Introduction

The capability of Space Situational Awareness (SSA) – monitoring and understanding real-time and foreseeable developments of activity in the orbital environment – has become a fundamental prerequisite for space security, both as a means for transparency, information advantage, and verification and as operational foundation for the resilience of space-based systems. While the major space actors maintain SSA capabilities to varying degrees (Lal et al. 2018), the US Strategic Command currently operates the most sophisticated SSA capability with dedicated data exchange arrangements to external state and non-state actors (West 2018).

Yet, not only is the safeguarding of the near earth environment as a global commons an international concern in the advent of an unprecedented scale and variety of activities across orbital regimes. The necessity for significant investment into development and operation of SSA sensor systems also lends itself to collaborative rather than unilateral efforts (McCormick 2013). In Europe, despite a range of sensor systems, governmental and commercial actors have been relying predominantly on SSA data provided by the United States. However, it has become paramount for Europe, particularly institutional actors such as the European Union, to protect their own space-based infrastructure, such as the Galileo navigation system. Furthermore, reaching a greater level of autonomy in space surveillance through a dedicated capability allows Europe to contribute to global burden-sharing in the domain of SSA and to enhance its position in international discussions (Pellegrino and Stang 2016, pp. 47–48; Dickow 2015, p. 123).

Hence, in recognition of the need for non-dependence in detecting risks in orbit and the opportunity offered by existing SSA legacies and advanced sensor capabilities in Europe, the European Union has since 2014 undertaken concrete efforts to consolidate a SSA capability. Initial focus was placed on one of the key elements of SSA (cf. European nomenclature (Rovetto and Kelso 2016)), Space Surveillance and Tracking (SST): sensor systems, such as radars, telescopes, and lasers, deliver data on the location and behavior of active and non-active spacecraft or debris, based on which risks can be evaluated on objects that are at risk of collision, have fragmented, or will reenter the atmosphere. By incentivizing the networking of hitherto discrete sensor assets already operated by separate entities in Europe, the European Space Surveillance and Tracking Support Framework (EU SST) today constitutes the EU’s primary SSA capability.

This chapter provides an overview about context, implementation, and perspective of the European Union’s Space Surveillance and Tracking Support Framework. Following an outline of the political developments leading up to its formation, an overview on the internal governance of EU SST and its organization as a cooperation of EU Member States and a council agency is provided. Subsequently, its three operational functions are described that network SST sensors process SST data and form the basis for SST services to a varied user community. The chapter concludes with a perspective on how EU SST is bound to develop as part of the upcoming space program of the European Union and how it slots into to the emerging technical discourse on future space traffic management and coordination regimes.

Governance

Background

The notion of devising and implementing a dedicated European SST capability emerged in the decade preceding the adoption of the legal basis in 2014. European actors – with impetus from the new space policy mandate of the Lisbon Treaty – became either more aware of pending space security challenges in general or had already begun specifically to tailor, develop, or analyze possible responses to the safety and security challenges in the space domain. Increased non-dependence from US capabilities and contribution to global burden-sharing was already a central consideration, including the necessary trade-off between sovereign requirements and a degree of collective autonomy.

In response to a changing security environment after the Cold War, the European Union had begun to assess emerging drivers for future crisis management and related space operational requirements. In the string of critical space-based services including Earth observation (EO) and position, navigation, and timing (PNT), a space surveillance system was highlighted as a fundamental capability gap and priority of a future European space program (Commission of the European Communities 2003; SPASEC 2005). This was understood both in the context of more independently meeting the needs of burgeoning space efforts in Europe but in turn also to contribute to global burden-sharing, particularly with regard to efforts of the United States (Conclusion of the Workshop on Security and Arms Control in Space and the Role of the EU, 2007, cited in ESA 2008, p. 6). A Space Council Resolution then underlined the need to fill the capability gap of SSA, in order to accommodate safeguarding of space-based assets and infrastructure (navigation and observation) on the one hand and enable non-compliance and treaty verification on the other (Council Resolution 2008).

In view of this, the need for cooperation across multiple actors – rather than unilateral efforts – including across the civil-military intersection had already been recognized as a necessary key characteristic of emerging SSA efforts of European state actors and supranational and intergovernmental bodies (Spasec 2005). Of the European Union Member States, only France, the United Kingdom, and Germany had operational space surveillance capabilities at the time (Pagkratis 2011, p. 98; Veclani et al. 2014, p. 39 and 40), which were integrated or coordinated to some extent with European or transatlantic partners. A UK asset (Fylingdales) was part of the US Space Surveillance Network (US SSN). A bilateral Franco-German use of space surveillance and tracking radars (GRAVES and TIRA) had been underway since 2006 (Pasco 2009, p. 34; McCormick 2015, p. 46) and was explored as a potential model for the pooling of capabilities in a broader European framework (Robinson 2011, p. 21) or for possible approaches to data exchange or processing (European Commission 2013b, p. 13).

