koenig-planner

WebAssembly bindings (npm package koenig-planner, Rust crate koenig-damico-planner-wasm) for the Koenig-D'Amico fuel-optimal impulsive maneuver planner, plus a client-side browser demo in the repo. The solver runs entirely in the browser — nothing leaves the machine.

Install (npm)

Published to npm as koenig-planner, built with wasm-pack --target bundler — your bundler (Vite / webpack / rollup / Next) wires up the .wasm automatically:

npm install koenig-planner

import { solve, version } from "koenig-planner";

// Chief orbit (deg / m), target relative orbital elements, and a cost model.
const request = {
  chief: { a: 25_000e3, e: 0.7, i: 40, raan: 358, argp: 0, mean_anom: 180 },
  t_i: 0,
  t_f: 117_990,
  dt: 30,
  w_meters: [50, 5000, 100, 100, 0, 400], // [δa, δλ, δeₓ, δe_y, δiₓ, δi_y]·a
  cost: { type: "piecewise" }, // or { type: "norm2" } / { type: "facemax" }
};

const outcome = solve(request); // typed SolveOutcome — never throws for a valid SolveRequest
if (outcome.status === "ok") {
  const { maneuvers, total_dv } = outcome.value;
  console.log(`${maneuvers.length} burns, Δv cost ${total_dv} m/s`);
} else {
  console.error(outcome.error.kind, outcome.error.message);
}

console.log(version());

This is a pure-compute solver with no DOM dependency. The --target web build in the Build section below is for running the bundled demo locally.

Interface

• solve(req: SolveRequest): SolveOutcome — typed; never throws for a valid SolveRequest (errors are a { status: "err", error: { kind, message } } value). Untyped JS passing a malformed object throws at the deserialization boundary before the solver runs; unknown keys are ignored on this path (unlike solve_json, which rejects them).
• solve_json(json: string): string — string-in/string-out escape hatch; returns the response JSON, or throws the serialized { kind, message } JSON on failure.
• version(): string — the crate version (used by the demo footer).

Types are generated by tsify and shipped in the pkg/*.d.ts produced by wasm-pack.

Build

wasm-pack build crates/wasm --target web      # → crates/wasm/pkg/
cd crates/wasm/www && npm install && npm run dev

crates/wasm/pkg/ is a generated wasm-pack artifact (gitignored) that the demo consumes via its file:../pkg dependency. npm run dev and npm run build rebuild it first (the predev/prebuild hooks), so the standalone wasm-pack build line is only needed once before the initial npm install, which must resolve file:../pkg.

Demo

crates/wasm/www is a React + React-Three-Fiber app (built with Vite) — the "Koenig-D'Amico Impulsive Control Solver" console. It takes a chief orbit, target ROEs, and a cost model and renders the plan entirely client-side: two interactive 3D scenes (the chief orbit in ECI, and the deputy's relative orbit in the RTN frame — both with per-maneuver Δv arrows and a swept primer arrow), a Δv timeline, per-maneuver RTN Δv components, primer-magnitude and primer-component charts, and a playback scrubber.

Test

This crate targets wasm32 only (it is never built for the host), so all tests run on the wasm target via wasm-pack:

wasm-pack test --node crates/wasm   # unit + boundary tests, in Node