The Short Orbital Flux Integration Program (SOFIP) is a computer code that has been developed to evaluate the space radiation environment encountered by geocentric satellites. It produces for a given input trajectory a composite integral orbit spectrum of either protons or electrons. Additional features include calculation of exposure index, peaks per orbit, percent time in electron trapping zones differential spectrum, and solar proton fluences (using SOLPRO). SOFIP is a structured, modularized code, which can perform all the functions of larger and more complex programs, if the correct modules are used. Care should be taken to use the correct epoch (1965 for solar minimum and 1970 for maximum) for the geomagnetic field in the calculation of magnetic field strength B and L-value. B/Bo and L are needed to determine trapped particle fluxes with the help of the electron (AE) and proton (AP) models. Otherwise, erroneous fluxes may result at low altitudes.
E. G. Stassinopoulos, J. J. Hebert, E. L. Butler, and J. L. Barth, SOFIP: A Short Orbital Flux Integration Program, NSSDC 79-01, Greenbelt, Maryland, 1979.