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    Presentation Presentation Presentation Transcript

    • The Role of Science and Operations in the James Web Space Telescope Mission Development Presenter D.G. Hunter Co-authors H.S. Stockman K.S. Long Track T5 May 20, 2004
    • JWST Science
      • Detect First Light (After the Big Bang)
        • First luminous objects - protogalaxies, supernovae, black holes
      • Assembly of Galaxies
        • Merging of protogalaxies, effects of black holes, history of star formation
      • Birth of Stars and Planetary Systems
        • How stars form in dust clouds
        • How chemical elements are produced and recirculated
      • Planetary Systems and the Origins of Life
        • Formation of planets
        • Direct observation of other systems
        • Outer Solar System
    • Observatory Design Features Science Instruments Spacecraft Sunshield 25 m 2 Primary Mirror
    • JWST Will Operate at Sun-Earth L2
      • L2 allows blocking Sun, Earth & Moon light
      • Passive cooling to ~50K
      • Stable environment
      • Easy communication
    • Science Instruments Guider MIRI NIRSpec NIRCam
    • Science Instruments
      • Mid-Infra-Red Instrument (MIRI)
        • 100x sensitivity over previous systems
        • Imaging and spectroscopy capability
        • 5 to 28 microns
        • Cooled to 7K by Cryostat or Cyrocooler
        • Combined ESA/NASA contributions
      • Fine Guidance Sensor (FGS)
        • Ensures guide star availability with >95% probability at any point in the sky
        • Includes Tunable filters for Narrowband Imaging
        • CSA provided
      • Near Infra-Red Camera (NIRCam)
        • Detects first light
        • 0.6 to 5 microns
        • 4 Imaging modules each with a 2.3’ x 2.3‘ FOV (short 4kx4k, long 2kx2k)
        • Coronagraph capability
        • FPA’s passively cooled to 30K
        • UofAz/LMATC instrument
      • Near Infra-Red Spectrometer (NIRSpec)
        • Studies galaxy formation, clusters, chemical abundances, star formation, and kinematics
        • 0.6 to 5 microns
        • Simultaneous spectra of >100 objects
        • 9 square arc minute field of view
        • FPA’s passively cooled to 30K
        • Resolving powers of ~100 and ~1000.
        • ESA provided with NASA Detectors & Microshutter
    • Operations
      • Five year mission lifetime - propellant tanks sized for 10 years
      • Guaranteed Time Observations for Instrument Scientists
      • General Observing via a peer reviewed proposal selection process (as for the Hubble Space Telescope)
      • Scheduling (long-term and short-term observation plans)
      • Event driven execution of uploaded operations plan
      • On-board procedures, high level commands
      • Data download and archive
      • On-the-Fly data calibration
    • Mission Schedule
    • Mission Participants
        • NASA
        • ESA
        • CSA
        • Project lead at Goddard Space Flight Center (GSFC)
        • Observatory Contractor: Northrop Grumman Space Technology (NGST)
        • Science and Operations Center at the Space Telescope Science Institute (STScI)
    • The STScI Hubble Heritage
      • Successful preparation and checkout of 10 instruments (+2 in SM4).
      • Proven and evolving software systems for all aspects of science operations:
        • Proposal management
        • Guide star selection (GSC II)
        • Science planning (APT)
        • Scheduling (Spike)
        • Hubble archive
        • “ On-the-fly” calibration management (OPUS)
        • Grants management (GMS)
      • Outstanding record of public and astronomical outreach
    • STScI Role in JWST
      • Manage the science program from observing program solicitation and selection to grants management and science outreach support.
