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Section 14.0 Flight Software

5. Space Technology. GSFC. “Tomorrow’s Technology Today”. Section 14.0 Flight Software. David K. Leucht FSW Lead Engineer. ST5 PDR June 19-20, 2001. Agenda. Requirements Heritage Unique Resources Estimates Design Concepts. FSW Applications Overview. 5. Space Technology. GSFC.

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Section 14.0 Flight Software

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  1. 5 Space Technology GSFC “Tomorrow’s Technology Today” Section 14.0 Flight Software David K. Leucht FSW Lead Engineer ST5 PDR June 19-20, 2001

  2. Agenda • Requirements • Heritage • Unique • Resources Estimates • Design Concepts

  3. FSW Applications Overview

  4. 5 Space Technology GSFC “Tomorrow’s Technology Today” FSW Requirements Heritage FSW 14 - 4 ST5 PDR June 19-20 2001

  5. Telemetry Output Requirements • 1 physical telemetry channel handles simultaneous real-time and playback downlink data (MRD 10303042) • 2 Commandable downlink rates, 1 Kbps and 100 Kbps (MRD 10303063): • 1 Kbps Real-time Telemetry Channel is system default (MRD 10303064) • 99 Kbps Playback Telemetry Channel(s) • 1 Kbps rate available at any point in orbit (MRD 10303066) • CCSDS, AOS, Telemetry formats (MRD 10303050, 10303051, & 10303052) • Virtual channels used to separate: • Real-time S/C housekeeping telemetry (VC0) • Playback S/C housekeeping telemetry (VC1 & VC11, for retransmit) • Playback S/C event telemetry (VC2 & VC12 , for retransmit) • Playback science telemetry (VC3 & VC13 , for retransmit) • Packet filtering based on reconfigurable tables • 90% Reuse from MAP • Design new output interface to C&DH (FIFO fill upon interrupt)

  6. Uplink Command Input Req’ts • 1 Kbps Uplink Rate (MRD 10303061) • CCSDS Telecommand formats (MRD 10303050 & 10303052) • using COP-1 Command Acceptance and Verification Protocol • Interfaces to Transponder via codeblocks input by C&DH • Error Reporting (MRD 10303032) • CCSDS protocol errors • Command data checksum verification • 60-90% Re-use of MAP Heritage (pseudo-randomization is at issue) • Remove support for redundant Transponders (MAP Heritage) • Design new Interface to C&DH for Codeblock input • De-randomization of CCSDS compliant, pRandomization is TBR

  7. Stored Command Requirements • Provide autonomous spacecraft commanding (MRD 10303010) • Absolute time-tagged sequences (ATS’s) • 2 ATS buffers (sized for 16 orbits, byte length is TBD) (MRD 30502000) • Execution synchronized with the S/C Clock • Provides 1 second time-tagged resolution (UTC Time) (MRD 10303031) • Only 1 ATS can be active at a time • Inactive ATS is used for loading, followed by a switch command • Relative time-tagged sequences (RTS’s) • 256 RTS’s (300 bytes each) active (count and size are still TBR) • Supports routine S/C housekeeping functions • Supports emergency S/C subsystem safing operations • Provides 1 second time-tagged resolution (MRD 10303031) • Multiple RTS’s can execute concurrently • Provide distribution of up to 8 stored commands per second • 1 RTS dedicated to execute on system startup • 95% re-use from MAP -- sizing, RTS count and loading of ST-5 specific needs

  8. Recorder Storage Requirements • 10 Mb recorder (MRD 10303020) • Recorder will be partitioned into the following independent segments: • S/C housekeeping in VR1; VR1 normal mode size 3.5 Mb TBR • S/C events in VR2; VR2 normal mode size 0.5 Mb (TBR) • Science telemetry in VR3; VR3 normal mode size 6 Mb (MRD 20301000) • Each partition (Virtual Recorder) is managed separately: • Partition Size (MRD 10303021) • Playback and continuous playback status • Store data during R/T downlink & recorder playback (MRD 10303022 & 10303023) • Overwrite Status • Provides for loadable Virtual Recorder memory reconfiguration • Packet filtering based on reconfigurable tables • Retransmission ground commands are supported by packet time or sequence # • 95% Reuse from MAP • ST-5 specific tables

