Methodology
How the edition was made: methods, the model card, the evidence cut and its age, the acceptance record and the glossary.
Contents
- ·Edition home
- ·Executive summary
- 1Orbit is shared infrastructure under growing load
- 2Key findings
- 3Systems and sectors at baseline
- 4Risks and capability
- 5Severe storm in a crowded low orbit
- 6Readings from the other desks
- 7The 2027 agenda
- 8Systems in depth
- AMethodology
- BData appendix
- CReferences and record
- ·Complete edition, for print
A.1Methods
The global baseline uses published values and four simple derivations. Each is shown in full so that any reader can reproduce it.
| No. | Derivation | Calculation | Result |
|---|---|---|---|
| (1) | Share of active satellites in one constellation | 11,148 ÷ 17,099 | about 65% |
| (2) | Share of catalogued objects that are spacecraft | 19,154 ÷ 34,054 | about 56% |
| (3) | Fall in CRASH Clock, 2018 to June 2025 | 164 ÷ 5.5 | about 30 times |
| (4) | Active satellites outside the largest constellation | 17,099 − 11,148 | 5,951 |
| Strength | Definition |
|---|---|
| STRONG | a disruption in the source system has historically changed the target system’s service or output within one season, in more than one region |
| MODERATE | an effect is documented but buffered or slower |
| WEAK | an effect is plausible but not documented at global scale |
| Label | Rule |
|---|---|
| Reported | value as issued by its source, with year |
| Inferred | reasoned from cited evidence; never a measurement |
| Estimated | Nexus analytical value with stated method |
| Scenario | conditional on stated assumptions |
| Expert input | structured editorial judgement awaiting evidence |
A.2Model card, Space System Model v0
- Model ID
- MDL-XT18-SPACE · v0.1
- Purpose
- represent orbital infrastructure as shared infrastructure coupled to space weather, navigation and timing, communications, cyber security, atmosphere and governance
- Family
- graph-based system of systems
- Inputs
- the cited sources of this edition; no proprietary data
- Method
- expert-specified coupling strengths (STRONG · MODERATE · WEAK) from assessments and analogue events
- Validation
- none yet, first validation against federation evidence in 2027
- Uncertainty
- qualitative; strengths are hypotheses, not measurements
- Domain of validity
- global scale; not for asset-, site- or country-level use
- Reproducibility
- strength table and sources published in this edition
20couplings
typed in v0
0strong
documented within one season
0moderate
documented, buffered
20weak
plausible, undocumented
A.3The baseline evidence cut
Every Nexus edition is published from a frozen evidence cut. The global baseline cut is documentary: it pins the exact edition of every source cited. Federation cuts begin with the first national Foundry cuts in 2027.
- Cut ID
- DC-XTECH-SPACE-GLOBAL-2026-B0
- Type
- baseline documentary cut
- Resolution policy
- pinned · as of 30 September 2026
- Sources pinned
- 43 cited sources, each at the edition and access date in the references
- Model runs
- none at baseline, analytical values are stated with their method
- Digest
- computed at freeze and recorded in the publication record
- Supersedes
- nothing, first cut of the series
- Superseded by
- the 2027 space annual cut
Lineage
- 01
source edition
- 02
pinned citation
- 03
finding
- 04
page
- 05
publication record
| Element | Baseline 2026 | 2027 global annual |
|---|---|---|
| Sources | cited global publications, pinned by edition | national, regional and sector cuts through one graph |
| Analysis | stated methods and editorial estimates | typed analysis specifications |
| Models | Space System Model v0 specification | model runs with receipts |
| Findings | twelve baseline findings | findings re-bound to federation evidence |
| Review | five passes scheduled | five passes on the exact digest |
A.4Evidence age and coverage
A 2026 global edition rests on evidence observed in many different years. This page shows each time base, so that no single year label hides older evidence.