      • Operate JWST - beginning in commissioning
      • Develop the science and operations ground systems
      • Perform ground segment verification
      • Perform end to end testing
      • Scientific and Public outreach
      • Support the Project and JWST teams during the development phase:
        • Mission architecture & system engineering
        • ISIM & Scientific instruments & ISIM flight software
        • Optics and wavefront sensing and control
        • Science and operations input to many working groups
    • The JWST Ground System
    • JWST Ground Processes Proposal Preparation Proposal Selection Science Planning Operations Scheduling Flight Operations Data Management Data Archive Ground Sys Engineering/ Maintenance Flight System Eng Testbeds & Simulators Flight Dynamics Wavefront Control Instrument Calibration Command Management Flight SW Maintenance Astronomers
      • Uplink
      • - Observation Plan
      • - Ephemeris
      • - Commands
      • Flight S/W
      • Ranging
      JPL Deep Space Network JWST Ground Processes and Key Relationships
      • Downlink
      • - Event Logs
      • R/T Eng Telemetry
      • Recorded Telemetry
      • Ranging
      • Flight S/W
      JWST - On-Line Documentation - Electronic Forms - Proposal Tools - TAC review - Electronic Forms - Long-term plan - Weekly schedule - WFE Sensing - WFE Control - Station Keeping - Weekly Schedule - Contact Schedule - Eng Activities - Command Loads - R/T Operations - Uplinks - State evaluation - Data capture - Eng Trend - L0 Processing - Sci Data QA - SI Calibration - Short Term Storage - Long-Term Storage (Sci & Eng) - Browsing - Retrieval - SI Calibration - Distribution - WFE Determination - Mirror Actuator Commands - FSW Upgrades - Patches - Tables - SI Procedures - Anomaly Analysis - GSW Requirements - Data Base Management - Vendor OS & Tools - Ground HW / SW Maintenance / Upgrades - H/W Testbeds - SW Simulators - System I&T - SSM/OTA/ISIM Test Environment - Orbit Determination - Station Keeping - Ephemeris - Momentum Monitoring - Anomaly Analysis - Eng Trend Analysis - Degradation Prediction - FSW Requirements - Algorithms - Reference Data - Performance Reports - Proposals - Science Data - Visit Scripts
    • The Planning System Interface
      • Exposure Time calculators
      • Optimum background/roll range
      • Orientation planning with Guide Star Catalog II
        • Target coordinates in JWST frame
        • NIRSpec target selection tool
        • Allowable & Optimum roll angles
        • Dither pattern selection and optimization
        • Predicted glare from bright objects
        • Acquisition/offset target selection
      • Calibration & engineering operations will also be planned using this planning tool.
      Hubble Planning Tool Advanced Camera for Surveys
    • Participation in Development
      • Inform the Observatory development process of the science and operations drivers for, and consequences of each design decision.
      • Ultimate objectives:
        • achieving a high scientific return,
        • reduced lifecycle cost,
        • efficient operations and design.
    • Influencing Development - 1
      • Develop and maintain the Mission Operations Concept
      • Systems Engineering
        • Participate in requirements development.
        • Evaluate the operations consequences for system level trades.
      • Science Instrument Teams
        • Develop operation concepts with common approaches
        • Develop the calibration plans
        • Gain knowledge of the instruments’ design & behavior
        • Develop the tools and resources the astronomy community will need for high yield science.
      • Flight software
        • Ensure commonality of commanding approaches, syntax and terminology
        • Develop on-board procedures.
    • Influencing Development - 2
      • Integration and Test
        • Develop and manage the Project Reference Database
        • Provide test conductors who will migrate to the operations team
        • Develop operations procedures - test against simulators and with the ground system in the loop with the flight systems.
      • Commissioning
        • Develop plans and procedures, working with the flight systems developers
        • Operate observatory.
    • Value Added - Mission Simulator
      • JWST Mission Simulator - simulates execution of science observations
        • Informed the transformation of the science objectives into the observatory requirements.
        • Important science influence on requirements
          • Field of Regard
          • Continuous viewing zone
          • Continuous exposure at same orientation…
      Anti-Sun LOS Allowable Observatory Field-of- Regard SUN Exclusion < 27° from Anti-Sun Exclusion Zone < 85 ° from Sun Observatory Field-of-Regard (FOR)
    • Value Added - Fine Guidance Sensor Architecture
      • Separation of Fine Guidance Sensor from Near-Infrared Camera.
        • Reduced operational complexity
        • Improved architecture for science
        • Improved management structure.
    • Value Added - Day in the Life Simulations
      • Developed prototype of flight software for event-driven operations including:
        • Executive and processing functions
        • On-board procedure scripts
        • Commands and telemetry for science instruments and spacecraft
      • Executed on top of Command and Data Handling System flight code running on a flight representative single board computer.
      • Loaded and ran six days of observation plans for three science instruments.
      • Produced detailed event logs plus memory and CPU statistics.
      • The exercise:
        • developed detailed requirements,
        • confirmed the event driven design with flight like operations,
        • produced flight like prototypes for the flight software.
      • Now preparing to implement more complex scenarios.
    • System Trades - Momentum Management
        • The JWST attitude required for each science observation results in solar torque being generated by the sunshield.
        • Unloading momentum disturbs the orbit.
        • Propellant consumption affects the mission lifetime.
        • Constraining the scheduling of observations to manage momentum accumulation adds significant complexity and may compromise science.
    • Ongoing Challenges
      • Aspects of operations are highly sensitive to the flight segment design, such as:
        • Momentum management - smaller sunshield is better
        • Stray light avoidance - larger sunshield is better
        • Both affect scheduling of science observations.
        • Importance of operations involvement in design trades
      • Funding profile - Pressures on Phase A/B funding
        • Lowest lifecycle cost often requires higher initial outlay but few missions have sufficient early funding.
        • Prioritization of effort in high impact areas.
      • Not everyone has learned the same lessons
        • Different missions follow different paradigms
        • Demonstrate merits of approach by example.