Generalized Orbital Add-on Technology for Microsatellites — mechanical, electrical, and software interface standard.
GOATSat decomposes every docking interaction into three independent, upgradeable contracts.
Standardized docking collar with funnel-guided blind-mate geometry for autonomous docking tolerance.
Hot-plug capable 6-group pin sequencing with deterministic FSM and hardware fault isolation.
Module discovery protocol over CAN-FD, SpaceWire, or Ethernet-TSN — profile-selectable per mission.
Every docking sequence is governed by a deterministic FSM. Any anomaly returns the system to S0 (safe) via controlled power isolation.
No module coupled or not electrically reliable. All rails disabled. PRESENT monitored.
Physical insertion detected. Debounce validation applied to avoid false positives from mechanical bounce.
Current-limited initialisation rail enabled. Module boots minimal MCU/FPGA logic only.
CAN stack active. Module announces ID, type, version, capabilities, and power profile.
Host evaluates energy budget. Assigns max current, ramp rates, and priorities. Explicit authorisation sent.
Main power rail energised via hot-swap/eFuse with inrush control. Overcurrent and undervoltage monitored.
High-speed PHY trained and link synchronised. Module switches to full operational mode.
Module fully coupled, powered, and communicating. Continuous health monitoring active.
Fault States — All transitions return to S0
PRESENT deactivates during S2–S7. Immediate power isolation. All rails disabled. Return to S0.
Excess current on VCC_IL or POWER. Hardware protection trips. Cooldown lockout applied before retry.
CAN timeout, version incompatibility, or power profile not concedible. POWER kept disabled. Return to S0.
The complete GOATSat v0.1 specification — including full connector electrical requirements, interoperability profiles, and protocol reference implementation — is available for download below.