The global magnetic field dominates many of the physical processes of geospace. It is critically important to predict and quantitatively model that field, given information on the state of the incoming solar wind. The ISTP project is an abundant source of data on the distribution and dynamics of the magnetic field and on that field’s response to the solar wind variations. Together with earlier sets of spacecraft magnetometer data, the new ISTP data will provide an unprecedented pool of experimental information on the magnetic environment of our planet. Combining this wealth of data with the newest mathematical methods for representing the geomagnetic field will significantly advance our knowledge on the structure and dynamics of the Earth’s magnetic environment.