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Sequence of Events Spreadsheet - PowerPoint

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					SpaceOps 2006




         The Cassini-Huygens
        Sequence Development
               Process



                     Jennifer Long Maxwell
                Cassini-Huygens Uplink Operations Engineer
         Jet Propulsion Laboratory/California Institute of Technology
SpaceOps 2006



     What is a “Sequence”?
• One or more programs containing commands to be
  executed at some desired time
   – Executes over some extended period of time (Cassini => ~ 5-6 weeks)
   – Usually an integrated product from many instrument / engineering
     teams
   – Constraint Checked (via software or manually checked)
   – Some portions simulated on a test bed (hardware or software)
• Decreases operations costs
• Creates an integrated plan for science and engineering
  activities
• Limited flexibility to changes at later development
  phases
SpaceOps 2006



    Sequence Generation Process
                 Science Planning                    Uplink Operations



                                                       Science and
                                                       Sequencing
        Integration             Aftermarket              Update
                                                         Process



       Implementation          SOP Update               Execution



   • Begins 4 years prior to to sequence execution
            10
            20 weeks prior sequence execution
   • Begins 2 years prior to to sequence execution
            15 weeks prior
     Executes for 5-6 weekssequence execution
    SpaceOps 2006



   DSN
                G70                     Integration     C/A
                                                                                        G70
   CIRS
   ISS
   RADAR
   UVIS
   VIMS
   INMS



             Negotiation takes place with scientists and a straw-man timeline is worked out.


Integrated
Timeline
                DSN       CIRS    ISS        VIMS     MAPS     RADAR    ISS             DSN

Riders
are added



        Based on the timeline, Op Modes and Telemetry Modes are determined
        DFPW Normal                     WU          RADAR RCS             DFPW Normal

           RTE_SPB          SNER_3        SNER_5A 3           SNER_8    SNER_3       RTE_SPB
SpaceOps 2006



                       Implementation
       • Pointing designs and instrument commands are added to
       subsequence files
         CIRS                    UVIS                RADAR       Turn to Earth




      • Subsequences are merged together and integrated
      product is constraint checked

      • Violations are identified for future fixes

      • Plan is archived until 20 weeks prior to sequence
      execution
SpaceOps 2006




         Aftermarket and Science
         Operations Plan Update
• Aftermarket
   – Timeline is reintegrated with new information
• SOP Update
   – Changes to pointing designs and instrument
     commands are used to update the plan on the shelf
   – DSN strategy is delivered and integrated
   – Product is handed off to Uplink Operations for
     detailed subsequence development
      SpaceOps 2006



     Overview of Cassini Uplink Process
                                                                                                Sequence
                                                                                               Virtual Team
                                                                          Subsequences
 Science Planning
                                                     Subseq.                (SASF)             Preliminary
  Process (SPP)/
Aftermarket Process                                  Generation                                Sequence
                                                      Sequence                                 Integration &
                                                     Virtual Team                              Validation
                                                                                                      • Prelim.
   • Tour SOP
                                                                                                        Integrated
   • SOP Updates
                                                     Subseq.                                            Sequence
   • Graphical Timeline
                                                                                                      • Validation
   • Time-Ordered List                               Generation
                                                                                                        Results
   • Integrated Activity Plan SASF
   • Integrated Pointing SASF                    SCO, IO, PI, and HPOC Core Function
                                                                                               Final
                                                                                               Sequence                       Sequence
                                                                         • CPF
                                                         ITL             • Valid. Criteria     Integration &                  Execution
                                                                                               Validation
                                                   SCO Core Function     • Validation
                                                                           Results                    • Integrated Seq. (CMD_DSN)
Cassini ULO Requirements / Design Review - lcm


                                                                                                                     • Uplink Signal
                                                                                                Sequence                               S/C
                                                                                                Radiation
                                                                                             MSSO Core Function
SpaceOps 2006



    Science and Sequence Update
              Process
• SOP Update vs. SSUP
   – More stringent configuration management
        • Sequence Change Requests (SCR)
        • Team Stripped Subsequence files
• Subsequence generation
   – SOP Update product is baseline
   – Errors fixed via SCR
   – Instrument deliver low level commands
      SpaceOps 2006




         Sequence Integration, Review
               and Validation
                                                              Sequence Change Request

                                                                                                                          Uplink
                                                                  Inertial Vector                       No
Team Subsequence                Integrated Product
                                                                    Definitions
      Files
                                                Analysis and
                   Merge                         Constraint                         Merge              Flyable integrated
                                                  Check                                                   sequence?       Yes
                                    Inertial Vector
                                      Definitions
                   Moveable                                                                           Yes
                     Block                                                            Flyable mini-
                   Extraction
                                                      Merge                            sequence?                  Uplink

