ISO 22663:2015

Overview

ISO 22663:2015 - Proximity-1 space link protocol - Data Link Layer defines the data-link-level behavior for short-range spacecraft communications (proximity links). Published by ISO and prepared by CCSDS (as CCSDS 211.0-B-5), the standard specifies the Data Link Layer structure including framing, medium access control (MAC), data services, and input/output (I/O) sublayers. It defines protocol data units, framing formats (including the Version‑3 transfer frame), expedited and sequenced data transfer, timing services, I/O control, and session establishment/termination procedures between a caller and responder. The Coding & Synchronization Sublayer and the Physical Layer are specified in separate CCSDS standards.

Key topics and requirements

• Framing and Protocol Data Units: Definitions of transfer frames (Version‑3 transfer frame) and header/data field organization for reliable proximity transfers.
• Medium Access Control (MAC): Rules for medium access in proximity environments to coordinate link sharing and avoid collisions.
• Data Services: Support for expedited (urgent) and sequenced-controlled data transfers, with procedures for sending/receiving operations and error handling.
• Input/Output (I/O) Sublayer: Interfaces and control for data I/O operations between higher layers and the data link.
• Timing Services: Time-tag recording, time correlation, and mechanisms to transfer time information to remote assets (important for synchronized operations).
• Session Management: Procedures and state diagrams for establishing, maintaining and terminating sessions between caller and responder (full duplex, half duplex, simplex modes).
• Conformance & Management: Includes Protocol Implementation Conformance Statement (PICS) proforma and normative annexes for implementers.
• Standards Scope Limits: ISO 22663:2015 does not specify specific implementations, service interface implementations, underlying technologies for procedures, or management/configuration activities.

Applications

ISO 22663:2015 is targeted at proximity space links used in:

• Orbiter-to-lander/rover communications during descent, landing, and surface operations
• Rendezvous, docking, and close-proximity servicing missions
• Short-range inter-satellite links and formation flying where near-field data exchange and time correlation are required
• Ground-to-spacecraft proximity test and verification scenarios

Who uses this standard

• Spacecraft systems and communications engineers
• Mission architects and planners for robotic and human spaceflight proximity operations
• Satellite and probe manufacturers integrating proximity communication subsystems
• Ground segment and operations teams responsible for link configuration and interoperability

Related standards

• CCSDS Proximity-1 Coding and Synchronization Sublayer (separate document)
• CCSDS Proximity-1 Physical Layer (separate document)
• Other CCSDS Blue Books referenced for interoperability and protocol stack alignment

Keywords: ISO 22663:2015, Proximity-1 space link protocol, data link layer, space communications, CCSDS, framing, medium access control, timing services, transfer frame, proximity links.