# Presentation: 115247

## GLAST Large Area Telescope:

**GLAST Large Area Telescope:**
**Status Report to SEUS**
**Steven Ritz**
**Goddard Space Flight Center**
**GLAST Deputy Project Scientist and **
**LAT Instrument Scientist**
**ritz@milkyway.gsfc.nasa.gov**

**see**** http://glast.gsfc.nasa.gov**
- and http://www-glast.slac.stanford.edu 	(LAT)
- http://gammaray.msfc.nasa.gov/gbm 	(GBM)
- http://glast.sonoma.edu                     	(E/PO)

**Notes:**
Ormes, Citrin at GBM PDR

## GLAST Science

**GLAST will do great science, with a very broad menu that includes:**
**Systems with supermassive black holes**
**Gamma-ray bursts (GRBs)**
**Origin of Cosmic Rays**
**Probing the era of galaxy formation**
**Discovery! (Particle dark matter?  Other relics from the Big Bang? Testing Lorentz invariance.  New source classes.)**

**GLAST connects the High Energy Particle Physics and High Energy Astrophysics communities.**

**Factor 30-100 improvement in sensitivity for E******** >100 MeV, with huge FOV (20% of the sky).**

## Sources

**EGRET 3****rd**** Catalog: 271 sources**

**Sources**

## Sources

**LAT 1****st**** Catalog: **
**>9000 sources possible**

**Notes:**
say EGRET in ~day-timescale

## Unidentified Sources

- _172 of the 271 sources in the EGRET 3__rd__ catalog are “unidentified”_

- Cygnus region (15x15 deg)

**Unidentified Sources**

- EGRET source position error circles are ~0.5°, resulting in counterpart confusion.
- GLAST will provide much more accurate positions, with ~30 arcsec - ~5 arcmin localizations, depending on brightness.

**Notes:**
L=17, b=-13, 20-30x10^-8, weakest egret sources will be localized with <arcminute precision (assumptions about spectra)

## Outline

**Project**
** ****Science Working Group/IDS’s**
** ****Science Support Center**
** ****Spacecraft procurement**
**E/PO**
**LAT (****20 MeV –  >300 GeV****)**
**GBM (****10 keV – 25 MeV)**
**Summary**