Meanwhile, the optional program for SSA at the European Space Agency (ESA) commenced work in 2009 (ESA 2008) borne out of earlier efforts in determining needs and requirements of a SSA system with a variety of stakeholders (Marta and Gasparini 2008, pp. 139–40) (Many of the participating countries were both ESA and EU Member States.). In this context, a range of studies explored possible approaches to a European SSA system: an architecture analysis examined three options of ground- and space-based SSA infrastructure, highlighting the merits of synergies of a comprehensive approach to including the monitoring of space objects and the space environment (Donath et al. 2009) (N.B. the different nomenclature of SSA in Europe to include SST, SWE, and NEO (the latter elements summarized as space environment in non-ESA contexts), in comparison to US nomenclature that included intelligence, surveillance, reconnaissance, environmental monitoring, and command and control (cf. Rovetto and Kelso 2016, p. 3)). Another comparative study on governance explored existing and potential models relating to organization and data policy, examining different models for decision-making including program-oriented and institution- or policy-oriented in the European Union (Pasco 2008). In trading off the constraints of national security interests with the potential of collective effort, it sketched the potential setup of a European supervisory authority overseeing the work of a managing organization, already accounted for different security requirements of the two central missions of space object surveillance (SST) and space environment monitoring (space weather and NEO).

At the same time, dialogue among the Member States of both EU and ESA was ongoing as to which body would be best suited to account for the political and practical security requirements of individual space actors involved in collective SSA efforts in Europe (Chow 2011, p. 11; Nardon 2007, p. 6). With the increasing involvement and consolidation of the European Union in space governance (Mazurelle et al. 2009, p. 18; Council Resolution 2010), additional EU bodies entered the debate. The EU’s European Defence Agency (EDA) defined military user requirements (EDA 2010), which were later fused with civilian mission requirements in a dedicated set of high-level SSA civil-military use requirements (Council of the European Union 2011). Consultations between the EU and EU Member States’ space agencies and ministries from 2009 onward had affirmed the emerging role of the EU as actor in space security matters and SSA in particular and were accompanied by further external studies on overall governance (European Commission 2013b, pp. 6–7).

As part of the continuing momentum for a European endeavor, a consensus emerged that an operational SST system be situated within the remit of an effort established and managed by the EU (Veclani et al. 2014, p. 40 and 74; Space Security Index 2012, p. 49–50). The de facto shift of the constituent national actors towards a setting as part of the European Union was formalized as part of the Space Council Resolution of 2010. It subsequently entailed a divestment from operational SST elements of ESA’s SSA program (McCormick 2015, p. 48; ESPI 2018, p. 54), which continued with renewed focus on research and development for SST and on space weather and near-Earth objects (Flohrer and Krag 2017).

Interactions were also extended beyond Europe to inform and engage with regard to emerging governance options. Existing bilateral channels on SSA between EU Member States and their US counterparts (Robinson 2011) were complemented by dedicated interactions on the EU side. In 2012, the US Department of State hosted an EU-US workshop on critical infrastructure protection and SSA with representatives of the European Union (lead by Directorate General for Internal Market who was coordinating internally and other organs including the EEAS, EU Satellite Centre, and EDA, among others), as well as ESA on the US side including also the Department of Defense (Vittet-Philipp and Savova 2012, p. 4).

Discussions on developments continued in the EU community. A proposal for a SST framework was prepared (European Commission 2013a), which posited a governance model of European Member States and highlighted the potential benefits and security-related challenges. A dedicated impact assessment laid out the results of a consultation process and the conclusion already foreshadowed earlier that “European SST services” ought to be led by the EU rather than ESA (European Commission 2013b, p. 22). In exploring intergovernmental governance models other than those of the existing EU flagship programs, the assessment highlighted potential Member States for participation in a governance model (Next to FR, UK, and DE also IT and ES), who could bring sensors from the national side or developed as part of the framework of the ESA SSA preparatory program, but it also emphasized the need for dedicated networking and upgrading of hitherto separate capabilities (ibid, 2013b, p. 12–13). An initial appraisal of this work by the European legislative then considered different levels of engagement between Member States and EU organs (European Parliament 2013). The EU Satellite Centre, which was discussed as an entity contributing to service provision (European Parliament 2014, p. 11), had already been working on the exploration of potential elements related to the user interface of European SST services (Chatard-Moulin 2013, p. 12).

In view of a wider understanding of space-related risks, a nascent EU SST Support Framework was understood as a countermeasure to the emerging risk of space debris. It was added to the inventory of safeguards against risks to critical infrastructure (European Commission 2014a, p. 56) and highlighted as a necessity for the promotion of autonomy and security of European space-based services and for shared threat assessment (EU Global Strategy, 2016, p 42 and 45).

Legal Basis

Finally, in 2014 the European Parliament and the Council adopted the legal basis establishing a “Framework for Space Surveillance and Tracking Support” (European Parliament and European Council 2014). Articulating the need for a safe, secure, and sustainable orbital environment and the need for resilience of European space-based infrastructure, the decision aimed at “ensuring the long-term availability of European and national space infrastructure, facilities and services which are essential for the safety and security of the economies, societies and citizens in Europe” (Art. 3). To this end, a “SST capability at European level and with an appropriate level of autonomy” was to be put in place (Art. 4). This was to include the establishment and operation of three functions, including a “sensor function consisting of a network of Member State ground-based and/or space-based sensors, including national sensors developed through ESA, to survey and track space objects and to produce a database thereof”; a processing function to “process and analyze the SST data at national level to produce SST information and services for transmission to the SST service provision function”; and a service function that would provide collision avoidance, reentry, and fragmentation analysis services (Art. 5.1) to entities of the European Union, its organs, Member States, and industry (Art. 5.2) (see section “Users”).

