Review

1
LAT Environmental Test Planning and Design
Review 3-4 May 2005 2.0 Dynamics Tests
John Ku kuj_at_slac.stanford.edu Naval Research
Lab Bldg 226 Rm 113 Call-in number
510-665-5437 Passcode 3992
2
Tue May 3 PM Agenda

• 2.0 Dynamics Tests (John Ku)
• 100 pm 2.1 Sine Vibe
• 100 2.1.1 Test Plan
• 130 2.1.2 Test Configuration
• 200 2.1.3 Test Logistics
• 220 2.1.4 Open Issues
• 230 pm 2.2 Acoustic
• 230 2.2.1 Test Plan
• 300 2.2.2 Test Configuration
• 330 2.2.3 Test Logistics
• 350 2.2.4 Open Issues
• 400 pm 2.3 Weight and CG
• 400 2.3.1 Test Plan
• 410 2.3.2 Test Configuration
• 415 2.3.3 Test Logistics
• 425 2.3.4 Open Issues
• 430 pm 2.4 Open Issues
• To get through these 57 Slides in 4 hours, we
  must average 4.2 minutes/slide

3
Sine Vibration Test Test Plan Overview

• Objectives of the test are well understood by all
• Verify the strength of the LAT and subsystem
  interfaces under PFQ loads and durations
• Measure primary natural frequencies (fn) of the
  primary modes of the LAT
• Determine transmissibility (Q) of the LAT
• Validate the math model used for coupled loads
  analysis
• Verify the workmanship and processes used in the
  manufacture and assembly
• Test Plan
• Third draft of test plan is out for review
  first major update in over a year
• Many technical details have been addressed in
  previous meetings the current draft is very
  mature and should be released in 1-2 weeks
• First comments in from GSFC mechanical branch
  have been minor and already incorporated
• Instrumentation list is nearing completion, but
  not finished yet
• Internal accelerometers defined and CAD layout
  complete
• Strain gauges (16 channels) on flexures defined
  (NRL can accommodate up to 40 channels, ¼ bridge)
  
• External accelerometer mathematical positions
  defined, but CAD layout needed

4
Sine Vibration Test Test Plan Overview

• Test Plan (Continued)
• Entrance/Exit Criteria are well understood by
  all from the test plan
• The sine vibe dynamic test is the first
  environmental test to be performed after arrival
  to NRL and the subsequent CPT. Criteria which
  must be met before this test can be executed are
• LAT mechanical integration is completeall
  visual, dimensional, and torque testing has been
  complete, and all travelers verified to be
  complete. The LAT is in its flight
  configuration, except as detailed in Section 8.3.
• All subsystem units/modules functioneach
  subsystem has passed its CPT following removal
  from the shipping container. Any performance
  discrepancies have been clearly documented.
• Ensure all E-GSE needed is installed and
  functioning. After moving and attaching the LAT
  to the vibration test equipment, ensure each
  subsystem has passed its LPT. All E-GSE cable
  harnesses have been removed from the LAT prior to
  test.
• All test instrumentation is in place and
  functioninginstrumentation has been verified to
  be securely mounted in the correct locations and
  oriented in the correct direction, as defined in
  the test procedure, and electronics are working
  correctly, and reading out signals. Cable
  harnesses for this instrumentation are connected
  and properly restrained for the test
• Pretest analysis which provides predictions for
  Fn and Q for significant modes at all test
  accelerometers
• Following the sine vibration test, an LPT will be
  performed. Prior to breaking test configuration,
  the following criteria must be met
• Visual inspection of the LAT indicates that there
  is no visible damage to the LAT
• Successful completion of the LPT verifies that
  all components and subsystems function properly
  after testing
• Rough analysis of test data shows that all
  recorded data is useable for analysis purposes
• Comparison of pre-test and post-test modal
  signatures match to within 5, or at the
  discretion of the test director, showing that
  modal frequencies have not changed significantly
  as a result of the test.

5
Sine Vibration Test Test Plan Requirements

• Test Requirements
• Instrument Verification Plan
• The tests will be performed to the levels
  published in the LAT environmental specification
  document, LAT-SS-00778
• The dynamics tests are to be performed in the
  mode in which the equipment will observe the
  environment
• LAT will be launched in a powered off mode
• The sine vibration tests will be performed with
  the article powered off

6
Sine Vibration Test Test Configuration

• The LAT is transported and supported on the TIP
• TIP is already installed for all handling before
  and after test
• TIP assembly uses SC flexures from Spectrum
• TIP is designed to simulate SC flexure/top deck
  interface, so it provides a nearly flight-like
  interface for the test
• Interface to both the slip table and expander
  head is by way of a simple bolt pattern that fits
  well with the LAT geometry

X/Y-Axis Vibration Configuration
Z-Axis Vibration Configuration
7
MGSE Requirements Flowing from Sine Vibe Test
Plans