  9. Time Management Requirements • All telemetry data, timetagged at the packet level (MRD 10303043) • Maintain time on the spacecraft with a resolution of at least 0.1 ms (MRD 20302000) • Correlate observatory time to ground time to within 5.0 mS (MRD 20500000) • Timetag Time Correlation Events to accuracy of 0.5 mS (MRD 20505000) • Provide ability to update & adjust on-board clock (MRD 20503000) • Provide commands to jam spacecraft time, UTC correlation Factor, and leap seconds • Provide commands to make delta time adjustments (-2ms <= adj <= 2ms) • Provide commands to make continuous delta time adjustment to correct for oscillator drift (-2ms <= adj <= 2ms) • Maintain UTC correlation factor and leap seconds onboard, UTC needed for Stored Command Processor • Time Correlation Events occur on Real-time Channel only (VC0) • 1 Time Correlation event every 162 Seconds • 64-bit time format: 32 bits seconds, 32 bits subseconds • ~100% Re-use from MAP

  10. Health & Safety Requirements • Health & Safety divided between 3 tasks • Health & Safety • Services processor’s Watchdog Timer • Monitor critical S/W tasks to assure execution, can effect restart of FSW • Monitor critical S/C event messages, can effect restart of FSW • 75% Re-use from MAP -- redesign Task check-in to minimize CPU overhead) • Telemetry & Statistics Monitor • Extract & limit check critical telemetry points from CCSDS telemetry packets • Provides derived (computed) monitor points • Initiates stored command sequence on limit failures • Maintains statistical data for each monitor point • 80% Re-use from MAP (most effort is developing and testing ST-5 specific monitor points) • Checksum • Continuously monitors static RAM and EEPROM • Checksum violation responses are TBD • 95% Re-use from MAP -- reconfigure for ST-5 memory space

  11. EDAC Management Requirements • Referred to as Memory Scrub • DRAM will be scrubbed in order to correct single bit flips and report uncorrectable multiple bit flips • Scrubbing rate is determined by radiation environment which is currently TBD (waiting for orbit, radiation & parts data) • Provides capability to scrub Processor Ram at a different rate than Recorder Memory • Provides commands to enable/disable Multi-bit Error detection and set scrub rate • 90% Re-use from MAP -- reconfigure for ST-5 memory space

  12. Software Manager Requirements • Provide capability to re-load software into RAM (MRD 10309060) • Memory Load & Dumps • Table Load & Dumps • Provide diagnostic capability to monitor key memory locations (memory dwell) • Manages system parameter tables and provides ability to load and dump tables for maintenance purposes • 90% Re-use from MAP • EEPROM load support to be removed • Reconfigure for ST-5 memory space and tables

  13. 5 Space Technology GSFC “Tomorrow’s Technology Today” FSW Requirements ST-5 Unique FSW Components 14 - 13 ST5 PSR June 19-20, 2001

  14. Transponder & CULPRiT Mgmt Reqts • Transponder (Transponder EICD) • Provide Command Interface for configuration and status query of Transponder • Provide Telemetry sampling interface for Transponder Status • Commands are issued to effect telemetry output from transponder • CULPRiT • Provide telemetry for monitor of CULPRiT performance (MRD 10103060) • Provide command to disable (bypass) CULPRiT • Provide Voltage Biasing Controller • All requirements related to controller are TBD • Need for controller may be obsolete, if most recent CULPRiT design is proven to work

