Guidance

Cross-government Space Domain Awareness (SDA) requirements

Updated 16 June 2026

1. Foreword

The decision to set broad strategic requirements for Space Domain Awareness (SDA) reflects the increasingly complex and dynamic nature of the space domain. Space has become crowded and contested, with actors undertaking activities ranging from satellite deployments for peaceful purposes to actions with potential security implications. A high-level approach acknowledges that SDA is not a singular, isolated effort but a multifaceted, interconnected endeavour.

Adopting a System of Systems (SoS) approach reflects the need to integrate a variety of sensors, capabilities and data sources to understand and respond to activities in space. This strategic focus enables flexibility and adaptability as threats and technologies evolve. By maintaining high-level requirements that are subject to regular review, the UK can remain agile as the space domain continues to develop.

A cross-government approach has been adopted to establish these high-level SDA requirements, forming the foundation of a dual-use, civilian and military SDA SoS. Regular reviews and ongoing collaboration with stakeholders are essential to keep pace with operational and technological change.

2. Introduction

In May 2024, the Ministry of Defence (MOD) and UK Space Agency launched a dual-use civilian-military National Space Operations Centre (NSpOC), delivering SDA through a centralised SoS. An initial set of cross-government Space Domain Awareness Requirements (hereafter “requirements”) were established to inform the development of the SoS, which spans the full SDA chain – from sensors and data processing through to readouts for policymakers.

Given the rapid evolution of the space domain, these requirements are reviewed continuously and refreshed annually, now in their third iteration [v3.0], to reflect the changing nature of the operating environment. These requirements provide transparency on the current operational vision for the UK SDA SoS, and inform industry and academia of potential future needs across government.

3. Context

The space domain has become increasingly congested and complex, driving the need for space surveillance and tracking to detect, track, and identify objects. Across UK Government, SDA is recognised as the ability to understand the space environment, including active objects and their activities, orbital debris, and natural phenomena such as space weather. It involves searching for, tracking, and characterising objects, risks, hazards, and threats, and forecasting processes in the Earth’s space environment, to enable informed decision-making that protects UK interests. For military operational purposes, it is centred on providing security-focused, decision-quality information that can be used to successfully mitigate adversary space effects and support the integration of allied space effects into multi-domain operations.

The 2025 Strategic Defence Review, Making Britain Safer: Secure at Home, Strong Abroad, set out the UK’s ambitious vision for the space domain, including its approach to SDA.  Together with the upcoming refresh of Joint Doctrine Publication (JDP) 0-40 UK Space Power, these documents will provide a clear strategic direction aimed at delivering improved SDA and a unified civil-defence approach. Collaboration across government is essential to achieving these objectives, with development of a resilient SDA capability identified as a priority over the next three years.

4. UK SDA Systems-of Systems

As part of this initiative, SDA is delivered through a SoS approach, leveraging international partnerships and commercial off-the-shelf solutions to complement national capabilities, whilst also safeguarding sensitive data and ensuring capability assurance. To realise this vision, a SoS is being adopted as the hardware and software backbone of the NSpOC capability.

This approach combines data from multiple sensors with operational and intelligence sources to enhance SDA. It encompasses space, ground, and link segments and is inherently dual-use, with sensor data supporting a range of civil and military functions. The focus is on developing a cohesive, integrated system that effectively analyses activities in space and delivers comprehensive domain awareness.

5. Cross-Government SDA Requirements

This initiative is underpinned by a set of UK SDA requirements developed and maintained by MOD, UK Space Agency, and other government stakeholders.

Some elements are sensitive in nature and have therefore been redacted from public versions. The full, unredacted requirements, covering measures of performance, justifications, and priority status, are maintained for UK Government purposes only.

Annexes A and B outline the current redacted set [v3.0] of UK SDA Requirements, covering both operational user requirements and technical system requirements. Annex A sets out the operational user requirements, including areas such as orbital event assessment, conjunction analysis, and space object characterisation. These requirements are designed to ensure that space activities are monitored, assessed, and understood comprehensively. Annex B details the technical system requirements, providing the technical specifications and criteria for the SoS. Specific requirements are identified, such as orbital regimes, object size detection criteria, sensor revisit rates, and resolvable separation distance, amongst others.

Across both Annex A and B, priority areas have been highlighted to demonstrate critical areas of focus for the UK government’s SDA aspirations. For a select number of system requirements, performance thresholds of an appropriate classification have also been included in Annex B. The publication of these requirements does not imply a commitment to issue a tender or contract in the future. The intention is to create awareness and maintain open communication, allowing for early engagement and clarity, without guaranteeing any specific procurement activities.

Owing to evolving requirements and further definition of operational needs, this document supersedes previously published versions. As such, some entries have been updated, modified or retired since the last published version. Furthermore, due to additional changes and an overall restructuring of the document, the current version features a revised numbering scheme which also replaces that used by previous versions.

NOTE: The Measure of Performance (MoP) figures and descriptions contained in this document are indicative thresholds designed to shape further development and are not reflective of the UK’s current capabilities or future goals.

