GCRI · Space and Earth Observation
Space debris and sustainability
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.
Space debris and sustainability on the record.
Space debris and sustainability: how the risk develops.
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.
Collisions breed debris
Each collision or breakup creates many fragments that can cause further collisions. In crowded orbits this can become self-sustaining.
Launch rates are rising
Large constellations are adding satellites to low Earth orbit at unprecedented rates, increasing traffic and conjunctions.
Disposal is often incomplete
Guidelines call for removing satellites from crowded orbits after missions, but compliance varies and failed satellites cannot manoeuvre.
Tracking has limits
Ground radars and telescopes track larger objects; smaller fragments that can still damage satellites are not routinely tracked.
Earth observation in the Arctic.
Land cover and vegetation over the Arctic, from NASA GIBS. Each layer carries its own date.
The interactive map needs JavaScript; the layer list and sources are below.
Layers 2
Earth observation, for this page
About this layer
- Evidence
- Observed
- Source
- VIIRS NOAA-20 corrected reflectance (NASA LANCE)
- Provider
- NASA LANCE
- Licence
- NASA open data
- Vintage
- daily; Satellite image
- Newest at build
- 2026-10-14
- Resolution
- about 250 m grid
- Uncertainty
- Satellite image. Satellite or model raster as the provider publishes it. Clouds, swath gaps and retrieval error leave gaps and noise; values are indicators, not measurements at a place.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Modelled (latest year GIBS publishes)
- Source
- MODIS Terra and Aqua land cover (MCD12Q1) (NASA LP DAAC)
- Provider
- NASA LP DAAC
- Licence
- NASA open data
- Vintage
- yearly; Satellite classification; latest year GIBS publishes
- Newest at build
- 2024-01-01
- Resolution
- about 500 m grid
- Uncertainty
- Satellite land cover classes for the year shown, including croplands; a classification with known errors, not a farm register.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Observed (clouds leave gaps)
- Source
- MODIS Terra EVI (NASA LANCE)
- Provider
- NASA LANCE
- Licence
- NASA open data
- Vintage
- daily; Satellite index; clouds leave gaps
- Newest at build
- 2026-10-13
- Resolution
- about 250 m grid
- Uncertainty
- Satellite vegetation index for the 8 days to the date shown, a habitat condition indicator; not a measure of species or biodiversity.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Observed (clouds leave gaps)
- Source
- MODIS Terra NDVI (NASA LANCE)
- Provider
- NASA LANCE
- Licence
- NASA open data
- Vintage
- daily; Satellite index; clouds leave gaps
- Newest at build
- 2026-10-13
- Resolution
- about 250 m grid
- Uncertainty
- Satellite greenness index over the 8 days to the date shown; an indicator of crop and pasture condition, not a yield estimate or a food security warning.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Estimated
- Source
- Gridded Population of the World v4.11 (NASA SEDAC (CIESIN, Columbia University))
- Provider
- NASA SEDAC (CIESIN, Columbia University)
- Licence
- CC BY 4.0
- Vintage
- null; Census-based estimate, static (2020)
- Resolution
- about 1 km grid
- Uncertainty
- Census-based estimate of people per square kilometre in 2020, shown as exposure context; not a count of people affected by any hazard.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Observed
- Source
- VIIRS Black Marble (VNP46A2) (NASA LAADS DAAC)
- Provider
- NASA LAADS DAAC
- Licence
- NASA open data
- Vintage
- daily; Satellite radiance, corrected for moonlight and atmosphere
- Newest at build
- 2026-10-12
- Resolution
- about 500 m grid
- Uncertainty
- Satellite night-time radiance for the date shown; lights are a proxy for electricity use and outages, not a measurement of supply or access.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
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.
Earth observation, framed on the Arctic.Satellite and model products as NASA publishes them, each with its own date. They are indicators, not assessments of any place.
