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Overview

Transfer frames are the fixed-format containers that carry Space Packets across a single point-to-point link. They add framing, addressing, and sequencing so the receiver can extract packets from the continuous bitstream and detect lost or misordered data.

Each point-to-point link uses one transfer frame protocol. The choice depends on the link direction and type.

  • TM — Telemetry Transfer Frame (132.0-B-3) for downlink
  • TC — Telecommand Transfer Frame (232.0-B-4) for uplink
  • AOS — Advanced Orbiting Systems (732.0-B-4) for high-rate downlink
  • Proximity-1 — short-range inter-spacecraft links (211.2-B-3)
  • USLP — Unified Space Data Link Protocol (732.1-B-3)