6. Annexes

6.1 Annex A: UK Space Domain Awareness Requirements – User Requirements

ID	Requirement Heading	Requirement Description	Priority
UKSDA-UR-01	UK Spacecraft Licensing & Compliance Monitoring	The SoS shall allow verification of compliance of UK-licensed spacecraft to licence conditions, for all orbits of interest and including beyond Earth orbit
UKSDA-UR-02	Monitoring of Space Debris Mitigation Compliance	The SoS shall allow assessment and monitoring of UK RSO compliance against UK space debris policy
UKSDA-UR-03	Monitoring of EM Spectrum Compliance	The SoS shall allow monitoring of the EM spectrum for compliance with spectrum regulation and detection of interference
UKSDA-UR-04	Monitoring of Orbital Position Compliance	The SoS shall support the monitoring of UK RSOs for compliance with regulations on orbital position
UKSDA-UR-05	Operational Space Picture	The SoS shall enable the development of a high-quality operational space picture, to enable decision-making by UK government
UKSDA-UR-06	SDA Data, Models and Tools	The SoS shall provide data, models, and tools to support predictive and retrospective analyses
UKSDA-UR-07	Command and Control	The SoS shall provide systems to enable the execution of timely C2	Priority
UKSDA-UR-08	RSO Characterisation	The SoS shall enable the characterisation of RSOs
UKSDA-UR-09	Warning Enabling Services	The SoS shall provide UK users with access to services for the provision of appropriate alerts and extant Warning Enabling Services as required, including but not limited to the following: Direct Ascent ASAT warnings; Space Weather alerts; Orbital Event notifications; Satellite Warning Services; International Treaty Obligations
UKSDA-UR-10	Cyber and EM Activity Monitoring	The SoS shall provide support to the monitoring and reporting of cyber and EM spectrum interference, jamming, and spoofing in, from and to space
UKSDA-UR-11	Space Environment Monitoring	The SoS shall support the generation and understanding of space weather and natural environment information, to enable effective decision making and actions	Priority
UKSDA-UR-12	Conjunction on Launch Assessment	The SoS shall support the identification and assessment of potential conjunctions on launch (COLA)
UKSDA-UR-13	Orbital Event Assessment	The SoS shall detect, characterise and attribute orbital events
UKSDA-UR-14	Space Sustainability	The SoS shall provide evidence and expertise to support sustainable space behaviour, inform understanding of sustainability of space, and inform decision making on UK position on sustainability
UKSDA-UR-15	Risk Assessment	The SoS shall provide adequate and appropriate risk assessment, of both terrestrial and in-space risks
UKSDA-UR-16	Terrestrial Risks from UK RSOs	The SoS shall support the assessment of terrestrial risks to life, property, public health and the environment from current and potential UK RSOs
UKSDA-UR-17	In-Space Risks from UK RSOs	The SoS shall support the assessment of in-space risks to life, property and the environment from current and potential UK RSOs
UKSDA-UR-18	Terrestrial Risks from Non-UK RSOs	The SoS shall support the assessment of terrestrial risks to UK life, property, public health and the environment from orbital debris and non-UK RSOs
UKSDA-UR-19	In-Space Risks from Non-UK RSOs	The SoS shall support the assessment of in-space risks to UK life, property and the environment from orbital debris and non-UK RSOs
UKSDA-UR-20	Risks to UK CNI	The SoS shall provide timely information to reduce the risk from in-space hazards to UK Critical National Infrastructure (CNI) or UK-licensed RSOs e.g. provision of conjunction warning and fragmentation break-up information
UKSDA-UR-21	Terrestrial Risks from UK Launch Activities	The SoS shall support the assessment of terrestrial risk to life, property, public health and the environment from UK launch activities
UKSDA-UR-22	Dual Use Applications	The SoS shall allow UK users to concurrently exploit both Civilian and Military capabilities and capacity, providing and/or requiring SDA
UKSDA-UR-23	Interoperability	The SoS shall support appropriate national, international, and commercial collaboration and data/information sharing
UKSDA-UR-24	Independent UK SDA Data and Assurance Capabilities	The SoS shall include sovereign and/or nationally-separable UK SDA sovereign assurance capabilities	Priority
UKSDA-UR-25	Independent UK SDA National Capabilities	The SoS shall include sovereign and/or nationally-separable UK SDA capabilities, including sufficient infrastructure to support capabilities and personnel	Priority
UKSDA-UR-26	Developing UK Industrial Capability	The SoS shall facilitate the development of a resilient and competitive UK SDA industry and academic community, capable of supplying high-quality products and services to domestic and international partners	Priority
UKSDA-UR-27	Space Control	The SoS shall generate and include sufficient SDA data to support Space Control activities, where appropriate	Priority
UKSDA-UR-28	Planetary Defence	The SoS shall support the planetary defence mission
UKSDA-UR-29	Airspace Management	The SoS shall support the provision of airspace management where impacted by space-related activities
UKSDA-UR-30	Spacecraft Operator Support	The SoS shall provide information to support spacecraft operator activities, including recovery from failure
UKSDA-UR-31	Independent UK SDA Skills and Expertise	The SoS shall support the development, maintenance and evaluation of UK national SDA skills and expertise	Priority
UKSDA-UR-32	Exercises and Wargames	The SoS shall enable Space Control exercises and wargames, using both simulated and live capabilities and data	Priority
UKSDA-UR-33	Development of TTPs and COAs	The SoS shall enable the development of operational TTPs and COAs

