Flight Software Charlie Wildermann Mike Blau Code 580.0

Flight Software Charlie Wildermann Mike Blau Code 580.0

Flight Software Charlie Wildermann Mike Blau Code 580.0 Code 582 August 16-17, 2005 NASAs Goddard Space Flight Center 19 - 1 FSW Requirement Flow-down Mission Requirements Document Level 2 GN&C Level 3 431-SPEC000063 FD HiFi C&DH 431-RQMT-000139 431-SPEC000062 431-SPEC000143 ACS Analysis ACS Hardware GN&C C&DH GN&C H/W ICD GN&C FSW Req GN&C Hardware Level 4 FSW Algorithms NASAs Goddard Space Flight Center GN&C FSW 431-RQMT-000168 C&DH Hardware C&DH FSW Req API

Instruments 431-ICD-000104109 Instrument Data ICDs C&DH H/W ICD C&DH FSW 19 - 2 Lunar Reconnaissance Orbiter (LRO) FSW System Level 2 Flow Down Key Requirements Level 2 Req. Level 3: Requirements Paragraph Concept/Compliance Requirement MRD-58 FSWR-1 The development of flight software for the LRO mission shall adhere to the LRO Mission Assurance Requirements (MAR) document (TBD number) and NPR-7150.2 Code 582 FSW development processes will meet these requirements MRD-127 FSWR-5 The flight software shall provide a capability to effect a cold reset of the flight software. The FSW shall initialize the C&DH hardware on cold reset. This initialization shall include the RAD750 microprocessor, the uplink and downlink hardware, the 1553 data bus, and the SpaceWire data links. Errors detected on startup shall be handled as defined in the LRO FDC ICD. Mostly heritage FSW from SDO and JWST MRD-127 FSWR-85 Upon time-out of the watchdog timer, the flight software shall effect a cold reset. HW registers allow FSW to detect reset type MRD-127 FSWR-7 The flight software shall provide default values for proper initialization of all key operating parameters following a power on or cold reset. Default contents for all data tables are stored in non-volatile memory MRD-127

FSWR-9 The PROM based boot loader shall provide a capability to validate the contents of the two EEPROM banks and run the code in the bank that passes validation. Redundant EEPROM banks are used to mitigate soft-bit problems MRD-122 FSWR-12 The flight software shall support an uplink rate of 4 kbps This rate is very easy with the RAD750 processor MRD-110 FSWR-11 The flight software command link shall utilize the CCSDS command path service protocol; both COP-1 and bypass modes shall be supported Heritage FSW from many missions (SDO most recently) MRD-110 FSWR-32 The flight software shall format the housekeeping downlink telemetry as recommended by the CCSDS AOS protocol Heritage FSW from many missions (SDO most recently) NASAs Goddard Space Flight Center 19 - 3 Lunar Reconnaissance Orbiter (LRO) FSW System Level 2 Flow Down Key Requirements Level 2 Req. Level 3: Requirements Paragraph Concept/Compliance Requirement MRD-131 MRD-132 FSWR-22 The flight software shall provide a stored command capability to receive, store, and later execute sequences of commands Heritage FSW from many missions (SDO most recently) MRD-50 MRD-134 FSWR-31 The flight software shall downlink sufficient housekeeping engineering data to the ground to allow nominal spacecraft operation and performance evaluation, as well as anomaly investigation and resolution

HK packet contents will be documented early, then reviewed by Ops and FSWM MRD-123 MRD-124 MRD-50 FSWR-36 The flight software shall support downlink rates specified in the LRO Mission Operations Concept Document (431-OPS-000042) section TBD. S-band rates will be easy to support. 100Mb Ka-band rate is facilitated by SSR hardware DMA MRD-118 FSWR-50 The flight software shall store 2 hours of housekeeping data in local SBC memory for later transmission to the ground station. Data packets stored in files. Code has Triana heritage MRD-50 FSWR-51 The flight software shall have the capability to record housekeeping telemetry at a sampling rate of up to 32kb/sec Recording rate for each HK packet is table driven MRD-110 FSWR-57 The flight software shall transmit stored data files to the ground using the CFDP protocol (class 2 service). CFDP code has been tested in FSW tech lab. NASAs Goddard Space Flight Center 19 - 4 Lunar Reconnaissance Orbiter (LRO) FSW System Level 2 Flow Down Key Requirements Level 2 Req. Level 3: Requirements Paragraph Concept/Compliance Requirement MRD-36 FSWR-64 The flight software shall communicate with the SSR over the Spacewire Bus as specified in the SSR User's Guide (doc name and number TBD) I/F is similar to the NFS standard. SSR is treated like a network file

