The Solar Polar Observing Constellation (SPOC) mission: combining polar exploration with operational space weather monitoring

The Sun’s polar regions remain one of its last unobserved frontiers. Observations of the magnetic field, convective flows, and coronal outflow conditions in the solar polar regions are the keys to accurately modeling and forecasting the solar cycle, solar wind conditions, and CME arrival times at Earth. This talk describes the Solar Polar Observing Constellation (SPOC), a mission that will for the first time enable continuous high-resolution imaging of magnetic field dynamics, high-latitude helioseismology, and coronal mass ejection tracking from a near-circular polar heliocentric orbit. SPOC will consist of two identical spacecraft, each equipped with a Compact Magnetic Imager (CMI, derived from the Solar Dynamics Observatory (SDO) Helioseismic and Magnetic Imager), the Naval Research Laboratory (NRL) Compact Coronagraph (CCOR), and in-situ solar wind and energetic particle instruments. Falcon Heavy launch vehicles will place the SPOC spacecraft into a Jupiter gravitational assist (JGA) orbit, achieving an 88-degree ecliptic inclination orbit, with the spacecraft passing over the solar poles within 4 years after launch. Ion engines will subsequently reduce the eccentricity of the orbits to below 0.05 at approximately 0.9 AU within 6 years after launch. Orbital phasing will place the spacecraft over alternate poles to enable continuous monitoring of the polar regions with operational-level redundancy of systems. The inclusion of CCOR will enable visualization and tracking of coronal mass ejections from above (or below) the ecliptic for the first time, greatly enhancing our ability to forecast CME arrival times at Earth or Mars. SPOC combines polar region trail-blazing, long-term polar helioseismology and magnetic imaging, and operational space weather monitoring in a single mission. Along with planned missions to the L1 and L5 Lagrangian points in the ecliptic, SPOC will enable an approach to the long-standing goal of continuous full-sphere measurements of the solar magnetic field, solar wind and CME outflow, and energetic particle flux – a goal that cannot be achieved with observations from the ecliptic plane alone.