Interactive 2D/3D lunar mission visualizations powered by NASA JPL HORIZONS data and curated runtime ephemeris artifacts.

Live pages:

• Landing/index: https://sankara.net/astro/lunar-missions/
• Mission pages: https://sankara.net/astro/lunar-missions/chandrayaan3/
• Orbit data status: https://sankara.net/astro/lunar-missions/orbit-data.html
• Assets status: https://sankara.net/astro/lunar-missions/assets-status.html

The full mission list is in the Mission Catalog section later in this README.

I created this animation for educational purposes. It has the following features:

• Real-world orbit data and predictions based on information available from JPL/NASA HORIZONS interface
• Rendering of the orbit in 2D and 3D
• Rendering with Earth-centered, Moon-centered, and Earth-Moon relative-frame origins
• Header pill strip for fast mission controls (origin, follow/view presets, plane, dimension, and visibility toggles), with synchronized Settings panel controls as fallback
• Multi-craft missions with per-craft styling, visibility pills, and per-craft timeline spans
• Camera from/to controls for mounted viewpoints (spacecraft, Earth, Moon)
• Optional auxiliary camera panels (desktop) for simultaneous craft->Earth and craft->Moon views
• Views aligned with J2000 reference axes
• Information on all earth bound and moon bound maneuvers (engine burns)
• Realistic textures for Earth and Moon in 3D mode
• Astronomically correct rendering of sunlight on Earth and Moon, poles, and polar axes
• Various animation controls for education - camera controls (pan, zoom, rotate), timeline controls, visibility controls
• A Joy Ride feature which lets you fly along with the spacecraft
• Relative-frame mode (mode=relative) to view Earth-Moon transfer geometry with Earth->Moon axis fixed
• Mission comparison mode (mode=compare) to overlay two missions in a single animation with a shared comparison clock and normalized Earth-Moon distance — see Orbit Comparison Mode
• Selectable orbit styles (Trail and Classic) with background-loaded style sidecars for authored missions such as CH3
• On startup, if current wall-clock time is within mission data span, runtime can auto-seek to Now, switch to realtime speed, and start playback
• Mission brief panels with authored Mission and HORIZONS Data text, programmatic timeline bars, a pilot orbit preview, and curated CC BY-SA image carousels

Prerequisites: Node.js (for the Vite dev server). Python is only needed for orbit-data tooling.

npm install
npm run dev

Open:

• http://localhost:7274/
• http://localhost:7274/index.html
• http://localhost:7274/chandrayaan3/
• http://localhost:7274/artemis2/?mode=relative
• http://localhost:7274/orbit-data.html
• http://localhost:7274/assets-status.html
• http://localhost:7274/moon-render-tuner.html
• http://localhost:7274/sky-render-demo.html

URL parameters:

• index.html - Landing page
• <mission>/ - Open a mission directly using its folder slug from assets/mission-catalog.json
• <mission>/?mode=relative - Relative-frame mode
• <mission>/?mode=compare&compareMission=<other> - Mission comparison mode (see Orbit Comparison Mode for the full URL contract)
• <mission>/?testMode=true - Test harness mode for deterministic test behavior
• mission.html?mission=<folder-slug> - Legacy shared link form; redirects to the matching clean mission URL

• Primary quick controls live in the header pill strip (#header-pill-strip) in the mission page shell (mission.html source template).
• The Settings panel (#settings-panel) remains available for the full control set and advanced options.
• Both surfaces are kept in sync through shared underlying inputs/event wiring (src/platform/js/ui/event-handlers.js), so changing one updates the other.

Runtime supports chebyshev, npz, and astronomy body sources, configured per mission via ephemeris_source / ephemeris_sources in config.json.

Current mission configs in this repo are set to chebyshev for SC, MOON, EARTH, and SUN by default.

For NPZ debugging, set "ephemeris_source": "npz" (or per-body overrides), and stage matching .npz files (for example geo-<SC>.npz, lunar-<SC>.npz, and landing-<SC>-geo.npz / landing-<SC>-lunar.npz when used).