  15. CCNT Mgmt Requirements • Issue Commands to CCNT • On-Board Commands require BlackJack Protocol Encoding (MRD 10102031) • Cross-link Housekeeping Data • UTC Time Updates • Science Event Alert • Others (TBD) • Uplinked Commands relayed without BJ Protocol Encoding (MRD 10102033) • Accept Telemetry from CCNT for Storage in SSR (MRD 10102032) • Do not decode BlackJack Protocol, just packetize in CCSDS and store for later downlink (fixed packet length of 256 bytes plus headers) • Support Inter-Spacecraft Communications (MRD 30300000 & 30301000) • Respond to Discrete CCNT input used to signal arrival of Science Event Alert (derived from design)

  16. Magnetometer Mgmt Requirements • Perform On-board Science Data reduction from 16Hz sample input rate to 8Hz sample storage rate, through simple averaging of data. (MRD 20201020) • Maintain 100 second deep FIFO of magnetometer data, stored in FIFO at 16 Hz (full data rate) • Provide autonomous instrument sensitivity setting • Monitor sensor data at least 1Hz (MRD 20201010) • 10 continuous seconds before switching sensitivity • To switch from Low to High: any 1 of 3 axes must exceed threshold (>= 800nT, TBR) • To switch from High to low, all 3 axes must fall below threshold (<= 600nT, TBR)

  17. Thermal Technologies (VECs) Reqts • Provide Command Interface for each VEC (Thermal ICD) • Manual Mode Select with argument of polarity • Autonomous Mode Select (no command arguments) • Sample telemetry from each VEC once every 5 seconds (Thermal ICD) • One discrete, 1 bit status from each VEC • One multiplexed analog signal from each VEC • 8 data per signal, multiplexed over 5 second period of time (TBR)

  18. ACS FSW Requirements (1 of 2) • Implement Sun Acquisition Mode (SAM) of ACS Controller(MRD 10305010) • Autonomously initiate SAM upon ELV separation(MRD 10305014) • Provide ability to enter SAM upon command, either real-time or stored command(MRD 10305013) • Autonomous SAM upon COLD or WARM Restarts is TBR (MRD says reset) • Sun within 25 degrees normal to solar arrays(MRD 10305012) • Generate autonomous MCGT pulses to reorient to and maintain required spin axis/Sunline geometry • MCGT commanding halted if: • (a) elevation angle variance exceeds a maximum threshold OR • (b) maximum thruster firing time is exceeded(MRD 10305015) • Must be able to maintain SAM indefinitely • Provide ability to enable/disable SAM processing(MRD 10305030)

  19. ACS FSW Requirements (2 of 2) • Perform 3 Additional ACS Modes (derived ACS Requirements) • Standby Mode • Supports nominal spacecraft operations • Process sensor data, but no thruster commanding • Maneuver Mode (MRD 10308000) • Execute ground issued MCGT commands to reorient spin axis to desired pointing • Open-loop control law execution • Delta V Mode (MRD 10308000) • Execute ground issued MCGT firing commands to modify orbit • Open-loop control law execution

  20. Thruster Management Requirements • Provide ability to command thruster On/Off duty cycles from 10% to 100% in 10% increments (MRD10101050) • Provide status telemetry to indicate previous actuation state of the valve (MRD 10101040) • Will have an enable command to C&DH (MRD 10302040) • Provide status telemetry to support estimating propellant supply pressure (MRD 10101031) • Pressure Transducer readings • Temperature readings • Tracking Thruster On-Time measurements • Employing Two Timers, programmed by FSW to control length of thruster firing: • Timer 1 used to offset thruster firing start time, relative to Sun Presence pulse (FSW arms, C&DH starts timer upon Sun Presence signal) • Timer 2 used to define length of thruster firing

  21. HK Data Acquisition Requirements • Sample HK data from all technologies and S/C subsystems for H&S assessments and technology validations (MRD 10303040) • Sample all Thermistors at least once per minute (Thermal ICD) • Sample all other S/C analog signals at TBD rate • Report Magnetometer (0.25Hz) and Sun Elevation (1Hz) for ground-based Attitude Determination (ACS need) • Sample Propellant Transducer at TBD rate (sample when commanded?) • Collect and report FSW status telemetry (baselining 0.125Hz, MAP was .25Hz with 2Kbps downlink, ST5 has 1 Kbps downlink) • Collect and report Transponder status telemetry at TBD rate • Collect and report Thermal Technologies (VECs) analog and digital status once every 5 seconds

