Integration Methods

Darksun ships with several orbital integrators so you can match solver cost to mission profile.

Integrator	Strengths	Use Cases
RK45 (Dormand–Prince)	Balanced accuracy vs. performance, adaptive step sizing	General mission design, medium-length simulations
DP87	Higher-order Runge–Kutta tuned for multi-body dynamics	Environments with strong perturbations and frequent events
IAS15	Radau-based, excellent long-term energy conservation	Multi-year propagation, precision manoeuvres
Verlet	Lightweight, symplectic fixed-step	Quick previews, visual fly-throughs
Symmetric Multistep 4	Symplectic multi-step integrator	Energy-sensitive transfers and resonant orbits

Select an integrator under Settings → Simulation. Switching between solvers prompts to adopt recommended tolerances; accept the suggestions to start from a stable baseline, then refine tolerances per mission.

Choosing Tolerances

• Short interactive runs – Prefer Verlet or RK45 with relaxed tolerances to keep UI cadence high.
• Perturbed environments – DP87 or IAS15 with tighter tolerances avoids cumulative drift when J2/J3, drag, or third-body effects dominate.
• Mission planning previews – Run RK45 in preview mode, then re-run with IAS15 before committing burns to avoid hidden energy drift.

Remember to align the integrator with the same frame as your reference data. Exported ephemerides assume ECLIPJ2000 inertial coordinates; switching frames without reprocessing initial conditions can mask integration errors.