• See the table, below, for a list of all MGSE/STE
  that is needed for conducting the sine vibe test
• Test Interface Plate
• TIP and mounting hardware capable of handling
  inertial loads of LAT during test
• TIP bolt pattern and size compatible with
  expander head and slip table
• TIP plate supported adequately to ensure stiff
  connection to slip table/expander head
• Dust Tent
• Capable of providing clean, dry environment
  before/during/after vibe testing
• Provides clearance around LAT for unrestricted
  motion during vibe
• Capable of being on/off-loaded from GPR to vibe
  table
• Heat Pipe Restraining Plates
• Supports DSHP/XLHP 3-way joints during vibe since
  Radiator VCHPs are not mounted
• Provides flight-like interface to simulate VCHP
  flange
• Chill Bars
• Capable of handling vibration loads (obviates
  need to de-/re-integrate them)

MGSE/STE Needed for Sine Vibe Testing
8
Auxiliary Cooling and Mechanical Handling

• Auxiliary cooling plans
• LAT needs to be cooled during LPTs between each
  vibe axis run and before and after
• Chill Bars one under each of the two X-wings on
  the Grid
• X-LAT Aux Cooling using fly-away cooling lines
  already mounted to X-LAT Plate
• This is room-temperature cooling to remove LAT
  process heat
• To simplify cooling connections, Chill Bars and
  X-LAT cooling will be designed to handle vibe
  loads
• Hoses will be disconnected using quick-disconnect
  fittings
• Handling and mechanical operating procedures
• LAT lifting procedure
• TIP mounting procedure
• Dust tent handling and operating procedure
• LAT auxiliary cooling system operating procedure

9
MGSE Issues for Sine Vibe Testing

• Dust Tent
• This is likely needed for sine vibe, but is still
  TBR
• If needed, how will dust tent be supported off of
  the slip table/expander head around the LAT,
  while the LAT is vibed?
• How do we access the LAT for electrical and aux.
  cooling interconnects before/after vibe testing?
• How is the Dust Tent handled with the LAT
• LAT is transported with the Tent hanging from the
  GPR
• After integration on the slip table, the Tent
  will need to be re-positioned onto the vibe table
  base
• Logistics in the vibe lab
• Space is tight in the vibe lab, and the LAT MGSE
  is large
• We will have 4 large-footprint objects in the lab
  nearly simultaneously
• LAT on the TIP
• GPR
• 4 x 4 Lift Fixture
• MGSE Cart
• Vibe lab also has 2 vibe tables and the expander
  head which will need re-positioning during our
  test
• We will be running through the handling logistics
  with paper dolls, then with the pathfinder, so we
  should be able to catch the problem areas early

10
MGSE Structural Analysis Status

• TIP was analyzed for lift loads and dynamic
  performance (see FEA Mesh shown at left)
• High margins were calculated for both cases
• Rough calculations for the mounting shoes were
  performed, with more detailed analysis to follow
• Conservative hand calculations show high margins
  for strength and stiffness
• Rough calculations for the test stand have been
  performed, wth more detailed analysis to follow
• Concentrated on regions of highest load
• Design is extrememly stout, and calculations show
  corresponding high strength margins

11
MGSE Structural Analysis TIP Lift case

• The TIP is only attached to the mounting shoes by
  16 screws, in a thinned section
• When lifted, how much will the TIP sag from its
  own weight? ? 148 microns (0.6 mils)
• How much stress is imparted from the prying
  loads? ? 3.02 MPa (241 MPa Yield)

12
MGSE Structural Analysis TIP Dynamic
Performance
Calculated First Mode 417 Hz Required
Performance gt225 Hz (1.5150 Hz)
13
MGSE Structural Analysis Mounting Shoes
14
MGSE Structural Analysis Test Stand
Test Interface Plate
LAT
Radiator SC Strut simulators
Test Stand
Radiator
15
Sine Vibration Test Test Plan Constraints

• EGSE Constraints
• Cables
• Disconnected during vibration
• Must be long enough to reach LAT while mounted to
  either expander head or slip table
• Cable trays or protection if laid on floor
• Cart with EGSE Hardware
• Portable, can be rolled out of the way
• Power interface to lab?

