1 SpaceOps 2002 Autonomous Operations For The Swift Mission T3-47 John Ong/Swift Software Systems Manager NASA/GSFC Code 582/ Mike Rackley/Swift Ground System Engineer NASA/GSFC Code 581/

2 SpaceOps 2002 Major Mission Goals Autonomously Detect & Observe Of Gamma-Ray Bursts (GRBs) Autonomously Slew To (I.e., “Chase”) GRBs (w/o Ground Intervention) Forward GRB Data (e.g., Position, Basic Characteristics) to Ground System Within 20 Seconds Perform Hard-X-Ray Survey (Through Pre-Scheduled, Time-Based Observation Plan) Perform Follow-On Observations (Through Continual Updating of Observation Plan) Quickly And Autonomously Distribute Newly Detected GRB Information To The Global Astronomy Science Community

3 SpaceOps 2002 Observatory Overview X Z Y BAT UVOT Sun Shade XRT Star Trackers XRT radiator BAT Power Box BAT IPE Boxes IRUs

4 SpaceOps 2002 Mission Characteristics Autonomous Slew Decision Capability Fast Slews: 50° in <75 seconds Low Earth Orbit, 22° Inclination Delta II , 3m Fairing Observatory Mass: ~1357 kg Average Power: ~983 W

5 SpaceOps 2002 Key Mission Ops Challenges Supporting 24x7 “Dynamic”, Autonomously Slewing S/C With An 8x5 Ops Staff –Observation of a Newly Detected GRB Causes Rescheduling of Observing Plan (Expected to Occur Daily) Generating Accurate As-Flown Schedule Given That The Pre-Planned Schedule Will Change Routinely –Utilizes Unique Observation Ids To Enable Mapping of As-Flown Schedule To Actual Observations Performing Data Processing With Minimal Staff –From Raw-Frame Files At Ground Station To Science Formatted Files At Data Center

6 SpaceOps 2002 Operations Concept Summary Autonomous GRB Detection & Repointing of S/C By Onboard Figure of Merit (FoM) Flight SW (FSW) –Occurs Approximately Once Per Day –Immediate Notification to Ground System So Others In Science Community Can Also Take Action to View Burst When Not Viewing a Newly Detected Burst, Spacecraft is Driven by Pre-Loaded Observation Plan –72-Hour Observation Plan Uplinked Daily For Newly Detected and Preplanned Bursts, All Observations Assigned a Unique Observation Number –Information on Actual Observations Reflected In FoM FSW Housekeeping (Observation Numbers, Times, Durations, etc.) –Ground System Develops As-Flown Schedule Using Observation Information Provided by FoM FSW

7 SpaceOps 2002 Operations Concept Summary Frequent, Dynamic Replanning Performed by Science and Flight Operations Teams –Must Account for Previous Preplanned Activities (Observation Plan), and How They Were Affected by the Autonomous Actions Taken by the Spacecraft (Newly Detected Bursts) Routine Spacecraft Communications With Ground Station –Approximately 6-10 Contacts Per Day (6 Minimum) –Contacts Used For Routine Operations (e.g., Data Dumps, Health and Safety Monitoring, Daily Commanding) Process for Getting Data from Malindi to the Science Users Quickly Fully Automated Science Team Able to Initiate Observations Quickly Via Target of Opportunity (ToO) Requests

8 SpaceOps 2002 System Architecture Diagram

9 SpaceOps 2002 System Architecture Highlights Burst Alert Messages Relayed to Ground in Real-Time Via the TDRSS Demand Access Service (DAS) –DAS Provides Near Continuous Coverage –Messages Relayed to GRB Coordinates Network (GCN) For Distribution to the Science Community in Near Real-Time –Link May Also Be Used to Provide Housekeeping Data to Operations Team in the Mission Operations Center (MOC) Malindi Ground Station Provides Ability to Dump Stored Housekeeping & Science Data to Ground and Conduct Day- to-Day Operations –Station Owned and Operated by Italian Space Agency (ASI) and Located in Kenya, Africa –Dump Data Automatically Transmitted to the MOC