Funding of 70 million Euros for a 5-year phase between 2016 and 2021 was set aside in parts from the Galileo and Copernicus funding streams for operational aspects, with additional funding earmarked for sensor upgrades from the EU research and development program, Horizon 2020, while significant previous investments of the participating Member States networking their assets were considered a prerequisite. The framework was designed not as an individual capability building exercise but as providing support to the networking and enhancement of existing and already emerging capabilities (That is until the start of the next so-called multiannual financial framework 2021–2027.).

A Consortium of European Member States in Cooperation with Council Agency

In order to participate as sensor and service providers, Member States of the European Union with ownership of or access to requisite SST sensors were invited to express interest and apply to the European Commission via their so-called national designated entities (in most cases space agencies) and, upon demonstrating eligibility, to form a Consortium.

Subsequently, in response to Decision 541 of the European Council and the European Parliament (European Parliament and European Council 2014) and the related implementing decision (European Commission 2014b) that set out formal application procedures, five Member States applied (France, Germany, Italy, Spain, and the United Kingdom). Each of their respective national designated entities – space agencies or their equivalents (CNES, DLR, ASI, CDTI, and UKSA) – submitted individual applications to the European Commission for joint participation in the SST Support Framework, demonstrating compliance with the criteria set out in Decision 541 and security aspects (ibid, p. 3). After an assessment by the European Commission, the five applications were deemed compliant and proceeded, according to the SST decision and implementing decision, to form a Consortium (European Commission 2014b).

A Consortium Agreement was signed by the heads of the participating space agencies in June 2015 (Via Satellite 2015; European Commission 2018a, p. 3). Encouraged by the decision, the partners of the SST Consortium collaborate with the EU Satellite Centre (EU SatCen), as an agency of the Council. An implementing arrangement was thus signed between the Consortium Member States and the EU SatCen in September 2015, thus formally constituting the SST Cooperation (ibid).

A tight timeframe between legal basis and proposed commencing of activities obliged the five-plus-one partners to proceed swiftly in setting up practical arrangements, applying formally for the requisite funding instruments earmarked by the European Union for this purpose, laying out technical activities for the initial services phase, and allocating resources among them in parallel (de Selding 2015). The activities were formally launched by the European Commission in January 2016 (European Commission 2018a, p. 3). This coincided with the aims set out in the 2016 Space Strategy, including a swift progression to reinforce and enhance the nascent SST activities further in view of the resilience of European space-based infrastructure (European Commission 2016, pp. 9–10).

A preparatory phase of six months focused on the fundamental coordination and preliminary joining of a distributed infrastructure, which involved the development of a service portfolio, an initial data and information policy, a model for internal burden-sharing in operations, the setup of front desk, and the acquisition of a first user cohort. Initial operations of the three SST services then commenced in July 2016 (European Commission 2018a, p. 4, 6; see also section “Services”).

As early as spring 2016, additional European Member States expressed an interest in joining the newly formed Consortium and started interactions. With an implementing act for an additional cohort adopted in late 2016, proceedings for the accession of further Member States commenced in 2017. Eleven Member States entered into a dialogue with the Consortium, of whom three decided to apply to the European Commission to join: Poland, Portugal, and Romania. They were found eligible in 2018 and formally completed the accession process with a fresh set of agreements in 2019. Eight other MS expressed an initial interest in participation in the SST Support Framework but refrained from an application to the Commission (European Commission 2018a, p. 8).

Internal Governance

The SST Consortium is neither a legal entity nor an EU agency but constitutes a formal cooperation of the space agencies of the participating EU Member States. Despite different capabilities and legacies in the realm of SST, the partners agreed to commence their collaboration on quasi-equal footing with regard to voting rights and budget allocation, in order to cultivate a culture of cooperation and consensus necessary for joint efforts at the intersection of policy and operations.

The EU SST framework employs a novel governance model for space cooperation in Europe that differs from current governance models of communautized efforts or previously trialed public-private partnerships, of the main EU flagship programs for navigation, Galileo, and Earth observation, or Copernicus, which represented either new capabilities that formerly did not exist or were not available at the required scale.

The internal organization of the SST Cooperation (the Consortium and SatCen) includes three layers – decision-making, management, and working levels – that are jointly implemented by all partners in cross-agency teams. On the bottom level, the working level is structured into operational activities (see section “Operations”). A management layer coordinates the execution of the activities, handles administrative matters relating to finances, and grants and reports on administrative matters to European Commission and Research Executive Agency. On the decision level, the governance of the Consortium is executed through three committees: the Steering, Technical, and Security Committee. Each committee is formally staffed by two delegates from each Member State, in some cases a civilian lead from the participating space agency and a second representative from the armed forces or ministries of defense. The Security Committee handles all matters regarding data policy and security assessment and oversees matters relating to operational risk. The Technical Committee addresses all operational, research and development matters. Both committees provide direct input to the working and operational levels of SST that are organized as working groups for specific activities (Gravier and Faucher 2018).