| Indicator | Observed | Released | Cadence | Next release |
|---|---|---|---|---|
| Catalogued objects | 2026 | as of 4 Aug 2026 | quarterly | next quarterly issue |
| Active satellites | 2026 | 26 Oct 2026 | continuous | next update |
| ESA debris estimates | 2024 | report of Apr 2025 | annual | next report |
| ESA launch and reentry data | 2025 | report of 14 Sep 2026 | annual | next report |
| May 2024 storm | 2024 | May 2024 · article May 2025 | per event | next severe storm |
| CRASH Clock | 2025 | Dec 2025 · revised Jun 2026 | one-off | peer review |
| GPS benefit study | 2019 | Oct 2019 | one-off | new studies |
| Satellite network attack | 2022 | Feb 2022 · May 2022 | per event | incident reports |
| Reentry emissions model | 2024 | Jun 2024 | one-off | measurement campaigns |
| EU Space Act | 2025 | Jun 2025 · Nov 2025 | per meeting | compromise text |
| System | Coverage | Thinnest dimension |
|---|---|---|
| Orbital population | GOOD | common basis across catalogues |
| Space weather | PARTIAL | forecast skill and exposure |
| Navigation | PARTIAL | non-US outage costs |
| Cyber | PARTIAL | ground-segment incident data |
| Atmosphere | THIN | measured emissions by species |
| Governance | PARTIAL | text and adoption of rules |
| Economy | THIN | industry size from the report itself |
| Supply and workforce | THIN | materials, launch capacity, people |
| Field | Source that would fill it | Blocker |
|---|---|---|
| Object and debris counts on a common basis across catalogues | national catalogues, ESA, public trackers145 | counts of 34,054 catalogued, about 40,000 tracked and about 50,000 large trackable use different bases and are not reconciled |
| Conjunction and maneuver counts by operator | operator reports, national catalogues | not retrieved; ESA gives conjunction counts only in a figure1 |
| Debris and satellite counts from the ESA 2026 report itself | ESA Space Environment Report 20262 | only the summary page was read; tracked object and fragmentation counts were not on it |
| Peer review of the CRASH Clock estimate | journal publication of the preprint9 | not located; earlier versions and press reports gave other values |
| Launch and reentry emissions by species, measured | atmospheric measurement campaigns, peer-reviewed studies102930 | only a modelling study was read10 |
| Industry size and investment from the report itself | Space Foundation report and SIA 2026 report2223 | the Space Foundation page returned an access error; the SIA page gave no figures; the 2024 value rests on search summaries |
| Text and current status of the EU Space Act | Commission proposal and Parliament records24 | proposal not opened; Council note read for November 2025 only14 |
| Date the FCC five-year rule applies to each licence | FCC order appendix11 | the order was read; the applicability date was not confirmed |
| Outage costs of navigation outside the United States | EU and national studies2135 | not retrieved; the study read covers US private-sector use15 |
| Backup navigation and timing capacity of critical sectors | national agencies, operators | not retrieved; rung stays LISTED |
| Supply chains and materials for satellites and ground segments | industry and trade statistics | not retrieved |
| Space workforce and launch capacity by country | national statistics, industry surveys | not retrieved; capability rung stays LISTED |
| Loss and insurance data for orbital assets | insurers, operators | not retrieved; no figure used |
| Capability rungs beyond tracking, rules and research | agencies, operators, laboratories | not reviewed |
A.5Evidence cards, two anchor sources
Issued by the NASA Orbital Debris Program Office in September 2026. Periodic, quarterly. Role: binds ORB-001 and the lead figure. Coverage: objects catalogued by one national network as of 4 August 2026.
EVD-XT18-001
NASA Orbital Debris Quarterly News, September 20264
Issued by ESA on 14 September 2026, with data through 2025. Annual. Role: binds ORB-004. Coverage: world launches and reentries; summary page read.
