GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section GLAST Large Area Telescope: Instrument Science Operations Center WBS: 4.1.B Critical Design Review Outline & Agenda Bill Craig Stanford Linear Accelerator Center Gamma-ray Large Area Space Telescope

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Outline  Overview of Technical Approach & Objectives  Requirements  Detailed Design  Ops Scenarios  Tools and Architecture  Build Process & Schedule  Management, Cost and Risks

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Agenda 8:30Introduction and committee charge (Rackley) 8:351.Overview (Craig) 9:102. Requirements (Martin) 9:353.1Commanding, Health and Safety Design (Bator) 10:103.2Flight S/W and Testbed Design (Fisher) 10:40Break and optional tour of LAT testbed 11:003.3Performance Verification & Optimization Design (do Couto e Silva) 11:303.4Science Data Products and Science Analysis Software (Dubois) 12:00Lunch Break 12:404.1Ops planning and interfaces (Bator Digel) 13:00 4.2Ops Scenarios (Bator) 13:305.Software Architecture (Culp) 14:306.Network and H/W architecture (Dubois) 14:457.RFA Status (Bator) 15:00Break 15:158.Management, Cost Schedule & Risks (Craig/Martin) 15:30Agenda Schedule Reserve/General Discussion of Remaining Issues 16:00Committee executive session 16:30Adjourn

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Overview: Technical Approach & Objectives Bill Craig Stanford Linear Accelerator Center Gamma-ray Large Area Space Telescope

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Review History  IOC Peer Design ReviewAugust 2001  LAT PDR/Baseline Review January 2002  Delta PDR/Baseline ReviewJuly 2002  LAT CDR/CD3May 2003  ISOC Peer Review (PDR)March 2004

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Review Purposes  At the 1 st ISOC Peer Review (March ‘04) a number of RFA’s were generated, primarily …..  The purpose of this peer review is to establish that the ISOC design is at a CDR-level: The detailed design — including schedule — is largely in place.  The Ground System Design Review (8/18-19) will build on the individual peer reviews of the ground system elements and interfaces between those elements.  The materials for this review may be found at: Ground system RFAs may be issued by the peer review panel and GLAST-related personnel in attendance, specifically for LAT ISOC areas.

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section The GLAST Mission LAT GBM-BGO GBM-NaI LAT (> 100 MeV, 1year)

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section GLAST Instruments, Spacecraft  Gamma-ray Large Area Space Telescope (GLAST) — successor to CGRO instruments EGRET and BATSE.  The Large Area Telescope (LAT) — GLAST’s main instrument The LAT is a NASA-DOE collaboration with foreign contributions. PI: Peter Michelson (Stanford & SLAC)  The GLAST Burst Monitor (GBM) — GRB context instrument The GBM is a MSFC-German collaboration. PI: Chip Meegan (NSSTC)  Spacecraft will be built by Spectrum-Astro.  Scheduled launch is February 2007, into low earth orbit.  Minimum mission is 5 years, with a goal of 10+ years!

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Large Area Telescope (LAT) Calorimeter—CsI logs Tracker—tungsten and silicon strip planes Anticoincidence Detector The LAT is a pair conversion telescope. –A  -ray is converted to an e + e - pair in one of 16 tungsten planes. –The leptons are tracked by 19 pairs (X-Y) of silicon strip planes. –The silicon strips and 8 planes of CsI “logs” measure the energy. –Plastic anti-coincidence scintillator tiles provide first line of defense against charged particles.

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section LAT Performance Characteristics  Energy Range: 300 GeV   E/E < 10% on axis for 0.1–10 GeV.  Peak effective area ~ cm 2  FOV ~ 2.4 sr (½ peak A eff at 52  off axis)  1  angular resolution < 0.1 GeV, < 10 GeV  Only a few events of the ~ 300 s -1 events telemetered to Earth will be photons.  Deadtime: ~ 20  s  In normal, scanning operation GLAST will survey the sky; thus most data will be taken at different angles to the LAT. Large field of view and large effective area mean that the LAT will be > 30  more sensitive than EGRET.