6.2 Annex B: UK Space Domain Awareness Requirements – System of Systems Requirements

ID	Requirement Heading	Requirement Description	Thresholds Civil/Military	Priority
UKSDA-SR-01	RSO Detection	The SoS shall be capable of detecting RSOs across all regions of interest	See Sub-Requirements
UKSDA-SR-01-001	RSO Detection (LEO)	The SoS shall be capable of observation of all RSOs in LEO exceeding a minimum characteristic length	Capable of detection of RSOs of ≥ 5 cm in characteristic length
UKSDA-SR-01-002	RSO Detection (MEO)	The SoS shall be capable of observation of all RSOs in MEO exceeding a minimum characteristic length	Capable of detection of RSOs of ≥ 20 cm in characteristic length
UKSDA-SR-01-003	RSO Detection (HEO)	The SoS shall be capable of observation of all RSOs in HEO exceeding a minimum characteristic length	Capable of detection of RSOs of ≥ 20 cm in characteristic length
UKSDA-SR-01-004	RSO Detection (GEO)	The SoS shall be capable of observation of all RSOs in GEO exceeding a minimum characteristic length	Capable of detection of RSOs of ≥ 20 cm in characteristic length
UKSDA-SR-01-005	RSO Detection (Cislunar)	The SoS shall be capable of observation of all RSOs in cislunar space exceeding a minimum characteristic length	Capable of detection of RSOs of ≥ 1 m in characteristic length
UKSDA-SR-01-006	RSO Detection (BEO)	The SoS shall be capable of observation of all RSOs in BEO exceeding a minimum characteristic length	Capable of detection of RSOs of ≥ 5 m in characteristic length
UKSDA-SR-02	RSO Surveillance	The SoS shall be capable of conducting surveillance on all RSOs detectable according to MoPs stated by UKSDA-SR-01 across all regions of interest	See Sub-Requirements	Priority
UKSDA-SR-02-001	RSO Surveillance (LEO)	The SoS shall be capable of conducting surveillance on all RSOs in LEO detectable according to MoPs stated by UKSDA-SR-01-001	Surveillance of all RSOs in LEO of ≥ 5 cm in characteristic length
UKSDA-SR-02-002	RSO Surveillance (MEO)	The SoS shall be capable of conducting surveillance on all RSOs in MEO, detectable according to MoPs stated by UKSDA-SR-01-002	Surveillance of all RSOs in MEO of ≥ 20 cm in characteristic length
UKSDA-SR-02-003	RSO Surveillance (GEO)	The SoS shall be capable of conducting surveillance on all RSOs in GEO, detectable according to MoPs stated by UKSDA-SR-01-004	Surveillance of all RSOs in GEO of ≥ 20 cm in characteristic length
UKSDA-SR-02-004	RSO Surveillance (Cislunar)	The SoS shall be capable of conducting surveillance on all RSOs in cislunar space, detectable according to MoPs stated by UKSDA-SR-01-005	Surveillance of all RSOs in cislunar space of ≥ 20 cm in characteristic length
UKSDA-SR-02-005	RSO Surveillance (BEO)	The SoS shall be capable of conducting surveillance on all RSOs in BEO, detectable according to MoPs stated by UKSDA-SR-01-006	Surveillance of all RSOs in BEO of ≥ 1 m in characteristic length
UKSDA-SR-03	RSO Tracking	The SoS shall be capable of tracking all RSOs detectable according to MoPs stated by UKSDA-SR-01 across all regions of interest	See Sub-Requirements	Priority
UKSDA-SR-03-001	RSO Tracking (LEO)	The SoS shall be capable of tracking all RSOs in LEO, detectable according to MoPs stated by UKSDA-SR-01-001	Tracking of all RSOs in LEO of ≥ 5 cm in characteristic length
UKSDA-SR-03-002	RSO Tracking (MEO)	The SoS shall be capable of tracking all RSOs in MEO, detectable according to MoPs stated by UKSDA-SR-01-002	Tracking of all RSOs in MEO of ≥ 20 cm in characteristic length
UKSDA-SR-03-003	RSO Tracking (HEO)	The SoS shall be capable of tracking all RSOs in HEO, detectable according to MoPs stated by UKSDA-SR-01-003	Tracking of all RSOs in HEO of ≥ 20 cm in characteristic length
UKSDA-SR-03-004	RSO Tracking (GEO)	The SoS shall be capable of tracking all RSOs in GEO, detectable according to MoPs stated by UKSDA-SR-01-004	Tracking of all RSOs in GEO of ≥ 20 cm in characteristic length
UKSDA-SR-03-005	RSO Tracking (Cislunar)	The SoS shall be capable of tracking all RSOs in cislunar space, detectable according to MoPs stated by UKSDA-SR-01-005	Tracking of all RSOs in cislunar space of ≥ 20 cm in characteristic length
UKSDA-SR-03-006	RSO Tracking (BEO)	The SoS shall be capable of tracking all RSOs in BEO, detectable according to MoPs stated by UKSDA-SR-01-006	Tracking of all RSOs in BEO of ≥ 1 m in characteristic length
UKSDA-SR-04	RSO Revisit Rates	The SoS shall achieve sufficient minimum revisit rates for routine and high priority RSO/UCTs in all regions of interest	See Sub-Requirements
UKSDA-SR-04-001	RSO Revisit Rates (LEO Routine Priority)	The SoS shall accommodate gaps in observation of RSO/UCTs in LEO for catalogue maintenance purposes no greater than as specified in MoPs	Capacity to achieve observation revisit on all catalogued LEO RSOs with gaps in observation no greater than 48 hours / 24 hours
UKSDA-SR-04-002	RSO Revisit Rates (MEO Routine Priority)	The SoS shall accommodate gaps in observation of RSO/UCTs in MEO for catalogue maintenance purposes no greater than as specified in MoPs	Capacity to achieve observation revisit on all catalogued MEO RSOs with gaps in observation no greater than 36 hours
UKSDA-SR-04-003	RSO Revisit Rates (HEO Routine Priority)	The SoS shall accommodate gaps in observation of RSO/UCTs in HEO for catalogue maintenance purposes no greater than as specified in MoPs	Capacity to achieve observation revisit on all catalogued HEO RSOs with gaps in observation no greater than 48 hours / 24 hours
UKSDA-SR-04-004	RSO Revisit Rates (GEO Routine Priority)	The SoS shall accommodate gaps in observation of RSO/UCTs in GEO for catalogue maintenance purposes no greater than as specified in MoPs	Capacity to achieve observation revisit on all catalogued GEO RSOs with gaps in observation no greater than 36 hours / 24 hours
UKSDA-SR-04-005	RSO Revisit Rates (Cislunar Routine Priority)	The SoS shall accommodate gaps in observation of RSO/UCTs in cislunar for catalogue maintenance purposes no greater than as specified in MoPs	Capacity to achieve observation revisit on all catalogued cislunar RSOs with gaps in observation no greater than 48 hours / 24 hours
UKSDA-SR-04-006	RSO Revisit Rates (BEO Routine Priority)	The SoS shall accommodate gaps in observation of RSO/UCTs in BEO for catalogue maintenance purposes no greater than as specified in MoPs	Capacity to achieve observation revisit on all catalogued BEO RSOs with gaps in observation no greater than 48 hours
UKSDA-SR-04-007	RSO Revisit Rates (LEO High Priority)	The SoS shall accommodate gaps in observation of high priority RSO/UCTs in LEO no greater than as specified in threshold/objective MoPs	Capacity to achieve observation revisit on 2000 LEO RSOs with gaps in observation no greater than 8 hours
UKSDA-SR-04-008	RSO Revisit Rates (MEO High Priority)	The SoS shall accommodate gaps in observation of high priority RSO/UCTs in MEO no greater than as specified in threshold/objective MoPs	Capacity to achieve observation revisit on 100 MEO RSOs with gaps in observation no greater than 8 hours
UKSDA-SR-04-009	RSO Revisit Rates (HEO High Priority)	The SoS shall accommodate gaps in observation of high priority RSO/UCTs in HEO no greater than as specified in threshold/objective MoPs	Capacity to achieve observation revisit on 100 HEO RSOs with gaps in observation no greater than 8 hours