## GLAST Project Master Schedule

**3/31/02**

**ID**

**Task Description**

- 1

- Project Flow

- 2

- LAT Instrument

- 3

- 4

- GBM Instrument

- 5

- 6

- Ground System

- 7

- DLV Launch Services

- 8

- 9

- 10

- Education & Public Outreach

- 11

- 12

- 13

- 14

- 15

- 16

- 17

- 18

- 19

- 20

- 21

- 22

- 23

- 1

- 1998

- 1999

- 2001

- 2002

- 2003

- 2004

- 2006

- Project Milestones

- Spacecraft

- Rev 5 – 01/31/02

- 1997

- 2000

- 2005

- 2

- 3

- 4

- 1

- 2

- 3

- 4

- 1

- 2

- 3

- 4

- 1

- 2

- 3

- 4

- 1

- 2

- 3

- 4

- 1

- 2

- 3

- 4

- 1

- 2

- 3

- 4

- 1

- 2

- 3

- 4

- 1

- 2

- 3

- 4

- 1

- 2

- 3

- 4

- Project Phasing

- Implementation

- Phase C/D

- Phase E

- MCR

- SPR

- SRR

- NAR

- Implementation
- Start

- Gamma
- 2001

- PDR

- CDR

- Launch

- LRR &
- FRR

- MOR

- Instrument
- Selection

- Pre-B/L
- Review

- B/L -
- PDR

- CDR

- Instr.
- AO

- Balloon
- Launch

- PER

- PSR

- Instrument
- Delivery

- Instrument
- Selection

- Instr.
- AO

- PDR

- CDR

- PER

- PSR

- Instrument
- Delivery

- RFO

- Spacecraft
- Selection

- PDR

- CDR

- PER

- PSR

- FOR

- SRR

- Advance
- Support

- ATP

- Launch Site
- Integration & Ops

- Launch Vehicle Development

- Software Builds

- S/C Accom Study

- MSI&T

- Design

- Build

- I&T

- S/C Accom
- Study

- Long Lead Procurements

- Independent
- Assessment

- SRR

- GBM/MPE
- TIM

- (S)I&T

- (S)I&T

- EPO
- Contract
- Begin

- Space Mysteries
- Module #1 &
- TOPS #3

- Space Mysteries
- Module #2

- Begin
- Ambassador
- Training

- TOPS
- #1

- TOPS
- #2

- Air PBS
- Special

- MOC
- Peer
- Rvw

- MOC
- PDR

- MOC
- CDR

- MOC
- ORR

- GMSEC
- Decision

- MOC
- RFP

- MOC
- Award

- R4

- R3

- R2

- R1

- I&T and Simulations

- Delta B/L PDR

**Phase A**

**Phase B**

**Long Lead Procurements**

**Preliminary Design**

**Pre-Phase A**

**Formulation**

## Project: Science Working Group

- Chaired by Project Scientist (Jonathan Ormes). Membership includes the Interdisciplinary Scientists and delegates from the instrument teams.
- Having bimonthly telecons and ~biannual sit-down meetings.
- Sit-down meetings have included daylong topical meetings directly involving the various communities: AGN (4/01 Baltimore, adjacent to **GAMMA2001**); Pulsars (12/01 UCSC); Bursts (planned for 9/02 Huntsville).
- Working groups on topics as needed, including observing planning (inputs to spacecraft design) and GRB coordination.
- see http://glast.gsfc.nasa.gov/science/swg/  for meeting minutes and activities
- GLAST science sessions at major conferences.  Suggestions welcome!

**Notes:**
Head Hawaii, Albuquerque, COSPAR

## Project: Science Support Center Accomplishments

- Roles and responsibilities defined at the SSC-IOC interface:** **
- SSC-LAT working group to define suite of science tools, establish software standards, and design key databases
- SSC scientists will participate in developing tools with LAT team
- SSC will have a backup Level 1 pipeline
- Staffing by mid-summer –  Manager, Science Lead,                  3 scientists, 2.5 scientific programmers, webmaster and administrative assistant (fraction of FTE)
- Documents
- PMDP revised
- SSC Functional Requirements Document revised
- Report of GLAST Data Products Working Group (with draft ICDs)
- Detailed WBS under development
- Event database under design

## Project: SSC Near-term Plans

- Staffing
- Documents
- Finish PDMP, SSC Functional Requirements Document
- Develop SSC WBS
- Databases
- Study and model organization of the event & photon databases
- Level 2 Science Tools
- SSC-IOC software working group to define tool suite
- Establish standards, requirements, and deadlines
- SSC scientists part of development groups
- Response functions
- Use of HEASARC CALDB in GLAST framework
- User Committee being formed

## Project: Spacecraft Procurement

- Spacecraft will be procured through the Rapid Spacecraft Development Office (RSDO) as a fixed-price contract.
- Two previous accommodation studies with vendors surfaced many issues and helped sharpen requirements.
- IMDC run (2/02) as a check of the project’s spacecraft baseline concept; useful as a benchmark in the proposal evaluation process.
- Draft RFO released.  Expect final RFO out end of April, selection by mid-summer.

## Project: Personnel

- Project continues to increase staffing as needed, particularly for system engineering (including new system engineer co-located at SLAC).
-  Recent senior personnel changes:
- Project manager: Liz Citrin [previously on MAP] (12/01)
- Deputy project manager: Al Vernacchio (4/02)

## Project: Other Items

- Heavy launch vehicle (Delta 2920H) baselined for purposes of mission planning.
- Observatory c.g. being closely monitored.
- Working to minimize the chance of a premature end to the scientific mission due to presence of deorbit propulsion system.
- Impacts of X-band bandwidth limitation for space sciences missions being accommodated in Ops planning.