16
Sine Vibration Test Test Configuration

• Mechanical Configuration
• Radiators not attached
• By agreement with the GPO, no mass simulators are
  needed
• Mounted to GD/Spectrum Astro-provided test
  flexures
• Test flexures will be proof tested at SLAC prior
  to GRID static test
• TIP to interface test flexures and slip
  table/expander head
• LAT Z-axis is always vertical
• Access to connectors needed (scaffold around
  expander head?) on X side
• Layout needed to check cable run lengths
• Electrical Configuration
• SLAC purchased accelerometers are voltage type
  and have 10-32 connectors, with a special
  proprietary triax connector
• Adapters will be needed to interface with NRL
  equipment
• ACD accelerometer interface to be verified
• Strain gauges do not have connectors (open leads)
• EGSE needed for LPTs between axes (Rich Baun to
  define requirements)

17
Sine Vibration Test Test Configuration
Instrumentation

• Test instrumentation by subsystem, total of 57
  channels, calibrated and installed by SLAC IT,
  final checkout by NRL

18
Sine Vibration Test Test Configuration
Instrumentation
19
Sine Vibration Test Test Configuration
Instrumentation
20
Sine Vibration Test Test Configuration
Instrumentation

• Four strain gauges installed per flexure for a
  total of 16 strain gauge channels
• Assumed to be 120 Ohm, ¼ bridge, GF2
• Strain gauges should be temperature compensated
  if possible
• The gauges and data acquisition equipment should
  be sized to capture a maximum strain of 2500
  microstrain (titanium has a yield strain of 7500
  microstrain) and have a 0.25 precision (6
  microstrain error)
• The combination of strain gauges will allow
  measurement of axial strain and bending strain
• Shear strain will not be directly measured, but
  may be ascertained from the combined strain
  readings of the two legs and pre-test analysis

21
Sine Vibration Test Planning Detailed Sequence

• Pre-test Activities
• Move dolly into position in vibration lab and
  disconnect LAT from dolly (SLAC-IFCT)
• Lift LAT and TIP onto expander head, and torque
  bolts (NRL)
• Cable Hook-ups and system checkouts
• Electrical connections to shaker system and accel
  tap checks (NRL)
• Electrical connections to EGSE and perform LPT on
  expander head (SLAC)
• Z-Axis Vibration Test
• Low-level Signature Sine Sweep to 150 Hz (sweep
  up and down)
• Set-up sheet printouts (NRL), verification and
  approval (SLAC)
• If LPT results are okay, disconnect EGSE cables
• Run test
• Output FRF data (NRL)
• Review Data (SLAC)
• Determine notching, if needed
• Provide feedback to test conductor
• Check pass/fail criteria for Modal Test
  requirement
• Give OK to proceed (SLAC), or decide alternate
  action is needed
• Half-level run to 50 Hz
• Set-up sheet printouts (NRL), verification and
  approval (SLAC)

22
Sine Vibration Test Planning Detailed Sequence
(cont.)

• Z-Axis Vibration Test (continued)
• Full-level run to 50 Hz
• Set-up sheet printouts (NRL), verification and
  approval (SLAC)
• Run test
• Output data hardcopies (NRL)
• Review Data (SLAC)
• Check peak levels
• Check pass/fail criteria for Modal Test
  requirement
• Give OK to proceed (SLAC), or decide alternate
  action is needed
• Low-level Signature Sine Sweep to 150 Hz
• Set-up sheet printouts (NRL), verification and
  approval (SLAC)
• Run test
• Output data overlays (NRL)
• Review Data (SLAC)
• Re-Check pass/fail criteria for Modal Test
  requirement
• Concurrent with data review, hook-up EGSE and
  perform LPT
• If data review and LPT are good, Give OK to break
  configuration, or decide is alternate action is
  needed
• Post- Z-Test / Pre- X-Test Activities
• Disconnect all electrical connections

23
Sine Vibration Test Planning Detailed Sequence
(cont.)

• X-Axis Vibration Test
• Low-level Signature Sine Sweep to 150 Hz
• Same steps as Z-axis test
• Give OK to proceed (SLAC), or decide alternate
  action is needed
• Half-level run to 50 Hz
• Same steps as Z-axis test
• Give OK to proceed (SLAC), or decide alternate
  action is needed
• Full-level run to 50 Hz
• Same steps as Z-axis test
• Give OK to proceed (SLAC), or decide alternate
  action is needed
• Low-level Signature Sine Sweep to 150 Hz
• Same steps as Z-axis test
• Concurrent with data review, hook-up EGSE and
  perform LPT
• If data review and LPT are good, Give OK to break
  configuration, or decide is alternate action is
  needed
• Post- X-Test / Pre- Y-Test Activities
• Disconnect EGSE electrical connections, leaving
  Accel cables connected
• Remove mounting bolts, lift and rotate LAT in
  place
• Lower LAT to slip table and torque bolts
• Perform vibration control system checkout (no
  EGSE hook-up here)

Shaker
Slip Table
Shaker
Slip Table
24
Sine Vibration Test Planning Detailed Sequence
(cont.)

