Prof. Jörg Hörandel (Radboud University Nijmegen)
One of the key observables to understand the origin and the sources of Galactic cosmic rays is their elemental composition. The abundance of elements is measured directly with detectors above the atmosphere on balloons and satellites. At energies exceeding 10^14 eV information on the composition is derived from the observation of extensive air showers. Results of recent measurements will be reviewed and the implications on our current understanding of the origin of Galactic cosmic rays will be discussed.