The highest-level decision-making body of the Consortium is the Steering Committee, which is responsible for all aspects of policy and strategy, decides on budget allocation, and guides operational and technical activities. Its Chair and Secretariat – who do not represent their Member State in order to afford a degree of neutrality – are supported by a Co-Chair and maintain all external dialogue, both with the European Commission and international partners, and represent the SST Cooperation formally in the SST Committee. (The first chairmanship term was served by Germany from 2016 to mid-2017, co-chaired by the United Kingdom, followed by France from mid-2017 to 2020, co-chaired by Germany and the United Kingdom until end of 2018 and co-chaired by Germany since early 2019). The Steering Committee also forms the core of a dedicated forum for exchange with the SatCen (Coordination Committee) that addresses matters specifically to service provision and front desk activities. A representative of the European Commission usually observes the meetings of the Steering Committee. The committee meets usually monthly for several days, in some phases quasi fortnightly or weekly. It takes decisions by consensus but can vote with qualified majority to avoid impasse.

Several changes in the internal governance were initiated by the Consortium and the European Commission in the course of the first two years of operation. Beyond the formal accession procedure of new partners managed by the Commission, these included measures countering the complex funding arrangements that proved administratively cumbersome for both the European Commission and the partners (i.e., the regular reapplication for and simultaneous management of several 18-month-long grants across three budget lines). Initiated internally by the Consortium, voting rights in the governance committees evolved from unanimity to qualified majority. The Consortium also facilitated a greater involvement of representatives of the European Commission in internal governance as observers in the Steering Committee since early 2017 (European Commission 2018a) and fundamentally changed the operational setup of the service provision model (see also section “Services”).

Interaction with European Union Stakeholders

The European Commission is formally responsible for facilitation of the implementation of the framework, interacting through regular meetings with the SST Cooperation, drawing up relevant coordination plans, and monitoring the execution of the grants in collaboration with the EU’s Research Executive Agency (European Commission 2018a, p. 8). Due to the supplementary nature of the support framework – rather than a fully fledged program for now – the interaction between the SST Cooperation and its EU Stakeholders is not characterized by a classic customer relationship; notwithstanding, the SST Cooperation reports formally to the Commission and REA through the mechanisms associated with the funding instruments, as well as informally through regular, generally monthly meetings.

A further reporting line from the Consortium to its EU stakeholders – which surfaced as a fixture in the formal committee context when the Consortium became operational – is set up via the SST Committee. The SST Committee is a body of 28 EU Member States that monitors the implementation of the SST framework. Chaired by DG Grow, the committee serves as the forum for presentation, discussion, and adoption of proposals for the implementation of the SST framework. It usually involves briefings by the Commission, invites regular reports by the Consortium, and allows MS to discuss progress and initiatives. The forum regularly includes observers, both from EU organs (i.e., European External Action Service, European Defence Agency) or external entities in view of specific subject matter. Two further fora for SST experts and users allow for periodic discussion on specific topics relating to requirements and needs.

Transatlantic Relationship

Since the first early exchanges between European and US stakeholders on emerging SSA capabilities in Europe, US actors have been observing the developments of European SSA closely. From a transatlantic perspective, engagement between Europe and the United States is constituted on three levels.

The Member States of the Consortium have each retained – some long-standing – bilateral relations with the United States, both through their space agencies and, crucially for SSA cooperation on policy and operational level, through their ministries of defense and armed forces (e.g., for data sharing arrangements and liaison officers, see also section “Data Processing and Data Policy”). These bilateral relationships, in turn, extend to the multilateral level and form the engine for the transatlantic relationship between the SST Consortium as a whole and its US counterparts. As a multilateral group, the Consortium maintains a regular exchange on working level with representatives from the United States (cf. also section on STM). On supranational level, the EU-US space dialogue led by the European Commission does not yet regularly include EU SST representatives in its delegation but has grown to take into account the perspectives of EU SST for discussions related to SSA and STM, either by including relevant reporting through Commission officials or, more recently, through invitation of the chair of the Consortium per se.

Operations

After a preparation period of 6 months from the activation of the financial instruments and budget lines, EU SST started providing operational services as a joint effort on 1 July 2016. While its governance is managed as a hybrid of virtual and co-located interaction, EU SST service provision is managed as a distributed European ground segment system incorporating the major functional elements set out in the legal basis of Decision 541.

Service Provision Model Based on Internal Specialization

Operations consist of three main functions as per Decision 541, which make up the operational elements of the SST capability (i.e., aside from the governance elements described earlier): sensor, data processing, and service functions. SST sensors from all partners contribute data; this data is analyzed in the processing function and feed a joint database and ultimately a catalogue; from this, products are derived for three services that are generated by the operation centers and passed on to the users via a front desk.

In the interest of a swift progression to providing services to the EU user community after the entry into force of the legal basis in 2014 and the formation of the SST Consortium in 2015, the service provision model at the outset of operations in 2016 mirrored the equal footing approach of the participating partners: the CA service was operated on a fleet allocation principle, i.e., spacecraft or fleet was distributed to different operation centers (OCs), and services provided according a common guaranteed baseline with added-value elements at the discretion and capability of each operation center. At the time, RE and FG services were provided on a monthly rotational basis by all centers.