UKSDA-SR-04-010	RSO Revisit Rates (GEO High Priority)	The SoS shall accommodate gaps in observation of high priority RSO/UCTs in GEO no greater than as specified in threshold/objective MoPs	Capacity to achieve observation revisit on 400 GEO RSOs with gaps in observation no greater than 12 hours
UKSDA-SR-04-011	RSO Revisit Rates (Cislunar High Priority)	The SoS shall accommodate gaps in observation of high priority RSO/UCTs in cislunar space no greater than as specified in threshold/objective MoPs	Capacity to achieve observation revisit on 100 cislunar RSOs with gaps in observation no greater than 24 hours
UKSDA-SR-04-012	RSO Revisit Rates (BEO High Priority)	The SoS shall accommodate gaps in observation of high priority RSO/UCTs in BEO no greater than as specified in threshold/objective MoPs	Capacity to achieve observation revisit on 100 BEO RSOs with gaps in observation no greater than 24 hours
UKSDA-SR-04-013	RSO Custody Maintenance (Event-Based)	The SoS shall enable dynamic, high-rate tracking of RSOs involved in upcoming or ongoing events	Capability to maintain a Category II orbit state on all event-based RSOs at all times during event
UKSDA-SR-05	Separation Distance	The SoS shall be capable of resolving all closely-spaced RSOs across all regions of interest	See Sub-Requirements
UKSDA-SR-05-001	Separation Distance (LEO)	The SoS shall be capable of identifying and independently tracking all closely-spaced RSOs in LEO in accordance with SR-07-013	Minimum separation distance 50 m / 10 m
UKSDA-SR-05-002	Separation Distance (MEO)	The SoS shall be capable of identifying and independently tracking all closely-spaced RSOs in MEO in accordance with SR-07-013	Minimum separation distance 500 m / 10 m
UKSDA-SR-05-003	Separation Distance (HEO)	The SoS shall be capable of identifying and independently tracking all closely-spaced RSOs in HEO in accordance with SR-07-013	Minimum separation distance 500 m / 10 m
UKSDA-SR-05-004	Separation Distance (GEO)	The SoS shall be capable of identifying and independently tracking all closely-spaced RSOs in GEO in accordance with SR-07-013	Minimum separation distance 500 m / 10 m
UKSDA-SR-05-005	Separation Distance (Cislunar)	The SoS shall be capable of identifying and independently tracking all closely-spaced RSOs in cislunar space in accordance with SR-07-013	Minimum separation distance 500 m / 100 m
UKSDA-SR-05-006	Separation Distance (BEO)	The SoS shall be capable of identifying and independently tracking all closely-spaced RSOs in BEO in accordance with SR-07-013	Minimum separation distance 5 km
UKSDA-SR-06	Minimum Feature Size	The SoS shall be capable of resolving physical features at a minimum spatial scale to enable characterisation of RSOs in all regions of interest	See Sub-Requirements
UKSDA-SR-06-001	Minimum Feature Size (LEO)	The SoS shall be capable of resolving RSO features at sufficient resolution to enable characterisation of RSOs in LEO	10 cm
UKSDA-SR-06-002	Minimum Feature Size (MEO)	The SoS shall be capable of resolving RSO features at sufficient resolution to enable characterisation of RSOs in MEO	10 cm
UKSDA-SR-06-003	Minimum Feature Size (HEO)	The SoS shall be capable of resolving RSO features at sufficient resolution to enable characterisation of RSOs in HEO	10 cm
UKSDA-SR-06-004	Minimum Feature Size (GEO)	The SoS shall be capable of resolving RSO features at sufficient resolution to enable characterisation of RSOs in GEO	10 cm
UKSDA-SR-06-005	Minimum Feature Size (Cislunar)	The SoS shall be capable of resolving RSO features at sufficient resolution to enable characterisation of RSOs in cislunar space	10 cm
UKSDA-SR-06-006	Minimum Feature Size (BEO)	The SoS shall be capable of resolving RSO features at sufficient resolution to enable characterisation of RSOs in BEO	10 cm
UKSDA-SR-07	RSO Characterisation	The SoS shall be capable of performing characterisation on all RSOs detectable according to MoPs stated by UKSDA-SR-01	See Sub-Requirements
UKSDA-SR-07-001	RSO Characterisation (Effective Rotation Rate)	The SoS shall be capable of deriving characterisation information on an RSO’s effective rotation rate
UKSDA-SR-07-002	RSO Characterisation (Effective Rotation Axis)	The SoS shall be capable of deriving characterisation information on an RSO’s effective rotation axis
UKSDA-SR-07-003	RSO Characterisation (Attitude/Pointing)	The SoS shall be capable of deriving characterisation information on an RSO’s pointing vector and/or attitude
UKSDA-SR-07-004	RSO Characterisation (Mass Properties)	The SoS shall be capable of deriving characterisation information on an RSO’s mass properties
UKSDA-SR-07-005	RSO Characterisation (Physical Dimensions)	The SoS shall be capable of deriving characterisation information on an RSO’s physical dimensions
UKSDA-SR-07-006	RSO Characterisation (Construction Materials)	The SoS shall be capable of deriving characterisation information on an RSO’s construction materials
UKSDA-SR-07-007	RSO Characterisation (Orbital Manoeuvre Capability)	The SoS shall be capable of deriving characterisation information on an RSO’s capability for performing orbital manoeuvres
UKSDA-SR-07-008	RSO Characterisation (RSO Type/Class)	The SoS shall be capable of deriving characterisation information on an RSO’s type/class (e.g. bus platform)
UKSDA-SR-07-009	RSO Characterisation (Subsystem Information)	The SoS shall be capable of deriving characterisation information on an RSO’s payloads and subsystems
UKSDA-SR-07-010	RSO Characterisation (Subsystem Activity)	The SoS shall be capable of deriving characterisation information on activity of an RSO’s payloads and subsystems
UKSDA-SR-07-011	RSO Characterisation (Mission Capability)	The SoS shall be capable of deriving characterisation information on an RSO’s capability for mission performance
UKSDA-SR-07-012	RSO Characterisation (Operational Status)	The SoS shall be capable of deriving characterisation information on an RSO’s operational status
UKSDA-SR-07-013	RSO Characterisation (RSO Identification)	The SoS shall be capable of deriving characterisation information on an RSO’s identity with respect to an RSO catalogue
UKSDA-SR-07-014	RSO Characterisation (Orbital and Manoeuvre History)	The SoS shall be capable of deriving characterisation information on an RSO’s history of orbital changes and manoeuvres
UKSDA-SR-07-015	RSO Characterisation (Deployment of Secondary Objects)	The SoS shall be capable of deriving characterisation information regarding the deployment of secondary objects by an RSO, or its capability or intent to do so
UKSDA-SR-07-016	RSO Characterisation (EM Activity)	The SoS shall be capable of deriving characterisation information on an RSO’s electromagnetic activity
UKSDA-SR-07-017	RSO Characterisation (Cyber Activity)	The SoS shall be capable of deriving characterisation information on an RSO’s cyber activity
UKSDA-SR-07-018	RSO Characterisation (Fault/Anomaly Detection)	The SoS shall be capable of deriving characterisation information which enables detection of faults and/or anomalies on board an RSO
UKSDA-SR-07-019	RSO Characterisation (Damage Assessment)	The SoS shall be capable of deriving characterisation information which enables assessment of damage or loss to an RSO
