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Version: 0.2.0

Time Warp

The WorldTime resource controls both the current simulation epoch and how quickly simulation time advances relative to real time.

WorldTime resource​

pub struct WorldTime {
    pub multiplier: u32, // default: 1
    pub epoch: Epoch,    // default: Epoch::now()
}

The default multiplier is 1 (real time). A multiplier of 60 makes one fixed tick advance the simulation epoch by 60× the normal timestep.

Changing time warp​

The change_time_warp system (registered in lib.rs Update) responds to key input:

KeyEffect
, (comma)Decrease multiplier
. (period)Increase multiplier

The multiplier is a u32 — it steps in whole-number increments.

Effect on propagation​

The fixed_physics_step system advances WorldTime::epoch each FixedUpdate tick. The time delta applied is fixed_dt * multiplier. The cache_eci_states system then calls propagator.state_eci(epoch) with the updated epoch, so all Keplerian positions advance at the scaled rate.

Effect on physics​

Avian3D physics runs inside the ManualPhysics schedule, which is driven by fixed_physics_step. The physics timestep itself is fixed at FIXED_HZ regardless of multiplier; only the orbital epoch advances faster. This is intentional: tether dynamics are a local physics simulation that must remain stable, while orbital propagation is an analytical calculation that can be freely time-scaled.