server. MRD-37 FSWR-63 The flight software shall copy local housekeeping data files to the SSR. Local storage is only for emergencies. SSR can hold many days worth of HK data. MRD-37 FSWR-65 The flight software shall store science data in files on the SSR, formatted as specified in the instrument data ICDs. File formats are unique to each inst. Facilitates data analysis at SOCs MRD-35 FSWR-68 The flight software shall use the 1553 bus to communicate with the relevant Observatory subsystems as specified in the LRO Electrical ICD (number TBD). Heritage FSW from many missions (SDO most recently) MRD-114 MRD-43 FSWR-72 The flight software shall maintain an onboard spacecraft time driven from the hardware mission elapsed timer (MET). Heritage FSW from many missions (SDO most recently) MRD-42 MRD-43 FSWR-73 The flight software shall support the ability to synchronize the spacecraft time clock to ground-based UTC. FSW maintains an adjustable S/C time correction factor (SCTF) MRD-20 MRD-133 FSWR-79 The flight software shall possess sufficient onboard autonomy to allow basic fault detection and correction. Telemetry monitoring/response is a standard FSW feature MRD-128 FSWR-95 The flight software shall provide the capability to load code and data from the ground to RAM

Allows checkout of FSW changes before making them permanent MRD-128 FSWR-96 The flight software shall provide the capability to load code and data from the ground to non-volatile memory. Allows FSW changes to be made permanent after checkout NASAs Goddard Space Flight Center 19 - 5 Lunar Reconnaissance Orbiter (LRO) FSW System Level 2 Flow Down Key Requirements Level 2 Req. Level 3: Requirements Paragraph Concept/Compliance Requirement MRD-20 MRD-133 FSWR-113 The GN&C flight software shall monitor the health of each sensor and actuator and provide status telemetry that can be monitored by the C&DH flight software. Manage GN&C Suite of Electronics MRD-41 FSWR-115 The GN&C flight software shall accept and validate spacecraft ephemeris tables. Validating critical ephemeris uplinks is standard FSW practice. MRD-41 FSWR-116 The GN&C flight software shall interpolate between spacecraft ephemeris tables entries to compute the ephemeris for a specific time Recent missions have used propagators, however we have access to a heritage interpolator. MRD-41 FSWR-117 The GN&C flight software shall accept and validate Lunar ephemeris tables Validating critical ephemeris uplinks is standard FSW practice. MRD-41

FSWR-118 The GN&C flight software shall interpolate between Lunar ephemeris tables entries to compute the ephemeris for a specific time. Recent missions have used analytic models, however the heritage s/c interpolator can be used for lunar ephemeris. MRD-49 FSWR-120 The GN&C flight software shall compute ground station position vectors in J2000 GCI coordinates. Similar to the problem of computing a TDRSS vector. MRD-49 FSWR-122 The GN&C flight software shall maintain an estimate of the 3 axis attitude of the observatory with respect to the J2000 GCI coordinates. Heritage FSW from many missions (SDO most recently) MRD-49 MRD-84 FSWR-126 The GN&C flight software shall support use of an uplinked target quaternion table. Heritage FSW from MAP. MRD-14 MRD-49 MRD-84 FSWR-127 The GN&C flight software shall compute a Lunar Nadir Positive-X Velocity (LNPXV) target quaternion. Similar to the Earth-pointing missions. NASAs Goddard Space Flight Center 19 - 6 Lunar Reconnaissance Orbiter (LRO) FSW System Level 2 Flow Down Key Requirements Level 2 Req. Level 3: Requirements Paragraph Concept/Compliance Requirement MRD-10 MRD-97 FSWR-130