10 SpaceOps 2002 System Architecture Highlights Science Team Can Add Target-Of-Opportunity (ToO) Requests To Observation Plan –Science Team Presents ToO Request To MOC –MOC Uplinks Via TDRSS - Uplink Must Be Scheduled, Not Always Available Like The DAS for Telemetry –Turnaround Within 60 Minutes Swift Data Center Provides Science Data Processing Functions –Receives Data Automatically From the MOC –Extracts Observations From Raw Packet Data –Converts Observations Into Science Formatted, Quick-Look Data Products and Makes Available to the User Community –Data Processing Pipeline Fully Automated

11 SpaceOps 2002 System Architecture Highlights Flight Operations Support in MOC Supported Via Standard Suite Of Automation Capabilities/Tools –Automatic Conduct Of Data Dumps From Spacecraft –Autonomous Monitoring Of Telemetry With Paging Of Offsite Personnel As Needed –Remote Data Access For Flight Operations Team –Automatic Ingest Of Orbit Information And Incorporation Into Planning Process –Automatic Generation of Analysis Products (e.g., Trend Plots And Statistics Reports)

12 SpaceOps 2002 Onboard Autonomy Via FoM FSW FoM FSW Schedules Actual Observations –Pre-Planned Targets (PPTs) Uplinked In Observation Plan Are Forwarded to FoM FSW ILO S/C ACS –Automated Targets (ATs) Consist Of Newly Detected GRBs & ToOs –Priority of Observations Based On Assigned Merit –Observing PPTs Given Priority When ATs Constrained FoM FSW Scheduling Requires Integrating Time-Based PPTs and Event-Based ATs –ATs Are To Be Observed ASAP for Pre-Defined Time –PPTs Can Be Pre-Empted By ATs BAT Assigns Observation Numbers for GRBs, Ground System Assigns For PPTs and ToOs

13 SpaceOps 2002 FoM FSW Target Observation Flow The unique capability which distinguishes Swift from all other astrophysics missions is the requirement to slew the spacecraft to acquire the newly discovered GRBs within the field of view of the Narrow-Field Instruments The scientific premium on rapid acquisition is so high as to preclude ground control of the slew request, so the Swift spacecraft must include an onboard decision process to enable an entirely automated response to unplanned slew requests (hence, the Figure of Merit)

14 SpaceOps 2002 FoM FSW Functional Interfaces S/C ATT STATUS PKT SLEW RESPONSE MSG VIEW CONSTRAINT MSG S/C SLEW REQUESTS Ground PPT REQUEST (via SCP) ToO REQUEST (via TDRSS) FoM MGMT CMDS Ground TDRSS MSGs FoM TLM PKTs Figure of Merit task HSKP PKT REQUEST MERIT UPDATE MSG Instr BAT NFIs NEXT OBSERVATION INFO MSG Inst BAT NFIs GRB POSITION MSG

15 SpaceOps 2002 Conclusions Swift Represents A New Class of Missions Requiring Autonomous S/C Repointing Without Ground Intervention –Not Possible For FOT To Be In Loop For Authorizing “Chasing” of GRBs –Onboard FoM FSW Will Manage Autonomous Slews - FOT Reassess and Replans Accordingly Vital That Ground Systems Work With Flight Data Systems Engineers Early-On To Ensure Capabilities Exists For Efficient & Cost-Effective Operations –Every PPT and AT Observation Assigned Unique Observation Number, Allowing for Correlation of Instrument Science Data –Actual Observation Information Downlinked In FoM Housekeeping Essential to Generation of As-Flown Schedule High Level of Automation of Data Processing Pipeline Required To Meet Funding Limits –Close Coordination Required Among Instrument, S/C, Malindi Ground Station, MOC, & SDC Personnel