This recommended standard addressees protocols and operational Space Traffic Coordination (STC) requirements critical to ensure flight safety and mitigate collision risk, from pre-launch safety assessment through manoeuvre plans, on-orbit collision avoidance support services, and end of mission disposal. This standard levies requirements of an STC system that will facilitate the provision of high-availability, timely, comprehensive and sufficiently accurate services to support the safe, efficient, and sustainable use of space. This STC standard addresses: • Protocols for collection and exchange of data relevant to space safety; • Protocols for creating, populating and operating an open architecture data repository to facilitate open data exchange; • Data integrity measures and standards to ensure quality from diverse sources; • Space Situational Awareness (SSA) data derived from multiple and diverse sources. • Measures to safeguard proprietary or sensitive data; • Owner-operator notification of flight plans and planned manoeuvres and sharing of orbital location data (ephemerides) • Timely and actionable warnings; sharing of catalogue data, to predict close approaches; • Interoperable formats to enable reliable messaging STC inputs and results, timely and actionable warnings, referencing extant CCSDS standards where applicable; • Exchange of catalogue data to predict close approaches and assess options for operator collision avoidance manoeuvre plans. • Formats to enable development of applications to leverage data and perform automated processes for collision avoidance. • Data protection measures • Coordination for satellites transiting Large Constellation (LC) radial shells This standard requires flexibility to accommodate our deeper understanding of the impacts upon the space environment created by increased and emerging space activities and to benefit from technological advances and refined capabilities.