Space Debris Tracker
Real-time tracking of 5,000+ orbital debris objects using CelesTrak TLE feeds, SGP4 propagation, and WebGL globe rendering — colour-coded by origin event and altitude band.
5,000+
Tracked debris pieces
3
Major origin events
5 s
Position update rate
1 h
TLE cache window
Data Pipeline
CelesTrak Multi-Group Feed
Three separate CelesTrak GP element-set groups are fetched in parallel: cosmos-2251-debris, fengyun-1c-debris, and iridium-33-debris. Each group contains NORAD-tracked TLEs for that specific debris cloud.
API Proxy & Deduplication
A Next.js Route Handler fetches all three groups, deduplicates by NORAD ID (the Cosmos 2251 / Iridium 33 groups overlap), and returns a single combined TLE text payload with 1-hour edge caching.
TLE Parsing & Classification
Each 3-line TLE block is parsed: NORAD ID from TLE line 1, inclination from TLE line 2. The satellite name is matched against known debris event keywords to classify origin (Cosmos, FenYun, Iridium, Other).
SGP4 Orbital Propagation
satellite.js `twoline2satrec()` converts TLE data into a numerical state vector (satrec). `propagate(satrec, now)` then applies the SGP4/SDP4 algorithm to compute ECI cartesian position and velocity at the current UTC time.
Coordinate Transformation
ECI coordinates are converted to geodetic (latitude, longitude, altitude above WGS-84 ellipsoid) using the Greenwich Mean Sidereal Time (GMST) rotation. Altitude band (LEO/MEO/GEO) is assigned from the computed height.
WebGL Globe Rendering
All debris positions are loaded into a single Three.js BufferGeometry particle system (`THREE.Points`) with per-vertex colour coding by origin event. Particles pulse via a requestAnimationFrame opacity animation. Clicking any particle raycasts to show orbital telemetry and draws a full-orbit Three.js Line directly in the globe scene.
Major Debris-Generating Events
FenYun-1C ASAT Test
11 Jan 2007China conducted a direct-ascent kinetic-kill ASAT test against its own ageing FenYun-1C weather satellite. The hypervelocity impact at 850 km generated the largest single debris cloud in history — over 3,500 trackable pieces and an estimated 150,000 fragments larger than 1 cm. The cloud spans altitudes from 200 km to over 4,000 km and will persist for decades.
Cosmos 2251 / Iridium 33 Collision
10 Feb 2009The first accidental hypervelocity collision between two intact satellites occurred over northern Siberia. The defunct Russian military satellite Cosmos 2251 struck the operational Iridium 33 commercial communications satellite at a closing speed of ~11.7 km/s. Both satellites were completely destroyed, producing two distinct debris clouds that together added more than 2,300 trackable objects to the NORAD catalogue.
Kosmos 1408 ASAT Test
15 Nov 2021Russia conducted a direct-ascent ASAT test against its own defunct Kosmos 1408 satellite, generating over 1,500 immediately trackable fragments. The debris cloud is at lower LEO altitudes (400–600 km) and decays faster than the FenYun cloud, but posed immediate conjunction risks to the ISS crew, who sheltered in their return vehicles for several hours.
Altitude Band Classification
Orbital altitude determines debris lifetime, affected assets, and long-term risk. LEO is by far the most dangerous regime due to high orbital velocity and proximity to operational crewed missions.
| Band | Altitude Range | Debris Density | Assets at Risk | Orbital Decay |
|---|---|---|---|---|
| LEO | 200 – 2,000 km | Highest | Active satellites, ISS, crewed missions | Years to decades |
| MEO | 2,000 – 35,586 km | Moderate | GPS, GNSS, navigation constellations | Centuries |
| GEO | ~35,786 km | Low but permanent | Communications, weather, broadcast satellites | Never — graveyard orbit required |
| HEO | > 36,186 km | Very low | Molniya, scientific missions | Centuries to millennia |
⚠️ The Kessler Syndrome
Proposed by NASA scientist Donald Kessler in 1978, the Kessler Syndrome describes a cascade scenario where orbital debris density in LEO becomes high enough that collisions generate more debris than natural decay removes — creating a self-sustaining chain reaction that renders entire orbital bands unusable.
Many researchers believe low LEO (~500–800 km) has already reached a tipping point for some debris populations. Each collision, like the 2009 Cosmos–Iridium event and the 2007 FenYun ASAT test visualised here, meaningfully increases cascade risk for all operators in the affected altitude band.
Tech Stack
Orbital data
CelesTrak GP/TLE (3 groups)
Propagator
satellite.js v5 (SGP4)
Globe renderer
globe.gl + Three.js
Earth texture
NASA Blue Marble Night
Update rate
5 s position refresh
TLE cache
1 h edge cache
Framework
Next.js 16 App Router
Debris objects
5,000+ tracked pieces
Data Source
CelesTrak General Perturbations (GP) Catalogue
Maintained by Dr T.S. Kelso (AMSAT), CelesTrak provides free, public access to the US Space Force 18th Space Control Squadron orbital element sets derived from the NORAD/Space Track catalogue. TLE data conforms to CCSDS OMM v2.0 and is refreshed approximately every 2 hours. Three specific debris groups are fetched for this demo: cosmos-2251-debris, fengyun-1c-debris, and iridium-33-debris.
API endpoint: celestrak.org/NORAD/elements/gp.php?GROUP={group}&FORMAT=tle