EVD-XT18-002
Satellite launch and reentry data in the ESA Space Environment Report 20262
| Dimension | EVD-XT18-001 | EVD-XT18-002 |
|---|---|---|
| Completeness | one national catalogue; objects large enough to track | summary page of the full report |
| Timeliness | box score dated 4 August 2026 | data through the end of 2025 |
| Revision | quarterly issues | annual reports |
| Method transparency | catalogue definitions stated in the issue | report and methods published |
| External validation | agency catalogue; no peer review | agency report; no peer review |
Evidence cards to follow in 2027
A.6Publication acceptance record
Editorial self-check at evidence close. Every applicable item carries a disposition; the remaining items are review, approval and deposit.
| Group | Area | Items | Pass | N/A | Pending |
|---|---|---|---|---|---|
| D1 | Identity and scope | 8 | 8 | 0 | 0 |
| D2 | Source and data | 12 | 9 | 1 | 2 |
| D3 | Analysis and models | 12 | 3 | 8 | 1 |
| D4 | Findings and claims | 9 | 8 | 0 | 1 |
| D5 | Figures, tables, maps | 10 | 6 | 2 | 2 |
| D6 | Editorial and citations | 10 | 8 | 0 | 2 |
| D7 | Review and approval | 13 | 0 | 0 | 13 |
| D8 | Artefact and design | 12 | 7 | 0 | 5 |
| D9 | Registry and release | 9 | 0 | 0 | 9 |
Publication gate
- Conditions met
- 14 of 23 at evidence close
- Blocking problems
- none recorded
- Open conditions
- reviews, approval of the exact digest, deposit, registry pointer
Not applicable at baseline
- Model runs
- first runs in Q1 2027
- Maps
- plates in Q2 2027
- Waivers
- none
A.7Status words
| Status | What it means |
|---|---|
| Observed | Measured directly and published by the source. |
| Reported | Published statistics of an official or institutional source. |
| Declared | Stated by the body concerned; not independently measured. |
| Estimated | A Nexus estimate from cited evidence, with its method in Annex A. |
| Modelled | Produced by a stated model from cited inputs. |
| Inferred | Reasoned from cited evidence; not measured. |
| Forecast | A projection by the cited source. |
| Simulated | A simulation result under stated assumptions. |
| Scenario | A conditional statement under stated assumptions; never a prediction. |
| Expert input | Expert judgement, recorded with its basis. |
| Candidate | Proposed for a later edition; not yet evidence. |
| Evidence-quality levels (EQL 1 to 5) grade the source behind a value; they are not a score of the subject. | |
A.8How the edition is made, released and corrected
Every edition is built from a sealed evidence cut, reviewed under three keys, signed and deposited before any site shows it as published; corrections go to Nexus Standards as change proposals and feed the next cut.
| Step | What happens | Source |
|---|---|---|
| 01 Evidence arrives from the pillars | Foundry seals observations and indicator series, Universe hands over after-action and scenario findings, and contributions are screened at every gateway, including this site’s. | |
| 02 The cut is sealed | On the cut date the evidence is pinned under one identifier, so anyone can rebuild the edition from exactly what it was built on. | |
| 03 The edition is assembled | The edition is drafted from its template and content pack. Agents may draft; they never publish and never decide. | |
| 04 The keys turn | At the publisher of record the truth key comes first: every value is checked against its source or stated method before the meaning and capital keys turn. No edition moves on until every key has been turned by a named steward. | |
| 05 The gate opens | A named approver releases one exact digest of the edition; any change after this point is a new version, never a silent edit. | |
| 06 Signed and deposited | The PDF, the web edition and the data bundle are signed together with a manifest and an RO-Crate description, and deposited on Zenodo with a concept and a version DOI. | |
| 07 Published on its desk’s site | Only then does the edition show as published on its desk’s Reports site, and the Collection lists it as a part. | |
| 08 Corrections go to Standards | Method and correction findings go to Nexus Standards as change proposals; citations, corrections and new contributions feed the next evidence cut. |
A teaching model of the process, not a forecast and not a record of any run; dates and counts on this page come from the programme record. Sources: Reports governance at GCRI Canada (2026); Zenodo, repository of record for Reports deposits (2026).