• Y-Axis Vibration Test
• Low-level Signature Sine Sweep to 150 Hz
• Same steps as X-axis test
• Give OK to proceed (SLAC), or decide alternate
  action is needed
• Half-level run to 50 Hz
• Same steps as X-axis test
• Give OK to proceed (SLAC), or decide alternate
  action is needed
• Full-level run to 50 Hz
• Same steps as X-axis test
• Give OK to proceed (SLAC), or decide alternate
  action is needed
• Low-level Signature Sine Sweep to 150 Hz
• Same steps as X-axis test
• Concurrent with data review, hook-up EGSE and
  perform LPT
• If data review and LPT are good, Give OK to break
  configuration, or decide is alternate action is
  needed
• Post- Y-Test Activities
• Disconnect all electrical connections
• Remove mounting bolts, lift and set LAT on
  handling dolly
• Attach LAT to handling dolly

25
Sine Vibration Test Configurations Deviations
From Flight

• The Radiators are not integrated to the LAT for
  this test.
• Structural interactions between the Radiators and
  the Grid are not captured
• This interface will be strength verified at the
  subsystem level
• Coverplates to constrain the down spout heat
  pipes (DSHPs) and X-LAT heat pipes (XLHPs) to
  prevent relative motion to the Grid
• This interface will be strength verified at the
  subsystem level
• The LAT is mounted to STE using test flexures
  which simulate the flight connection to the SC
• The STE and test flexures will be included in the
  pre-test FEA analysis, so its impact on the
  response of the LAT will be understood.
• Since the Radiators and SC are not included in
  this test, not all flight cable harnesses and
  supports will be integrated for this test
• These cables and their associated support
  brackets will not be adequately verified by this
  test
• Workmanship for these flight connections and
  harnesses will be accomplished with the
  Observatory level sine vibration test.

26
Sine Vibration Test Document List and Status

• LAT-MD-00408 LAT Instrument Performance
  Verification Plan
• LAT-MD-02717 LAT Environmental Test Sequence
• LAT-MD-01196 LAT Dynamics Test Plan
• LAT-MD-01533 LAT EGSE Plan
• LAT-MD-00649 LAT Transportation and Handling
  Plan
• LAT-MD-00404 LAT Contamination Control Plan
• LAT-SS-00778 LAT Environmental Spec
• LAT-TD-00890 LAT Instrumentation Plan

27
Sine Vibration Test Test Logistics

• Test Personnel
• Test support personnel have been identified (to
  be verified)
• Test Director John Ku (SLAC)
• Test Conductor Bob Haynes (NRL)
• Discipline Lead Jim Haughton (NRL)
• Facility ManagerBill Raynor (NRL)
• MGSE Lead Martin Nordby (SLAC)
• EGSE Lead Mike Huffer (SLAC)
• Test Script Lead Rich Baun (SLAC)
• High-bay operations Paul Dizon (NRL)
• Quality Assurance Joe Cullinan (or Doug
  Bartholomew) (SLAC)
• IT Ken Fouts (SLAC)
• Subcommittees will be assembled from the
  appropriate personnel above, with expert
  consultation brought in if needed
• Potential Vibration Experts Paul Baird Chris
  Fransen Bill Haile

28
Sine Vibration Test Test Logistics

• Many logistics have already been worked out
  these remain
• Complete and release drawings/model of slip table
  and expander head
• Verify slip table and expander head size, inserts
  and pattern
• Clearance to off-load frame on expander head
• Verify that Test Interface Plate fits completely
  on expander head
• Verify that LAT clears bracket parts on slip
  table
• Develop paper doll work-up to verify we have
  floor space for 2 carts, GPR, and 4x4 Lift
  Fixture
• Lay out EGSE cable routing and locate EGSE crates
• Identify what contamination and humidity control
  is needed in vibe facility
• Is GN2 purge neccesary?
• Cleanliness (need blanket?)
• CG Alignment / sensitivity of equipment to
  offsets (by analysis TBD)
• Instrumentation patch panels and cable supports
  (ensure all connectors interfaces)
• Complete detailed design and analysis of TIP and
  flexure mount brackets (In-process)
• Verify response / control channel capability
  (NRL)
• Contingencies
• Need to be prepared to perform a modal test if
  the LAT frequencies do not meet expectations
• Modal test will not need additional
  instrumentation
• May require the use of portable shaker with
  stinger to RMB or other hardpoint

29
Sine Vibration Test Open Issues

• Complete structural analysis of MSGE
• Complete pre-test analysis, including a
  simulation of LAT on fixtures
• 10 action items are open and being tracked.
• 9 have clear closure paths and are actively being
  worked on
• 1 action not addressed yet is not a high
  priority, as MGSE has not been designed yet

30
Acoustic Test Test Plan Overview

• Objectives of the test are well understood by all
• The objective of the acoustic test is to
  demonstrate that the fully integrated LAT is
  capable of withstanding acoustic noise loads,
  simulating launch conditions.
• A secondary objective is to verify the acoustic
  analysis, i.e. that the LAT components were
  qualified to high enough levels of Random
  vibration
• Test Plan
• Third draft of test plan is out for review
  first major update in over a year
• Many technical details have been addressed in
  previous meetings the current draft is very
  mature and should be released in 1-2 weeks
• First comments in from GSFC mechanical branch
  have been minor and already incorporated
• Instrumentation list is nearing completion, but
  not finished yet
• Internal accelerometers defined and CAD layout
  complete
• Strain gauges (16 channels) on flexures defined
  (NRL can accommodate up to 40 channels, ¼ bridge)
  
