Christopher Krupiarz ChristopherKrupiarz jhuapledu Solar Probe Plus A NASA Mission to Touch the Sun Overarching Science Objective To determine the structure and dynamics of the Suns coronal magnetic field understand how the solar corona and wind are heated and accelerated and deter ID: 756179
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Flight Software Overview
Christopher KrupiarzChristopher.Krupiarz@jhuapl.edu
Solar Probe Plus
A NASA Mission to Touch the SunSlide2
Overarching Science ObjectiveTo determine the structure and dynamics of the Sun’s coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what mechanisms accelerate and transport energetic particles.
27 October 2015Slide3
Observatory: Anti-Ram Facing View
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Observatory: Ram Facing View
27 October 2015Slide5
High Level Concept of Operations
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Block Diagram
27 October 2015Slide7
APL Developed Single Board Computer (x3):UT699E LEON3FT (Sparc V8 architecture) 80MHz from
Cobham Colorado Springs32 MB SRAM with EDAC8 MB of MRAM (Non-Volatile Memory) 6.4 MB usable3.2 MB per logical bankFPGA facilitates NVM image verification during bootBoot loader executes out of NVM256Gbits (32GBytes) NAND Flash Bulk Memory (SSR) on processor boardMemory mapped I/OSBC interfaces
UARTs to Avionics Redundancy Controller (ARC)SpaceWire to spacecraft and instrument subsystems as well as other single board computersFSW DesignHardware Environment27 October 2015Slide8
Flight Software Driving Requirements(1 of 2)
Manage software operations on three processors
Uplink command data files using CFDPProvide additional uplink in BD modeManagement of files on the SSR (256Gbit)Allow for reset in sufficient time for Solar Array SafingRetention of critical spacecraft information through processor resetsCommunicate to spacecraft elements external to computerSpaceWire transactionsBoot time27 October 2015Slide9
Flight Software Driving Requirements(2 of 2)
Operate a 3-axis stabilized spacecraft
Uplink data range of 7.125bps to 2KbpsDownlink frames at rates from 10bps up to 1MbpsDownlink recorded data files using CFDPDistribution of time and status Manage spacecraft time tagged commandsCollect instrument dataManage spacecraft subsystem commands and collect spacecraft housekeeping dataRecord and downlink spacecraft housekeeping and instrument dataSupport fault protection & limited autonomous instrument safing27 October 2015Slide10
FSW DesignFSW Functionality (1 of 2)
BootSimple boot loader; no commanding/telemetryCommand and Data Handling (C&DH)Command managementUplink: receive transfer frames from transponderCommands: real-time, macros, time tags, autonomyPackets extracted and distributed locally or to a S/C subsystemTelemetry
Receive telemetry from subsystems/individual applicationsSSR managementRecord/playback spacecraft and instrument data to/from a file system27 October 2015Slide11
FSW DesignFSW Functionality (2 of 2)
Command and Data Handling (C&DH) (Continued)AutonomyAutonomous fault detection and safing/switchover on PrimeSoftware managementMemory object loading, CPU utilization, etc.Guidance and Control (G&C)G&C sensor interface management, Three-axis control, momentum maintenance
Cruise phase & thruster control, 50 Hz attitude control, 1 Hz attitude estimation27 October 2015Slide12
FSW DesignSoftware on Three Processors
Prime, Hot Spare, Backup Spare are all running the same softwareApplications are controlled by Scheduler messagesMessages drive degree of application functionalitySome applications have knowledge of SBC logical stateReduce power consumption and processor loadingPrime sends Hot Spare (and Backup Spare during encounter) a status message at 1 Hz
Data includes:Current spacecraft configurationRaw star tracker dataCurrent time dataCurrent accumulated SA flap & feather and HGA step countsCurrent spacecraft FM mode(s)Safe Mode – Solar Array entry timeG&C code on spare will verify raw star tracker dataHot Spare promoted to Prime on Prime demotionG&C primed via previously received messageScheduler sends full compliment of messages to applications27 October 2015Slide13
FSW DesignFSW Context Diagram (Prime)
27 October 2015Slide14
JHU/APL Flight Software
1990s/Early 2000sNEAR/ACE/TIMEDEven now, some of our code dates back this era2000sMESSENGER/New Horizons/STEREOModify Last Mission 27 October 2015Slide15
JHU/APL Flight Software
2000sCan we make the code more modular?IRAD to make that happenRadiation Belt Storm ProbesFleshed out many capabilities of using NASA/GSFC Core Flight Executive (cFE)Collaboration with NASA/MSFCRadiation Belt Storm Probes (Van Allen Probes)First full m
ission adaptation of cFEEvolved into Core FSWSolar Probe PlusFirst reuse of Core FSW on major mission27 October 2015Slide16
Operating SystemReal-Time Executive for Multiprocessor Systems (RTEMS) with support from OAR Corporation
Build tools and RTEMS distribution from Cobham GaislerFSW DesignSoftware Layers (1 of 4)
RTEMS Real-Time Operating System27 October 2015Slide17
Operation System Abstraction Layer (OSAL)Provided by NASA/GSFC
Enables easy porting of applications that ran over VxWorks on the Van Allen ProbesFSW DesignSoftware Layers (2 of 4)
RTEMS Real-Time Operating SystemOperating System Abstraction Layer (OSAL)27 October 2015Slide18
NASA GSFC Core Flight Executive (cFE) middlewareProvided by NASA/GSFC
Enables common flight executive functionsWell documented application programmer interface (API)Project-independent configuration managementApplications are modular, independent, and decoupledFSW DesignSoftware Layers (3
of 4)RTEMS Real-Time Operating SystemOperating System Abstraction Layer (OSAL)Core Flight Executive (cFE)27 October 2015Slide19
Mission FSW Applications and LibrariesSignificant reuse from Van Allen Probes
New developmentIncludes SpaceWire/CFDP Uplink/Flash file systemFSW DesignSoftware Layers (4 of 4)
RTEMS Real-Time Operating SystemOperating System Abstraction Layer (OSAL)Core Flight Executive (cFE)SchedulerMemory Manager
Command IngestCommand ManagerAutonomy
Time
Tags
Record
Memory
Objects
Playback
ITF
Manager
File Manager
External SBC
G&C
H/K Monitor
S/C
Interfaces
Telemetry
Output
File Ingest
CPU
CFDP
SPP
High Reuse From Van Allen Probes
Low Reuse From Van Allen Probes
New for SPP
27 October 2015Slide20
Software Running on Three ProcessorsAmount of operation depends upon functionality
Minimal operation is only receiving commands and producing telemetryFSW DesignFunctionality Across Processors
RTEMS Real-Time Operating SystemOperating System Abstraction Layer (OSAL)Core Flight Executive (cFE)SchedulerMemory ManagerCommand Ingest
Command ManagerAutonomy
Time
Tags
Record
Memory
Objects
Playback
ITF
Manager
File Manager
External SBC
G&C
HK Monitor
S/C
Interfaces
Telemetry
Output
File Ingest
CPU
CFDP
SPP
Full Operation
Reduced Operation
Minimal Operation
27 October 2015Slide21
Questions?
Solar Probe Plus Flight Software
27 October 2015