This provisional philosophy of each partner performing all functions was superseded in spring 2018 by an approach of specialization that is used to date, where each Consortium partner performs a pre-defined subset of the overall functions. Thus, pairs of OCs work in hot redundancy for the CA service, while all partners contribute offline and collaborate on post-analysis of events. The evolved service portfolio harmonizes products for all services. This internal burden-sharing constitutes a model of functional specialization, whereby specific partners are responsible for European level service provision (the French and Spanish OCs for collision avoidance service, Italian OC for both reentry and fragmentation) and data processing side (German OC), while all individual partners contribute sensor data.

The current EU SST capability uses existing assets (sensors and operation centers) that are virtually coordinated and complemented through joint efforts in combining discrete elements into an overall value chain. Across the three functions, operations are led by the operation centers of the participating Member States (COO for France, GSSAC for Germany, UKSpOC for the United Kingdom, ISOC for Italy, S3TOC for Spain, SSAC-PL for Poland, COpE for Portugal, and COSST for Romania). These are civilian, military, or civilian-military and may integrate capabilities or expertise of additional actors of the SSA ecosystem in Europe, including industrial subcontractors or scientific institutes for development, staffing, or operation of selected infrastructure.

Sensor Network

The EU SST sensor network has grown since initial operations, from 33 sensors in December 2017 of the initial Consortium of 5 partners (European Commission 2018a, p. 4) to a current total of 51 sensors made available for operations by its 8 partners. The network currently comprises of 12 radars (5 surveillance, 7 tracking), 35 telescopes (19 surveillance, 16 tracking), and 4 laser ranging stations. They provide coverage of all orbit regimes (LEO, MEO, HEO, and GEO) (European Commission 2018a, p. 4). The majority of sensors, including all radars and lasers, is located on European landmass (with the highest latitude site being Fylingdales in the United Kingdom); over a dozen additional telescopes afford coverage through locations in other geographical regions, including overseas territories or sites accessible through partners in the southern hemisphere. No space-based sensors are currently part of the system. Some Member State partners integrate assets or data from commercial or private entities (European Commission 2018a, p. 8). With the sensor network enlarged by additional Consortium partners, operational reviews are conducted annually to assess performance and contribution of each sensor.

The sensors operate at varying degrees of availability that are pre-defined and traded off among the partners. Control and tasking are retained by the respective Member States through their operation centers. On a network level, interactions are coordinated through the participating operation centers, which may send and receive tasking requests from other OCs and convene remotely for regular briefings.

The data provided from the sensors are shared either routinely in quasi real time or on request, depending on sensor type. They complement the data received through the 18th Space Control Squadron of the US Strategic Command in Vandenberg Air Force Base that are accessed through bilateral sharing agreements (for classified and nonclassified information). European measurements are thus systematically provided for the operation of each service, with dedicated campaigns performed for specific events: for collision avoidance services, in case of high-interest events (HIE) and upon request of the nominal OC in charge of the service, all tracking radars and surveillance and tracking telescopes are activated to refine the orbit of the secondary object. For reentry services, upon request of the nominal OC, all tracking radars are activated to follow the reentry and provide European measurements; for fragmentation services, still upon request of the nominal OC, all radars and telescopes are tapped into according to their orbit regime.

Data Processing & Data Policy

The data derived from the contributing sensors is shared according to pre-defined principles. For surveillance telescopes, data is shared on a daily basis; for tracking radars, tracking telescopes and lasers in quasi real time (daily or on request); and for surveillance radars on a daily basis.

During initial services, data exchange was performed manually between the operation centers. Today, the growing network of sensors, and the increase in European data necessitated a dedicated platform for the ingestion and exchange of data and for further processing in view of setting up a European catalogue. Measurements from the sensors are hence fed into, stored in, and shared via a common platform so-called European database. After development work, the database went operational in April 2019 and is hosted, in line with the service provision model of functional specialization, by one of the operation centers (German OC).

The database constitutes the basis for building and maintenance of the precursor European catalogue currently in development. The operation centers providing the SST services will use the European precursor catalogue for service provision, in complementation of CDM received from the United States.

One of the main challenges posited for the Consortium at the outset was the design of an effective data policy due to the sensitive domain of SSA (Marta 2015, p. 9 and 10). The data currently handled on a multilateral level inside the Consortium is not classified, while any required filtering is performed on the sensor side. For the sharing and exchange of data for operational purposes, the Consortium operates on the basis of a dedicated data and information policy drawn up prior to initial operations in 2016 and reviewed in 2018 by the requisite internal body, the Security Committee. Since 2019, a fresh review has been underway to revise the documents in view of the requirements posed by an enlarged Consortium with additional security constraints of the individual partners.

In absence of a multilateral sharing agreement, the architecture of existing bilateral arrangements relevant to the exchange of SSA data are being taken into account. The data and information policy specifically address interactions for the purposes of EU SST by the Consortium partners. Initiating and concluding general SSA data sharing arrangements are not within the remit of the Consortium but the prerogative of the individual partners’ military and national security stakeholders.

All Consortium MS have general security agreements for the protection of classified material with each other, constituting the prerequisite for any exchange of classified documents or other material. In the past few years, all partners concluded bilateral data sharing agreements with the United States for bilateral exchange of unclassified SSA data or are finalizing their respective arrangements (US STRATCOM 2019). France, Germany, and the United Kingdom have bilateral SSA data sharing agreements with the United States that also covers the exchange of classified SSA data, in addition to liaison officers of each of their respective Air Forces situated at the US Joint Force Space Component Command (JFSCC), formerly Joint Functional Component Command for Space, Vandenberg. Finally, two Member States of the Consortium, France and Germany, are currently the only partners to have concluded a bilateral SSA data sharing agreement with each other, covering the exchange of both unclassified and classified SSA data.