• External accelerometer mathematical positions
  defined, but CAD layout needed

31
Acoustic Test Test Plan Overview

• Test Plan (Continued)
• Entrance/Exit Criteria are well understood by
  all from the test plan
• The LAT acoustic test is performed immediately
  following the LAT sine vibe test. Criteria which
  must be met before this test can be executed are
• LAT mechanical integration is completeall
  visual, dimensional, and torque testing has been
  complete, and all travelers verified to be
  complete. The LAT is in its flight
  configuration, except as detailed in Section
  10.3.
• All subsystem units/modules functioneach
  subsystem has passed its CPT following removal
  from the shipping container. Any performance
  discrepancies have been clearly documented.
• Ensure all E-GSE needed is installed and
  functioning. After moving and attaching the LAT
  to the vibration test equipment, ensure each
  subsystem has passed its LPT. All E-GSE cable
  harnesses have been removed from the LAT prior to
  test.
• All test instrumentation is in place and
  functioninginstrumentation has been verified to
  be securely mounted in the correct locations and
  oriented in the correct direction, as defined in
  the test procedure, and electronics are working
  correctly, and reading out signals. Cable
  harnesses for this instrumentation are connected
  and properly restrained for the test.
• Following the acoustic test, an LPT will be
  performed. The criteria for declaring a
  successful completion of the acoustic test are
• Visual inspection of the LATindicating that
  there is no visible damage to the LAT
• Successful completion of the LPTverifying that
  all components and subsystems function properly
  after testing
• Preliminary analysis of test dataverify that all
  recorded data is useable for analysis purposes
• No significant mode shiftspre- and post-test
  signatures match within 5 showing modal
  frequencies have not changed as a result of
  testing

32
Acoustic Test Test Plan Requirements

• Test Requirements
• Instrument Verification Plan
• The tests will be performed to the levels
  published in the LAT environmental specification
  document, LAT-SS-00778
• The dynamics tests are to be performed in the
  mode in which the equipment will observe the
  environment
• LAT will be launched in a powered off mode
• The acoustic test will be performed with the
  article powered off

33
MGSE/STE for Acoustic Testing

• LAT (on the TIP) is mounted on the Test Stand for
  acoustic testing
• LAT TIP mounts to Test Stand then Radiators are
  integrated
• LAT is rolled into the acoustic chamber, then
  jacked off its casters
• Dust Tent remains over the LAT for the entire
  operation, including during testing (TBR)
• SC top deck simulator
• A circular honeycomb-core panel is mounted in the
  hole of the TIP
• This simulates the acoustic behavior of the SC
  top deck
• There is free access to the underside of the TIP
  through the Test Stand to integrate and
  instrument this

Test Interface Plate
LAT
Radiator SC Strut simulators
Test Stand
Radiator
Acoustic Test Configuration
34
MGSE Requirements Flowing from Acoustic Test Plans

• See the table, below, for a list of all MGSE/STE
  that is needed for conducting the acoustic test
• Test Interface Plate
• TIP accommodates a top deck acoustic simulator
• Top deck acoustic simulator adequately simulates
  the acoustic behavior of the SC
• Dust Tent
• Capable of providing clean, dry environment
  before/during/after acoustic testing
• Provides clearance around LAT
• Does not impact the acoustic response of the LAT
  or acoustic environment in the chamber during
  testing
• SC Strut Simulators
• Provides flight-like interface to simulate SC
  struts that support the Radiators
• Interface with Radiator at flight interface, and
  with Test Stand
• Chill Bars
• Capable of handling acoustic loads (obviates need
  to de-/re-integrate them)

MGSE/STE Needed for Acoustic Testing
35
Auxiliary Cooling and Mechanical Handling

• Auxiliary cooling plans
• LAT needs to be cooled during LPTs before and
  after acoustic testing
• Chill Bars one under each of the two X-wings on
  the Grid
• X-LAT Aux Cooling using fly-away cooling lines
  already mounted to X-LAT Plate
• This is room-temperature cooling to remove LAT
  process heat
• To simplify cooling connections, Chill Bars and
  X-LAT cooling will be designed to handle acoustic
  loads
• We may be able to leave all hoses and fittings
  connected during the test (TBR), otherwise will
  quick-disconnect them
• Handling and mechanical operating procedures
• LAT lifting procedure
• Radiator integration procedure
• Test Stand handling and operating procedure
• Dust tent handling and operating procedure
• LAT auxiliary cooling system operating procedure

36
MGSE Issues for Acoustic Testing

• Dust Tent
• This is likely needed for acoustic testing, but
  is still TBR
• If needed, what is impact of dust tent on
  acoustic environment in the chamber?
• Dust tent will need to be designed to not
  overly-attenuate sound pressure levels
• Transportation issues
• The acoustic chamber has a ¾ door sill/threshold
• We plan to build a ramp to roll up and over the
  sill
• This will definitely by prototyped with the
  pathfinder, since the LAT c.g. is moderately high
• Test Stand will be moved into the room with an
  electric forklift
• We need to verify that it can position the LAT
  adequately

37
Acoustic Test Test Plan Constraints

• EGSE Constraints
• Cables
• Disconnected during vibration
• Must be long enough to reach LAT while mounted to
  either expander head or slip table
• Cable trays or protection if laid on floor
• Cart with EGSE Hardware
• Portable, can be rolled out of the way
• Power interface to lab?