Documentation hub: docs/README.md
Developer workflow/build/CI guide: docs/developer.md
System design index: docs/design/design.md

Shared authored mission panel content lives in:

• assets/mission-briefs.json
• assets/mission-images.json

Mission config authoring workflow:

• edit assets/*/data/config.json5 (maintainer source with comments)
• compile runtime JSON with npm run configs:compile (writes assets/*/data/config.json)
• verify sync with npm run configs:check
• run npm run configs:lint before push when mission config timing or phase/event structure changed; current CI uses this stricter check

This repository contains runtime app code, mission config, and UI assets.

Generated orbit/ephemeris artifacts are maintained in the sibling data repository (moon-mission-data), including:

• *-cheb.json
• *-cheb.json.gz
• *.npz
• *-meta.json
• authored style sidecars such as geo-style.json / lunar-style.json

App-managed tracked exceptions that stay in this repo include the current Moon runtime profile images under images/moon/ and social/share images under images/social/.

CI/deploy workflows stage those artifacts into this app during build/deploy.

Useful audit commands:

make data-audit
# or
npm run audit:data-boundary

Repo-boundary process details:

• docs/operations/repo-sync-playbook.md
• docs/operations/mission-data-current-state.md

The animation has 2D and 3D rendering modes.

The 2D mode uses SVG and D3 JS. Planetary orbits are rendered as ellipses based on orbital elements. Spacecraft orbits are rendered using line segments using position data.

The 3D mode uses THREE JS.

jQuery is used in parts of the UI, with a lightweight compatibility dialog shim (src/platform/js/ui/jquery-ui-dialog-stub.js) instead of full jQuery UI.

Orbit data is fetched offline from JPL/NASA HORIZONS. This data is processed and converted into Chebyshev polynomial format for efficient interpolation. The runtime supports Chebyshev/NPZ/Astronomy body providers, and current mission configs default to Chebyshev for all major bodies.

Time Systems: Runtime ephemeris sampling currently uses UTC-based Julian date helpers for Chebyshev/NPZ lookups, while TDB-based helpers are used for astronomical orientation math (for example lunar pole calculations). UTC is used for user-facing event times and display. See docs/design/design.md for detailed technical/design notes.

The project includes automated testing with Vitest + Playwright.

make test

make test runs the primary UI + visual regression suite (test/ui.test.js) on http://localhost:8111.

Current CI gate:

• npm run configs:lint
• npm run test:unit

For strategy and full-suite commands (ui, mission-smoke, chebyshev-accuracy), see:

• docs/guides/testing.md

At present the page can be hosted statically. There are no server components needed. However, you need to serve it over HTTP (not file://) to avoid module/fetch/CORS issues.

CI workflows stage runtime mission assets from a separate data repository before publishing. Staged assets include orbit artifacts (*-cheb.json, *-cheb.json.gz, manifests, optional .npz / *-meta.json, and orbit-style sidecars such as geo-style.json / lunar-style.json), mission screenshots (assets/*/images/), additional shared runtime media, and optional vendored runtime libraries (third-party/).

Tracked app-managed exceptions such as the Moon profile textures under images/moon/ and share images under images/social/ are copied from this repo during deploy rather than staged from moon-mission-data.

By default workflows use:

• MISSION_DATA_REPO = kvsankar/moon-mission-data
• MISSION_DATA_REF = main

You can override these via GitHub repository variables with the same names. No extra token is needed when the data repo is public.

Current workflow behavior:

• .github/workflows/ci.yml runs on push, pull request, and manual trigger.
• .github/workflows/deploy-hetzner.yml is manual-only (workflow_dispatch) for sankara.net deploys.

The Hetzner workflow stages mission data and publishes the full app plus runtime asset set to sankara.net. Use it when shipping app-shell changes, new missions, new manifests, or updated runtime assets.

Production note:

• sankara.net is served by nginx, not Apache. The live legacy redirect from mission.html?mission=<slug> to /<slug>/ is implemented in nginx config on the VPS, not in this repo's .htaccess.
• The repo's mission.html remains a noindex,follow compatibility shell so legacy shared links still work even if a host ignores server-side rewrites.
• .htaccess is kept only for cache-header behavior on Apache-like hosts; it is inert on production.

