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

Distribution Wiring Harness

Main Power Distribution Cable Runs and Connector Assemblies

The main power distribution cable runs and connector assemblies form the physical wiring harness that routes electrical power from bus architecture to subsystem load interfaces. Utilizing Kapton-insulated, silver-plated copper conductors and hermetically sealed circular connectors, the harness must maintain less than a two percent end-to-end voltage drop across a 100-year operational lifetime. Lunar deployment subjects these assemblies to thermal cycling fatigue across solder joints and crimps, long-term vacuum radiation and ultraviolet degradation of polyimide insulation, and lunar dust ingress at mating interfaces. To protect against common-mode failures, redundant conductor paths maintain a physical separation of more than 30 centimeters along titanium cable tray brackets.

Main power cable runs, connector assemblies, and wiring harnesses physically routing electrical power from bus architecture to all subsystem load interfaces.

Purpose

Provides the physical copper path for power delivery, with connectors designed for 100-year vacuum operation, thermal cycling, and dust exclusion.

Context

The physical realization of the power distribution topology, connecting L2-PDM-BUS segments through L2-PDM-SWGR switches to all L1 subsystem power input interfaces.

Principles

▸Cable sizing must account for voltage drop, thermal dissipation, and derating over lifetime
▸Connector reliability dominates overall harness reliability
▸Routing must avoid thermal hot spots and radiation-sensitive areas
▸Redundant cable paths must be physically separated to prevent common-mode failures

Typical implementations

▸Kapton-insulated silver-plated copper conductors
▸Hermetically sealed circular connectors (MIL-DTL-38999 heritage)
▸Redundant cable runs on physically separate routing paths
▸Cable trays with thermal standoffs from structure
▸Shielded cables for EMI-sensitive adjacent signal paths

Lunar considerations

▸Kapton insulation must be evaluated for 100-year UV and radiation degradation
▸Connector sealing against lunar dust ingress at all mating interfaces
▸Thermal cycling fatigue of solder joints and crimps over 100 years
▸Cable mass is a significant driver of total system mass budget
▸No connector maintenance or re-mating possible after deployment

Specifications

Functional

primary function	Physically route electrical power from distribution buses to all subsystem load interfaces via cable runs and connectors
inputs	Electrical power from L2-PDM-BUS via L2-PDM-SWGR
outputs	Electrical power to all L1 subsystem power input interfaces
voltage drop percent	<2 end-to-end
connector cycles	designed for zero re-mate (permanent installation)
cable derating	per NASA-STD-4003 or equivalent
physical separation cm	>30 between redundant paths

Physical

materials	Silver-plated copper conductors, Kapton polyimide insulation, Hermetically sealed connectors, Titanium cable tray brackets
vacuum	True
radiation tolerant	True
dust sealed	True

Operational

thermal range c	-173, 127
lifetime years	100

Interfaces

Provides

→ALL_L1_SYSTEMSPhysical power connectionscritical
Cable runs and connectors delivering power to each subsystem's power input interface

Requires

←Power Bus ArchitectureBus connection pointscritical
Physical attachment points on bus bars for cable termination
←Primary StructureCable routing structureessential
Structural mounting points, cable trays, and routing channels