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section LAT & GBM Spectral Coverage, FOV LAT FOV GBM FOV

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Observations  GLAST can point “anytime, anywhere:” – The orientation of the Sun relative to solar panels and radiators is a physical constraint, but does not affect pointing flexibility. – Observing efficiency dictates keeping the Earth out of the central part of the field-of-view (FOV).  Two basic observing modes: – Survey mode—the LAT scans the sky continuously. For uniform exposure over short time periods, the spacecraft will rock every orbit ~ 30º about the zenith direction perpendicular to the orbital plane. – Pointed mode—the LAT points at a source. Also, the LAT may point autonomously, e.g. in response to a GRB alert.  The LAT FOV is very large and source fluxes are low. Therefore, survey mode will usually be the most efficient mode to build up exposure over the sky.

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Data Levels  Level 0—the cleaned-up telemetry: packets are time-ordered; repeated packets are removed; packet accounting information recorded  Level 1—data processed by the instrument teams and ready for astrophysical analysis. LAT events are calibrated, reconstructed, characterized as photon/non-photon, and described physically {energy, arrival time, origin, …}.  Level 2—results of routine data analysis, e.g., timing analysis and spectral fits.  Level 3—compendia of Level 2 data, e.g., catalogs.  Ancillary data—the astrophysical analysis will require, e.g., a model of the diffuse background, and a database of pulsar ephemerides.

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Mission Phases  The mission has 3 phases: – Phase 0—the ~ 60 day checkout period after launch – Phase 1—the 1 year sky survey while instrument teams calibrate their instruments. Except for observations of transients, the data are restricted to the instrument teams and a small number of guest investigators. – Phase 2—the rest of the mission until deorbit. The GI program drives the observations; however, simulations predicate that survey mode is still expected to predominate.  Yearly GI cycles; Cycle 1 will coincide with Phase 1. – Cycle 1: approximately one dozen GIs will be selected. – Subsequent cycles: approximately 100 GIs per cycle.

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section LAT ISOC’s Role in the GLAST GDS

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section LAT ISOC View of Ground System

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Objectives  The LAT ISOC consists of several functional elements within WBS 4.1.B, and science data products and science analysis software produced under WBS 4.1.D (the SAS) all organized to safely operate the instrument and produce the LAT’s science data products.  Functions: –Maintain and modify FSW and testbed –Command generation, health and safety monitoring –Performance verification and optimization –Process and archive Level 1 and Level 2 data –Develop and optimize the software pipeline that produces the higher level products  These functions are organized as teams that share personnel

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Commanding, Health and Safety  The Commanding, Health and Safety (CHS) team is responsible for: –generation and validation of commands and command sequences, –passing commands on to the GSSC, –verifying these commands were executed, –receiving Level 0 data from the MOC, –logging and archiving of all commands and Level 0 data, –monitoring that data to ascertain and track the health and safety of the instrument, –continuous knowledge of the configuration of the LAT.

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Flight Software  The Flight Software (FSW) team is responsible for: –Updating and validation of all flight software files, –Debug or problem fixes to the FSW, –Implementation, and validation on the instrument test bed of authorized upgrades to FSW, –Continuing maintenance of the instrument test bed to ensure it is available to validate code and command sequences as well as to investigate any anomalies seen on orbit

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Performance Verification and Optimization  The Performance Validation and Optimization team (PVO) is responsible for: –instrument calibration from low level through IRFs, –continuous monitoring of the LAT science performance, identification of instrument performance trends and resolution of anomalies, –generation and initial validation of algorithms that improve on-orbit performance of the LAT, –management of test and calibration data collected pre- launch. –Configuration and maintenance of the LAT reference geometry and the LAT Monte Carlo Model.

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Science Products  The Science Products Team is responsible for –Generation, archiving and distribution of the Level 1 data, –Generation, archiving and distribution of specific Level 2 data needed for reference, –Transient source detection, –Configuration control over all pipeline code and generated data sets.