38
Acoustic Test Test Configuration

• Mechanical Configuration
• Radiators attached (with flight thermal joint)
• Need to ensure thermal joint has enough time to
  cure (7 days RT)
• Mounted to GD/Spectrum Astro-provided test
  flexures
• Test flexures will be proof tested at SLAC prior
  to GRID static test
• Mounted on LAT acoustic test stand
• LAT Z-axis is vertical
• Access to connectors needed (ladder around MGSE)
  on X side
• Layout needed to check cable run lengths
• Electrical Configuration
• SLAC purchased accelerometers are voltage type
  and have 10-32 connectors, with a special
  proprietary triax connector
• Adapters will be needed to interface with NRL
  equipment
• ACD accelerometer interface to be verified
• Strain gauges do not have connectors (open leads)
• EGSE needed for LPTs between axes (Rich Baun to
  define requirements)

39
Acoustic Test Test Configuration
Instrumentation

• Test instrumentation by subsystem, total of 57
  channels, calibrated and installed by SLAC IT,
  final checkout by NRL

40
Acoustic Test Test Configuration
Instrumentation

• The STE will be centered in the acoustic chamber,
  rotated to an angle of approximately 20-30
  degrees, as measured between the Radiator surface
  and chamber sidewall
• Additionally, there will be a plastic sheet
  placed under the STE to help identify any items
  that may come loose as a result of the acoustic
  vibration.

41
Acoustic Test Planning Detailed Sequence

• Pre-test Activities
• Chamber Setup and empty cell calibration
• This is needed to verify the test cell is clean
  and ready to accept the LAT for testing
• The empty cell calibration will verify that the
  specified sound pressure levels can be achieved
• Move LAT on dolly (radiators already installed)
  into chamber and set orientation to the
  appropriate angle
• Cable Hook-ups and system checkouts
• Electrical connections to shaker system and accel
  tap checks (NRL)
• Electrical connections to EGSE and perform LPT on
  expander head (SLAC)
• LPT on acoustic test stand
• Low-Level run at -6 dB for 30 seconds (establish
  pre-test signature, review data)
• Set-up sheet printouts (NRL), verification and
  approval (SLAC)
• If LPT results okay, disconnect EGSE cables and
  close chamber door
• Purge chamber of air
• Run Test
• Output Data, accel ASDs and strain gauge SSDs
  (NRL)
• Review data (SLAC)
• Check for dead channels
• Review mic average for level and chamber
  uniformity
• Review Grms values for obvious anomalies

42
Acoustic Test Planning Detailed Sequence (cont.)

• Full-Level run at -0 dB for 60 seconds (impart
  full SPL, check SPL, linearity, review data)
• Set-up sheet printouts (NRL), verification and
  approval (SLAC)
• Run Full level Test
• As level steps up to -3dB, check critical channel
  linearity and record data
• Hold at full level for 60 seconds
• Immediately following full level run, perform low
  level run
• Do not review data between full level and
  post-test low level run
• Output Data accel ASDs and strain gauge SSDs
  (NRL)
• Review data (SLAC)
• Check for dead channels
• Review mic average that PFQ level is met and
  chamber uniformity
• Review Grms values for linearity
• Give Okay to proceeed (SLAC), or decide if
  alternate action is needed

43
Acoustic Test Planning Detailed Sequence (cont.)

• Low-Level run at -6 dB for 30 seconds (Signature
  check, review data, complete axis)
• Output Data (NRL)
• Review data (SLAC)
• Check for dead channels
• Review mic average for level and chamber
  uniformity
• Review pre- and post- test overlays for frequency
  shifts and amplitude changes
• Give Okay to proceeed (SLAC), or decide if
  alternate action is needed
• Post- Acoustic Test Activities
• Fill chamber with air (may be done automatically
  following final low-level run)
• Connect EGSE and perform LPT
• Visually inspect plastic sheet under LAT
• If everything looks okay, give okay to break
  configuration
• Disconnect all electrical connections
• Move LAT out of chamber

