TraCSS-EU SST Joint Studies & Service Comparison
Background
Space debris and collision avoidance are challenges for all spacecraft, regardless of their nation of registry. As laid out in the Office of Space Commerce’s Vision for Global SSA Collaboration, international cooperation is key to enhancing data consistency, coverage, and transparency.
Both the Traffic Coordination System for Space (TraCSS) and the European Union Space Surveillance and Tracking (EU SST), in partnership with the commercial space situational awareness (SSA) industry, will offer free space SSA services to spacecraft operators worldwide to prevent in-orbit collisions.
A series of studies, conducted by personnel from both programs, highlight similarities and differences between the two systems. These studies represent a step toward greater transparency and collaboration as the space sector continues to grow. The TraCSS and EU SST teams are committed to continuing their work with global partners to promote space safety and sustainability.
Service Comparison
At the 2024 Advanced Maui Optical Surveillance (AMOS) Conference, the Office of Space Commerce and the European Union released a joint paper (copyright © 2024 Advanced Maui Optical and Space Surveillance Technologies Conference (AMOS) – www.amostech.com) comparing the services provided by OSC’s TraCSS and the EU SST capability.
A detailed breakdown reveals significant alignment between TraCSS and EU SST, particularly in collision avoidance services (see table below). Some differences remain in the availability of maneuver screenings and anomaly reporting. The study also identifies potential future developments, such as launch collision avoidance and improved operator ephemeris, aimed at addressing the evolving needs of the space industry.
SST & TraCSS Services Comparison Summary Table (as of August 2024)
| Service | EU SST | TraCSS |
|---|---|---|
| 1. SSA Information as a Service | ||
| 1.1 Contact information | No | Yes |
| 1.2 Satellite attributes | No | Yes |
| 1.3 O/O ephemerides with planned maneuvers | No | Yes |
| 1.4 Catalog of space objects | Future Phase | Yes |
| 2. In-Orbit Collision Avoidance Service | ||
| 2.1 Routine catalog and O/O ephemerides screening and CDM production | Yes | Yes |
| 2.2 Risk Assessment and Detection and Notification of High Interest Events/Emergency Events | Yes | Yes |
| 2.3 Additional tracking on the secondary and/or primary objects | Yes | Yes |
| 2.4 Basic CAM Options for selection by O/O² | Yes | Yes |
| 2.5 Candidate CAM Screening | Yes | Yes |
| 2.6 For selected HIE/Emergency Events, dialogue with O/O | Yes | Yes |
| 3. Candidate Maneuver Screening | No | Yes |
| 4. Spacecraft Anomaly Reporting | No | Yes |
| 5. Reentry Monitoring Service | Yes | Future Phase |
| 6. Fragmentation Notification and Analysis Service | Yes | Yes (Notification Only) |
| 7. Potential Future Services Under Consideration | ||
| 7.1 Launch Collision Avoidance service | TBD | Future Phase |
| 7.2 Improved O/O Ephemerides | TBD | TBD |
| 7.3 Space Weather Information and Atmospheric Drag Model | No | TBD |
| 7.4 Traffic Coordination Platform as a Service | TBD | TBD |
Opportunities for SSA Information Sharing
There are multiple independent national and regional space situational awareness systems around the world. These systems use sensors to track objects in space, estimate their present and expected future location, and identify any close approaches between two objects that could potentially result in a collision.
Advanced warning of these potential collisions allows spacecraft operators to determine whether it is necessary to carry out a maneuver to avoid a potential collision and coordinate with counterpart operators, if necessary. These services are essential to global spaceflight safety and sustainability. However, each of these systems uses different data sources and different algorithms and processes, and thus, they can be expected to produce at least somewhat different solutions.
To minimize the extent to which spacecraft operators receive conflicting information, it is important to facilitate coordination and information sharing among these systems. However, there are many questions about what international coordination could or should entail. What types of information should be shared, and why? What are the highest priorities for information sharing and coordination? What procedures might be needed to enable coordination?
