ed greville 28 june 2001
DESCRIPTION
SuperNova / Acceleration Probe (SNAP). Flight Software. Ed Greville 28 June 2001. Flight Software Overview. C&DH Flight Software ACS Flight Software ACE Flight Software SI Flight Software Development Testbeds & Simulators. Flight Software C&DH Functions. Propagate Spacecraft Ephemeris - PowerPoint PPT PresentationTRANSCRIPT
Ed Greville
28 June 2001
Flight Software
SuperNova / Acceleration Probe(SNAP)
Flight SoftwarePage 2
SNAP June 28, 2001Goddard Space Flight Center
C&DH Flight Software
ACS Flight Software
ACE Flight Software
SI Flight Software
Development Testbeds & Simulators
Flight Software Overview
Flight SoftwarePage 3
SNAP June 28, 2001Goddard Space Flight Center
Flight SoftwareC&DH Functions
Command Ingest Receive CCSDS code blocks and distributeStored Command Processing Relative and Absolute time driven command sequenccesTelemetry Output Downlink data device driver, realtime protocol stackData Storage Manage all stored data as CCSDS packetsPayload Manager Science Instrument Telemetry/Command I/FPower Control Solar Array Control, Battery State of Charge, Switching, MonitoringHousekeeping Engineering telemetry from C&DH, ACS, other S/C subsystemsHealth & Safety Monitor Critical subsystemsTelemetry & Monitoring Telemetry limit checking & statisticsFile Manager Manage data filesTask Manager Task monitoring & ControlScheduler Coordination of time driven activitiesSoftware Manager Table load I/O peek and poke, Mem load and dumpSystem Tables General repository for S/C and operational parameters Software Bus Software task intercommunicationExternal Bus I/F External Bus DriversChecksum Detect changes in critical data or codeMemory Scrub Memory error correctionSelf Test Check InterfacesS/C Clock Time mangement & distributionOperating System
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SNAP June 28, 2001Goddard Space Flight Center
Flight SoftwareACS Functions
Propagate Spacecraft Ephemeris
Validate Ephemeris Update Compute Solar Ephemeris Compute Lunar Ephemeris Process HGA Data Generate HGA Commands Correct For Velocity Aberration Process DSS Data Process CSS Data Process Thruster Data Process RW Data Process IRU Data Process ST Data Process Fine Guidance Data Select Sun Vector Compute Total Momentum Estimate State Vector
Execute H/W Safemode Execute Sunpoint Mode Execute Slew Mode Execute Science Mode Select Guide Star Acquire Guide Stars Identify Guide Stars Compute/Check Target
Quaternion Check For Occultation Generate RWA Commands Generate Hydrazine Thrust
Cmds. Generate ST Commands Generate Fine Guider Commands Detect ACS Fault Process ACS Faults ACS Utilities
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SNAP June 28, 2001Goddard Space Flight Center
Flight SoftwareSI Software Functions
On/Off Read out CCD Extract event data Mechanism control Mode Management Read out alignment data Exposure control State data collection (housekeeping,
telemetry) Save dark current readings Dump dark current table SI thermal control External Data interfaces
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SNAP June 28, 2001Goddard Space Flight Center
Flight Software C&DH Development & Test Bed
C&DH
(ACS)
DynamicSimulator
Spacecraft External Data Bus
Ground Systemor Simulator
R-T raw data
simulator
Development
Workstation
SerialInterface
SI simulator
High-speedserial I/F
Flight SoftwarePage 7
SNAP June 28, 2001Goddard Space Flight Center
Flight SoftwareACS Development & Test
Bed
ACS
(C&DH)
DynamicSimulator
Spacecraft External Data Bus
Ground Systemor Simulator
R-T raw data
Simulator
Development
Workstation
SerialInterface
ACE
Guider
Simulator
High-speedserial I/F
Flight SoftwarePage 8
SNAP June 28, 2001Goddard Space Flight Center
Flight SoftwareSI Development & Test Bed
C&DH(ACS Stubs)
Instrument
Processor
Spacecraft External Data Bus
Ground Systemor Simulator
Development
Workstation
SerialInterface
FPE Interface
Simulator
High-speedserial I/F
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SNAP June 28, 2001Goddard Space Flight Center
Flight Software Risk Assessment
No new concepts or technology
Early C&DH development supports ACS
and SI software development and eases
integration
Typical software risks apply Good industry practices Adequate test time Adequate test resources Adequate documentation
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SNAP June 28, 2001Goddard Space Flight Center
Flight SoftwareIssues and Concerns
Overall flight software system engineering including testbeds can benefit cost and schedule in the long run.
Instrument software estimate may be low because there are several instruments and the functions and commonality between them has not been studied.