44
Acoustic Test Configurations Deviations From
Flight

• The LAT is mounted to STE, which is intended to
  simulate the influence of the SC volume and
  geometric proximity on acoustic pressures
  immediately adjacent to significant LAT surfaces,
  such as the Radiators and XLAT plate
• The SC top deck and lower radiator strut mounts
  were identified as the critical regions for SC
  simulation
• The top deck simulator will be of the same
  construction as the SC top deck and will be
  attached to the TIP MGSE
• The lower radiator strut mounts will have a
  similar interface with the radiators and the
  stiffnesses will be approximated, but
  cross-coupling and stiffness differences will not
  be captured in this test
• SC-LAT cabling is not connected for this test, so
  these connections, the cable harnesses, and the
  attachment methods are not verified as part of
  this test
• These will be verified at the Observatory
  acoustic test

45
Acoustic Test Document List and Status

• LAT-MD-00408 LAT Instrument Performance
  Verification Plan
• LAT-MD-02717 LAT Environmental Test Sequence
• LAT-MD-01196 LAT Dynamics Test Plan
• LAT-MD-01533 LAT EGSE Plan
• LAT-MD-00649 LAT Transportation and Handling
  Plan
• LAT-MD-00404 LAT Contamination Control Plan
• LAT-SS-00778 LAT Environmental Spec
• LAT-TD-00890 LAT Instrumentation Plan

46
Acoustic Test Test Logistics

• Test Personnel
• Test support personnel have been identified (to
  be verified)
• Test Director John Ku (SLAC)
• Test Conductor Bob Haynes (NRL)
• Discipline Lead Jim Haughton (NRL)
• Facility ManagerBill Raynor (NRL)
• MGSE Lead Martin Nordby (SLAC)
• EGSE Lead Mike Huffer (SLAC)
• Test Script Lead Rich Baun (SLAC)
• High-bay operations Paul Dizon (NRL)
• Quality Assurance Joe Cullinan (or Doug
  Bartholomew) (SLAC)
• IT Ken Fouts (SLAC)
• Subcommittees will be assembled from the
  appropriate personnel above, with expert
  consultation brought in if needed
• Potential Vibration Experts Paul Baird Chris
  Fransen Bill Haile

47
Acoustic Test Open Issues

• Many logistics have been closed already the
  logistics that still need consideration are
• Lip at threshold (how to transport into room)
• Accommodation for moving Test Stand over ½ door
  sill
• Use pneumatic wheels or air bearings?
• Cleanliness (need blanket?) is rating worse
  than 100K?
• Instrumentation feedthrough and cable supports
• Is a dust tent needed around LAT in acoustic
  chamber
• What type of panels are needed in/around LAT to
  simulate SC response
• Complete structural analysis of MSGE
• Complete pre-test analysis
• Verify top plate simulator attached to TIP MGSE
  adequately replicates SC response
• 5 action items are open and being tracked.
• All actions have clear closure paths and are
  actively being worked on

48
Weight and CG Test Test Plan Overview

• Objectives
• The primary objective of this test is to measure
  and/or calculate the overall mass and CG of the
  fully integrated LAT, to verify that it meets the
  IRD 433-IRD-0001 requirements of
• Mass is less than 3000 kg
• Z-cg is a maximum of 185mm above the LAT
  Interface Plane (LIP)
• Because of the difficult involved in measuring
  Zcg, this requirement will be verified through
  calculations, based on measurements of all LAT
  constituents.
• From the Xcg and Ycg measurements and comparison
  with calculated values, an appropriate confidence
  level can be established and applied to the Zcg
  calculations.
• X-cg and Y-cg are within 20mm of LAT Coordinate
  System (LCS) Z-axis
• A secondary objective is to verify measured mass
  properties match well when compared with the math
  model mass matrix.
• Due to the complexity of measuring moments of
  inertia, only mass and CG properties will be
  validated. Differences will be reconciled by
  updating the math model to reflect measured
  values
• Since structural dynamics is intimately tied with
  mass and stiffness, mass property updates are
  important to preserve the true dynamic behavior
  of the LAT.
• Test Plan
• This is a new addition to the test plan draft 3
• Many technical details have been addressed in
  previous meetings the current draft is very
  mature and should be released in 1-2 weeks
• All needed instrumentation has been identified,
  but MGSE design is still needed

49
Weight and CG Test Test Plan Overview

• Test Plan (Continued)
• Entrance/Exit Criteria from the test plan
• The LAT mass properties test is performed
  following the LAT thermal vacuum test and the
  subsequent CPT and removal of the radiators.
  Criteria which must be met before this test can
  be executed are
• LAT Radiators have been removed and the LAT,
  Flexures and TIP have been moved into the mass
  properties test areavisual inspection verifies
  that all the LAT has been re-configured
  correctly. All travelers verified to be
  complete. The LAT is in its flight
  configuration, except as detailed in Section
  10.3, below.
• All subsystem units/modules functioneach
  subsystem has passed its CPT following TVAC. Any
  performance discrepancies have been clearly
  documented.
• All non-fly-away accelerometers and other test
  instrumentation, cables and harnesses are
  removed.
• Following the mass properties test, an aliveness
  will be performed. The criteria for declaring a
  successful completion of the mass properties test
  are
• Visual inspection of the LATindicating that
  there is no visible damage to the LAT
• Successful completion of the aliveness
  testverifying that all components and subsystems
  are still properly interconnected.
• Preliminary analysis of test dataverify that all
  recorded data is useable for analysis purposes

