Long-term variations and short-term fluctuations of cosmic rays affect observations on board long-lived space missions. We have developed a parameterization of Galactic Cosmic-Ray (GCR) fluxes for various levels of solar modulation during opposite polarity periods on the basis of experimental data. In spite of a general agreement among different results on protons, antiprotons, electrons and positrons, some contradictory clues have been found both at solar minimum and maximum during negative polarity periods. Future, low error data will help to clarify this scenario. We illustrate the implications of the results of this work for the LISA mission.

Proceedings of the 30th International Cosmic Ray Conference; Rogelio Caballero, Juan Carlos D'Olivo, Gustavo Medina-Tanco, Lukas Nellen, Federico A. Sánchez, José F. Valdés-Galicia (eds.); Universidad Nacional Autónoma de México, Mexico City, Mexico, 2008; Vol. 1 (SH), pages 485-488