A series of sporting hosted on Ganymede by Applied Science and Robotics, to give an arena for technology over biological modification. The Proving Grounds is something like Robot Wars writ very very large, massive custom machines clash against each other with the scream of steel on steel, and the entire region shakes. This battle of mechanical monstrosities is the main feature of the Proving Grounds and there’s an ongoing series of tournaments leading up to the big game, but a range of other tech-focused sporting events have been built up around the Proving Grounds arena on Ganymede. From the HSD Core rulebook, 2.0 (p. 45) or 1.0 (p.69)