Observation of particles of solar, interplanetary, interstellar, and galactic origins, spanning the energy range from solar wind ions to galactic cosmic ray nuclei.
 

The study of these energetic particles will contribute to our understanding of the formation and evolution of the solar system as well as the astrophysical processes involved.
 

Powered by solar cells, the spacecraft has a design life of at least five years, and it returns data in daily tape recorder dumps; even today, ACE continues to provide space weather reports and warnings of geomagnetic storms.