The PHOIBOS Mission : Probing Heliospheric Origins with an Inner Boundary Observing Spacecraft

Fifty years after the Sputnik launch and the beginning of the Space Physics era the time has come for the in-situ exploration of one of the last frontiers in the solar system - the solar corona and inner heliosphere. We present the PHOIBOS (Probing Heliospheric Origins with an Inner Boundary Observing Spacecraft) concept, which has been submitted to the ESA Cosmic Vision program. PHOIBOS is a mission of exploration and discovery designed to make comprehensive measurements in the never-observed region of the heliosphere from 0.3 AU to as close as 3 solar radii from the Sun's surface. The primary scientific goal of PHOIBOS will be to determine the structure and dynamics of plasmas and magnetic fields in the outer solar atmosphere which give rise to the corona, the solar wind and the heliosphere. The two main characteristics of the PHOIBOS mission are : (i) use of retractable solar panels that avoid the use of RTGs (Radioisotope Thermoelectric Generators) and (ii) insertion in the final operational orbit (4 Rs to 3.7 AU with an inclination up to about 60 deg.) by using electric propulsion and Earth and Venus flybys. With these characteristics, the PHOIBOS concepts fit very well within the new NASA "Solar Probe Lite" study.