Speculation: The Proving Grounds likely opened after the collapse of Stellarum’s Ganymede shipyards, with or without the assistance of Pulse, as some much-welcome fun and excitement in the Whisper Recession period. These amazing battle games are based on massive robots and spectacular backdrops, but require less transportation than Pulse’s events, which is welcome during a system-wide travel ban.

The huge, defunct industrial zones of Stellarum’s corporate zones make sense as the backdrop to these games.

Reference: Suggested by Ganymede writeup

Date Notes: No direct reference, dating this to the Whisper Recession is pure conjecture.