For development, you can use the Vite dev server:

npm run dev

Or Python's built-in server:

python -m http.server 7274

Or Node.js http-server:

npx http-server

Each deployment now publishes machine-readable metadata:

• /deployment/version.json - deployed app/data repository commits, CI run metadata, and artifact summary
• /deployment/runtime-asset-manifest.json - required runtime assets and SHA-256 values from moon-mission-data
• /deployment/file-manifest.json - file list + SHA-256 for the deployed static tree

For the production site this is available at:

• https://sankara.net/astro/lunar-missions/deployment/version.json

The Hetzner deploy workflow also runs a post-deploy parity audit (rsync --dry-run --checksum --delete) and fails if the remote tree differs from the staged deployment output.

Quick CLI check:

python scripts/show-deployed-version.py

Current catalog missions are grouped below using the same broad families as the landing page.

• Chandrayaan 1 (India - 2008)
• Chandrayaan 2 (India - 2019)
• Chandrayaan 3 (India - 2023)

• Artemis 1 (United States - 2022)
• Artemis 2 (United States - 2026)

• Apollo 8 S-IVB (United States - 1968)
• Apollo 9 S-IVB (United States - 1969)
• Apollo 10 LM Snoopy (United States - 1969)
• Apollo 10 S-IVB (United States - 1969)
• Apollo 11 S-IVB (United States - 1969)
• Apollo 12 S-IVB (United States - 1969)

• Lunar Orbiter 1 (United States - 1966)
• Clementine (United States - 1994)
• Lunar Prospector (United States - 1998)
• LRO (United States - 2009)
• LADEE (United States - 2014)
• Lunar Trailblazer (United States - 2025)

• CAPSTONE (United States - 2022)
• THEMIS-ARTEMIS (United States - 2007-2011)
• THEMIS-ARTEMIS Overview (United States - 2007-2011)
• THEMIS-ARTEMIS Lagrange Transfer (United States - 2010)
• THEMIS-ARTEMIS Lunar Capture (United States - 2011)
• Lunar Flashlight (United States - 2022)
• SLIM (Japan - 2023)

• SMART-1 (ESA - 2003)
• SELENE / Kaguya (Japan - 2007)
• KPLO Danuri (South Korea - 2022)
• Nozomi (Japan - 1998)
• JUICE (ESA - 2023)

• ISEE-3 / ICE (United States - 1978)
• Wind (United States - 1994)
• WMAP (United States - 2001)
• STEREO (United States - 2006)
• TESS (United States - 2018)

• GRAIL (United States - 2012)
• GRAIL SS Stage (United States - 2011)
• LCROSS Shepherd (United States - 2009)
• LCROSS Centaur (United States - 2009)

• HGS-1 (United States - 1997)

• Jon D. Giorgini for helping with the JPL/HORIZONS interface and data. He was very responsive whenever I mailed him my queries. He has been of great help since 2013 for the Mars Orbiter Mission until now for the Chandrayaan 3 mission.

• Members of the Bangalore Astronomy Society (http://bas.org.in/) for their valuable feedback

• Members of the Reddit r/isro (https://www.reddit.com/r/ISRO/) community for their valuable feedback

Current planning/docs split:

• Runtime architecture and the completed refactor record: docs/design/architecture/target-architecture.md
• Active product/backlog planning: docs/design/roadmap/orbit-ux-and-refactor-roadmap.md
• Historical modernization/refactor plan: docs/archived/modernization-plan-2026.md

The broad runtime rearchitecture is effectively complete, so the archived modernization plan is kept for history rather than as the current source of direction.

See docs/guides/ai-tools.md for how AI tools are used in this repo (and where tool-specific notes live).

• https://mgvez.github.io/jsorrery/
• https://github.com/Flowm/satvis
• https://github.com/CoryG89/MoonDemo
• http://stuffin.space/
• https://theskylive.com/3dsolarsystem