  22. PSE Management Requirements • Provide autonomous S/C power safeing (MRD 10305020) • Commands to enable/disable autonomous power safeing (MRD 10305030) • Power safeing achieved via Load shedding (MRD 10305021) • Provide Command & Telemetry interface to power switching electronics • Provide on-board Battery State of Charge calculation • Provide on-board Battery FDC • Monitor: • Battery Temperature • Battery Voltage • Battery Current • Battery State Of Charge

  23. Science Event Detection (1 of 2) • Employ CCNT to communicate Science Events (MRD 20403000) • Employ Magnetometer Data to sense Science Events (MRD 20404000) • 1 Sec (TBR) Response time from Science Event detection to response on S/C 2 & 3 (MRD 20402000)

  24. Science Event Detection (2 of 2) • Autonomously detect, respond and communicate occurrences of Science Events (MRD 20401000) • Only one Science Event processed per orbit (MRD 20404020) • Maintain Data buffer of 16 Hz Mag data (100 S deep) (MRD 20404010) • Commands to En(Dis)able Science Event Feature (MRD 10305030) • Parameters to Science Detection Algorithm will be modifiable • 4 Modes of operation (Science Validation Plan): • Trigger Enabled, Listen Enabled • Trigger Enabled, Listen Disabled • Trigger Disabled, Listen Enabled • Trigger Disabled, Listen Disabled

  25. Cross-Link Exchange of HK Data • Utilizes same communication path as Science Event Alerts • TBD data packet broadcast to other members of constellation (MRD30301010) • CCNT employed to perform broadcast operation • Receiving spacecraft stores the cross-linked data packet for later downlink (MRD 30301010) • When received from CCNT (via CCNT’s S-band) the packet is encoded in BlackJack Protocol, simply packetize in CCSDS and store the packet into recorder for later downlink. • Data packet must contain Spacecraft ID in the packet data region (MRD 30301020) • Commands to enable and disable feature (MRD 10305030)

  26. FSW Startup Modes • Boot Mode • Provides ability to load EEPROM from GSE (MRD 10309050) • Autonomously transitions to COLD Restart when GSE absent • Cold Restart • Power-up, watchdog reset, ground command, or s/w detected anomaly • Code copied to RAM from EEPROM • Data initialized • Warm Restart • Ground command or s/w detected anomaly • Code copied to RAM from EEPROM • Data preserved in current state

  27. Processor Performance Req’ts • Launch Margins • 20 % margin on RAM (MRD 10309030) • 5 % margin on EEPROM (MRD 10309040) • 20 % margin on I/O Bandwidth (MRD 10309020 -- TBR) • 20 % margin on instruction execution (MRD 10309010)

  28. 5 Space Technology GSFC “Tomorrow’s Technology Today” FSW Requirements Resource Estimates ST5 PDR June 19-20, 2001

  29. Memory Resource Estimates • Core MAP Heritage Instruction and Initialized Data: 0.98 Mbytes, with average total of 75 Kbytes/task (13 Tasks) • Estimate 12 Add’l Tasks @ 75 Kbytes each for Code and Initialized Data yields 0.9 Mbytes • EEPROM • MAP Heritage: 0.98 Mbytes • New Code: 0.90 Mbytes • BootStrap: 0.26 Mbytes • SubTotal: 2.10 Mbytes • 5 % margin: 0.20 Mbytes (5% of 4 Mb) • Grand Total: 2.30 Mbytes Required (est); C&DH Providing 4 MB) • DRAM • MAP Heritage: 1.8 Mbytes (incl .5 MB for S/W Bus buffers) • New Code: 1.3 Mbytes([1.3MB/12] MAP Avg Task need * 12 new tasks) • SubTotal: 3.1 Mbytes • 20 % margin: 1.4 Mbytes (20% of 7 Mb) • Grand Total: 4.5 Mbytes Required (est); C&DH Providing 7 MB)

