Watch the James Webb Space Telescope loop around the Sun-Earth L2 point on a procedural halo path - scrub the halo-day slider to move Webb, and the panel lists the published distance, period, and station-keeping figures.
Play orbit animates one halo circuit compressed on screen; pause and drag the halo-day slider from 0 to 168 to inspect Webb at any point on the loop. The orange dots mark station-keeping burns, spaced roughly every 21 days, that keep the telescope on its halo path.
The small panel on Webb always keeps its bright face toward the Sun (white line) so the dark instrument side stays in shadow - that geometry is what lets Webb's infrared detectors stay cold without a mechanical cooler for most of the observatory. Earth-to-L2 distance, halo period, and station-keeping cadence in the panel are NASA and STScI published figures.
JWST L2 Halo Orbit 3D Explorer
Watch the James Webb Space Telescope loop around the Sun-Earth L2 point on a procedural halo path - scrub the halo-day slider to move Webb, and the panel lists the published distance, period, and station-keeping figures.
Drag to orbit the view, scroll or pinch to zoom, and press Play orbit to animate one halo circuit. Scrub the halo-day slider from 0 to 168 to pause Webb at any point on the loop, and toggle the station-keeping burn markers to see roughly how often the telescope needs a nudge to stay on path.
The facts panel lists an Earth-to-L2 distance of about 1.5 million km, a halo period that NASA Science gives as about 168 days and STScI docs give as about 180 days, a halo distance from L2 of about 250,000 to 832,000 km, and station-keeping burns roughly every 21 days.
- Procedural halo loop around the Sun-Earth L2 point, tilted out of the ecliptic plane
- Play orbit animates one halo circuit compressed on screen; halo-day slider scrubs 0 to 168 days
- Station-keeping burn markers toggle on or off, spaced roughly every 21 days along the path
- Webb's sunshield always keeps its bright face toward the Sun so the instrument side stays in shadow
- Real published figures in the panel; Earth, Sun, and L2 distances are compressed and disclosed
- Runs fully in the browser with the vendored three.js engine - no account, no upload
Students use it to connect why L2 keeps Webb in Earth's shadow-free but thermally stable neighborhood, teachers point to the sunshield geometry when explaining how the telescope stays cold enough for infrared observations, and curious readers scrub the slider to see how far the halo path swings above and below the ecliptic.
| Quantity | Published value | Source |
|---|---|---|
| Earth-to-L2 distance | about 1.5 million km | NASA JWST orbit page |
| Halo orbit period | about 168 days (NASA Science) / about 180 days (STScI) | NASA Science, STScI JWST User Documentation |
| Halo distance from L2 | about 250,000-832,000 km | NASA JWST orbit page |
| Max out-of-ecliptic excursion | about 520,000 km | NASA JWST orbit page |
| Max Earth-Webb distance | about 1.8 million km | NASA JWST orbit page |
| Station-keeping burns | about every 21 days | NASA JWST orbit page |
Everything renders on your device with WebGL. The 3D engine loads once (about 0.7 MB) and is cached; no scene data is sent to a server.
The scene is an educational halo-orbit visualization tuned to teach the L2 geometry and station-keeping cadence - the halo loop is a simplified approximation, not a precomputed ephemeris, and it does not track Webb's real position right now.
For a step-by-step walkthrough, read the JWST L2 Halo Orbit 3D Explorer step-by-step guide. The Space 3D collection also includes a Lagrange Points explorer for the general five-point geometry and an N-Body Sandbox for free-form gravity play.
Frequently Asked Questions
What does the JWST L2 Halo Orbit 3D Explorer show?
A procedural halo path around the Sun-Earth L2 point, about 1.5 million km beyond Earth on the side away from the Sun. Webb moves along the tilted loop, orange dots mark roughly where station-keeping burns happen, and the panel lists the published distance, period, and excursion figures.
Why does Webb orbit L2 instead of Earth?
At L2 the Sun, Earth, and Moon stay roughly behind the telescope, so its sunshield can block all three heat sources at once and keep the infrared instruments cold. A tight halo loop around L2 also keeps Webb out of Earth's and the Moon's shadow, which would otherwise chill and then reheat the observatory on a cycle.
Why do the panel's period figures differ?
NASA's mission orbit page cites about 168 days for one halo circuit; STScI's technical documentation cites about 180 days (roughly six months). Both figures are published by the mission teams and are shown side by side rather than averaged into an invented number.
What are the orange station-keeping markers?
They mark roughly where Webb needs a small thruster burn, about every 21 days, to stay on its halo path around the unstable L2 point. Toggle them off to see the halo loop on its own.
How is the sunshield geometry shown?
A small panel on the model always keeps its bright face pointed toward the Sun, while a darker instrument marker sits on the opposite side. That is a simplified stand-in for how Webb's five-layer sunshield keeps the telescope's cold side permanently shaded.
Is this a real-time tracker or a physics simulation?
No. The halo loop is a simplified Lissajous-style approximation of the real quasi-periodic orbit, not a precomputed ephemeris, and it does not show Webb's real position right now. On-screen distances are compressed for readability; the table figures are the real published NASA and STScI values.