L2-PDM-SWGR CRITICAL POWER ENERGY Level 2 · hardware

Switching & Relay Gear

Solid-State Switching and Fault Isolation Relay Assembly

The solid-state switching and fault isolation relay assembly provides the actuation layer for lunar power routing, executing autonomous bus reconfiguration and fault isolation in under one millisecond across distribution networks. Built around silicon carbide MOSFET dies on aluminum nitride substrates in hermetically sealed packages, the hardware maintains an on-state resistance below 10 milliohms without mechanical contact wear. Lunar deployment mandates solid-state architecture because the ambient vacuum precludes contact lubricants, while managing switch losses during peak loads requires careful thermal management. Furthermore, silicon carbide devices provide the radiation tolerance necessary over standard silicon to prevent gate oxide degradation across a 100-year cumulative operating lifetime.

Solid-state switches and fault isolation relays enabling autonomous bus reconfiguration, load switching, and fault isolation across the power distribution network.

Purpose

Provides the actuation layer for all power routing decisions, enabling the system to isolate faults, reconfigure buses, and connect or disconnect loads without mechanical wear.

Context

Operates on the bus architecture (L2-PDM-BUS) under commands from load management (L2-PDM-LOAD) and protection (L2-PDM-PROT) systems.

Principles

▸Solid-state power controllers eliminate mechanical contact wear for extreme longevity
▸Redundant switch paths ensure no single switch failure isolates a critical load
▸Sub-millisecond switching times enable rapid fault isolation
▸Each switch includes built-in current sensing for local protection

Typical implementations

▸Silicon carbide (SiC) MOSFET-based solid-state power controllers
▸Redundant cross-tie switches between bus segments
▸Latching relays for long-term configuration hold (zero quiescent power)
▸DDI (Digital Data Interface) command and status interface

Lunar considerations

▸SiC devices offer superior radiation tolerance over silicon IGBTs
▸No lubricants available for mechanical contacts in vacuum
▸Thermal management of switch losses during peak load switching
▸100-year cumulative radiation dose effects on gate oxide integrity

Specifications

Functional

primary function	Provide solid-state switching and relay actuation for power bus reconfiguration and fault isolation
inputs	Switch commands from L2-PDM-LOAD and L2-PDM-PROT, Bus power from L2-PDM-BUS
outputs	Switched power paths, Switch state telemetry to L2-PDM-MON
switching time ms	<1
on state resistance mohm	<10
current rating a	TBD per channel
redundancy	dual-redundant for critical paths

Physical

materials	Silicon carbide MOSFET dies, Aluminum nitride substrates, Hermetically sealed packages
vacuum	True
radiation tolerant	True
dust sealed	True

Operational

thermal range c	-173, 127
lifetime years	100

Interfaces

Provides

→Power Bus ArchitectureSwitching actuationcritical
Provides bus segment reconfiguration through cross-tie and isolation switches
→Power Monitoring & MeteringSwitch state telemetryessential
Reports switch positions and health status to monitoring system

Requires

←Load Management SystemSwitching commandsessential
Receives load management commands for scheduled power routing changes
←Protection & Fault IsolationFault isolation commandscritical
Receives emergency isolation commands from protection system