Integrator3D

Solar System Visualiser & Numerical Integrator for 64-bit Windows.

Integrator3D is an interactive OpenGL solar-system visualiser built around a high-accuracy numerical integrator. It propagates spacecraft, asteroids, comets and satellites through the real gravitational field of the solar system — using JPL ephemerides for the perturbing bodies — and shows the result in a live 3D view.

This repository also contains BSPMerge, the companion tool that builds the ephemeris files Integrator3D reads, and the shared LIB/ library both are built on.

Downloads: grab the latest packaged build from the Releases page.

Features

Numerical integration

• IAS15 — 15th-order Gauss–Radau with adaptive step size (based on the ReBOUND package).
• RKN11B — 11th-order Runge–Kutta–Nyström (based on the KSP Principia mod).
• DP87 — 8th-order Dormand–Prince (based on the libode library).
• Optional non-gravitational forces (atmospheric drag, solar radiation pressure).

Ephemeris

• Reads a compact custom BSPX format (chunked Chebyshev coefficients, built from JPL DE442 and NASA Horizons small-body kernels).
• Perturbers are evaluated directly from the ephemeris during integration.

Interactive 3D viewer

• OpenGL rendering with an interactive camera, textured bodies, and orbit trails.

Observation planner (Ephemeris window)

Works from a geographic observing site (latitude/longitude) with topocentric apparent positions (light deflection + aberration):

• An all-sky "what's observable" pass for a single epoch (filtered by altitude, limiting magnitude, twilight sky-glow, and solar/lunar elongation).
• Event prediction over a time interval: solar & lunar eclipses; lunar occultations (planets by default), planetary occultations (satellites by default), and minor-body occultations (catalogue stars by default). Most occulter→occulted combinations are supported; the defaults are the fast, commonly useful pairs.
• Occultation events include the ground track (sub-shadow point on the WGS-84 ellipsoid).

Target import

Load the object you want to integrate from several sources:

• JPL Horizons vector tables.
• Satellite TLEs (.tle / .2le) — an accurate state vector at the TLE epoch via a full SGP4/SDP4 propagator (near-Earth and deep-space), rotated TEME→J2000/ICRF.
• JPL Small-Body Database CSV — batch-import many bodies from an SBDB query export, choosing which ones via a multi-select dialog.
• Geometric orbital elements entered directly.
• Osculating-elements window with one-click copy to clipboard (tab-separated, spreadsheet-ready).

Ephemeris builder (BSPMerge)

• One-click pipeline: downloads JPL planetary/satellite kernels (and optional Horizons small-body data), auto-loads and filters them, and merges everything into a single .bspx file for Integrator3D.

What's new in v1.2.1

• Greatly expanded observation planner (eclipses & occultations from an observing site).
• Satellite TLE import with a full SGP4/SDP4 propagator.
• JPL SBDB CSV batch import with multi-select.
• Copy osculating elements to clipboard.
• Bundled Gaia DR3 star catalogue (data\gaia.fits) for asteroid star-occultations.

See the v1.2.1 release notes for the full list.

Requirements

• 64-bit Windows.
• A CPU with AVX2/FMA3 (essentially every desktop/laptop CPU since ~2013). A numerically identical compatibility build is included for older CPUs.
• An OpenGL-capable GPU (any modern integrated or discrete graphics).

Getting started (packaged build)

1. Download Integrator3D-win64.zip from the latest release and extract the Integrator3D folder anywhere (keep all files together).
2. Run BSPMerge.exe → Download → Start to build a .bspx ephemeris file (first run).
3. Run Integrator3D.exe and open the .bspx you built via the Load command.

Full end-user notes — including the Gaia catalogue and Windows SmartScreen guidance — are in Integrator3D/README.txt.

Building from source

Built with Embarcadero RAD Studio / Delphi 12 for the Win64 platform. Add the LIB/ directory to the Delphi library search path (Tools → Options → Language → Delphi → Library), then build from the IDE or with MSBuild:

msbuild Integrator3D\Integrator3D.dproj /p:config=Release /p:platform=Win64
msbuild BSPMerge\BSPMerge.dproj         /p:config=Release /p:platform=Win64

Output binaries go to <Project>\Win64\Release\.

Repository layout

Path	Contents
Integrator3D/	The main OpenGL viewer / integrator application.
BSPMerge/	Ephemeris builder — merges JPL/Horizons kernels into .bspx.
LIB/	Shared library: celestial mechanics, ephemeris I/O, SGP4/SDP4, vector/quaternion math, AVX2 kernels.

Acknowledgements

• NASA/JPL — DE442 planetary ephemerides and the Horizons system.
• ReBOUND — the IAS15 Gauss–Radau integrator.
• KSP Principia — the RKN11B integrator.
• libode — the DP87 integrator.
• D. Vallado, Revisiting Spacetrack Report #3 — the SGP4/SDP4 model.
• ESA Gaia DR3 — the star catalogue used by the occultation planner.

License

Released under the MIT License. © 2026 galahad2069.