Transcript Mechanical/Thermal

GLAST LAT Project
Mechanical Systems
Mechanical Systems
November 2003 GSFC Status
Marc Campell, Subsystem Manager
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GLAST LAT Project
Mechanical Systems
Accomplishments
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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.
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GLAST LAT Project
Mechanical Systems
Accomplishments (Cont.)
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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.
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GLAST LAT Project
Mechanical Systems
3 Month Milestones Dec - Feb
Milestone Description
Grid Box detailed stress analysis
(Combined with below)
Deliver 1 x 4 Grid to I&T
Original
Date
08/03/03
09/03/03
Grid MRR
09/12/03
Radiator MRR
09/03/03
X-LAT Plate MRR
Current
Date Major Reqmnts to Achieve Milestone
12/17/03 Final approved analysis report memo released.
Notes
Analysis complete.
Final report due 11/21/03
Jan 04 Complete 1x4 testing - static load test.
Complete less report.
Modify Top Flange & cable chaseways
Complete
Drill TRK interface after test.
Pending resloution ofTKR-Grid
interface design mods
12/18/03 Award 4X4 Grid contract.
Contract awarded 7/29
Close open items list - Grid dwg released, Grid TRK IDD, QE ECD 11/14/2003
plan
Grid Box Design Review complete
Complete 10/23/03
12/16/03 Spec & IDD complete and released to LM.
Spec released 10/15/03
LM 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 this
LM needs Sh 4 of Rad IDD to complete heater & sensor
could proceed without this
installation dwg
Radiator integration study
Verify design can be integrated as is.
Feb 04
Release of X-LAT Plate IDD
LM complete design
LM complete analysis
Draft out for review ECD Jan 04
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GLAST LAT Project
Mechanical Systems
3 Month Milestones (cont)
Milestone Description
Grid Assembly MGSE
Grid Assembly #1 Operations complete
Order TCS flight hardware
Original Current
Date
Date Major Reqmnts to Achieve Milestone
04/06/04 04/06/04 define TRK interface requirements
release Top Assy dwgs
design MGSE
Procure MGSE
04/20/04 04/20/04 Top assy drawings released
Order misc hardware
Write Assy plans & procedures
REC Grid #1 need date is 3/30/04
Update of LAT instrumentation plan
Determine qual+ flight+spares qty for each component
Get parts approved on EEE parts list
Notes
in work
in work
ECD 2/4/04
ECD 4/6/04
in work
after drawing release
ECD 1/15/04
Late start
Spreadsheet updated
Gunther?
Complete
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GLAST LAT Project
Mechanical Systems
Issues & Concerns
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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
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GLAST LAT Project
Mechanical Systems
Open Flight Design Issues
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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.
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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
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GLAST LAT Project
Mechanical Systems
Open Flight Design Issues (Cont)
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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
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GLAST LAT Project
Mechanical Systems
Schedule
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Budgeted Cost Work Scheduled
Budgeted Cost Work performed
Schedule Variance
$6.276M
$6.236M
$40K
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GLAST LAT Project
Mechanical Systems
MECH Critical Path
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GLAST LAT Project
Mechanical Systems
MECH Critical Path (Cont)
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GLAST LAT Project
Mechanical Systems
Program Threats
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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
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