Orbiting Geophysical Observatory 5 (OGO 5) magnetospheric ion-composition data (H + , He + and O + ) have been retrieved from old magnetic tapes archived at the National Space Science Data Center (NSSDC). The highly compressed binary format was converted into a user-friendly ASCII format and these data have been made available online. We have inspected the reliability and consistency of this data set. Comparisons with the IRI-2012 climatological model and the FLIP theoretical model revealed a shift of absolute and relative ion densities with time. Here we have developed a correction procedure for the individual H + , He + and O + ion density measurements. We investigated plasmapause locations based on the density gradients in H + , and He + . The correlation coefficient between these locations was determined to be ~0.886 with the typical difference in L about 0.1. The electron density at the He + plasmapause location based on the corrected data for all cases was >100cm −3 .