As approaches to data sharing are currently being further consolidated inside the Consortium, they must reconcile operational needs and individual security constraints with the features afforded by the evolving data processing function, and the general developments on a global level (i.e., developments on the US side with open architecture for data sharing; cf. also below for STM). Specific technical exercises on data sharing are therefore currently underway with relevant partners in the United States.

Services

Since 2016, the SST Cooperation has been providing three operational SST services as outlined in the Decision 541: collision avoidance service, reentry analysis, and fragmentation analysis service.

The collision avoidance (CA) service is provided by the French and Spanish OCs (COO and S3TOC) operating in hot redundancy. Satellites or fleets of satellites are allocated when a user registers for the service via the front desk (see section “Users”). The CA service constitutes an added-value service, whereby several sources of data are used: conjunction data messages (CDM) from the United States and CDM generated autonomously from European sensor data, in addition to ephemeris provided by the spacecraft operator. The EU SST service complements US CDM through automatic acquisition, checks, and analysis of all incoming information; it provides alerts based on a threshold pre-defined by the registered user on three levels of risk (high interest, interest, information); and issues recommendations for avoidance maneuvers. Observation campaigns are conducted for high-interest events (HIE). There is direct interaction with the spacecraft operator to support decision-making as to whether to take an avoidance action. For LEO and GEO, timelines of identification of incoming risks, tasking requests to EU SST sensors and EU SST CDM generation, and notification of operators range from 7 to 14 days prior to the time of closest approach (TCA). Products provided to the operator include information on events, objects, miss distance, etc. They are complemented where needed, based on a dialogue with users, by mitigation recommendations, maneuver design, and maneuver support.

The reentry (RE) service is under the responsibility of the Italian Space Operations Centre (ISOC). It consists of two main products, a list of upcoming reentries and reentry warning reports. Updated every 2–3 days, the list of upcoming reentries covers objects for which a reentry epoch within a period of up to 30 days has been computed, including object name, type, maximum latitude, size, and reentry prediction date range. Reentry warning reports are provided at least 3 days in advance of risky reentries and are updated as needed, including a final report to confirm the reentry. The user is actively notified and provided with information including details of the reentering object, estimated ground track, and uncertainty window.

The fragmentation (FG) service, also handled by ISOC, addresses fragmentations in orbit and consists of two products, a short-term and medium-term report. The short-term report is provided as soon as possible after a fragmentation event and includes the number of detected fragments and type of fragmentation. A medium-term report provides all additional available information including additional objects, orbit data, Gabbard diagram, and fragment cloud distribution and evolution. A current review of the fragmentation alert services foresees the addition of further features and a long-term analysis product of the event.

Users

The products related to all three services are generated by the operation centers and passed on to the user through the service provision portal operated by the SST front desk, which is under the responsibility of the EU Satellite Centre. The services are free of charge, are available 24/7, and are currently accessible to European users, including organs of the European Union (European Commission and Council of the EU, European External Action Service), public and private spacecraft owners and operators, and European Member States and their research institutions, civil protection authorities, and space agencies. In view of some interest expressed by specific non-European users, discussions are ongoing on the oversight level of the program on EU level for potential future inclusion of external users.

Since the start of operations in July 2016, user uptake has grown to a current total of 104 registered users from 60 organizations in 18 EU Member States as of September 2019. The collision avoidance service has 43 registered users from 21 organizations (whereby, a small number are still completing the interface control documents related to the registration process). EU SST hence currently protects 129 spacecraft across all orbital regimes (40 in LEO, 30 in MEO, 59 in GEO) from the risk of collision. These users include European constellations such as the Galileo satellite navigation fleet, as well as fleets by commercial communications providers, military assets, and spacecraft operated by governmental entities. While some users use the products to corroborate existing processes, most integrated the SST collision avoidance service as an integral part into the value chain of routine operations (Monham 2018). For reentry analysis, there are 71 users from 47 organizations and for fragmentation analysis 60 users from 40 organizations.

As part of a so-called user interaction mechanism overseen by the European Commission and handled by the EU SatCen, regular user feedback is integrated in service portfolio development.

Perspectives

Alongside the paradigmatic change in orbital utilization in the current decade, the global landscape of SSA is in the process of evolving significantly. As more actors bring various capabilities and interests to the table, elements such as governance and infrastructure come to the fore as key foci of international discourse in policy and operations (Lal et al. 2018). Security concerns have to be reflected on in light of post-Cold War practices of collaboration and transparency that have already overturned multilateral sharing practices in domains such as satellite imagery but must also cater to new risks and threats identified by major space-faring actors. Geographical opportunities for sensor sites and an array of cutting-edge and legacy sensor systems must be traded off with advanced operational needs of unprecedented orbital utilization, in order to define effective ground-based architectures. Moreover, the fusion, synthesis, and exchange of data and products from multiple sources need to be understood for SSA use cases that are likely to bifurcate broadly to include monitoring and coordination of large-scale orbital traffic on the one hand and the observation and verification of sophisticated proximity operations on the other.