Data: NASA GIBS · ASTER GDEM · Blue Marble · © OpenStreetMap contributors · Natural Earth · NASA EONET · NASA JPL OPERA DIST-ALERTSources and licences
- We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- VIIRS near-real-time products (flood, land surface temperature, snow cover, corrected reflectance), NASA LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- MODIS land products (vegetation indices, gross primary production, land cover), NASA LP DAAC and LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- Center for International Earth Science Information Network (CIESIN), Columbia University. 2018. Gridded Population of the World, Version 4 (GPWv4): Population Density, Revision 11. NASA Socioeconomic Data and Applications Center (SEDAC). Licensed under CC BY 4.0. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). doi:10.7927/H49C6VHW. CC BY 4.0
- VIIRS Black Marble night-time lights, NASA Goddard Space Flight Center; distributed by the NASA Level-1 and Atmosphere Archive and Distribution System (LAADS DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- ASTER GDEM is a product of METI and NASA (ASTER Global Digital Elevation Model V003, NASA LP DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). Cite as: NASA/METI/AIST/Japan Spacesystems and U.S./Japan ASTER Science Team (2019). ASTER Global Digital Elevation Model V003. doi:10.5067/ASTER/ASTGTM.003. NASA open data
- Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com. Public domain
- © OpenStreetMap contributors (ODbL), via NASA GIBS (coastlines, boundaries, roads and place names). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). ODbL
- Blue Marble, NASA Earth Observatory; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- Context on the globe and flat map: coastlines, boundaries, roads and place names from NASA GIBS reference layers (OpenStreetMap data, ODbL, © OpenStreetMap contributors); Blue Marble imagery as an optional base; 3D terrain and the elevation read-out from the ASTER GDEM elevation colour index (5 m to 200 m classes, exaggerated for legibility). Boundaries are drawn as published and imply no position on any territory.
- Live events: NASA Earth Observatory Natural Event Tracker (EONET); events are indicative and keep their original source links.
- Live: NASA EONET Events are indicative, not authority warnings.
- Observed (EO): NASA JPL OPERA DIST-ALERT (contains modified Copernicus Sentinel data 2026). We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS).
- NASA GIBS: We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS).
- Past year, daily temperature and sunshine (NASA POWER): These data were obtained from the NASA Langley Research Center (LaRC) POWER Project funded through the NASA Earth Science/Applied Science Program..
- Weather data by Open-Meteo.com (https://open-meteo.com/), licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/).
- Optional layers (11 sources in the layer list: live, forecast, observed and context) print their provider credit on the map and here when switched on; forecasts are model output and derived indices are estimates.
Layers and dates
- True colour: VIIRS NOAA-20 corrected reflectance, NASA LANCE · 13 Oct 2026
- Land cover type (IGBP), yearly: MODIS Terra and Aqua land cover (MCD12Q1), NASA LP DAAC · 2024
- Enhanced vegetation index, rolling 8 days: MODIS Terra EVI, NASA LANCE · 13 Oct 2026
- Vegetation greenness (NDVI), rolling 8 days: MODIS Terra NDVI, NASA LANCE · 13 Oct 2026
- Population density, 2020: Population: CIESIN, Columbia University, Gridded Population of the World v4.11 (2018), NASA SEDAC, CC BY 4.0 · static
- Night-time lights, daily: VIIRS Black Marble (VNP46A2), NASA LAADS DAAC · 12 Oct 2026
Orbital sustainability protects services every domain uses.
Sustainability studies are designed for the Foresight Outlook series. The COPUOS guidelines (2019), IADC mitigation guidelines and ESA’s annual Space Environment Report frame the evidence.
- Debris environment analyses.
- Mitigation compliance studies.
Space safety console.
The screen a team would use to follow this subject: its measures, states and decisions. Names are examples and values are illustrative.
Space safety console
Space debris and sustainability · Orbit shell 550 km · Week 19
Conjunctions
| 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 |
Manoeuvre plan
- Delta-v
- 0.15 m/s
- Window
- T-10 h
- Fuel left
- 42 pct
- Decision
- operator
What is measured, and how well.
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 |
Model space debris and sustainability as a system. Run the cascade.
Assembled from the Nexus Standards area profile Climate risk standards: the hazards it names, the systems and sectors that carry the loss, the controls that dampen it and the data that observe it. Choose the components, pick an initiating hazard and step through the cascade. The Map view places the run on an example geography with open data. Every coupling weight is a stated assumption you can change. A teaching model, not a forecast, an assessment or a certification. To model a place of your own choosing, open the full System Builder.