50
Weight and CG Test Test Plan Constraints

• MGSE Constraints
• Platform to distribute weight into three load
  cells
• Must be stiff enough to carry load from TIP (four
  points) to load cells (three points), i.e. to
  evenly distribute load from the four flexures
• Must be light enough to not affect load cell
  accuracy (use load cells with highest possible
  accuracy and precision load cell precision
  generally goes down with increased capacity)
• Must have a way to precicely locate the LAT and
  TIP with respect to some arbitrary reference
  coordinate system
• Must be able to accommodate the LAT in 0 and 90
  degree orientations
• EGSE Constraints
• Cables
• Disconnected during vibration
• Cart with EGSE Hardware
• Portable, can be rolled out of the way
• Power interface to lab?

51
Weight and CG Test Test Configuration

• Mechanical Configuration
• Radiators not attached
• MGSE to hold DSHP and XLHP attached
• Mounted to GD/Spectrum Astro-provided test
  flexures
• Test flexures will be proof tested at SLAC prior
  to GRID static test
• TIP to interface test flexures and weight and CG
  test platform
• LAT Z-axis is always vertical
• All unnecessary instrumentation removed (such as
  removable accels)
• Electrical Configuration
• No electrical connections to the LAT
• 16 Strain gauges and 3 load cells are the only
  instrumentation needed
• EGSE needed to verify aliveness after weight
  and CG test

52
Weight and CG Test Test Configuration
Instrumentation

• Test instrumentation by intrument type Load
  cells installed by NRL Strain gauges installed
  by SLAC IT

53
Weight and CG Test Planning Detailed Sequence

• Weight and CG Run
• Instrumentation checkuse dummy masses to verify
  that all instrumentation is operational and
  taking useful data
• Align LAT on test platform
• Measure overall mass and centers of gravity
• Rotate LAT 90 degrees and align to test platform
• Measure overall mass and centers of gravity
• Aliveness Testexecute aliveness test after LAT
  has been packed in shipping container

54
Weight and CG Test Configurations Deviations
From Flight

• The LAT is mounted to STE (flexures and TIP),
  which is not part of the flight LAT structure.
• Radiators not attached
• Radiator mass will be added to the LAT math model
• MGSE to hold DSHP and XLHP attached
• The added weight will be subtracted from the LAT
  math model
• The added weight is insignificant and within the
  measurement precision of the load cells
• SC-LAT connector savers are attached during this
  test
• The added weight will be subtracted from the LAT
  math model
• The added weight is insignificant and within the
  measurement precision of the load cells

55
Weight and CG Test Document List and Status

• LAT-MD-00408 LAT Instrument Performance
  Verification Plan
• LAT-MD-02717 LAT Environmental Test Sequence
• LAT-MD-01196 LAT Dynamics Test Plan
• LAT-MD-01533 LAT EGSE Plan
• LAT-MD-00649 LAT Transportation and Handling
  Plan
• LAT-MD-00404 LAT Contamination Control Plan
• LAT-SS-00778 LAT Environmental Spec
• LAT-TD-00890 LAT Instrumentation Plan

56
Weight and CG Test Test Logistics

• Test Personnel
• Test support personnel have been identified (to
  be verified)
• Test Director John Ku (SLAC)
• Test Conductor Bob Haynes (NRL)
• Discipline Lead Jim Haughton (NRL)
• Facility ManagerBill Raynor (NRL)
• MGSE Lead Martin Nordby (SLAC)
• EGSE Lead Mike Huffer (SLAC)
• Test Script Lead Rich Baun (SLAC)
• High-bay operations Paul Dizon (NRL)
• Quality Assurance Joe Cullinan (or Doug
  Bartholomew) (SLAC)
• IT Ken Fouts (SLAC)
• Subcommittees will be assembled from the
  appropriate personnel above, with expert
  consultation brought in if needed
• Potential Vibration Experts Paul Baird Chris
  Fransen Bill Haile

57
Weight and CG Test Test Logistics

• Many logistics have been worked out already the
  remaining logistical issues are
• Where to perform this test
• How to precisely align the LAT with respect to
  the load cells
• Finalize load cell selection
• Ensure load cells availability
• Ensure load cells meet precision requirements
• Provide load cell ICD to SLAC for MGSE design
• Other work to be performed
• Design the weight and CG Test platform to the
  requirements
• Perform structural analysis of MGSE and test
  platform
• A/I Closure plans
• Currently NO OPEN ACTION ITEMS!!!