UKSDA-SR-07-020	RSO Characterisation (Passivation Activity)	The SoS shall be capable of deriving characterisation information which enables verification of passivation activity performed by an RSO
UKSDA-SR-07-021	RSO Characterisation (Space-Enabled Capabilities)	The SoS shall support the characterisation of an RSO’s space-enabled infrastructure; terrestrial and/or space-based
UKSDA-SR-07-022	RSO Characterisation (RSO or Operator Intent)	The SoS shall be capable of deriving information towards an RSO’s intent or that of its operator
UKSDA-SR-07-023	Change Detection	The SoS shall be capable of detecting and reporting changes to characterisation parameters
UKSDA-SR-07-024	Characterisation Evidence	The SoS shall deliver all characterisation products and assessments with supporting data, evidence and accuracy information
UKSDA-SR-07-025	Characterisation Products (Routine Priority)	The SoS shall deliver characterisation products and assessments for routine priority RSOs in a timely fashion alongside associated confidence information and supporting evidence	Weekly
UKSDA-SR-07-026	Characterisation Products (High-Priority)	The SoS shall deliver characterisation products and assessments for high-priority RSOs or events in a timely fashion alongside associated confidence information (but may omit supporting evidence if necessary)	24 hours
UKSDA-SR-07-027	Characterisation Frequency	The SoS shall provide characterisation information on routine and high-priority RSOs at a sufficient cadence	See Sub-Requirements
UKSDA-SR-07-027-001	Characterisation Frequency (Routine Priority [LEO])	The SoS shall provide characterisation information on routine priority LEO RSOs at a sufficient cadence	400 LEO RSOs per month
UKSDA-SR-07-027-002	Characterisation Frequency (Routine Priority [MEO])	The SoS shall provide characterisation information on routine priority MEO RSOs at a sufficient cadence	All UK / all catalogued MEO RSOs monthly
UKSDA-SR-07-027-003	Characterisation Frequency (Routine Priority [HEO])	The SoS shall provide characterisation information on routine priority HEO RSOs at a sufficient cadence	All UK / all catalogued HEO RSOs monthly
UKSDA-SR-07-027-004	Characterisation Frequency (Routine Priority [GEO])	The SoS shall provide characterisation information on routine priority GEO RSOs at a sufficient cadence	All UK / all catalogued GEO RSOs monthly
UKSDA-SR-07-027-005	Characterisation Frequency (Routine Priority [Cislunar])	The SoS shall provide characterisation information on routine priority cislunar RSOs at a sufficient cadence	All UK / all catalogued cislunar RSOs monthly
UKSDA-SR-07-027-006	Characterisation Frequency (Routine Priority [BEO])	The SoS shall provide characterisation information on routine priority BEO RSOs at a sufficient cadence	All UK / all catalogued BEO RSOs monthly
UKSDA-SR-07-027-007	Characterisation Frequency (High Priority [LEO])	The SoS shall provide characterisation information on high priority LEO RSOs at a sufficient cadence	All high priority LEO RSOs weekly
UKSDA-SR-07-027-008	Characterisation Frequency (High Priority [MEO])	The SoS shall provide characterisation information on high priority MEO RSOs at a sufficient cadence	All high priority MEO RSOs weekly
UKSDA-SR-07-027-009	Characterisation Frequency (High Priority [HEO])	The SoS shall provide characterisation information on high priority HEO RSOs at a sufficient cadence	All high priority HEO RSOs weekly
UKSDA-SR-07-027-010	Characterisation Frequency (High Priority [GEO])	The SoS shall provide characterisation information on high priority GEO RSOs at a sufficient cadence	All high priority GEO RSOs weekly
UKSDA-SR-07-027-011	Characterisation Frequency (High Priority [Cislunar])	The SoS shall provide characterisation information on high priority cislunar RSOs at a sufficient cadence	All high priority cislunar RSOs weekly
UKSDA-SR-07-027-012	Characterisation Frequency (High Priority [BEO])	The SoS shall provide characterisation information on high priority BEO RSOs at a sufficient cadence	All high priority BEO RSOs weekly
UKSDA-SR-08	RSO Catalogue Maintenance	The SoS shall manage and maintain a catalogue of RSOs and UCTs with orbital state, characterisation and other data/information, including but not limited to sufficient RSO revisit rates		Priority
UKSDA-SR-08-001	RSO Catalogue	The SoS shall host and maintain a database of current and archival orbital state information, characterisation and other data/information
UKSDA-SR-08-002	RSO Catalogue Access	The SoS shall ensure that RSO catalogue products are accessible to relevant government agencies and international partners with appropriate controls
UKSDA-SR-08-003	RSO Identifiers	The SoS shall maintain a unique, internal ID for each RSO (and candidate RSO/UCT) which enables mapping to other, external catalogues
UKSDA-SR-08-004	Observation-to-Track Association	The SoS shall associate each RSO observation with a specific track and assign a probability of association
UKSDA-SR-08-005	Track-to-Track Correlation	The SoS shall be capable of track-to-track correlation to support catalogue maintenance and/or UCT processing
UKSDA-SR-08-006	Track-to-Catalogue Association	The SoS shall associate each RSO observation/track with an existing catalogued RSO or support creation of a new catalogue entry via registration of a UCT
UKSDA-SR-08-007	Track-to-Catalogue Association Probability	The SoS shall assign each RSO observation/track with a probability of association against each potential catalogued RSO
UKSDA-SR-08-008	UCT Generation	The SoS shall assign RSO observation/track data as a UCT in cases where association of RSO observation/track data to an existing catalogued RSO is inconclusive
UKSDA-SR-08-009	Track Quality	The SoS shall be capable of producing tracks of sufficient length and accuracy to enable propagation forward to the next planned observation window as per UKSDA-SR-04
UKSDA-SR-09	Detection and Monitoring of Orbital Events	The SoS shall detect, monitor and provide notifications and warnings on orbital events		Priority
UKSDA-SR-09-001	Orbital Event Assessment	The SoS shall be capable of identifying, assessing and refining information on high-priority RSOs and other events or activities
UKSDA-SR-09-001-001	Orbital Event Assessment (Orbit Insertion)	The SoS shall be capable of identification, assessment and reporting of events which generate new RSOs (e.g. launch or on-orbit break-up events)
UKSDA-SR-09-001-002	Orbital Event Assessment (Orbital Manoeuvres)	The SoS shall be capable of identification, assessment and reporting of orbital manoeuvres performed by an RSO
UKSDA-SR-09-001-003	Orbital Event Assessment (Orbital Parameter Changes)	The SoS shall be capable of identification, assessment and reporting of changes in orbital parameters exhibited by an RSO
UKSDA-SR-09-001-004	Orbital Event Assessment (Release of Secondary Objects)	The SoS shall be capable of identification, assessment and reporting of releases of secondary objects by an existing RSO
UKSDA-SR-09-001-005	Orbital Event Assessment (DA-ASAT)	The SoS shall be capable of identification, assessment and reporting of direct ascent anti-satellite -related activity