At this point in time, European SST efforts also find themselves part of a dynamic debate close to home. As integration of SST capabilities is seen to take up speed (West 2018, p 11), the future of SSA capabilities in Europe and their operational, R&D, and political elements are being discussed on various levels including governmental (civilian and military programs and their bilateral partners), intergovernmental (European Space Agency), and – most crucially – supranational (European Union) levels.

Evolution as a Sensor Network

As part of ongoing programmatic activities inside EU SST, the three main functions of sensors, data processing, and services are complemented by dedicated efforts for the upgrade and maintenance of sensors, in line with a vision for an enhanced architecture for the timeframe until 2028. With the recent enlargement of the Consortium to eight Member States, the network of operational radars, telescopes, and laser stations has already grown to include wider global coverage. As further participants may join the effort in the short- and midterm, the integration and trade-off of additional sensor assets and the targeted use of funds to support further developments are being assessed.

A fundamental part of this work consists of architecture studies currently being undertaken by the Consortium on request of the European Commission, with a focus on the sensor layer of the EU SST ground segment, in order to plan structured upgrades of specific sensors and optimize their use in the evolving sensor network between 2021 and 2028 (2021–2027 constitutes the upcoming budgetary timeframe of the multiannual financial framework of the European Union.). To this end, sensors – both existing and under development – are being examined as part of an added-value analysis, in order to determine an optimal architecture in view of possible degrees of autonomy in different orbital regimes and prioritize sensors for upgrade accordingly. Specifically, the architecture studies involve the examination of several dozens of possible architectures until 2028, by simulating both sensor coverage and cataloguing performance, in view of a population of objects in orbit that evolves across time.

In consultation with the European Commission, these studies take into account the underlying philosophy of EU SST as a support framework that all but complements significant past and future investment of its Member States through funds for operation, maintenance, and upgrade, with limited EU co-funding assumed to consist of less than 50% in the future and two conservative budgetary scenarios of the upcoming EU space regulation (cf. next section). For GEO, a complete European autonomous surveillance capability for objects larger than 35 cm is feasible by 2028 with classical and wide field-of-view telescopes. For MEO, Europe could feasibly catalogue 80% of objects larger than 35 cm in the same timeframe. For LEO, Europe could be able to catalogue 9,000–11,000 objects larger than 7–10 cm by 2028 within the tentative budgetary constraints of the proposed EU space program.

Finally, while new sensor systems come online and legacy systems are due for upgrading in the short term, the Consortium is also set to lose valuable assets with the potential exit of the United Kingdom from the European Union. While this will signify the loss of a valued partner, the UK’s interactions with the transatlantic SSA community have been long-standing. Since some partners of the SST Consortium actively engage in a range of multilateral space operations activities such as the Combined Space Operations (CSpO) initiative (US Air Force 2019), bi- and multilateral relations are likely to be maintained predominantly beyond the European Union SSA context.

Evolution in the EU Space Program

The ongoing architecture studies are linked to the opportunities posed by the proposed space program of the European Union (European Commission 2018b). While its draft legal basis is yet to be completed, the overarching context is all but decided: the draft regulation foresees a maturation of the current EU SST Support Framework into a sub-component of a dedicated SSA program, a notion already foreshadowed in the call for enhancing the SST framework into a fully fledged SSA program in the European Space Strategy of 2016 (European Commission 2016, p. 10). The SSA program will be situated next to the flagship programs for Earth observation (EO) and position, navigation, and timing (PNT), as part of a dedicated package of new “security components,” which include SSA and Governmental Satellite Communications.

The SSA component is proposed to predominantly include SST, next to small-scale elements of space weather (SWE) and near-Earth objects (NEO), and will be furnished with a comparably minor share of the proposed overall 16 billion Euro budget. The current governance model of a Consortium or partnership of EU Member States – rather than a communautized program of all Member States or a public-private partnership – is being affirmed and carried forward, with an opportunity for the accession of additional Member States of the European Union. The philosophy and mechanisms of internal governance remain largely unchanged. Indeed, certain elements proposed and implemented under the first two leadership terms of the current Consortium are being explicitly prescribed: these include functional specialization of key capability elements such as services or catalogue by a specific actor or tandem of actors, mechanisms that strengthen increased transparency, and involvement of representatives of the European Commission.

Given the dual aspect and increased security angle of the program, the context of EU SST in the evolving European ecosystem will be further complemented through instruments for cooperation put in place by the European Union in the defense domain such as the European Defence Fund (EDF), its precursor European Defence Industrial Development Program (EDIDP), and Permanent Structured Cooperation (PESCO). It remains a subject of discussion as to how these will be utilized by European actors to address SSA elements while avoiding duplication of key capabilities. Further developments will need to be seen in context also of recent national policies, such as the 2019 French Defence and Space Strategy, which posits SSA as a key domain, or the impending space policy of NATO that may manifest a need for a recognized space picture across a similar but different range of partners.

