A method is proposed for obtaining the in-track wind component by exploiting the different ways in which two satellite-borne instruments interact with the airstream. It makes possible the completion of the three-dimensional wind vector from measurements which yield at most two components. This is especially important during geomagnetic storms when winds can cause serious errors in density measurements made by a single instrument. The method can be used to retrieve valuable information from existing data bases which contain measurements by three-axis accelerometers and chambered instruments such as closed-source mass spectrometers or pressure gages. ¿ American Geophysical Union 1992