Post on 20-Jan-2016
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11 SpaceOps 2002
Autonomous Operations For The Swift Mission
T3-47
John Ong/Swift Software Systems ManagerNASA/GSFC Code 582/301-286-8435
Mike Rackley/Swift Ground System EngineerNASA/GSFC Code 581/301-286-5528
22 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
33 SpaceOps 2002
Observatory Overview
X Z
Y
BAT
UVOTSun Shade
XRT
Star Trackers
XRT radiator
BAT Power Box
BAT IPE Boxes
IRUs
44 SpaceOps 2002
Mission Characteristics
• Autonomous Slew Decision Capability • Fast Slews: 50° in <75 seconds
• Low Earth Orbit, 22° Inclination
BAT(Burst Alert Telescope)
XRT(X-Ray Telescope)
UVOT(Ultra-Violet Optical Telescope)
Position Accuracy 5 arcmin 5 arc seconds 0.3 arc secondsEnergy Range 15 keV to 150 keV 200 eV to 10 keV 170 to 650 nm WavelengthFOV 2 Steradians 23.6 x 23.6 arc minutes 17 x 17 arc minutesPSF HPD 17 arcmin 15" @ 1.5 keV 0.9" @ 350 nm
Effective Area (cm2) 5200 110 @ 1.5 keV
Telescope ~4 ft x 8 ft Coded Mask Wolter I, 12 shells30 cm Aperture Modified Ritchey-
ChretienFocal Length 1 m 3.5 m F12.7Timing Resolution 100 micro-sec 1 secDetector 32,000 individual CZT MAT CCD-22 (EEV) Intesified CCDDetector Format 128 pixels/DM, 256 DMs 600 x 600 pixels 256 x 256 pixels
Sensitivity 0.2 photons/cm2/sec 2x10
-14 erg-cm
-2-s
-1 (10
4 sec) B=24.0 (White light, 1000 sec)
Detector Modes Burst, Survey Photon Counting, Imaging, Timing Photon Counting
• Delta II 2420-10, 3m Fairing
• Observatory Mass: ~1357 kg
• Average Power: ~983 W
55 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
66 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
77 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
88 SpaceOps 2002
System Architecture Diagram
White Sands Complex (WSC)MalindiGround Station
SWIFTTDRS
S-Band CMD/TLM2.25 Mbps downlink (RT & PB TLM)
2 kbps uplink (Normal Commanding)
NCC
MissionOperations Center
(MOC)
SwiftData Center
Commands
Command, H/K, Science
PSU
GSFC
JSC
OpticalTelescopes
RadioTelescopes
Quick-look L0 Data
Prod.FITS data
Observation Requests
Observation Results
e.g. Chandra
e.g. HET
e.g. VLA
Alerts, TOO Commanding,Contingency H/K,Tracking
SwiftScience Center
Data Analysis Tools
Alerts,H/K
HEASARC
GSFCGSFC
November 13, 2001 Revision J
GCN
GSFC
Front-End
MAF/MAR&DAS CMD/TLM1 kbps downlink (Alerts & H/K)
125 bps uplink (ToORequests)
SN Scheduling & Status
Burst Alerts
Satellites
Science Teams,
Community
ISAC
UKDC
2-Line Elements
BAT
UVOT/XRT
Flight Software
Maintenance
Spacecraft
GSFC
PSUSpectrum Astro
Flight DynamicsFacility
GSFC
Orbit Data
NORAD
Tracking Data
Kenya
ASINetFucinoGateway
Fucino, Italy
ASINet US Gateway
384 kbps Leased Line
Quick-look Data & Products
S/W UpdatesObservatoryData
White Sands Complex (WSC)MalindiGround Station
SWIFTTDRS
S-Band CMD/TLM2.25 Mbps downlink (RT & PB TLM)
2 kbps uplink (Normal Commanding)
NCC
MissionOperations Center
(MOC)
SwiftData Center
Commands
Command, H/K, Science
PSU
GSFC
JSC
OpticalTelescopes
RadioTelescopes
Quick-look L0 Data
Prod.FITS data
Observation Requests
Observation Results
e.g. Chandra
e.g. HET
e.g. VLA
Alerts, TOO Commanding,Contingency H/K,Tracking
SwiftScience Center
SwiftScience Center
Data Analysis Tools
Alerts,H/K
HEASARC
GSFCGSFC
November 13, 2001 Revision J
GCN
GSFC
Front-End
MAF/MAR&DAS CMD/TLM1 kbps downlink (Alerts & H/K)
125 bps uplink (ToORequests)
SN Scheduling & Status
Burst Alerts
Satellites
Science Teams,
Community
ISAC
UKDC
2-Line Elements
BAT
UVOT/XRT
Flight Software
Maintenance
Spacecraft
GSFC
PSUSpectrum Astro
BATBAT
UVOT/XRTUVOT/XRT
Flight Software
Maintenance
Spacecraft
GSFC
PSUSpectrum Astro
Flight DynamicsFacility
GSFC
Orbit Data
NORADNORAD
Tracking Data
Kenya
ASINetFucinoGateway
Fucino, Italy
ASINet US Gateway
384 kbps Leased Line
Quick-look Data & Products
S/W UpdatesObservatoryData
99 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
1010 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
1111 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)
1212 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
1313 SpaceOps 2002
FoM FSW Target Observation Flow
PPT request Burst Event Uplink ToO
ScheduledPPT
CandidateAT
FoM PPT FoM AT
ObservedTarget
From Ground(via SCP)
From BATFrom Ground(via TDRSS)
• 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)
1414 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
Figureof
Merittask
HSKP PKT REQUEST
MERIT UPDATE MSG
Instr
BAT
NFIs
NEXT OBSERVATION INFO MSG
Inst
BAT
NFIs
GRB POSITION MSG
1515 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