Explorer 13 (S55A)

Explorer 13 was injected into a geocentric orbit of moderate eccentricity using a Scout launch vehicle. The objectives of the flight were to test vehicle performance and guidance and to investigate the nature and effects of micrometeoroids on the spacecraft systems. The scientific instrumentation consisted of cadium sulfide-cell, wire-grid, piezoelectric, pressurized-cell, and foil-type micrometeoroid detectors. The spacecraft was a 1.93-m-long, 61-cm-diameter cylinder. The orbit was lower than planned, and the spacecraft reentered the atmosphere on August 28, 1961, after only slightly more than 2 days in orbit. No penetrations were recorded by this satellite during experiment operations. This aided in determination of useful flux limits for subsequent experiment design.