1

GLAST LAT Project

Mechanical Systems

Mechanical Systems Mechanical Systems November 2003 GSFC StatusNovember 2003 GSFC Status

Marc Campell, Subsystem Manager

2

GLAST LAT Project

Mechanical Systems AccomplishmentsAccomplishments• Accomplishments during November/December

– Heat treatment and straightening of Grid #1 complete. Heat treat samples tested and exceed all requirements.

– Billet #2 ultrasonic inspected (no flaws) and shipped to Tapemation for storage.

– Grid Spacecraft insert and Grid-CAL insert EM strength testing complete.

– Released 33 of 35 Mech drawings for Grid Manufacturing package. All model changes have been made to the Grid drawing – awaiting final approval for release.

– Grid Box Top Assembly drawings 1st draft complete.– Closed 20 open issues in preparation of Grid MRR on 12/18– Issued Rev 2 of Grid Machining SOW to Tapemation.– X-LAT Plate design review held. Design approach approved.– CCB approved MECH mass increase.

3

GLAST LAT Project

Mechanical Systems Accomplishments (Cont.)Accomplishments (Cont.)• Accomplishments during November/December

– Supported LM preparations for Radiator MRR 12/16– Downspout and Top Flange Heat Pipes complete. Awaiting SLAC

buyoff (Jan 04).– Radiator Acoustic analysis with LAT model complete. Loads are

about the same and will not impact design.– Radiator insert and spool testing completed.

4

GLAST LAT Project

Mechanical Systems 3 Month Milestones Dec - Feb3 Month Milestones Dec - FebMilestone Description

Original Date

Current Date Major Reqmnts to Achieve Milestone Notes

Grid Box detailed stress analysis(Combined with below)

08/03/03 12/17/03 Final approved analysis report memo released. Analysis complete.Final report due 11/21/03

Complete 1x4 testing - static load test. Complete less report.Modify Top Flange & cable chaseways CompleteDrill TRK interface after test. Pending resloution ofTKR-Grid

interface design modsAward 4X4 Grid contract. Contract awarded 7/29Close open items list - Grid dwg released, Grid TRK IDD, QE plan

ECD 11/14/2003

Grid Box Design Review complete Complete 10/23/03Spec & IDD complete and released to LM. Spec released 10/15/03LM complete Radiator TCS & mechanical designs. LM finalizing design w/ VCHP

overtemp thermostat for redundant power

Close RFA on weld X-rays Kennedy has safety issue. EEE parts list approved. LM parts need to be submitted for

approval. Vendor test of thermostats is an issue.

Radiator stress analyses complete. Acoustic analysis being re-done with our FEM inputs ECD 12/12/03

LM complete MLI blanket drawings could proceed without thisLM needs Sh 4 of Rad IDD to complete heater & sensor installation dwg

could proceed without this

Radiator integration study Verify design can be integrated as is.

X-LAT Plate MRR Feb 04 Release of X-LAT Plate IDD Draft out for review ECD Jan 04LM complete designLM complete analysis

Radiator MRR 09/03/03 12/16/03

Grid MRR 09/12/03 12/18/03

Deliver 1 x 4 Grid to I&T 09/03/03 Jan 04

5

GLAST LAT Project

Mechanical Systems 3 Month Milestones (cont)3 Month Milestones (cont)

Milestone DescriptionOriginal

DateCurrent

Date Major Reqmnts to Achieve Milestone NotesGrid Assembly MGSE 04/06/04 04/06/04 define TRK interface requirements

release Top Assy dwgsdesign MGSEProcure MGSE

in workin workECD 2/4/04ECD 4/6/04

Top assy drawings released in workOrder misc hardware after drawing releaseWrite Assy plans & procedures ECD 1/15/04 REC Grid #1 need date is 3/30/04 Late startUpdate of LAT instrumentation plan Spreadsheet updatedDetermine qual+ flight+spares qty for each component Gunther?Get parts approved on EEE parts list Complete

Order TCS flight hardware

Grid Assembly #1 Operations complete 04/20/04 04/20/04

6

GLAST LAT Project

Mechanical Systems Issues & ConcernsIssues & Concerns• Close last remaining issues prior to the start of detailed machining of the

grid – need successful MRR.• Grid to I&T delivery date – schedule continues to compress.• To maintain schedule Grid Box Assy tests are being performed on Grid

#2 after start of I&T or deleted. This increases risk.• X-LAT plate & Radiator delivery schedule due to late starts.• 1 x 4 Grid delivery date to I&T.

– Need to resolve and implement modified Grid – TRK interface

7

GLAST LAT Project

Mechanical Systems Open Flight Design IssuesOpen Flight Design Issues• Grid-TRK interface - define Grid datum & TRK tooling interface

– Working group in progress• RFA’s closure

– Working with Pat Hascall & Bernie Graf• Radiator integration sequence

– Study underway – drawing analysis indicates feasibility.• Radiator VCHP Helium leak rate may impact ACD PMT’s

– How to evaluate the impact in a timely manner (dispersion analysis)– LM can substitute another inert gas, but it impacts ground

performance (not on-orbit).– LM ready to start VCHP’s now.

• Heat leak from Grid to Radiator may exceed values used in LAT thermal analysis. In analysis, a Ti Radiator Mount Bracket (RMB) was assumed instead of Alum.– Re-run thermal model to determine impacts to Grid heater power. 2

options if it is a problem• Allocate more heater power for Grid• Reduce thermal isolator size & re-analyze Radiator loads

8

GLAST LAT Project

Mechanical Systems Open Flight Design Issues (Cont)Open Flight Design Issues (Cont)• TCS – location of Grid heaters, thermostats, RTD’s and associated

wiring needs to be resolved• Define GBA Static Load test requirements & plans

– Prelim plan presented at Peer Review• LAT integration sequence affects MECH drawing tree & testing

– DSHP’s & all EMI Skirts may be removed at start of I&T

9

GLAST LAT Project

Mechanical Systems ScheduleSchedule• Budgeted Cost Work Scheduled $6.276M• Budgeted Cost Work performed $6.236M• Schedule Variance $40K

10

GLAST LAT Project

Mechanical Systems MECH Critical PathMECH Critical Path

11

GLAST LAT Project

Mechanical Systems MECH Critical Path (Cont)MECH Critical Path (Cont)

12

GLAST LAT Project

Mechanical Systems Program ThreatsProgram Threats• Top 6 threats to maintaining schedule

– Highly compressed, success oriented schedule– Interdependencies on other Subsystems– Manpower availability (Engr’s & Tech’s)– Closure of open items for Grid manufacturing– EM tests and flight designs are being performed in parallel –

increases impact of any EM test failure– LM does not get their requested information in a timely manner

• Top 3 threats to staying within cost– Interdependencies on other Subsystems– TCS costs

• Prototype may require PDU, SIU & GASU boards• Much of work being performed by ELEC

– EM program taking longer than budgeted