UNIRAD is a software package developed by BIRA-IASB for ESA to evaluate radiation-belt and solar particle event fluences and doses expected in a spacecraft from a definition of the mission characteristics. The UNIRAD suite of programs provides information about the radiation environment in an arbitrary Earth orbit, predicting satellite exposures to particle fluxes, the resulting radiation dose, and the resulting damage-equivalent fluences for solar cell degradation calculations. Recently, UNIRAD has been extended with two new programs that model the anisotropy of trapped particle flux distributions at low altitudes. Various problems have been identified in the existing NASA radiation belt models AE-8 and AP-8. New models developed in the ESTEC/WMA-sponsored TREND study (Trapped Radiation ENvironment Development) are being added to UNIRAD. These models include: new trapped proton flux maps based on data from AZUR (proton telescopes), SAMPEX (PET) and UARS (PEM), and trapped electron models developed with data from CRRES (MEA) and ISEE (KED). WWW-based access to UNIRAD is also being developed as part of the Space ENvironment Information System (SPENVIS).