Parameterization of galactic cosmic-ray fluxes during opposite polarity solar cycles for future space missions

Galactic cosmic-ray (GCR) long-term variations and short-term fluctuations affect observations on board long-lived space missions. We have developed a parameterization of proton and helium 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 p, p, e⁺ and e^?, some contradictory clues have been found both at solar minimum and maximum during negative polarity periods (A<0). We illustrate the implications of the results of this work for and with missions like LISA (Laser Interferometer Space Antenna).