UKSDA-SR-09-001-006	Orbital Event Assessment (Co-Orbital ASAT)	The SoS shall be capable of identification, assessment and reporting of co-orbital anti-satellite -related activity
UKSDA-SR-09-001-007	Orbital Event Assessment (RPO)	The SoS shall be capable of identification, assessment and reporting of on-orbit rendezvous and proximity operations activity
UKSDA-SR-09-001-008	Orbital Event Assessment (Docking)	The SoS shall be capable of identification, assessment and reporting of on-orbit docking activity
UKSDA-SR-09-002	Generation of Event Notifications and Warnings	The SoS shall be capable of producing notifications and/or warnings of all events of interest with user definable thresholds at varying levels of severity		Priority
UKSDA-SR-09-003	Delivery of Event Notifications and Warnings	The SoS shall provide notifications and/or warnings for appropriate users in a timely fashion.		Priority
UKSDA-SR-09-004	Post-Event Attribution	The SoS shall provide data, software and analysis which can support any necessary attribution processes for relevant events in space whether natural, accidental, irresponsible or nefarious
UKSDA-SR-10	Operational Space Picture	The SoS shall manage and maintain a high-quality operational space picture and deliver associated output products
UKSDA-SR-10-001	Task Management	The SoS shall enable management of SDA tasks; e.g. creation, assignment, tracking, prioritisation and execution of user tasks
UKSDA-SR-10-002	Joint Intelligence Preparation of the Operating Environment	The SoS shall generate and utilise JIPOE products to inform SDA and other missions/tasks
UKSDA-SR-10-003	Output Data Products	The SoS shall support the delivery of data products to support mission operations
UKSDA-SR-10-004	I&W Generation	The SoS shall support the generation of indicators and warnings for events affecting space systems, communications links, payloads, or ground infrastructure
UKSDA-SR-10-005	Decision-Quality Information	The SoS shall generate decision-quality data products
UKSDA-SR-10-006	Human Consumption	The SoS shall produce human-readable data products to facilitate action by decision makers		Priority
UKSDA-SR-10-007	Public Utilisation	The SoS shall produce visualisation outputs which enable interpretation of events by non- space specialists		Priority
UKSDA-SR-11	Analysis Capabilities	The SoS shall provide modelling and simulation capabilities to support catalogue maintenance, orbital propagation, manoeuvre planning and other support tasks
UKSDA-SR-11-001	Data Fusion	The SoS shall be able to fuse multiple data types and/or models
UKSDA-SR-11-002	Orbital State Propagation	The SoS shall have capability to propagate orbit states and associated forces backwards and forwards in time
UKSDA-SR-11-003	Conjunction on Launch Assessment	The SoS shall enable the conduct of COLA
UKSDA-SR-11-004	Manoeuvre Planning	The SoS shall be capable of the planning and optimisation of spacecraft manoeuvres
UKSDA-SR-11-005	COA Generation	The SoS shall be capable of supporting the production of COAs in response to all events of interest
UKSDA-SR-11-006	Mission Impact Reports	The SoS shall be capable of ingesting user/mission impact assessments and incorporate data/information as appropriate
UKSDA-SR-11-007	Space Environment Modelling and Simulation	The SoS shall support modelling, simulation and characterisation of the entire space environment, including orbital debris
UKSDA-SR-12	Data Curation (Direction and Collection)	The SoS shall facilitate the direction and collection of data, including the tasking of sensors and supporting services / sources for the acquisition of data
UKSDA-SR-12-001	Data Request	The SoS shall be capable of requesting data and receiving a confirmation receipt within a discrete timeframe
UKSDA-SR-12-002	Observation Timeliness	The SoS shall initiate collection data within a specified timeframe after confirmation of receipt of data request
UKSDA-SR-12-003	Event-Based Observation Timeliness	The SoS shall initiate collection data within a specified timeframe after confirmation of receipt of data request surrounding a high-priority event
UKSDA-SR-12-004	Data Delivery Latency	The SoS shall ensure delivery of data and/or products from contributing sensors or sources with minimal latency or delay
UKSDA-SR-12-005	Sensor Tasking and Optimisation	The SoS shall be capable of scheduling and optimising the collection of data on an RSO by a sensor network
UKSDA-SR-12-006	Cross-Cueing	The SoS shall be capable of cross-cueing of different sensors in the system
UKSDA-SR-12-007	Flexible Tasking	The SoS shall have flexible tasking capabilities based on user and mission priorities
UKSDA-SR-13	Data Curation (Ingest)	The SoS shall ingest data and information which supports SDA analysis
UKSDA-SR-13-001	Data Ingest	The SoS shall be able to ingest data from all SoS sensors and all relevant data formats according to UKSDA-SR-14-001
UKSDA-SR-13-002	I&W Ingest	The SoS shall be able to ingest indicators and warnings from other sensor systems, government agencies and allied partners
UKSDA-SR-13-003	Interface Control Documentation	The SoS shall only accept data which is accompanied by an appropriate ICD
UKSDA-SR-14	Data Curation (Management and Quality Assurance)	The SoS shall perform management of data, products, information and data sources to ensure efficient and effective exploitation for SDA purposes	See Sub-Requirements
UKSDA-SR-14-001	Data Formats	The SoS shall use appropriate data formats and standards (e.g. those developed by the CCSDS) for data generated by, or for, the SoS
UKSDA-SR-14-002	Quality Assurance	The SoS shall ensure that quality assurance is undertaken on all data, products and artefacts in order to ensure suitable performance
UKSDA-SR-14-003	Data Flagging and Purging	The SoS shall allow for the flagging and/or purging of data assessed to be spurious/inaccurate
UKSDA-SR-14-004	Data Audit Trail	The SoS shall ensure that all data, products and artefacts are accompanied by an appropriate audit trail, including applied data sources, metadata and contextual information
UKSDA-SR-14-005	Uncertainty Data	The SoS shall accompany all generated data, products and artefacts with appropriate information regarding uncertainty
UKSDA-SR-14-006	Sensor Bias and Accuracy	The SoS shall be able to utilise observation data that includes sensor biases and accuracy
UKSDA-SR-14-007	Calibration	The SoS shall handle and incorporate sensor calibration data
UKSDA-SR-14-008	Timing Accuracy	The SoS shall ensure that data is timestamped with sufficient accuracy	1 millisecond accuracy
UKSDA-SR-14-009	Timing Precision	The SoS shall ensure that data is timestamped with sufficient precision	1 nanosecond precision
UKSDA-SR-15	Data Curation (Storage and Access Control)	The SoS shall provide a multi-user (Civilian, Military and Commercial) data access route via a data repository and a shared software capability		Priority
UKSDA-SR-15-001	Data Storage	The SoS shall include and utilise a data repository which is capable of storing current and archival data
UKSDA-SR-15-002	Scalability of Data Storage	The SoS shall include and utilise a data repository which is scalable and flexible
UKSDA-SR-15-003	Access Controls	The SoS shall manage access to data via definable user access rights and controls in line with UKSDA-SR-16