Evolution in the Context of Space Traffic Management

In light of the emergence of large constellations with fleets of dozens, hundreds, or even thousands of spacecraft operated by private entities, the community of practice is increasingly discussing the notion of space traffic management (STM) or coordination. In absence of an unambiguous, shared definition of the concept among space-faring actors, the debate on STM gathers different perspectives that encompass technical and operational approaches linked to the exchange of data and information and to reflections on legal and regulatory aspects.

An emerging consensus in the discussion posits that on the one hand, STM activities will have to be addressed and implemented in the context of security political concerns that also impinge upon sovereign aspects (Becker 2019). On the other, future efforts in this evolving domain will also inevitably foot on a kind of multilateral or coordinated interaction between various global stakeholders (Lewis et al. 2018, p. 22 and 35). As the current SST framework is set to mature as part of the consolidation of the European space program in the coming decade, it will hence have to be seen in – and continue to consolidate its position within – the context of burden-sharing with transatlantic partners.

Recent developments in the United States saw the issuing of Space Policy Directive 3 (SPD-3) (Whitehouse 2018). SPD-3 proposes an integrated interagency approach towards STM. The US Department of Commerce is directed to act as a new civil focal point for public interface and on orbit SSA data sharing, while the US Department of Defense maintains the authoritative catalogue in view of its core national security mission. SPD-3 posits the main aspects of a space traffic management regime, including SSA data, STM services, and STM science and technology, and also addresses national orbital debris mitigation policy, as well as global engagement. While the latter two, national regulation for space debris mitigation and global engagement for the promotion of norms of behavior, remain the remit of individual Member States, in Europe to date, it is the aspect of technical and operational STM that resonates most with EU SST. Essentially, the activities of EU SST as a civilian SSA actor today correspond to the technical and operational aspects of the STM initiative in the United States in view of data sharing through a repository (open architecture data repository in the United States and European database in the EU) and the provision of basic and added-valued services (e.g., collision avoidance).

In response to the US developments, the dialogue in Europe on STM has picked up momentum. It increasingly forges links between the current body of thinking on potential regulatory needs, existing operational and technological capabilities of government actors, and commercial entities that explored operational and governance aspects on SST (Tortora 2019). Senior representatives of the European Commission have described the Union’s SST activities to constitute the basis for a future European STM regime (Bieńkowska 2019).

Finally, the shift of responsibilities of the US Department of Defense to the Department of Commerce will nevertheless leave bilateral agreements between military SSA actors that allow the current sharing of US CDM with Consortium Member States untouched. Beyond these fundamental bilateral channels between the United States and the individual EU SST Member States, the Consortium maintains a regular dialogue with US stakeholders from the Department of Defense, Department of State, and Department of Commerce in mutual pursuit of a collaborative approach .

Conclusion

Space Surveillance and Tracking constitutes a fundamental capability to support and enable the operation of space-based services and assets. In view of foreseen activity in orbit of unprecedented scale, coupled with the growing criticality of – and risk to – space-based services, the domain of SSA will be salient in the mid- and long term. It will likely be pursued both by those state actors that operate their own maneuverable space assets and have a primary interest safeguarding them, and by state and non-state actors that can bring pertinent technology and infrastructural elements to the table.

In its comparatively short history, the implementation of the EU Space Surveillance and Tracking Support Framework has seen the convergence of a diverse group of stakeholders in a novel model for space cooperation in Europe. For some Member States, the inception of EU SST presented an opportunity to foster nascent engagement and interest in the domain of SSA; for others it serves as a multilateral forum to draw on existing rich legacies and make those available to the wider community. By employing a communal but tailored bottom-up approach to an SST system, EU SST allowed for a comparably rapid progression to fundamental operational services while honoring long-standing security constraints articulated by its key actors. A streamlined governance enables leverage for both the European Union and those state actors with long-standing operational and political investment in the SSA domain, and at the same time encourages increased participation by those state actors who begin to recognize SSA as an important field. It allows the contribution of industry actors to those parts of the SSA value chain deemed meaningful and effective by individual governmental actors while binding the latter in a joint effort of cooperation.

Borne out of the need to advance a strategic capability for the European community, EU SST hence constitutes an effort to consolidate and enhance capabilities of traditional and emerging space actors, as well as an exercise in transparency building within and beyond Europe. In fusing external data from the United States with that of an expanding distributed sensor network operated by European actors, SST services are provided free of charge to an increasingly large user community in Europe that includes commercial, governmental, and intergovernmental users who operate fleets of spacecraft or handle civil protection. Through an approach of layered dependencies among the Member States contributing to EU SST in Europe and as a European collective vis-à-vis transatlantic partners, the framework advances global burden-sharing of safeguarding strategic space assets. It also ties into the efforts of promoting the sustainability of the orbital environment and constitutes a building block for future operational activities in the area of space traffic management and coordination.

As integral component of the planned European Union space program, European SST activities are set to mature into a program in their own right, with an enhanced catalogue, services, and a globally distributed sensor architecture that affords greater levels of autonomy across orbital regimes. As such, the evolution of the SST capability of the European Union must be observed in the context of capabilities of global activity: like other major efforts, it faces the challenge and opportunity to slot into the global ecosystem of different governmental and commercial actors developing and operating existing and next-generation SSA capabilities; it contributes to the contemporary dialogue of global community on how to ingest of multiple sources of data and process for meaningful, actionable products; and must convene in organizational frameworks that take into account the different contributions and requirements of a highly diverse community.