The GN&C flight software shall compute the total angular momentum in the body reference frame. Heritage FSW from many missions. MRD-8 MRD-90 MRD-91 FSWR-131 The GN&C flight software shall provide a CSS Sun Pointing attitude control mode. Heritage mode from many missions. FSW implements algorithms supplied by GN&C MRD-9 MRD-49 FSWR-134 The GN&C flight software shall provide a science attitude control mode. Heritage mode from many missions. FSW implements algorithms supplied by GN&C MRD-10 MRD-88 MRD-97 FSWR-137 The GN&C flight software shall provide a Delta-H control mode. Heritage mode from many missions. FSW implements algorithms supplied by GN&C MRD-10 MRD-87 FSWR-140 The GN&C flight software shall provide a Delta-V attitude control mode. Heritage mode from many missions. FSW implements algorithms supplied by GN&C MRD-20 MRD-133 FSWR-143 The GN&C flight software shall monitor the performance of each control mode and provide status telemetry that can be monitored by the C&DH flight software. Heritage GN&C and C&DH FSW relationship. MRD-10 MRD-87 FSWR-147 The GN&C flight software shall send propulsion commands at the control law execution rate.

Typically send actuator commands at the controller rate. NASAs Goddard Space Flight Center 19 - 7 Lunar Reconnaissance Orbiter (LRO) FSW System Level 2 Flow Down Key Requirements Level 2 Req. Level 3: Requirements Paragraph Concept/Compliance Requirement MRD-15 MRD-84 FSWR-149 The GN&C flight software shall read SA orientation data at 1 Hz (TBD) and compute a solar array normal to sun angle. Standard requirement when a spacecraft has articulating arrays. MRD-15 MRD-84 FSWR-150 The GN&C flight software shall command the SA gimbals at 1Hz (TBD) to orient the SA normal to the sunline. A 1Hz rate can easily be accommodated by a RAD750 processor. MRD-16 MRD-84 FSWR-153 The GN&C flight software shall read HGA orientation data at 5 Hz (TBD) and compute an HGA-pointing direction vector in the spacecraft body frame. Standard requirement when a spacecraft has a gimbaled HGA. Note mechanical complexities when tracking can present challenges. MRD-16 MRD-84 FSWR-154 The GN&C flight software shall command the HGA gimbals at 5Hz (TBD) to point the HGA towards a ground station. 5Hz can be accommodated. Note the rate could be much higher depending on the intelligence HGA controller NASAs Goddard Space Flight Center 19 - 8

LRO Flight Software Architecture Spacecraft Data Recorder Checksum EDAC Memory Scrubber Memory Manager Memory Dwell Self Test GN&C Applications (5) Instrument Manager Software HK Data Storage Scheduler Stored Commanding File Manager Local Storage Health & Safety Manager New C&DH Task CFDP File Transfer Inter-task Message Router (SW Bus) 1553 Bus Support Telemetry Output Command Ingest Software Bus Time Services Executive Services Event Services

Table Services Heritage C&DH Task Cmd (UDP COP-1) New GN&C Task Summit Chip cFE Task NASAs Goddard Space Flight Center S-Band COMM (up/down) Transponder Real-time Telemetry (UDP) Backup path for files (CFDP) 19 - 9 LRO FSW Verification Pre-release verification Peer reviews of SW design Code walkthroughs Unit tests Post-release verification in FSW lab Build Tests Requirements verification matrix of L4&L5 rqmts Verification of final build System Tests Verify L3 requirements and selected L4s Run on FlatSat IV&V WVa group validates process and run code analysis Code 300 SQA participates throughout SW development NASAs Goddard Space Flight Center 19 - 10 LRO FSW Summary LRO FSW architecture defined VxWorks, cFE forms the SW core Heritage FSW subsystems selected from Triana and SDO FSW development process defined Developed and documented by code 582 for CMMI compliance LRO-specific process documents are in work FSW development labs being prepared Lab designs baselined Most components in house or on order FSW team members identified and ready to work FSW is ready to proceed with preliminary design NASAs Goddard Space Flight Center 19 - 11

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