A rocket equipped with solid state detectors sensitive to ions/protons and ENA with energies above 20 keV was launched into the poleward leap phase of the auroral substorm. The rocket reached an altitude of 454 km, that is into the region of intense charge exchange for precipitating ions. At low altitudes the pitch angle distribution of the precipitating particles was observed symmetric with respect to the magnetic field line. At higher altitudes this changed, the particle flux did not exhibit symmetry around the magnetic field as would be expected for a charged particle beam. This asymmetry and the fact that it only occurs at high altitudes is interpreted to indicate the detection of ENA, most likely hydrogen in our case. The ENA arrive from a specific azimuthal direction. The observations are consistent with calculations of the atmospheric spreading of the precipitating protons due to charge exchange. The importance of charge transfer collisions in the ion-outflow problem is considered. ¿ American Geophysical Union 1996