1. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 1 GLAST Large Area Telescope: IOC Subsystems WBS: 4.1.B David Lung Stanford Linear Accelerator Center IOC Subsystem Manager dlung@slac.stanford.edu Gamma-ray Large Area Space Telescope

2. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 2 Topics IOC Overview –Key Events –Interfaces –Requirement flow –Data path –Commanding path LAT Operations –Launch and turn on –A day in life

3. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 3 IOC Overview Gamma-ray Large Area Space Telescope

4. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 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. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 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. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 6 IOC Functional Architecture

7. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 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. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 8 Ground Operations – Commanding Path 2 Kbps Ground Network Command Rate

9. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 9 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. Command & Telemetry Database

10. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 10 Requirement Flow Changes since PDR

11. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 11 LAT Operations Gamma-ray Large Area Space Telescope

12. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 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. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 13 LAT Analog Telemetry

14. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 14 LAT Turn On State Diagram

15. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 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. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 16 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 A Day In Life of LAT Typical Contact Schedule for a 24 hour period (Example is Malindi)

17. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 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. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 18 Cost and Schedule Summary Gamma-ray Large Area Space Telescope

19. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 19 Budget, Cost, Performance

20. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 20 Cost/Schedule Status ItemIn k$ Budget at Complete2,512 Budgeted Cost of Work Scheduled (a)542 Budgeted Cost of Work Performed (b)486 Actual Cost of Work Performed262 Cost Variance22446.1% of (b) Schedule Variance-56-10.3% of (a) Status as of March 31, 2003:

21. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 21 CCB Actions Affecting 4.1.B Change Request #DescriptionStatus LAT-XR-01752-02SLAC/HEPL Labor Escalation Rates Approved -$40K

22. GLAST LAT ProjectCDR/CD-3 Review May 12-16, 2003 Document: LAT-PR-01967 Section 5 IOC Subsystem 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