DESCRIPTION
The PolarStore-2S is a 3U SpaceVPX (VITA 78) payload storage module housing two space-grade SATA III solid-state drives with a combined capacity of 4 TB. Drives are connected to the host OBC directly via SpaceVPX data plane SERDES lanes — no on-board processor or intermediate controller is present. This passive architecture concentrates reliability in the host OBC, allows recording policy and FDIR to be managed entirely in firmware, and eliminates any independent firmware update dependency. The PolarStore-2S is the primary mass-storage companion module for the OBC-Polar VPX recorder firmware personality.
KEY FEATURES
- 4 TB SATA Storage, 2× 2 TB space-grade SATA III SSDs — hot-swap capable via wedge-lock bay
- 550 MB/s per Drive, Sequential read per drive; 1.1 GB/s aggregate via SpaceVPX data plane
- 2× SERDES Lanes, SATA III over SpaceVPX Fat Pipe — no front-panel cabling required
- 30 krad TID, Radiation-tolerant drives and signal conditioning — latch-up immune
- Conduction-Cooled, VITA 48.2 wedge-lock — no fans or cold plates required
- Dual-Redundancy Option, Two PolarStore-2S modules configured as RAID 1 via OBC firmware policy
- Passive Architecture, No on-board processor — host OBC manages FDIR, wear-levelling, and data policy
- VITA 78 Compliant, 3U SpaceVPX SLT3-PAY payload slot — compatible with all CAVU backplanes
- 3 DWPD Endurance, Drive writes per day — 5-year mission-lifetime rated, >1 year data retention
- OBC-Polar VPX Ready, Pre-validated with SATA III SERDES personality; zero NRE integration
- Low Power, ~6 W nominal from 5 V / 12 V backplane rails
- Compact Mass, ~180 g — minimal impact on system mass budget
DRIVE SPECIFICATIONS
- Drive count: 2 (fixed)
- Drive type: Space-grade SATA III solid-state drive — industrial-temp, high-endurance
- Capacity per drive: 2 TB
- Total raw capacity: 4 TB
- Interface per drive: SATA III — 6 Gbps (3 Gbps fall-back)
- Sequential read: Up to 550 MB/s per drive (1.1 GB/s aggregate)
- Sequential write: Up to 520 MB/s per drive
- Random read (4K): Up to 95,000 IOPS per drive
- Random write (4K): Up to 30,000 IOPS per drive
- Endurance: >3 DWPD; rated 5-year mission lifetime
- Data retention: >1 year powered off at +55°C
HOST INTERFACE & POWER
- Host interface: SATA III via 2× SpaceVPX data plane SERDES lanes (Fat Pipe)
- On-card logic: Passive — no processor, no controller, no firmware
- SERDES lanes used: 2 (one per drive, 6 Gbps each)
- Power supply: 5 V and 12 V from SpaceVPX backplane P0/J0
- Power nominal: ~6 W (both drives active)
- Power idle: ~2 W (drives in low-power state)
RADIATION & ENVIRONMENT
- TID tolerance: >20 krad (Si) — drives and signal path
- SEL immunity: Latch-up immune signal conditioning
- Operating temp.: −40°C to +85°C conduction-cooled (VITA 48.2)
- Non-op temp.: −55°C to +125°C
- Shock: Per MIL-STD-810 Method 516
- Vibration: Per MIL-STD-810 Method 514
- Vacuum: Fully compatible — no convection cooling paths
MECHANICAL
- Form factor: 3U SpaceVPX (VITA 78) Payload Module
- Slot profile: SLT3-PAY
- Dimensions: 100 × 160 mm (220 mm depth option)
- Connector: VITA-46 MULTIGIG RT2
- Cooling: Conduction-cooled, VITA 48.2 wedge-lock
- Mass: ~180 g
SYSTEM COMPATIBILITY
- OBC-Polar VPX: Native — SATA III recorder personality pre-validated
- SpaceVPX-BP-SS: Compatible — any SLT3-PAY slot
- SpaceVPX-BP-DS: Compatible — any SLT3-PAY slot, dual-string capable
- RAID 1 operation: Two PolarStore-2S modules — host OBC mirrors via SERDES
- PolarStore-4S: Can co-reside on same backplane for mixed config