## E/PO & PR Programs Summary

- GLAST Ambassadors program: Develop, distribute and field test GLAST material, train other teachers at local and national conferences.  First five Ambassadors chosen, five more positions opening in 2004.  Summer workshop @ SSU: July 02.
- GLAST exhibit booth
- Printed materials
- TOPS Learning Systems (2002-2004)
- Active Galaxies poster now available. Over 3500 distributed so far this year.
-  GLAST EPO flyer part of SEU folders distributed – 10,000 distributed during 2001 teacher’s conferences.
-  About 1000 GLAST Program flyers distributed
- PBS TV Show
- Discussions with Tom Lucas are underway – negotiations ongoing w/ PBS
- Part of SEU Museum Exhibit (“Cosmic Questions”)
- GLAST Video now available on line -- 3000 CDs are being printed
- Science brochure and mission fact sheet; press releases; newsletter articles.
- Telescope network (w/ Mattox, RCT-Kitt Peak, others under discussion)

**Notes:**
Lynn press officer and E/PO lead; Gehrels PR.  connected to SWIFT via Sonoma and joint AAS displays

## Exhibit Booth

-  AAS in DC in January 2002
-  Expanding Your Horizons at SSU in March 2002
-  AAS Albuquerque in June 2002

## LAT Status (PI: Michelson)

- High-altitude balloon flight of prototype LAT tower; achieves all objectives – August 2001
- Flight hardware engineering model development underway
- NASA-DOE agreement _signed_ January 2002!
- Reviews:
- February 2001: first joint NASA-DOE LAT review
- August 2001: joint NASA-DOE interim LAT review
- January 2002: joint NASA-DOE PDR/Baseline review.
- Result: LAT passes PDR “with flying colors”, except thermal subsystem which requires delta-PDR “due to a recently directed change to repackage the radiators to allow a maximum spacecraft diameter, and thus, the maximum number of potential spacecraft vendors to bid for the spacecraft contract.”.  Of the 11 subsystems, 4 were not baselined (ACD, I&T, Mech/Thermal, Calorimeter).  [DOE Baseline review includes a rigorous grassroots cost and schedule review – unusual for NASA projects at this stage.]
- SLAC Director’s review April 16-18.
- Delta PDR/Baseline review June 17-19 2002.

## GLAST LAT Overview: Design

**Si Tracker**
**pitch = 228 μm**
**8.8 10****5**** channels**
**12 layers × 3% X****0**
**+ 4 layers × 18% X****0**
**+ 2 layers**

**Grid (& Thermal Radiators)**

**Flight Hardware & Spares**
**16 Tracker Flight Modules + 2 spares**
**16 Calorimeter Modules + 2 spares**
**1 Flight Anticoincidence Detector**
**Data Acquisition Electronics + Flight Software**

**3000 kg,  650 W (allocation)**
**1.8 m ******** 1.8 m ******** 1.0 m**
**20 MeV – >300 GeV**

**CsI Calorimeter**
**Hodoscopic array**
**8.4 X****0****     8 × 12 bars**
**2.0 × 2.7 × 33.6 cm**

**  ****cosmic-ray rejection **
**  ****shower leakage   **
**     ****correction**

**LAT managed at SLAC**

**Notes:**
MANAGED AT SLAC: tower, France

## LAT Schedule

**GLAST scheduled for launch in March 2006**

## LAT Balloon Flight: Goals

**Validate the basic LAT design at the single tower level.**
**Show the ability to take data in the high isotropic background flux of energetic particles in the balloon environment.**
**Record events for use as a background event data base. **

**Purpose of balloon test flight:  expose prototype LAT tower module to a charged particle environment similar to space environment and accomplish the following objectives:**

**All Objectives met by Balloon Flight on ****August 4, 2001**

## Flight and Operation: Launch on August 4, 2001

**The balloon reached an altitude of 38 km, with a float time of 3 hours.**

**First results (real-time data): trigger rate as a function of atmospheric depth. The trigger rate never exceeded 1.5 KHz, well below the BFEM capability of 6 KHz.**

**Flight and Operation: Launch on August 4, 2001**

- All Subsystems Performed Properly

**background event candidate:**

**gamma event candidate:**

**Notes:**
100K EVENTS TELEMETERED TO GROUND

## LAT Issue: Calorimeter and the CNES Situation

**Background:**
- March 5: CNES technical review recommends “pass” for French technical and management plans
- However, R. Bonneville informs group that CNES funding severely impacted -- can likely only provide 1-2M Euros of planned (~8M Euros) CNES funding; (no previous indication that CNES funding was in jeopardy)
**Actions taken:**
- Letters and phone calls to CNES by IN2P3 and CEA/DSM directors, DOE, NASA, and prominent concerned scientists.
- Commitment obtained from CEA management to push for full restoration from CNES and to maintain efforts on GLAST CAL in the meantime.
- Meeting held on March 21 with CNES DG (Brachet) & Deputy DG (Bonnet) and IN2P3, CEA management and French LAT team leadership:
- Urgency of situation communicated to CNES leadership, support expressed for French participation in GLAST, given French history of scientific work in the field and its importance
- Brachet calls for emergency meeting of CNES Science Policy Committee to consider full restoration of planned CNES commitments
**Emergency meeting of CNES Policy Committee scheduled for April 19**

