ASPIICS, a Giant Formation Flying Coronagraph Onboard the PROBA-3 Mission

Abstract:

PROBA-3 is the next ESA mission in the PROBA line of small technology demonstration satellites. PROBA-3, to be launched in 2022, is a mission dedicated to the in-flight demonstration of precise formation flying techniques and technologies. The PROBA-3 mission will place two small satellites in a highly elliptical orbit around the Earth. The two satellites will fly in a precise formation, producing a very long baseline solar coronagraph called ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun). One spacecraft will carry the optical telescope, and the second spacecraft will carry the external occulter of the coronagraph. The inter-satellite distance of around 150 m will allow observing the inner corona close to the solar limb with very low straylight. The technological challenges and scientific objectives of PROBA-3 will be discussed. Due to its unique field of view and low straylight, PROBA-3/ASPIICS will fill the gap between the fields of view of coronal extreme-ultraviolet imagers (SDO/AIA, Solar Orbiter/EUI) and traditional externally occulted solar coronagraphs (SOHO/LASCO, STEREO/COR2). This will allow a significant advance in a number of unsolved problems in solar physics, like the coronal magnetic field configuration, slow solar wind formation, and CME initiation.