PSR Section 8

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Section 8 Mechanical
. . . Pete Alea Swales Aerospace
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Topics

• Satellite Changes since Pre-Environmental Review
• Current Mechanical Configuration
• Verification
• Vibro-Acoustic Testing
• Post Environmental Testing
• Alignment Check
• Solar Array Deployment
• Loads Assessment
• Mass Properties
• Issues
• Bay 4 Panel Replacement
• AST rework and vibration test
• Hyperion Connector Jackpost Rework

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Satellite Changes since PER

• Completed sub-system integration prior to
  vibro-acoustic testing
• WARP
• ACI Optics module and electronics
• Flight Hyperion Instrument Electronics
• Star Tracker
• XPAA S-Band Antenna
• Thermal Louver
• Installed inserts into Bay 1 panel for WARP
  Star Tracker filter boxes
• Mass mockups of the calorimeters were used during
  the environmental test program. Swales/GSFC
  flight calorimeters will be added to the exterior
  of the Bay 4 equipment panel on December 18, 1999

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Current Mechanical Configuration

• As of 11/18/99, the following components have
  been de-integrated
• LFSA (returned to LM for rework) Thermal Louver
  (removed for flight battery integration)

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Configuration Status
EO-1 Satellite in Clean tent at GSFC
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Vibro-Acoustic Verification

• Satellite environmental testing was performed in
  accordance with the following plans procedures
• Modal Test SAI-PLAN-341
• Shock Test SAI-PLAN-341 SAI-PROC-739
• Vibration Test SAI-PLAN-307 SAI-PROC-739
• Acoustic Test SAI-PLAN-320
• Mass Properties SAI-PLAN-319 (Test planned for
  February 10, 2000)

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Shock Test Overview

• Two shock tests were conducted by lifting the
  satellite and TPAF approx. 3 and dropping the
  TPAF onto a foam pad
• No major deviation to the satellite shock test
  plan or procedure was required
• Launch vehicle contractor performed all clampband
  operations including installation of pyrotechnic
  devices

EO-1 Satellite Prior to Clampband Release
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Shock Test Results Summary

• The source shock level was measured to be approx
  1200 gs at the separation plane accelerometer
• Shock response levels were generally below the
  max level specified in the EO-1 Verification Plan
  and Environmental Specification (SAI-SPEC-158)
• Some exceedances were recorded on the nadir deck
  at the base of the ALI pallet. No impact to
  sub-system function or performance has been
  observed.

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Vibration Test Overview
X-Axis Configuration
Y-Axis Configuration
Z-Axis Configuration

• The sine vibration test was conducted in three
  axes. The satellite was subjected to protoflight
  sine levels 1.25 time maximum expected flight
  loads.
• The X Y-axes test was performed on the C220
  lateral slip table and the Z-axis test on the
  exciter in the vertical configuration with the
  use of a head expander
• The MAP Spacecraft vibration test fixture was
  used for this test along with the six force
  response transducers.

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Test Limit Accelerations

• Pre-Test analysis was performed to determine the
  correlation between the S/C the instrument CG
  response accelerations and the corresponding
  pre-selected measurement location
• These levels were used during the test to
  limit/notch the test input levels

Limiting Response Accelerations
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Vibration Test Specification
Pre-Test Unnotched Specification
Post-Test Notched Specification
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Vibration Test Response Summary
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Vibration Test Results

• Test results are documented in Swales/EO-1 Test
  Summary Report (EO1-TSR-027) and the Vibration
  Facility Report ATAC-23-15-0821
• Unexpected satellite dynamic response was
  observed during the vibration test. Pre-test
  predictions of the fundamental frequencies were
  16.8 17.9 Hz for the Y X axes bending modes.
  Testing showed the frequencies to be 21.8 23.9
  for Y X axes respectively.
• This discrepancy was traced to the boundary
  conditions assumed between the conical transition
  adapter and zenith deck. The pre-test model
  assumed pinned boundary conditions for the bolted
  flange at the interface. In reality, this
  preloaded flange acts more like a clamped joint.
  When the model was changed to a clamped boundary
  condition, the fundamental frequencies increased
  to 20.4 Hz and 22.6 Hz for the Y and X axes -
  which is within 6 of the test frequencies.

