SpaceVPX-BP-DS
3U SpaceVPX Dual-String Backplane
SpaceVPX VITA 78 8 Slots Dual-String Active / Standby Redundancy
DESCRIPTION
The SpaceVPX-BP-DS is a 3U SpaceVPX (VITA 78) dual-string backplane providing full active / standby redundancy across eight slots: two System Controller slots (SLT3-CTL, designated OBC-A and OBC-B), one Utility Switching slot (SLT3-SWI, for SpaceUM-Polar), and five Payload slots (SLT3-PAY). Both OBC slots have independent full-plane connectivity — control, data, expansion, and utility — to all payload slots. The SpaceUM-Polar monitors both controllers and executes autonomous string switchover in the event of an OBC fault, with sub-millisecond recovery. All CAVU SpaceVPX payload modules are compatible without modification.
KEY FEATURES
- 8-Slot Dual-String: 2× SLT3-CTL + 1× SLT3-SWI + 5× SLT3-PAY — full mission-critical redundancy
- Independent Full Planes: Both OBC slots carry independent control, data, expansion, and utility planes to all PAY slots
- SERDES Dual-Path: Dual Fat Pipe and Thin Pipe data-plane routing — active path selected by SpaceUM
- Per-Slot LCL: SpaceUM-Polar applies latching current limiters per payload slot on both strings
- PSU-Polar-3U Ready: Power input from a single or redundant PSU-Polar-3U power supply card
- All CAVU Modules: All PolarStore, SpaceUM, OBC-Polar VPX, and OBC-64 VPX are plug-compatible
- Sub-ms Switchover: SpaceUM-Polar executes autonomous OBC-A ↔ OBC-B switchover without ground intervention
- SpaceWire Dual-Hub: OBC-A and OBC-B each source independent SpaceWire star topologies to payload slots
- PCIe Dual-Root: PCIe Gen2 ×4 from each OBC slot independently; switch card supports fan-out
- Space-Grade PCB: High-speed laminate, ≥12 layers, controlled differential impedance
- Mission-Heritage Design: Topology aligned with NASA SpaceVPX dual-string reference architecture
- Upgrade From BP-SS: Direct system upgrade path from single-string SpaceVPX-BP-SS
SLOT PROFILES & PLANE CONNECTIVITY
- Total slots: 8 (2× SLT3-CTL + 1× SLT3-SWI + 5× SLT3-PAY)
- OBC-A slot (SLT3-CTL): Slot 1 — String A primary controller; full plane connectivity to all PAY slots
- OBC-B slot (SLT3-CTL): Slot 2 — String B standby controller; full plane connectivity to all PAY slots
- SpaceUM slot (SLT3-SWI): Slot 3 — SpaceUM-Polar monitors both strings; executes autonomous switchover
- Payload slots (SLT3-PAY): Slots 4–8 — dual-path SERDES data plane; receive SpaceWire from active string
- Control plane: SpaceWire star from each OBC independently; SpaceUM routes active string to PAY
- Data plane: Dual Fat Pipe / Thin Pipe SERDES per slot; active path controlled by SpaceUM
- Expansion plane: PCIe Gen2 ×4 from each OBC; switch card extends to multiple PAY slots
- Clock: Dual 100 MHz reference clocks — SpaceUM selects active source per string
ELECTRICAL SPECIFICATIONS
- Input voltage: 5 V, 12 V, 3.3 V via P0/J0 utility connectors; dual input for PSU redundancy
- Max slot current (5V): 5 A per slot (40 A total backplane capacity at 5 V)
- SpaceWire links: 5× per OBC (one to each PAY slot) — dual independent star hubs
- SERDES data plane: Up to 12.7 Gbps per lane; dual-path per PAY slot
- PCIe bandwidth: PCIe Gen2 ×4 per OBC slot (independent paths)
- PCB laminate: Rogers 4350B or equivalent space-qualified high-speed laminate
- PCB layers: ≥12 layers; controlled differential impedance 100 Ω (±5%)
- ESD protection: TVS diodes on all I/O lines; full chassis ground tie-down
MECHANICAL
- Form factor: 3U SpaceVPX (VITA 78) Backplane
- Dimensions: ∼420 × 180 mm
- Connector per slot: VITA-46 MULTIGIG RT2
- Operating temp.: −40°C to +85°C
- Mass: ∼550 g (PCB + connectors)
- Mounting: 6× M3 threaded standoffs to chassis
COMPATIBLE SYSTEMS
- OBC-Polar VPX: SLT3-CTL A and B
- OBC-64 VPX: SLT3-CTL A and B
- SpaceUM-Polar: SLT3-SWI — required for dual-string
- PolarStore-2S/4S: SLT3-PAY — SATA storage
- PolarStore-2N/4N: SLT3-PAY — NVMe storage
- PSU-Polar-3U: Single or redundant pair
