RAILS_CHUNK

How often, in ticks, a coasting entity's sphere-of-influence tests may run.

A coast is evaluated at whatever tick a frame lands on, but the tests that can change something — entering a moon's sphere, leaving a planet's — run only on ticks that are multiples of this, so that a frame jumping ten thousand ticks and a frame stepping them make the same tests at the same instants and land on the same frame. One second: a crossing is noticed at most a second late, which at Earth's 30 km/s is 30 km into a sphere 900,000 km across, well inside the 5% hysteresis the boundary already carries.

simulation/src/world.ts:131