From analysis of the background measured by the EUV spectrometer aboard the German-U.S. satellites Aeros A and B the spatial distribution of unidentified particle fluxes received east of the South American coast could be established. From January 1973 through August 1974, in the height range 700--800 km the center of the configuration (near 30¿S, 40¿W) drifted by about 3¿ in latitude. During the same time the orientation of the oval (contours of equal particle flux) rotated anticlockwise by about 30¿.