Circuit Breaker / Fuse Network
Rad-Hard Solid-State and Thermal Fuses
The circuit breaker and fuse network is a 10-kilogram electrical protection assembly housed in a 316L stainless steel enclosure that isolates distribution faults before they propagate. Operating without magnetospheric radiation shielding, the system utilizes solid-state devices rather than wear-prone mechanical switches to support a 25-year operating life. The unit integrates 50 radiation-hardened silicon carbide solid-state circuit breakers providing a 100-microsecond trip response, backed by 20 irreversible thermal fuses at the top of the distribution tree. Programmable trip curves adjust for aging-derated loads, allowing multi-tier selective fault coordination while consuming five watts of continuous power.
Multi-tier fault protection using rad-hard solid-state current limiters (SSCBs) and thermal fuses to clear faults before they propagate.
Purpose
Multi-tier fault protection using rad-hard solid-state current limiters (SSCBs) and thermal fuses to clear faults before they propagate.
Context
Child of L2-PDM-PROT within the Lunar Ark system
Principles
- ▸Solid-State Circuit Breakers (SSCB) with sub-millisecond response
- ▸Thermal fuses as last-resort backstop
- ▸Coordination per IEC 60364 selective-tripping principles
- ▸Programmable trip curves match downstream device ratings
- ▸Self-test by injecting test current
Typical implementations
- ▸RHRPMICL1A Space-Qualified Programmable Integrated Current Limiter
- ▸ISS Remote Power Controller (RPC) family heritage
- ▸ST Microelectronics BCD6s SOI rad-hard power ICs
- ▸TI Space rad-hard current limiters
Lunar considerations
- ▸Solid-state better than mechanical for long-life space
- ▸Thermal fuses irreversible — used only at top of tree
- ▸Programmable curves accommodate aging-derated loads
Specifications
Functional
| primary function | Multi-tier fault protection using rad-hard solid-state current limiters (SSCBs) and thermal fuses to clear faults before they propagate. |
| sscb count | 50 |
| trip time us | 100 |
| thermal fuses | 20 |
Physical
| mass kg | 10 |
| materials | SiC SSCB power FETs, Rad-hard MCU, 316L SS enclosure |
| vacuum compatibility | True |
Operational
| power consumption w | 5 |
| thermal range c | -40, 70 |
| lifetime years | 25 |
| mtbf hours | 300000 |
Interfaces
Provides
- Protected bus segments
- Trip event telemetry
Requires
- Over-current trip inputs
- Over-temp trip inputs
Cite this entry
Lunar Ark Codex. "Circuit Breaker / Fuse Network" (L3-PDM-PROT-FUSE). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-PDM-PROT-FUSE
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.