UKSDA-SR-15-004	Agility	The SoS shall utilise a user configurable (push/pull) data delivery approach for current and archival data for maximum utility based on mission needs
UKSDA-SR-16	Data Curation (Governance)	The SoS shall enable the governance and dissemination of data to UK MOD and Civil operators and international partners
UKSDA-SR-16-001	Data Protective Marking	The SoS shall hold and disseminate data at the lowest possible protective marking (where possible), as per policy and security requirements
UKSDA-SR-16-002	Classification Handling	The SoS shall provide a facility to modify the classification level or handling caveats of data, products or other artefacts
UKSDA-SR-16-003	Data Sharing Rules	The SoS shall tag data with appropriate sharing rules/restrictions to enable maximum sharing without commercial/classification compromise
UKSDA-SR-16-004	Data Dissemination	The SoS shall hold and disseminate data in accordance with applicable security classification guides and handling/encryption policies (where required)
UKSDA-SR-17	Licence Compliance and Monitoring	The SoS shall support the analysis of compliance to licence conditions for UK licenced spacecraft in all regions of interest
UKSDA-SR-17-001	Licence Compliance and Monitoring (Space Debris Mitigation)	The SoS shall enable assessment of compliance with space debris mitigation guidelines or other applicable requirements
UKSDA-SR-17-002	Licence Compliance and Monitoring (EM Spectrum)	The SoS shall support monitoring of the EM spectrum to assess regulatory compliance and/or identify spectrum interference
UKSDA-SR-17-003	Licence Compliance and Monitoring (Orbital Position and Behavioural Norms)	The SoS shall support monitoring of RSO orbital position
UKSDA-SR-18	Monitoring of Cyber and EM Activity	The SoS shall support the monitoring and reporting of non-kinetic (e.g. cyber, electromagnetic or optical/laser) activity; for example, interference, jamming and spoofing in, from and to space
UKSDA-SR-18-001	Monitoring of Cyber and EM Activity (Ground to Space)	The SoS shall support monitoring of the EM spectrum from ground to space and provide reporting products to relevant users regarding cyber and EM activity
UKSDA-SR-18-002	Monitoring of Cyber and EM Activity (Space to Ground)	The SoS shall support monitoring of the EM spectrum from space to ground and provide reporting products to relevant users regarding cyber and EM activity
UKSDA-SR-18-003	Monitoring of Cyber and EM Activity (Space to Space)	The SoS shall support monitoring of the EM spectrum from space to space and provide reporting products to relevant users regarding cyber and EM activity
UKSDA-SR-18-004	Monitoring of Cyber and EM Activity (Reporting)	The SoS shall provide reporting on cyber and EM activity to relevant users with appropriate timeliness
UKSDA-SR-19	Space Environment Monitoring and Forecasting	The SoS shall support space environment monitoring through utilisation of space weather data, modelling and decision-tool processing capabilities	See Sub-Requirements	Priority
UKSDA-SR-19-001	Space Environment (Products)	The SoS shall utilise and deliver space environment products to support operational needs and post-event analysis
UKSDA-SR-19-002	Space Environment (Forecasting)	The SoS shall deliver forecasts for space weather with appropriate outlook epochs	Capable of generating forecasts with a 4-day epoch
UKSDA-SR-19-003	Space Environment (Impact Assessment)	The SoS shall be capable of processing space environment data to produce assessment of impacts to specific missions
UKSDA-SR-19-004	Space Environment (Natural Environmental Changes)	The SoS shall be capable of identifying and assessing natural changes to the space environment
UKSDA-SR-19-005	Space Environment (Artificial Environmental Changes)	The SoS shall be capable of identifying and assessing artificial changes to the natural space environment
UKSDA-SR-20	Launch & Ballistic Tracking	The SoS shall be capable of detecting and tracking launch and ballistic activities, including sub-orbital events
UKSDA-SR-20-001	Detection of 50-100 km Launch Activity	The SoS shall be capable of detecting launch and ballistic activities that exceed 50 km altitude but do not exceed 100 km altitude
UKSDA-SR-20-002	Tracking of 50-100 km Launch Activity	The SoS shall be capable of tracking launch and ballistic activities that exceed 50 km altitude but do not exceed 100 km altitude
UKSDA-SR-20-003	Detection of 100+ km Launch Activity	The SoS shall be capable of detecting launch and ballistic activities that exceed 100 km altitude
UKSDA-SR-20-004	Tracking of 100+ km Launch Activity	The SoS shall be capable of tracking launch and ballistic activities that exceed 100 km altitude
UKSDA-SR-20-005	Tracking of Space Launch Material	The SoS shall support the tracking and analysis of debris and other material arising from space launch activity
UKSDA-SR-21	SoS Capability	The SoS shall include resilient sensor, processing and analysis capabilities to deliver operational SDA
UKSDA-SR-21-001	SoS Capability (Coverage Resilience)	The SoS shall be capable of acquiring observation data 24 hours per day, applying appropriate redundancy where required
UKSDA-SR-21-002	SoS Capability (Independence)	The SoS shall include UK-owned systems to provide additional data and security resilience by reducing UK dependency on other nations, and providing timely and UK prioritised access to trusted data sources		Priority
UKSDA-SR-21-003	SoS Capability (Adaptability)	The SoS shall be easily reconfigurable and scalable		Priority
UKSDA-SR-21-004	SoS Capability (Infrastructure)	The SoS shall maintain capacity of sufficient physical and digital infrastructure
UKSDA-SR-21-005	SoS Capability (Skilled Personnel)	The SoS shall maintain capacity of sufficiently skilled SDA personnel
UKSDA-SR-21-006	SoS Capability (Tools and User Interfaces)	The SoS shall include adequate data analysis and visualisation tools to enable operational SDA
UKSDA-SR-21-007	SoS Capability (Interoperability)	The SoS shall include sufficient infrastructure to enable interoperability between UK agencies and with all partners at all relevant levels of classification
UKSDA-SR-21-008	SoS Capability (Assurance)	The SoS shall include appropriate assurance capabilities		Priority
UKSDA-SR-21-009	SoS Capability (System Automation)	The SoS shall utilise automated workflows, however, human intervention shall remain possible across the data chain, from sensor tasking through to data interpretation		Priority
UKSDA-SR-21-010	SoS Capability (User Training)	The SoS shall include appropriate training materials to enable appropriate user integration.		Priority
UKSDA-SR-21-011	SoS Capability (Resilience)	The SoS shall be resilient to single-point failures
UKSDA-SR-21-012	SoS Capability (Failure Modes)	The SoS and all individual hardware and software elements shall fall into appropriate safe modes upon failure
UKSDA-SR-21-013	SoS Capability (Recovery)	The SoS shall be repaired within a specified timeframe upon failure, in accordance with individual system requirements
UKSDA-SR-21-014	SoS Capability (Ongoing Support)	The SoS shall ensure that all component software and hardware is supported and maintained throughout its lifetime