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Vibration Test Results (continued)

• Another lateral mode of interest, a local
  Y-axis/theta-X mode of the Hyperion instrument,
  was predicted at 36.5 Hz with the pre-test model.
  During Y-axis testing, this mode occurred at
  42.5 Hz. When the boundary condition change
  discussed previously was made to the model, the
  analytical frequency increased to 38.1 Hz, which
  is now just 10 lower than the test frequency.
• For the thrust axis, no axial mode of the
  spacecraft was predicted below 50 Hz. This was
  verified by the thrust axis testing which showed
  no significant axial responses below 50 Hz.

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Vibration Test Conclusions

• All the objectives of the test program were meet
• Satellite aliveness test were performed at
  various times between axes with no major problems
  observed

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Acoustic Test Overview

• The acoustic test was performed on the integrated
  satellite in the GSFC acoustic test facility in
  Building 10
• The satellite was lifted off the transportation
  dolly and raised into the center of the
  microphones acoustic field
• No deviation to the satellite acoustic test plan
  was required

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Acoustic Test Levels
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Acoustic Test Response Summary
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Acoustic Test Results

• Test results are documented in Swales/EO-1 Test
  Summary Report (EO1-TSR-028) and the Acoustic
  Facility Test Report ATAC-21-07-1116
• Desired test levels were achieved. Minor
  deviation in the higher frequencies acceptable
• Highest measured response were recorded on the
  solar array panels
• The post acoustic test solar array deployment was
  nominal
• Satellite aliveness test was performed at the
  completion of the acoustic test with no major
  problems observed
• All objectives of the test program were met

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Pre/Post Environment Alignment Verification

• Baseline alignment measurements were performed
  after all flight components were installed and
  prior to the start of environment testing
• Alignment measurements were recorded for the IRU
  and star tracker w/r to the ACI Optical Cube
• Post environment measurements were made to verify
  that component alignment was maintained

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Flight Load Verification

• Final flight loads analysis was completed by the
  launch vehicle contractor on 10/14/99
• The side table compares the VLA loads to the
  previous coupled loads analysis 
• The instrument and spacecraft loads are enveloped
  by the previous CLA
• There were some local accelerations of components
  that are slightly higher in this load cycle, but
  are not considered significant

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Satellite Mass Properties Summary

• Subsystem weight were measured prior to
  installation on the satellite the solid model
  is updated based on latest measured weights
• Inertia properties are calculated from solid
  model
• Final satellite mass will be within flight
  allocation
• Allocation 588 Kg
• Projection 573 Kg

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Satellite Mass Properties Plan

• The satellite mass properties test plan,
  SAI-PLAN-319, has been created to provide the
  facility test requirements
• The satellite center of gravity in the X-Y plane
  and the moment of inertia about the Z-axis will
  be measured and compared to the prediction from
  the CAD solid model
• The test will be preformed on the Miller Mass
  Properties Table in Building 15 on February 10,
  2000
• The satellite will be placed on the Thermal
  Vacuum Test fixture with the clampband installed

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Mechanical Alignment Plan

• Satellite ground alignment plan (SAI-PLAN-206)
  established system requirements
• ALI ACI Optics Module has been co-aligned to
  within 2 arc-mins. The ACI OM was pinned to the
  satellite nadir deck
• The following alignment measurements have been
  performed, at Swales, to establish the spacecraft
  primary reference frame
• S/C MRC to S/C datums
• S/C SRC to MRC
• IRU SRC will be mapped to the S/C MRC star
  tracker reference cube, at the launch site
• ALI HSA reference cubes will be mapped to the
  S/C MRC

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Issues

• None ! Currently there are no open mechanical
  problem reports!
• No residual risk items remain for the satellite
  mechanical system
• We are ready to ship !