Ulysses (EPAC)

Ulysses was a European space probe which studied the sun and the solar wind. As the first probe ever, it observed the sun’s poles and the solar system from above.

Bild: ESA/Dave Hardy

The observations led, among other things, to the discovery that the solar wind behaves completely different over the sun’s poles than it does in the orbit of the planets.

IRF participated together with German colleagues with the EPAC instrument (Energetic Particle Composition). The instrument consisted of four identical telescopes measuring electrons (several hundred keV) and different ions (MeV) using semiconductor detectors.

Operating period: October 1990 – June 2009.

Orbit: The space probe was in a heliospheric orbit, over the poles of the sun.

Principal Investigator (PI): Dr E. Keppler (Max Planck Institute, Germany)

Contact at IRF: Masatoshi Yamauchi, yamau@irf.se

Created by Annelie Klint Nilsson at

Last modified by Annelie Klint Nilsson at