Hazards
- Sea-level rise
- Coastal flood (set off downstream)
- Storm surge (set off downstream)
- High-tide flooding (set off downstream)
- Coastal erosion (set off downstream)
- Saltwater intrusion (set off downstream)
- Estuary flood (set off downstream)
- Coastal habitat squeeze (set off downstream)
- Wetland loss (set off downstream)
- Mangrove loss (set off downstream)
- Groundwater flood (set off downstream)
- Climate-driven migration and relocation (set off downstream)
- Mass displacement (set off downstream)
Systems and couplings
Controls
NS-0Constitution and principlesNS-1The UNI and the artefact catalogue (grammar v0.2: domain, sector, region and environment segments)NS-3Risk record UNIs (grammar, legacy crosswalk, allocation authority)NS-3bDataset and product metadata profile (STAC, DCAT, PROV-O)NS-9Contextual UNIs (deployments, instances, programme instances)NS-11Verification and monitoring (evidence, attestations, zero-trust conformance observation)NS-14Conformance and crosswalk to external standardsNRS-H65Hazard family: Planetary boundary transgressions (NHS-1 planet.boundary)NRS-H62Hazard family: Compound and multi-hazard events (NHS-1 sys.compound)NRS-H71Hazard family: Deep-time and cosmic catastrophes (NHS-1 planet.deep-time)NRS-H79Hazard family: Mental health crises (NHS-1 health.mental)NRS-H75Hazard family: Climate-sensitive illness (NHS-1 health.climate-sensitive)NRS-H7Hazard family: Large-scale circulation anomalies (NHS-1 atmo.climate-mode)
Observation
- ERA5 reanalysis (Copernicus Climate Data Store) (listed for reference)
- CMIP6 climate projections (Copernicus Climate Data Store) (listed for reference)
- NGFS Scenario Explorer (listed for reference)
- INFORM Risk Index (listed for reference)
- Number of deaths, missing persons and directly affected persons attributed to disasters per 100,000 population
- Total greenhouse gas emissions per year
- Direct economic loss attributed to disasters in relation to global GDP
Example geography
- Pacific Island states: 150 hexagonal cells
- Night lights tonight, outages (VIIRS Day/Night Band), NASA GIBS
- Surface water through cloud, 30 m (OPERA DSWx-S1 radar), NASA GIBS
- Rain rate, last half hour (IMERG), NASA GIBS
- Vegetation disturbance alerts, 30 m (OPERA DIST-ALERT), NASA GIBS
Where the evidence comes from.
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 |
How space debris and sustainability is modelled, measured and tested.
The model, its assumptions, its data and its uncertainty, in the form a scientist or engineer would check. Structures follow published methods. The values drawn are illustrative, not findings.
Earth observation chain
How a satellite or sensor record becomes evidence on space debris and sustainability, and where each step adds uncertainty.
- 01 · Acquireorbit, sensor and revisitUncertainty: gaps from cloud and orbit
- 02 · Calibrateradiometric and geometricUncertainty: sensor drift
- 03 · Correctatmosphere and terrainUncertainty: aerosol and slope assumptions
- 04 · Retrieve or classifythe variable or the classUncertainty: model and training error
- 05 · Validateagainst ground truthUncertainty: sample design and size
- 06 · Publishwith error bars and lineageUncertainty: stated, never hidden
Who decides, and what the evidence serves.
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 |
Outputs this topic produces
- Orbital congestion summaries by region
- Compliance analyses of debris mitigation
- Collision risk methods reviews
- Evidence notes on space sustainability rules
What experts ask.
Orbital scientists and space engineers ask how to keep orbits usable.
- How many objects are in each orbital region, and how well are they tracked?
- How does collision risk change as large constellations are deployed?
- How long does debris remain in different orbits, and what removes it naturally?
- Which practices, such as disposal at end of life and collision avoidance, are most effective?
- How can tracking data and operator intentions be shared to coordinate safely?
Why debris can cascade.
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.
How the evidence is built, and where it stops.
- 01
Tracking and cataloguing
Radar and optical tracking of objects, with space systems expertise. Small debris is largely untracked.
- 02
Orbital dynamics modelling
Predicting trajectories and decay, grounded in physics. Atmospheric drag is uncertain, especially during solar activity.
- 03
Collision risk assessment
Estimating conjunction probabilities with statistical methods. Uncertain orbits produce many false alarms.
- 04
Long-term environment modelling
Simulating debris populations over decades. Results depend on assumptions about future launches and compliance.
How it is studied, and what the methods cannot say.
- 01Space systems and satellite servicesMission continuity analysis · Space segment resilience · Debris compliance assessmentApplied here
- 02Physics and quantum scienceRadiative transfer for atmospheric correction · Microwave scattering · Orbit determinationApplied here
- 03Spatial statistics and geostatisticsArea estimation with error-adjusted counts · Stratified sampling designApplied here
- 04High-performance, cloud and edge computingAnalysis next to the archive · Reproducible processing chains · National data cubesApplied here
Where this page’s references lead.
The bodies and documents this page is read against. Status and editions change; each link goes to the issuing body.
Questions and answers.
What is space debris?
What is the Kessler syndrome?
How are collisions avoided?
Does debris fall back to Earth?
Can debris be removed actively?
Does the platform track objects in orbit?
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