Lifecycle, one state at a time: Draft, Computed, Evidence bound, Reviewed, Approved for release, Published, Corrected, Superseded. This edition is a draft.
A.9Glossary and abbreviations
| Term | Meaning |
|---|---|
| Baseline Edition | the inaugural annual edition that fixes the reference state for the series |
| WEFH+B | water, energy, food, health and biodiversity, the national nexus core |
| Coupling | a typed dependency through which one system transmits to another |
| Protection gap | the share of losses not covered by insurance |
| Capability ladder | LISTED → EXISTS → ADEQUATE → TESTED → DEMONSTRATED |
| EQL | evidence-quality level, 1–5 |
| Evidence cut | a frozen resolution of exact sources and versions |
| NNC · NLC · NWG | National Nexus Consortium · National Leadership Council · National Working Groups |
| Abbreviation | Expansion |
|---|---|
| ESA | European Space Agency |
| EU | European Union |
| FCC | US Federal Communications Commission |
| GEO | geostationary orbit |
| GNSS | global navigation satellite system |
| GPS | Global Positioning System |
| ITU | International Telecommunication Union |
| LEO | low Earth orbit |
| MEO | medium Earth orbit |
| NOAA | US National Oceanic and Atmospheric Administration |
| SSN | US Space Surveillance Network |
| TLE | two-line element set |
A.10Technical annex
| Item | Annex | Contents | Status |
|---|---|---|---|
| A.1 | Indicator definitions | the global indicator set, with units and sources | IN THIS EDITION |
| A.2 | Coupling strengths | the twenty-cell matrix and its rationale | IN THIS EDITION |
| A.3 | Scenario specification | SCN-XT18-STM-01 assumptions and signposts | IN THIS EDITION |
| A.4 | Capability placements | rung evidence for fifteen functions | IN THIS EDITION |
| A.5 | Model diagnostics | first runs and validation | 2027 |
| A.6 | Sensitivity analyses | influence of coupling strengths | 2027 |
| A.7 | Cluster notes | cards for the major orbital shells and ground-segment clusters | 2027 |
| A.8 | Review statements | pass-by-pass review record | AT RELEASE |
A.1 · indicator definition: CRASH Clock
- Construct
- time to a possible catastrophic collision if satellites stopped maneuvering or situational awareness were severely lost
- Unit
- days
- Method
- computed from catalogued orbits and conjunction frequency under stated assumptions
- Source
- arXiv preprint, revised June 20269
- Uncertainty
- earlier versions and press reports gave other values; assumptions drive the result
- Known limits
- a model metric, not a forecast; peer review not located
Notes
Numbers are the edition’s reference numbers, so a note reads the same in every chapter. The full list, with every source and its licence, is in Annex C. Annex C, references
- 1ESA (ed.), ESA Space Environment Report 2025 (summary page dated 1 April 2025; data through the end of 2024). European Space Agency, Paris. Observation year 2024. Accessed 2026-11-03.back
- 4NASA Orbital Debris Program Office (ed.), Orbital Debris Quarterly News, Volume 30, Issue 3, September 2026 (satellite box score as of 4 August 2026; launch table May to July 2026). National Aeronautics and Space Administration, Houston. Observation year 2026. Accessed 2026-11-03.back
- 5NASA Orbital Debris Program Office (ed.), Orbital debris frequently asked questions (more than 34,000 objects catalogued as of August 2026; about 100 million millimeter-sized pieces; 41 ISS avoidance maneuvers since 1999). National Aeronautics and Space Administration, Houston. Observation year 2026. Accessed 2026-11-03.back
- 2ESA (ed.), ESA Space Environment Report 2026 (summary page dated 14 September 2026; data through the end of 2025; the full report PDF was not opened). European Space Agency, Paris. Observation year 2025. Accessed 2026-11-03.back
