New Tasks per Requirement:
R-DM-001
Create a master Data Dictionary spreadsheet or table (CSV + LaTeX version) with required columns:
Signal name
Source subsystem (sensor / MCU / OBC)
Units
Bit depth
Nominal rate (Hz)
Priority class (HIGH / MED / LOW / DEBUG)
Packet class
Storage file type
Notes (calibration, scaling, edge cases)
Enumerate every signal mentioned in:
Section 6.1 (preliminary signals)
Fault and event logs
MCU diagnostics
Command acknowledgements
Assign unique IDs for each signal (numeric or enum-based).
Define scaling rules (e.g., raw ADC → physical units).
Produce:
A LaTeX table for the Design Book (CoDR-ready)
A machine-readable version (CSV / JSON) for firmware use
Add a versioning scheme and changelog.
R-DM-002: DM shall guarantee timestamp accuracy to within 10 ms of OBC master time
Owner: Time & Sync Engineer
Define the time synchronization packet format sent from OBC → Payload MCU:
Absolute mission time
Time since boot
Drift correction field
Write a timing budget showing:
Link latency
MCU processing delay
Worst-case error margin < 10 ms
Specify how often sync packets are sent (e.g., every N seconds).
Define MCU-side logic for:
Applying offset corrections
Rejecting outlier sync packets
Preserving monotonic timestamps
Produce:
Timing block diagram
Error budget table
One-page explanation for CoDR reviewers
R-DM-003: DM shall store at least 48 hours of full-rate science and housekeeping data
Owner: Storage & Capacity Analyst
Compute data generation rates for:
Science
Housekeeping
Faults/events
Debug (if enabled)
Calculate 48-hour storage requirement with:
No compression
With compression (if applicable)
Add margin for:
File system overhead
Worst-case fault logging bursts
Produce a storage budget table:
Bytes/sec
Bytes/hour
Total bytes / 48 hr
Validate storage feasibility against:
Selected memory hardware
Power constraints
Flag any risks or trades for PDR.
R-DM-004: DM shall support data compression for science data files
Owner: Compression & Data Reduction Lead
Identify candidate algorithms (e.g., LZ4, DEFLATE).
Benchmark (or estimate):
Compression ratio
CPU cost
RAM usage
Power impact
Define:
Which data types are compressible
When compression is applied (real-time vs batch)
Specify file format metadata:
Compression flag
Algorithm ID
Original length
Write a clear decision rationale for CoDR:
Why compression is needed
Why chosen approach is acceptable
R-DM-005: DM shall implement three priority classes: HIGH, MEDIUM, LOW
Owner: Data Flow & Scheduling Lead
Map every packet type to a priority class.
Define queue behavior for each priority:
Max depth
Drop policy
Preemption rules
Specify behavior during:
Downlink windows
Storage pressure
Power-limited modes
Produce:
Priority flow diagram
Queue state machine
One example scenario (e.g., fault during science)
R-DM-006: DM shall detect and log data corruption
Owner: Data Integrity Engineer
Define CRC or hash algorithm used in packets.
Specify:
Where CRC is computed
Where it is checked
What happens on failure
Create a fault code list for corruption events.
Define severity levels and escalation logic.
Design example FaultLog entries:
CRC fail
Malformed packet
Sequence mismatch
Add test cases to V&V plan.
R-DM-007: DM shall provide a complete command dictionary and routing logic
Owner: Command & Interfaces Lead
Enumerate all payload-relevant commands.
For each command, define:
Command ID
Arguments
Valid ranges
Acknowledgement behavior
Define routing paths:
OBC → MCU
MCU → subsystems
Specify:
Invalid command handling
Retry / timeout behavior
Produce a Command Dictionary table aligned with ICDs.
R-DM-008: DM shall recover data continuity after a payload MCU reset
Owner: Fault Recovery Engineer
Define reset detection logic.
Specify how:
Sequence IDs resume
Timestamps remain monotonic
Files are closed and reopened
Define event markers for resets.
Write a reset recovery flow diagram.
Identify worst-case data loss window and justify acceptability.
R-DM-009: DM shall define and enforce onboard storage retention policies
Owner: Storage Policy Owner
Define retention rules per priority class.
Specify deletion order under storage pressure.
Define thresholds for:
Warnings
Forced purges
Safe-mode transitions
Create a retention policy table.
Write example scenarios:
Storage fills during comms outage
Debug logs enabled accidentally
R-DM-010: DM shall provide Communications with packet structures for downlink
Owner: Comms Interface Lead
Finalize packet header and payload definitions.
Ensure packet sizes are compatible with:
Link MTU
Comms framing
Provide:
Packet class definitions
Priority mapping
Downlink ordering rules
Produce a packet specification document shared with Comms.
Walk Comms through one full downlink example.