block I satellite power systems has revealed an unanticipated level of degradation. This paper presents further data on the performance of the power systems on one of the early Block I vehicles. It has been proposed that the origin of this anomalous degradation is photochemical deposition of contaminant films on the surface of the solar array. More detailed modeling of contaminant flow to the solar array supports this hypothesis. A flight test planned for a Block IIA vehicle will more definitively test the efficacy of preventing this degradation mechanism by Sealing vehicle body vents.