Getting new science from old topside sounder data with new analysis technique

The Alouette and ISIS topside sounder satellites recorded a great wealth of information about the topside ionosphere during their long period of operations from 1962 to 1990. So much though that only a small percentage was analyzed during the mission life time. A data restoration effort first digitized the analog data and then developed the TOPIST software for automated inversion of the ionograms to electron density profiles [1,2]. We present the data base established with the help of this data restoration project and discuss some of the science results obtained with these data.