6.3 Annex C – Acronyms and Definitions

Acronym	Definition	Additional Notes
BEO	Beyond Earth Orbit	The region extending beyond cislunar space (but bounded within the Solar System), where the gravitational effects of the Earth and Moon cease to be the primary forces acting on an RSO
C2	Command and Control	C2 combines two concepts: Command (The authority vested in a member of the armed forces for the direction, coordination, and control of military forces) and Control (The authority exercised by a commander over part of the activities of subordinate organizations, or other organizations not normally under their command, encompassing the responsibility for implementing orders or directives). [JDP 0-40 UK Space Power]. Within the scope of this document, the term pertains to command and control of sensors and other systems, the NSpOC, space enterprise, multi-domain integration and multi-national operations
Catalogue	Catalogue	A database of RSO-specific positional, characterisation, and/or other data/information. This database may also include equivalent data/information on UCTs, or potential future RSOs or analyst test objects
Category X Orbit State	Category X Orbit State	A descriptor for the quality of a computed orbit state, achieved according to AFAT (access, fidelity, accuracy, timeliness). The following indicative categories of positional state uncertainty are currently considered, each with a spherical error of 90%: Category I: State uncertainty less than 10m; Category II: State uncertainty between 10m and 250m; Category III: State uncertainty between 250m and 2km; Category IV: State uncertainty between 2km and 10km; Category V: State uncertainty between 10km and 150km; Category VI: State uncertainty greater than 150km
CCSDS	Consultative Committee for Space Data Systems	A multi-national committee that develops space standards and formats for space data
Characterisation	Characterisation	The process by which sensor observations and other data provide actionable insights towards the identify, behaviour and physical properties of an RSO
Characteristic Length	Characteristic Length	A measure of the approximate size of an RSO, according to its total volume divided by its (minimum) cross-sectional area
Cislunar Space	Cislunar Space	The volume of space above 37,000km altitude, where the gravitational effects of both the Earth and Moon have significant influence over a spacecraft. As a guide, this may extend to approximately 500,000km altitude in the Earth-Moon rotating system
CNI	Critical National Infrastructure	Assets that are essential for the functioning of UK society and/or the economy
COA	Course of Action	A viable plan developing in order to accomplish a particular goal; for example, a collision avoidance manoeuvre
COLA	Conjunction on Launch Assessment	A group of processes for orbital downrange clearance, predominantly the process of identifying potential conjunctions between the planned trajectory of a launch vehicle in time against other catalogued space objects. Such objects include active and inactive spacecraft and debris, as well as UCTS and analyst test objects. NOTE: Within the United States, the process is known as Launch Collision Avoidance Analysis (L-COLA).
Data Curation	Data Curation	The process of collecting, ingesting, organising and managing data for exploitation by a user
Data Fusion	Data Fusion	The process of synthesising multiple datasets, potentially from different sources, to enhance understanding of a particular problem (for example, RSO orbit determination).
EM	Electromagnetic	Physical interaction among electric charges, magnetic moments and electromagnetic fields
GEO	Geosynchronous Earth Orbit	The region above MEO, populated by RSOs with altitudes between 35,586km and 37,000km. It can be further subdivided into the following volumes: Geostationary: Equatorial orbits at circa 35,786km altitude and 0 degrees inclination; Geosynchronous: Orbits with altitudes between 35,786 ± 200km and -15° < inclination < 15°; Inclined Geosynchronous: Orbits with altitudes between 35,786 ± 200km and inclination > 15° or < -15°; Graveyard: Orbits of any inclination between 35,986km and 37,000km
HEO	Highly Elliptical Orbit	RSO orbits possessing an eccentricity ≥ 0.25; typically used for transfer orbits but with other applications, e.g. Molniya orbits. RSOs in such orbits may pass through one or more other regions: for example, RSOs in a geostationary transfer orbit which traverse through LEO, MEO and GEO during one orbit. For surveillance and/or tracking purposes, it should be considered that a HEO RSO should be observable at any point in its orbit or trajectory
I&W	Indicators and Warnings	Intelligence products designed to provide timely forewarning of potentially hostile actions
JIPOE	Joint Intelligence Preparation of the Operating Environment	An analytical methodology that produces intelligence assessments, estimates and other products to support operations planning [JDP 2-00 Intelligence, Counter-intelligence and Security Support to Joint Operations]
LEO	Low Earth Orbit	The region extending up to 2,000km altitude, and where RSOs occupy orbits with both apogee and perigee below 2,000km
MoP	Measure of Performance	Threshold or Objective target for a requirement, quantifying performance required from the UK SDA system of systems
MEO	Medium Earth Orbit	The region above LEO, extending from 2,000km to 35,586km in altitude
Mission Impact Assessment	Mission Impact Assessment	A process to evaluate the potential effects of an event on a ground- or space-based system, and the expected effect on their ability to perform their mission objectives
Observation	Observation	A point measurement from a sensor at a single instant in time; e.g. (azimuth, elevation, time)
Operational Space Picture	Operational Space Picture	A shared, consolidated and comprehensive view of the current orbital situation, providing decision-makers with a single, consistent understanding of the environment
Orbit State	Orbit State	An RSO’s instantaneous position and velocity, represented in vector format within a defined reference frame (e.g. Cartesian)
Orbital Event	Orbital Event	An event occurring in space involving one or more RSOs; e.g. a conjunction, on-orbit break-up or atmospheric decay
Orbital Region	Orbital Region	A particular volume of space around the Earth, typically defined in terms of altitude; e.g: Low Earth Orbit (LEO); Medium Earth Orbit (MEO); Geosynchronous Earth Orbit (GEO); etc.
Planetary Defence	Planetary Defence	Observation, tracking and modelling of natural near-Earth objects whose orbits create an impact hazard to Earth
RPO	Rendezvous and Proximity Operations	Rendezvous: The process by which an RSO performs manoeuvres to match the orbital parameters and relative motion of another. Proximity Operations: Two (or more) RSOs operating in approximately the same orbit, typically within a few kilometres or less
RSO	Resident Space Object	A man-made object in space; excluding objects on sub-orbital trajectories
SDA	Space Domain Awareness	The provision of security-focused, decision-quality information that can be used to successfully mitigate adversary space effects while supporting the integration of allied space effects into multi-domain operations [JDP 0-40 UK Space Power]
SoS	System of Systems	A set or arrangement of interdependent systems that are related or connected to provide an enhanced measure of capability. The loss of one component system will degrade the performance of the whole but not necessarily affect the performance of individual systems. In the case of the UK SDA SoS, it includes (but is not limited to) sensors, software, data ingestion, data storage, data handling, data dissemination, data processing and analysis, training and simulation, data and information visualisation, and interface (internal and external) capabilities
SSA	Space Situational Awareness	The provision of sufficient understanding of the risks and hazards associated with domain congestion and complexity to enable safe and effective space operations [JDP 0-40 UK Space Power]
SST	Space Surveillance and Tracking	The detection, tracking and identification of objects in or entering the space domain, using data from sensor observations and satellite operators, sufficient to deliver effective space situational awareness, space domain awareness and missile warning [JDP 0-40 UK Space Power]
Surveillance	Surveillance	Persistent monitoring of a particular region of space for the purpose of detecting RSOs
Terrestrial	Terrestrial	Located on the ground, at sea or in the air
Track	Track	A consecutive sequence of multiple observations from a sensor, correlated as belonging to the same RSO
Tracking	Tracking	Directed detection of a specific RSO or UCT, and generation of a sequence of positional information
UCT	Uncorrelated Track	A series of observations (track) which cannot be correlated against an existing object in the catalogue. Such observations could arise from a newly-launched object, or from an existing object which has deviated sufficiently from its last known trajectory
UK RSO	UK Resident Space Object	An RSO which is licensed (including of the operator and procurement of launch licences), registered and/or operated by the UK or a UK entity