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GLAST Large Area Telescope: IOC Subsystems WBS: 4.1.B David Lung

Gamma-ray Large Area Space Telescope. GLAST Large Area Telescope: IOC Subsystems WBS: 4.1.B David Lung Stanford Linear Accelerator Center IOC Subsystem Manager dlung@slac.stanford.edu. Topics. IOC Overview Key Events Interfaces Requirement flow Data path Commanding path

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GLAST Large Area Telescope: IOC Subsystems WBS: 4.1.B David Lung

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  1. Gamma-ray Large Area Space Telescope GLAST Large Area Telescope: IOC Subsystems WBS: 4.1.B David Lung Stanford Linear Accelerator Center IOC Subsystem Manager dlung@slac.stanford.edu

  2. Topics • IOC Overview • Key Events • Interfaces • Requirement flow • Data path • Commanding path • LAT Operations • Launch and turn on • A day in life

  3. Gamma-ray Large Area Space Telescope IOC Overview

  4. Key Events • IOC Subsystem Peer Review – November 2003 • IOC Subsystem CDR – February 2004 • IOC readiness dates to support the Mission Ground Readiness Testing • Ground Readiness Testing #1: November 2004 • First transmission of Level 0 data from MOC to IOCs • IOC Ready by August 2004 • Ground Readiness Testing #5: September 2005 • Required Level 1 processing with transfer of results to SSC • IOC Ready by September 2005

  5. Instrument Operations Center Overview • Receive Level 0 data telemetry packets from Mission Operations Center (MOC) • Perform science data production to generate Level 1 products • Build and verify commanding plan for LAT instrument • Support housekeeping monitoring of the instrument for health and safety • Verify instrument performance and trending • Archive all Level 0 telemetry packets and Level 1 products

  6. IOC Functional Architecture

  7. Ground Operations – Data Path Science Telemetry: 300 Kbps orbit average 20 Mbps X-band data rate 2.5 Mbps S-Band: Real-time telemetry (Housekeeping) , memory dumps, and engineering data dumps

  8. Ground Operations – Commanding Path 2 Kbps Ground Network Command Rate

  9. Command & Telemetry Database • The command and telemetry database is being developed by Flight Software (FSW) for engineering model testing • The schema describing commands and telemetry will written in a standard meta language (XML or MySQL) • The choice of meta language will be influenced by the ease of creating/changing/maintaining the data base. • Schema design will be driven by the details of the ITOS and AstroRT data bases - We must have the ability to translate to either • Close coordination between FSW, I&T and IOC • IOC will build upon and maintain the software and database produced by I&T.

  10. Requirement Flow Changes since PDR

  11. Gamma-ray Large Area Space Telescope LAT Operations

  12. Launch Conditions • LAT instrument is OFF from pre-launch through spacecraft solar array deployment and thermal stabilization • 96 telemetry points will be used for LAT monitoring via the spacecraft bus prior to LAT turned-on • Temperature • Voltages • S/C unregulated survival feeds enabled the following LAT heaters • Radiator Antifreeze • Grid Make-up • Post S/A deployment and first contact, the S/C PRU will enable the regulated VCHP feed • VCHP reservoir heaters

  13. LAT Analog Telemetry

  14. LAT Turn On State Diagram

  15. Instrument Turn-On Sequence • Once the spacecraft has establish power positive, thermal stabilization, and out-gassing - the LAT instrument shall be turned-on • The LAT turn-on is a set of ground command with verification sequences • Verify telemetry prior to the next operation • Temperatures • Voltages/Currents • Turn-on profiles • State • Additional monitoring telemetry are available as the PDU, GASU, and TEMs are turned-on • PDU: 157 • GASU: 57 • TEM: 640

  16. A Day In Life of LAT • Data acquisition • Rocking • Pointed observation • Repoint • Prior to entering the pre-defined South Atlantic Anomaly (SAA) event, the spacecraft sends LAT a signal safing the high-voltage power supplies within the ACD PMT • Return to data acquisition upon exiting SAA • Approximately 6 contacts per day, less than 10 minutes per pass Typical Contact Schedule for a 24 hour period (Example is Malindi)

  17. LAT Operation Modes • LAT operation modes are simple • Observation modes • Instrument is acquiring data • Valid science data • Standby Modes • Instrument is acquiring data • Invalid science data • Safing Modes • Instrument in HW Safe or OFF

  18. Gamma-ray Large Area Space Telescope Cost and Schedule Summary

  19. Budget, Cost, Performance

  20. Cost/Schedule Status • Status as of March 31, 2003:

  21. CCB Actions Affecting 4.1.B

  22. Procurements • Long-Lead Procurements • Major Upcoming Procurements Near-Term (< 4 months) • none • Major Upcoming Procurements Long-Term (>4 months) • IOC Facility Procurements • Servers, Workstations, Peripherals • Test Equipment • Minor Upcoming Procurements • none

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