- 9Thiele, S., Heiland, S.R., Boley, A.C. and Lawler, S.M., An Orbital House of Cards: Frequent Satellite Close Conjunctions, arXiv:2512.09643, submitted 10 December 2025, version 3 of 29 June 2026 (abstract page read; preprint, peer review not located; the abstract of this version gives 5.5 days and 164 days). arXiv, Ithaca. Observation year 2025. Accessed 2026-11-03.back
- 10Ferreira, J.P., Huang, Z., Nomura, K. and Wang, J., Potential Ozone Depletion From Satellite Demise During Atmospheric Reentry in the Era of Mega-Constellations, Geophysical Research Letters 51, 2024, DOI 10.1029/2024GL109280 (full text read; modelling study). American Geophysical Union, Washington. Observation year 2022. Accessed 2026-11-03. doi:10.1029/2024GL109280back
- 29UNVERIFIED, not opened: Ryan, R.G. and others, Impact of Rocket Launch and Space Debris Air Pollution on Stratospheric Ozone and Global Climate, Earth’s Future 10, e2021EF002612, 2022, cited from memory. Observation year 2022. Accessed 2026-11-03.back
- 30UNVERIFIED, not opened: Maloney, C. and others, study of satellite reentry aluminum in the atmosphere, Journal of Geophysical Research: Atmospheres, April 2025, taken from a search-result summary that says its modelling did not include interactive ozone chemistry. Observation year 2025. Accessed 2026-11-03.back
- 22SIA (ed.), State of the Satellite Industry Report, 2026 edition covering fiscal year 2025 (web page read; the executive summary was not read and no figure is used). Satellite Industry Association, Washington. Observation year 2025. Accessed 2026-11-03.back
- 23UNVERIFIED, not opened: Space Foundation (ed.), The Space Report 2025 Q2 (global space economy USD 613 billion in 2024, about 7.8% growth, about 78% commercial), taken from search-result summaries; the page returned an access error. Space Foundation, Colorado Springs. Observation year 2024. Accessed 2026-11-03.back
- 24UNVERIFIED, not opened: European Commission (ed.), Proposal for a Regulation on the safety, resilience and sustainability of space activities in the Union (EU Space Act), COM(2025) 335, published 25 June 2025, taken from search-result summaries; the Council note gives 26 June 2025 as the transmission date. European Commission, Brussels. Observation year 2025. Accessed 2026-11-03.back
- 14General Secretariat of the Council (ed.), Note 15830/25, Regulation on the safety, resilience and sustainability of space activities in the Union (EU Space Act), progress report for the Competitiveness Council of 8 and 9 December 2025, interinstitutional file 2025/0335 (COD), 26 November 2025. Council of the European Union, Brussels. Observation year 2025. Accessed 2026-11-03.back
- 11FCC (ed.), Second Report and Order, FCC 22-74, Mitigation of Orbital Debris in the New Space Age, IB Docket Nos. 22-271 and 18-313, adopted 29 September 2022, released 30 September 2022. Federal Communications Commission, Washington. Observation year 2022. Accessed 2026-11-03.back
- 21EUSPA (ed.), Galileo (web page last modified 25 September 2026; no satellite count on the page). European Union Agency for the Space Programme, Prague. Observation year 2026. Accessed 2026-11-03.back
- 35UNVERIFIED, not opened: Royal Academy of Engineering (ed.), Global Navigation Space Systems: reliance and vulnerabilities, March 2011, cited from memory; the page returned an error. Royal Academy of Engineering, London. Observation year 2011. Accessed 2026-11-03.back
- 15NIST (ed.), Economic Benefits of the Global Positioning System to the US Private Sector (news page dated 2 October 2019, updated 3 February 2025; study by RTI International sponsored by NIST; about USD 1.4 trillion in 2017 dollars, 1984 to 2017). National Institute of Standards and Technology, Gaithersburg. Observation year 2019. Accessed 2026-11-03.back
- 6Parker, W.E. and Linares, R., Satellite Drag Analysis During the May 2024 Gannon Geomagnetic Storm, arXiv:2406.08617, 2024 (abstract page read; preprint). arXiv, Ithaca. Observation year 2024. Accessed 2026-11-03.back