                                                                                               No



                                                                                        Live Update
                                                                                          Process
     SpaceOps 2006



                             Real Time Activities
Instrument
Teams                               Memory            Automated
             Sequence                            No
                                  management          Sequence
             Activity File         needed?            Processor

                                         Yes


                                  SVTL add
                                   memory
                                  directives



                                Command Review
                                  and Approval        Uplink
SpaceOps 2006


       Sequence and Command Radiation
SpaceOps 2006



                   Lessons Learned
• Distributed Operations
        • Virtual teams
        • CIMS Database
        • Ancillary Files Distribution
• Pointing Designs
        • Attitude Strategy Spreadsheet
        • Waypoint Strategy
• Trajectory Updates
        • Pointing Margin
        • Ground and Live Moveable Blocks
        • Live Update Process
SpaceOps 2006



            Lessons Learned cont‟d
• Software Development
        • Deferred development
        • Multi-mission software
        • High-speed simulator
• Sequence Development Timeline
      • Multiple sequences in development
      • Standardization and automation of processes
   – Memory Management
        • Instrument expanded blocks
        • Cyclics
        • Memory Regions
SpaceOps 2006



                Conclusion
SpaceOps 2006



                Backup
SpaceOps 2006



     Objectives of a “Sequence”
•   Uplink a “plan” to execute for some extended period of time
     – Decrease operations costs
          • Not required to interact with S/C on daily basis
          • People can work on other tasks
     – Integrates various instrument and engineering activities
          • Ensures the activities play together (data volumes, power margin, bus bandwidth,
            simultaneous science observations, etc.)
          • Provides a single integrated sequence product for operations personnel


•   Contrast to daily commanding
     – Increased operations costs (more frequent software runs / validation costs)
          • Costs magnified with increased instrument payload
     – Light Time Penalty
     – However, easier to accommodate DSN changes
SpaceOps 2006



    Sequence Generation Process
SpaceOps 2006




 Sequence Integration, Review and
            Validation
• Preliminary phase – 2 cycles; Final phase -1 cycle
• Cycle consists of
   –   Merge of subsequences
   –   Moveable block extraction and generation
   –   Flight rule and constraint check
   –   Vector generation and integration into sequence
   –   Changes require SCR
   –   Testing of first time events in the Integration and Test Lab
   –   Instrument Expanded Block processed and delivered
• Results in conflict-free, integrated, uplinkable distributed
  sequence
SpaceOps 2006



                Real Time Activities
• Generated during and after sequence
  development
• Team submit command file
• SVTL integrates memory management
  commands
• System level commands reviewed
• Instrument internal commands may be
  processed via Automated Sequence
  Processor
SpaceOps 2006



          Sequence and Command
                Radiation
• Prepares the DSN complex for radiation of
  commands to Cassini
   – Signal received by DSN complex
   – Command is verified by name and creation time
   – Mission controller verifies file and moves to radiation
     queue
   – SVTL or S/C Engineer gives final „go‟
   – Command packets are transferred to the DSN
     complex and radiated to the spacecraft
   – File is verified onboard through registration in
     sequence memory or execution of command files
SpaceOps 2006



                Lessons Learned
   •   Distributed Operations
   •   Science Observations
   •   Software Development
   •   Spacecraft Complexity and Limitations
SpaceOps 2006



                Distributed Operations
• The Cassini- Huygens Science and Engineering
  Team is made up of scientists and engineers
  from all over the world
   – Virtual Operations Teams
   – Cassini Information Management System (CIMS)
     database
   – Sequence Phase List of Ancillary Files (SpLAF)
SpaceOps 2006



                Science Observations
• Pointing Design
   – Instrument fixed on body of spacecraft
   – Tools that were designed to overcome this challenge:
        • Science Planning Attitude Strategy Spreadsheet (SPASS)
        • Waypoint Strategy
• Trajectory Updates
   – Need to incorporate new information into existing plan
        • Pointing Margin
        • Ground and Live Moveable Blocks
        • Live Update Process
SpaceOps 2006



                Software Development
   – Ground software had to be developed to check the
     330 flight rules
   – Deferred development
   – Multi-mission software
   – High Speed Simulator
SpaceOps 2006



            Spacecraft Complexities
• Sequence development long before
  sequence execution; multiple development
  processes
   – Standardization, Automation, and Tool
     Development
• Memory management
   – IEBs
   – Cyclics
   – Memory regions

				
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