The Global Centre for Risk and Innovation (GCRI)
Orbits around Earth are filling with active satellites and debris: dead satellites, rocket bodies and fragments from collisions and explosions. Collisions create more fragments, raising risk for all users. This page sets out how debris accumulates and how collision risk is managed, how orbital congestion is measured, and what evidence serves the agencies, operators and regulators responsible for keeping orbits usable.
GCRI · In development · service level R0
Space debris is the population of non-functional human-made objects in orbit, from dead satellites and rocket bodies to collision fragments. Collisions create more debris, launch rates are rising, disposal compliance varies and small fragments go untracked, threatening the long-term usability of key orbits.
For space debris and sustainability, in GCRI's spatial-intelligence reading, the map opens on true-colour imagery and land cover with true colour from NASA GIBS, framed on the Arctic; every other NASA layer, live feed and forecast waits in the layer list.
The interactive map needs JavaScript; the layer list and sources are below.
Layers 2
Earth observation, for this page
Keyboard, with the map focused
Hold Ctrl or ⌘ and scroll to zoom
Latest available
NASA GIBS / EOSDIS · ASTER GDEM (METI, NASA) · Blue Marble (NASA) · © OpenStreetMap contributors (ODbL) · Natural Earth
Loading the latest NASA imagery.
Drag to move. Ctrl or ⌘ and scroll, pinch or the buttons to zoom; hover for the values under the pointer; reset returns to the region.
For space debris and sustainability, in GCRI's spatial-intelligence reading, the map opens on true-colour imagery and land cover with true colour from NASA GIBS, framed on the Arctic; every other NASA layer, live feed and forecast waits in the layer list.Satellite and model products as NASA publishes them, each with its own date; indicators, not assessments of any place; claim ceiling INTEGRATED.
Layers and dates
The working screen behind this subject: its structure, terms and states. Names are placeholders and values illustrative.
Space debris and sustainability · Orbit shell 550 km · Week 19
| CJ-1191 | SAT-3 vs debris | 302 | 0.00068 | Monitor |
| CJ-3954 | SAT-1 vs SAT-x | 805 | 0.000022 | None |
| CJ-9340 | SAT-4 vs debris | 60 | 0.0015 | Manoeuvre |
Orbital congestion and stewardship. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.
Each collision or breakup creates many fragments that can cause further collisions. In crowded orbits this can become self-sustaining.
Large constellations are adding satellites to low Earth orbit at unprecedented rates, increasing traffic and conjunctions.
Guidelines call for removing satellites from crowded orbits after missions, but compliance varies and failed satellites cannot manoeuvre.
Ground radars and telescopes track larger objects; smaller fragments that can still damage satellites are not routinely tracked.
Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.
| Term | Definition |
|---|---|
| Conjunction | A close approach between two objects in orbit that may require assessment or a manoeuvre. |
| Post-mission disposal | Removing a spacecraft from a protected orbit at the end of its mission. |
| Passivation | Removing stored energy from a spacecraft to prevent later explosions. |
Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.
| Indicator | Unit | Cadence | Source type | Label |
|---|---|---|---|---|
| Tracked objects in orbit | count by orbit region | monthly | Space surveillance catalogues | OBSERVED |
| Estimated objects above size thresholds | count by size class | per assessment | Statistical debris models | MODELLED |
| Active satellites | count | monthly | Catalogues and operator data | OBSERVED |
| Collision avoidance manoeuvres | count | annual | Operator reports | REPORTED |
| Post-mission disposal success | percent of missions | annual | Agency environment reports | ESTIMATED |
| Fragmentation events | count | annual | Agency reports | OBSERVED |
The topic as a computational graph: named sources feed the methods, an evidence review gates the outputs, and the decisions stay with the authorities that hold them.
Fig. 02Nodes carry their type, two metric rows and a state; connectors show what feeds what; dashed frames name the owners; the timeline is the cadence. Design of the pipeline, not a record of a run.
Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.
| Source | What it gives | Licence class |
|---|---|---|
| ESA Space Environment Report and DISCOS database | Debris population, compliance and trends | Public report; DISCOS by registration (to check) |
| Space-Track and CelesTrak | Orbital element sets for tracked objects | Space-Track by registration and terms; CelesTrak public |
| UNOOSA Online Index of Objects Launched into Outer Space | Registration of launched objects | Public, UN terms of use |
| IADC reports | Debris mitigation guidelines and studies | Public, IADC terms |
| NASA Orbital Debris Program Office quarterly news | Debris environment updates | Public domain, US government |
Space and Earth Observation prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.
| Who decides | The question | Evidence this page serves |
|---|---|---|
| Space agencies and licensing authorities | What disposal and design rules to require | Compliance analyses; congestion summaries |
| Satellite operators | How to manage collision risk and disposal | Conjunction and risk methods |
| UN COPUOS member states | How to strengthen long-term sustainability guidelines | Environment trends |
Orbital scientists and space engineers ask how to keep orbits usable.
Objects in low orbit are gradually slowed by the thin upper atmosphere and eventually re-enter, but at higher altitudes debris can remain for decades to centuries. Collisions and explosions create fragments, many too small to track yet large enough to damage a satellite at orbital speeds. A long-recognised concern is that, beyond a certain density, collisions could generate debris faster than it is removed, making some orbits progressively more hazardous.
Operators reduce risk by designing satellites to avoid break-ups, manoeuvring to avoid predicted collisions and removing satellites from valuable orbits at end of life. The effectiveness of these measures depends on compliance across many operators, on accurate tracking and on sharing information about planned manoeuvres.
Radar and optical tracking of objects, with space systems expertise. Small debris is largely untracked.
Predicting trajectories and decay, grounded in physics. Atmospheric drag is uncertain, especially during solar activity.
Estimating conjunction probabilities with statistical methods. Uncertain orbits produce many false alarms.
Simulating debris populations over decades. Results depend on assumptions about future launches and compliance.
The current service level is R0: information and enquiries. An enquiry receives a reference and names the next step; applications, payments, compute allocations and registrations open only when their team, terms and review capacity exist.