At the 2025 AMOS Conference, the TraCSS and EU SST published a follow-on joint study (copyright © 2025 Advanced Maui Optical and Space Surveillance Technologies Conference (AMOS) – www.amostech.com) advances our understanding through a case study of information sharing cooperation between the two systems (table below).
Opportunities for Programmatic and Operational Information Sharing Among SSA Systems
| EU SST Service | TraCSS Service | Potential Programmatic Information Sharing | Potential Operational Information Sharing | |
|---|---|---|---|---|
| Program Overview | 1) Program Policy and Strategy. 2) Objectives of the system. 3) System architecture. 4) Services provided. 5) Timeline of the program. 6) Future Development Plans. | |||
| Services | ||||
| 1. Routine catalog and O/O ephemerides screening and CDM production. | Yes | Yes | 1) Sensor network architecture description. 2) Use of O/O ephemerides and guidance to O/O on ephemeris covariance method. 3) Processes used to evaluate the quality of operational data (inputs & outputs). 4) Cadence of CA screening along with updates of cadence of screening inputs. 5) Screening volume(s). 6) Process to identify primary CDM. 7) Hard body radius information source and/or calculation approach. 8) Space weather information source and update cadence. 9) Methodology for calculating probability of calculation. 10) Standard format used for CDM. 11) CDM update frequency. 12) Orbit propagation method and/or drag/force model used for orbit propagation. | 1) O/O ephemerides. 2) Estimated orbits from sensor data. 3) Hard body radius and other spacecraft attributes. 4) Space weather information. 5) Conjunction Data Messages. 6) Operational O/O contact information. 7) Data quality assessment outputs. |
| 2. Risk assessment and detection and notification of high-interest events/emergency events. | Yes | Yes | 1) Procedures, criteria, and thresholds for defining high-risk events. 2) Sources of information on spacecraft maneuverability (if relevant). 3) Procedures for alerting spacecraft operators of high-risk events. 4) Additional information and/or tools provided to operators. 5) Response excepted from operators (if applicable). 6) Method for communication with operators. 7) Procedures for after-event evaluation (if relevant). | 1) High-risk CDMs |
| 3. Additional tracking on the secondary and/or primary objects. | Yes | Yes (future) | 1) Procedures for pursuing additional tracking. 2) Potential timing of updated observations. | |
| 4. Basic CAM options for selection by O/O. | Yes | Yes (future) | 1) Procedures for generating and providing collision avoidance options. | |
| 5. Candidate CAM screening. | Yes | Yes | 1) Process for enabling candidate CAM maneuver screenings. | |
| 6. For selected HIE/Emergency events, dialogue with O/O. | Yes | Yes | 1) Protocol for dialogue with spacecraft operations (if relevant) 2) Conditions for engaging in dialogue with spacecraft operators (if relevant). 3) Limitations on dialogue with spacecraft operators. 4) Common questions from spacecraft O/Os. | 1) Shared dialogue with operators. |
| Candidate Maneuver Screening | No | Yes | 1) Process for screening candidate maneuvers (if relevant) | |
| Spacecraft Anomaly Reporting | No | Yes | 1) Process for anomaly reporting (if relevant). 2) Process for sharing anomaly information (if relevant). | 1) Anomaly reports. |
| Reentry Monitoring Service | Yes | Yes (future) | 1) Description of re-entry monitoring service. 2) Process for developing re-entry predictions. | 1). Re-entry predictions. |
| Fragmentation Notification and Analysis Service | Yes | Yes (notification only) | 1) Description of fragmentation and/or analysis service. 2) Process for sharing fragmentation notifications. | 1) Fragmentation notifications. |
Coordination between EU SST and TraCSS is an important first step, but to support global spaceflight safety, it is important to expand coordination to other SSA providers around the world. The overall goals and processes described here with respect to cooperation between EU SST and TraCSS also apply to other SSA systems. Improved transparency, compatibility, and interoperability among independent systems would help to ensure spacecraft operators receive more consistent guidance on spaceflight safety issues and events. It would also facilitate improved coordination among spacecraft operators.