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Science Analysis Software  The Science Analysis Software Team is responsible for –Development and maintenance of the pipeline machinery –Development and maintenance of the simulation, reconstruction and event classification software –Development and maintenance of the calibration algorithms, including low level and Instrument Response Functions –Development and maintenance of the quicklook transient analyses –Development and maintenance of the high-level diagnostics derived from reconstruction and classification –Development and maintenance of the high-level analysis tools –“Help desk” support of ISOC staff

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section ISOC Organization Documentation

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section ISOC Organization Changes Since PDR  LOF, SOG, SAS structure refined –Eliminates barriers between functions, personnel will be shared amongst the functions –Reduces segregation between scientists and engineers implied by LOF/SOG structure.  All requirements are written for the ISOC, not pushed down to the functional units.  Craig has been holding ISOC manager position, Cameron will take over on Aug 16 th. Lung was holding deputy position; Martin now holds that position, assisted by Lung.  Overall LAT organization change now has ISOC reporting to Drell as deputy project manager.

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section LAT ISOC Major Changes Since 1 st Peer Review  New architecture (e.g. use of ITOS)  Revised requirements (significant help from GSFC)  Rewritten operations plan reflects new requirements and organization.  Staffing and cost plan in place  Staff additions (Craig, Culp, Martin, Steele, Lemon)

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section RFAs (1/2) No.RFA SummaryRequestorActioneeStatus 1Need ISOC Management Plan & ApproachR. SchweissW. CraigClosed 8/02 2Need overall functional block diagram illustrating the functional capabilities and data flow during various phases R. SchweissL. BatorClosed 7/15 3Risk AnalysisR. SchweissW. CraigClosed 6/9 4Reschedule ISOC CDRM. Rackley/ C. Young D. LungClosed 6/9 5Level III requirements for the LOF and SOG are not completeM. RackleyL. BatorClosed 7/19 6Staffing plan and profileM. Rackley/ C. Young W. Craig/ D. Lung Closed 7/26 7Define the ISOC reports for internal use and external useM. RackleyL. BatorClosed 7/28 8The ISOC does not yet know what system it is using to process Observatory HSK data or perform the commanding M. RackleyL. BatorClosed 6/24 9Describe lesson learned & approachM. RackleyW. CraigClosed 6/9 10ISOC verification does not involve early opportunities to validate/test using LAT instrument M. Rackley/ N. Johnson L. Bator Closed 8/2

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section RFAs (2/2) No.RFA SummaryRequestorActioneeStatus 11Verify LAT modesM. DavisL. Bator W. Craig J. Martin Submitted 12Understand the number of writes to EEPROMC. YoungL. BatorClosed 8/02 13ISOC detailed development scheduleK. LehtonenW. Craig S. Culp Closed 8/02 14Enter a more formal agreement with SLAC management on required data storage and processing requirements N. JohnsonW. CraigClosed 7/15 15ISOC organization structure & communicationsN. JohnsonJ. MartinClosed 7/19 16Define mechanism for ISOC requirements being placed on I&T and SAS N. JohnsonJ. MartinClosed 7/19 17Define LOF/SOG toolsR. CorbetL. Bator S. Culp Closed 8/03 18Specify plans and requirements for automation of Ops softwareR. Corbet/ M. Rackley L. Bator S. Culp Closed 8/03 19Specify plans and requirements for Ops SW to be of sufficient robustness R. CorbetS. Culp Closed 8/03 20Specify what other ground system elements will be involved in LAT operations R. CorbetW. Craig L. Bator Closed 8/02

GLAST LAT ProjectISOC CDR, 4 August 2004 LAT-PR-04500Section Summary  Major changes since March peer review  Architecture in place –Based largely on existing tools –Tools mapped directly to requirements  Planning ISOC verification with Test Bed and 3 demos prior to first Ground Readiness Test  Ready to build, first software release is in April 2005.