  The POLAR-2 Gamma-Ray Burst (GRB) Polarimetry mission is a follow-up to the
successful POLAR mission. POLAR collected six months of data in 2016-2017 on
board the Tiangong-2 Chinese Space laboratory. From a polarization study on 14
GRBs, POLAR measured an overall low polarization and a hint for an unexpected
complexity in the time evolution of polarization during GRBs. Energy-dependent
measurements of the GRB polarization will be presented by N. de Angelis in
GA21-09 (August 2nd). These results demonstrate the need for measurements with
significantly improved accuracy. Moreover, the recent discovery of
gravitational waves and their connection to GRBs justifies a high-precision GRB
polarimeter that can provide both high-precision polarimetry and detection of
very faint GRBs. The POLAR-2 polarimeter is based on the same Compton
scattering measurement principle as POLAR, but with an extended energy range
and an order of magnitude increase in total effective area for polarized
events. Proposed and developed by a joint effort of Switzerland, China, Poland
and Germany, the device was selected for installation on the China Space
Station and is scheduled to start operation for at least 2 years in 2025.
