SPADEX (Space Docking Experiment) consists of two 200kg satellites, which will attempt to dock with each other. This test is part of ISRO's planned Indian Space Station and its Chandrayaan-4 mission. The secondary payload, POEM-4 (PSLV Orbital Experiment Module-4) includes various secondary experiments, including from satellite builder TakeMe2Space and commercial SAR service provider PierSight.