SRGW2021 will bring together storage-ring experts, accelerator scientists and members of the gravitational physics community. It will survey and discuss topics such as: (1) the past and recent work on the use of storage rings to detect - or generate - gravitational waves; (2) the expected cosmic signals, their frequency and amplitude; (3) the dependence of detection sensitivity on the ring size and other parameters; (4) example sensitivities to tides, earthquakes etc.; (5) possible enhancement strategies such a special optics, particular magnets and advanced diagnostics ; (6) gravity research based on accelerator technologies; and (7) a future R&D and measurement roadmap. SRGW2021 will be held in safe virtual space. It consists of short sessions of maximum 3 talks each, distributed between early February and middle or end of March 2021.  Sessions will be held on : Tuesday 2 February  2021 (from 15h00 Geneva time), Thursday 18 February 2021 (from 14h30), Thursday 4 March 2021 (from 14h30),  Thursday 11 March 2021 (from 14h30), Thursday 18 March 2021 (from 14h30) - see Timetable.