Build a ship, launch it, fly real patched-conic orbits around the Sun / Earth / Moon.
Experiment: zero-g asteroid mining — drill and slice chunks into collectible shards.
Tune body generation, preview the invisible fracture grid, and drill to see how it breaks.
Build a body from rock / metal / ice / dirt / shale / water — faults, and how each material fractures.
Click a block to shatter it — spiderweb cracks, material by material. Click fragments to break them down.
Throwaway tests of rendering engines (Three.js, Pixi). Not the game.