  30. CPU Resources

  31. CPU Resources (Core C&DH Estimates)

  32. CPU Resources (New S/W Background Estimates)

  33. CPU Resources (Config dependent processing)

  34. 5 Space Technology GSFC “Tomorrow’s Technology Today” Flight Software FSW Design Concept ST5 PDR June 19-20, 2001

  35. Identified Interrupts (Nominal) • Sun Presence * Rate: 0.33 Hz @ 20 RPM • Uplink (Codeblock Ready) Rate: 16 Hz @ 1Kbps • Downlink (FIFO 1/2 full) Rate: 9.9 Hz @ 100Kbps, 0.099Hz @ 1Kbps • 1 Hz Clock * Rate: 1 Hz • Time Correlation Rate: once every 162 Sec (0.006 Hz) • Transponder Tlm Data Ready * Rate: 7 Hz (TBR, 7 register reads to get status) • Magnetometer Input Rate: TBD (1 Hz) • CCNT Packet Input * Rate TBD (~16 Hz peak, C&DH has flow ctrl) • CCNT Packet Output * Rate TBD ( <= 1 Hz) • CCNT Science Event Rate: twice per orbit, max • S/C Analog Sampling Complete * Rate: TBD (0.1 Hz avg, governed by FSW) • VEC 1 Analog Sampling Complete Rate: once every 5 Sec (0.2 Hz) • VEC 2 Analog Sampling Complete Rate: once every 5 Sec (0.2 Hz) • Thruster Pulse Complete (TBR) Rate: TBD • O/S Scheduler * Rate TBD (20 Hz) Peak interrupt loading is governed by the external devices being operated. Worst case interrupt loading ( * ) is estimated to be 47 Hz peak (45 Hz average) and assumes neither Uplink or Downlink are operating while CCNT is performing attitude solutions during its validation operations. RF is not expected to be active due to power constraints.

  36. Identified Interrupts (Exception) • Uplink Underflow Rate: on exception • Uplink Overflow Rate: on exception • Downlink Underflow Rate: on exception • Downlink Overflow Rate: on exception • Downlink Out-Of-Synch Rate: on exception • Transponder Command Parity Error Rate: on exception (transponder generated) • Transponder Telemetry Parity Error Rate: on exception (C&DH generated) • CCNT Communications Error (TBR) Rate: on exception (framing, parity, over/underflow) • Magnetometer Input Error (TBR) Rate: on exception (framing, parity, over/underflow) • EDAC Uncorrected Error Rate: on exception • EDAC Corrected Error Rate: on exception • NDP Exception Rate: on exception • Memory Access Violation Rate: on exception

  37. Identified Tasks (MAP Heritage) • Command Ingest (uplink command) • Telemetry Output (downlink telemetry) • Data Storage (recorder management) • Stored Command (absolute & relative time sequence management) • Time Code (time management) • Health & Safety (watchdog and task management) • Memory Scrub (EDAC memory management) • Checksum (memory integrity management) • System Manager (table and memory load/dump management) • Memory Dwell (memory dwell management) • Telemetry & Statistics Monitor (on-board FDC management) • Software Bus (message routing and management) • 1 Hz Time Mark (1 second synchronization, interrupt driven)

  38. Identified Tasks (New Software) • ACS Controller (Sun Acquisition, maneuver management) • Transponder Management (configuration and telemetry collection) • HK Data Acquisition (acquire and packetize HK data spacecraft) • Magnetometer Management (science event & sample storage mgmt) • CCNT Input Management (input CCNT packets for storage, TBR) • CCNT Output Management (protocol wrapping and packet output) • VECs Management (configuration commanding) • Power Switching Management (configuration commanding) • Battery Management (BSOC and FDC management) • CULPRiT Controller (Voltage Bias Controller) • CodeBlocks Input (accept codeblocks from C&DH, interrupt driven) • SRAM Input (input MAG, Analog, and CCNT (TBR) data, interrupt driven)