## GBM (PI: Meegan)

- provides spectra for bursts from 10 keV to 30 MeV, connecting frontier LAT high-energy measurements with more familiar energy domain;
- provides wide sky coverage (8 sr) --  enables autonomous repoint requests for exceptionally bright bursts that occur outside LAT FOV for high-energy afterglow studies (an important question from EGRET);
- provides burst alerts to the ground.

*Simulated GBM and LAT response to time-integrated flux from bright GRB 940217*
*Spectral model parameters from CGRO wide-band fit*
*1 NaI (14 o) and 1 BGO (30 o)*

## GBM Status

- April, 2001: GBM funding included in NASA budget.
- July 27, 2001: Southwest Research Institute selected by MSFC to provide Data Processing Unit.
- Oct. 23, 2001: Jena Optronic selected by MPE to provide detectors and power supplies.
- Feb. 28, 2002: Increase in GBM mass allocation to 85 kg approved.
- March 7, 2002: Increase in GBM power allocation to 65 W approved.
- April 9-11, 2002: GBM PDR
- There are no significant technical or management problems, and no changes to instrument capabilities.

## GBM Collaboration

**University of Alabama**
** ****in Huntsville**

**NASA**
**Marshall Space Flight Center**

**Max-Planck-Institut für **
**extraterrestrische Physik**

**National Space Science & Technology Center**

**Michael Briggs**
**William Paciesas**
**Robert Preece**

**Charles Meegan (PI)**
**Gerald Fishman**
**Chryssa Kouveliotou**

**Giselher Lichti (Co-PI)**
**Andreas von Keinlin**
**Volker Schönfelder**
**Roland Diehl**

*On-board processing, flight software, systems engineering, analysis software, and management*

*Detectors, power supplies, calibration, and analysis software*

## GBM Instrument Design: Major Components

**12 Sodium Iodide (NaI)**
** ****Scintillation Detectors**

**2 Bismuth Germanate (BGO)**
** ****Scintillation Detectors**

**Data Processing**
**Unit (DPU)**

- Characteristics
**5-inch diameter, 0.5-inch thick**
**One 5-inch diameter PMT per Det.**
**Placement to maximize FoV**
**Thin beryllium entrance window**
**Energy range: ~5 keV to 1 MeV**
- Major Purposes
**Provide low-energy spectral coverage in the typical GRB energy regime over a wide FoV**
**Provide rough burst locations over a wide FoV**

- Characteristics
**5-inch diameter, 5-inch thick**
**High-Z, high-density**
**Two 5-inch diameter PMTs per Det.**
**Energy range: ~150 keV to 30 MeV**
- Major Purpose
**Provide high-energy spectral coverage**** to overlap LAT range over a wide FoV**

- Characteristics
**Analog data acquisition electronics for detector signals**
**CPU for data packaging/processing**
- Major Purposes
**Central system for instrument command, control, data processing**
**Flexible burst trigger algorithm(s)**
**Automatic detector/PMT gain control**
**Compute on-board burst locations**
**Issue r/t burst alert messages**

## Summary

- Project:
- Ramping up science preparations (SSC, SWG, Instrument teams)
- Spacecraft procurement process in full swing
- Mission PDR in October
- LAT:
- Successful balloon flight
- Successfully completed PDR, with one delta-PDR/baseline (for Thermal system) scheduled; delta-baseline review for 3 additional subsystems in June.
- NASA-DOE agreement paves the way for remaining international agreements
- CNES funding issue pending
- Building engineering models of flight hardware
- GBM:
- Main vendors selected
- PDR this week
- E/PO:
- vibrant and broad program; cooperation with other missions (e.g., SWIFT)