The solar probe mission: A search for the origin of the solar wind and an unprecedented view of the solar surface

Despite significant advances in space exploration, in particular with the recent observations from Ulysses and SOHO, the basic questions of solar wind origin and solar surface topology over the poles can only be resolved with a near-Sun Solar Probe mission. Flying along a trajectory perpendicular to the Earth-Sun line during its perihelion passage, Solar Probe will use in-situ and imaging measurements to provide the first three-dimensional view of the corona. direct high spatial and temporal resolution observations of solar polar regions and magnetic fields, and local sampling of the near Sun environment down to 3 R-s from the solar surface. The trajectory will enable the first helioseismic measurements over the poles. The high sampling rate will enable the resolution of fine magnetic structures at all latitudes starting from the pole, through imaging and plasma and field in situ measurements. The NASA Solar Probe is an approved mission to be launched in 2007 with a first perihelion pass at solar maximum in 2010 and a second perihelion pass in 2014 at solar minimum. This review summarizes the latest observations and measurements of the solar wind. It describes the baseline NASA Solar Probe mission, its prime objectives, and its science core payload.