  39. Identified Support Software • Operating System (baselining Vx-Works to leverage MAP efforts) • Algebra Libraries (MAP heritage) • NDP Exception Handling (MAP heritage) • EDAC Exception Handling (MAP heritage) • Thruster Firing Management (to command firings) • CCNT Protocol Builder (to format commands output to CCNT)

  40. Build 1 Core C&DH + Power Switch & Thruster * Uplink Command Processing (T) * Telemetry Output (T) * Time Management (T) * 1 Hz Time Mark (T) * Table Management (T) * Memory Up/Down Load Management * Health & Safety (T) * Memory Checksum FDC (T) * EDAC Refresher and FDC (T) CodeBlock Input Processing (T) Transponder Management (T) Thruster Firing Management HK Data Acquisition Management (T) Power Switching (T) SRAM Input (T) FSW Build Plan Build 2 Controllers, Instruments and Safety • * Recorder Management (T) • * Stored Command Processor (T) • * Telemetry & Statistics Monitor (T) • * Memory Dwell (T) • Attitude Controller (T) • Magnetometer Data Management (T) • CCNT Data Input (T -- TBR) • CCNT Data Output (T) • Battery FDC and State of Charge (T) • VECs Technologies Support (T) • CULPRiT Controller (T) • Science Event Management • Cross-Link HK Data Exchange • (T) := Task

  41. FSW Configuration Management • All work products will be managed for configuration • Web-based Discrepancy Reports during S/W development • Primary communication of FSW changes • DRs used throughout life-cycle & trace all changes to work products • Web-based Document Center for distributing documentation • Source Codes maintained by developers until Build Test • After delivery to Build Test, team manages all changes via CM plan • Prior to Build 2 delivery, Development Team manages change • After Build 2 is delivered to Project, manage change via Project CCB • Commercial CM Tool to manage source codes and documents • Document access per Project plan • Source codes access per NASA requirements

  42. Documentation DocumentNumberStatus • FSW Product Development Plan ST5-495-072 Draft • FSW Configuration Management Plan ST5-495-053 Draft • FSW Test Plan ST5-495-065 Draft • FSW Build 1 Verification Matrix ST5-495-066 ------ • FSW Build 2 Verification Matrix ST5-495-067 ------ • FSW Acceptance Test Plan ST5-495-068 ------ • FSW Requirements Specification ST5-495-021 Preliminary • ACS, FSW Requirements Specification ST5-495-069 Preliminary • FSW Requirements Traceability Matrix incorporated into FSW Reqts Spec. • FSW Command List ST5-495-070 Preliminary • FSW Telemetry List (in excel) ST5-495-071 Preliminary • FSW Quality Records List ------ ------

  43. FSW Test Planning • Requirements and Design tested informally by peer review, Formally tested at FSW SRR/PDR and FSW CDR • Generally, Heritage Components tested for Build Integration • Walkthrus and Inspections are not planned for heritage components • However, all new I/Fs will be unit tested • New, non-Heritage S/W Components will be fully tested • Subjected to Formal Inspection (NASA-STD-2202-93) • Unit Tests after inspection. • Developers Test thru board integration, independent test team performs Build Verification & supports Acceptance and S/C I&T • Build Verification Test Plan exists in draft form • Build Acceptance Test Plan is TBR • Regression Test performed at all levels appropriate to the change

  44. FSW Test Planning -- IV&V • NASA’S W. Va IV&V Facility will provide: • Software engineering process definition, implementation and improvement • Analysis of mission-critical software and documentation, focusing on spacecraft flight software and external communications and instrument interfaces • Independent review of Product Development Plan, FSW Requirements, CM Plan, Test Plan. • Identification of strategies formitigating Project risks associated with software • Catastrophic/Critical/High Risk Functions List (CFL)

  45. FSW Development & Test Simulators

  46. FSW, GSE/Simulator Deliveries

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