orbital-mechanics-kit

Small, dependency-free toolkit for classical two-body orbital mechanics. It covers the pieces you keep re-deriving: a Kepler-equation solver, anomaly conversions, period / mean-motion, the vis-viva equation, apsides, and a Hohmann transfer estimator.

All angles are in radians (helpers degToRad / radToDeg are provided). Lengths are in km and the default gravitational parameter is Earth's.

Install

npm install orbital-mechanics-kit

Usage

import {
  solveKepler,
  meanToTrue,
  orbitalPeriod,
  hohmannTransfer,
  MU_EARTH,
} from "orbital-mechanics-kit";

// Eccentric anomaly for M = 60deg, e = 0.3
const E = solveKepler(Math.PI / 3, 0.3);

// Period of a 7000 km circular orbit (seconds)
const T = orbitalPeriod(7000);

// LEO -> GEO Hohmann budget
const { total } = hohmannTransfer(6678, 42164, MU_EARTH);

API

• solveKepler(M, e, tol?, maxIter?) — Newton solve of M = E - e sin E.
• eccentricToTrue(E, e) / meanToTrue(M, e) — anomaly conversions.
• orbitalPeriod(a, mu?), meanMotion(a, mu?).
• visViva(r, a, mu?) — orbital speed at radius r.
• apsides(a, e) / elementsFromApsides(rp, ra).
• hohmannTransfer(r1, r2, mu?) — { dv1, dv2, total, transferTime }.

References

• Vallado, Fundamentals of Astrodynamics and Applications, 4th ed.
• Curtis, Orbital Mechanics for Engineering Students, 3rd ed.

License

MIT