INTERNATIONAL TECHNICAL SAFETY FORUM

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INTERNATIONAL TECHNICAL SAFETY FORUM
Personnel and Machine Protection During
Environmental Testing of the Gamma-ray Large
Area Space Telescope
Joe Kenny jkenny_at_slac.stanford.edu Frank
ONeill fgo_at_slac.stanford.edu Stanford
Linear Accelerator Center
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Environmental Test Review
INTERNATIONAL TECHNICAL SAFETY FORUM

• GLAST LAT

Dimensions 2 x 2 x 1.5 m
Dimensions 2 x 2 x 1.5 m
An orbital gamma-ray observatory using e-/e pair
production to map the gamma-ray sky
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Environmental Test Review
INTERNATIONAL TECHNICAL SAFETY FORUM
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Environmental Test Review
INTERNATIONAL TECHNICAL SAFETY FORUM

• To assure the telescope will survive launch, the
  LAT is

shaken and blasted with sound to
simulate launch conditions.
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Environmental Test Review
INTERNATIONAL TECHNICAL SAFETY FORUM

• To assure the telescope will work in orbit, the
  LAT is

heated, cooled, placed in a vacuum, and
subjected to nonionizing electromagnetic
radiation.
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Environmental Test Review
INTERNATIONAL TECHNICAL SAFETY FORUM

• LAT ENVIRONMENTAL TESTS

-- Vibration -- Electromagnetic compatibility --
Acoustic -- Simultaneous thermal and
vacuum punctuated with limited- and
comprehensive performance tests (LPTs and CPTs)
to assure LAT viability
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Environmental Test Review
INTERNATIONAL TECHNICAL SAFETY FORUM

• LAT ENVIRONMENTAL TESTS

SHAKE
ZAP LISTEN
BLAST
HEAT/COLD/VACUUM
Simulations to ensure full function after launch
and in orbit
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Environmental Test Review
INTERNATIONAL TECHNICAL SAFETY FORUM

• LAT ENVIRONMENTAL TESTS

configurations
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Environmental Test Review
INTERNATIONAL TECHNICAL SAFETY FORUM

• LAT ENVIRONMENTAL TESTS

EMI/EMC
Acoustic
Thermal-Vacuum
Vibration
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Environmental Test Review
INTERNATIONAL TECHNICAL SAFETY FORUM

• LAT System Safety Engineering Activities
• System safety activities to date included three
  written plans
• LAT Environmental Test Hazard Analysis review,
  approved
• Safety team coverage
• SLAC and NASA cooperated to provide direct
  monitoring by safety personnel during critical
  phases (LAT manipulation, table chamber
  installations, ODH-controlled chamber entries,
  etc.)
• Safety team
• Two NASA and two SLAC safety engineers

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Environmental Test Review
INTERNATIONAL TECHNICAL SAFETY FORUM

• GLAST LAT Environmental Test Hazard Analysis
• Analyzes threats to the LAT and personnel from
  arrival date (NRL) to ship date from NRL
• MGSE (includes all in-NRL transit and handling)
• EGSE
• Dynamics Testing
• EMI/EMC Testing
• T-Vac
• Hazards N.O.S.
• Proposes mitigations
• Assesses post-mitigation of relative risks for
  each threat
• End product is a validation matrix for checkoff
  before and during testing

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Environmental Test Review
INTERNATIONAL TECHNICAL SAFETY FORUM

• Mitigations LAT, GENERIC
• Collision w/floor, dropped objects, etc.
• MGSE design-safety factors proof testing
• Hoist forklift operator, rigger training and
  certification
• Use of approved procedures for critical lifts
• Diaper pins, light-bulb sleeves, etc.
• Clearance
• Verification of clearance w/test load during
  Pathfinders
• Damage during transit
• Test/certify shipping container w/test load
• Truck driver w/valid CDL
• Mitigations Human, GENERIC
• Crushed/struck by dropped object
• Hard hats, safety footwear when threat exists,
  roped-off areas
• Electric shock
• Hard hats when threat exists, roped-off areas
• Slips, trips, falls, sprains/strains
• Rapid removal of transient trip hazards
• SLAC personnel will adhere to JHAMs (includes
  PPE requirements)

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Environmental Test Review
INTERNATIONAL TECHNICAL SAFETY FORUM

• Mitigations LAT, SPECIFIC
• Overtesting
• Vibe
• Redundant input and output cutoff mechanisms
• Voltage limits are determined from trials w/test
  load
• EMI
• Limit test-signal source by input and output
• Calibrate monitors pre-test
• Acoustic
• Employ 8 monitors for cutoff
• Thermal-Vacuum
• CDACS acceptance-tested before LAT installation
• Redundant hard- and software based limits
• At least 2 operators present at all times
• Anechoic foam particles (EMI/EMC)
• Build grounded tent around LAT

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Environmental Test Review
INTERNATIONAL TECHNICAL SAFETY FORUM

• Mitigations LAT, SPECIFIC contd
• ESD
• LAT is bagged in ESD-dissipative film most of
  the time
• All workers are ESD-trained and will adhere to
  work requirements
• Helium (T-Vac Transit)
• Verify cryo compressor pump PMs
• Operators know how to spot and deal with pump
  failures
• LAT shipped in N2-filled hermetically-sealed
  container
• Electrical overcurrent, cable miswiring
• Redo acceptance testing after all internal
  configuration breaks
• Acoustic chamber fire
• VESDA in chamber
• Pre-action sprinklers
• Verify NRL compliance with its own NRLINST
  5101.3C, which contains design, administrative
  controls, procedures, inspection, and
  responsible-person requirements

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Environmental Test Review
INTERNATIONAL TECHNICAL SAFETY FORUM

• Hazards Human, SPECIFIC
• Human exposure to testing environments
• ODH (Acoustic, and T-Vac)
• Chambers cleared of personnel before tests
• Acoustic chamber has low-O2 door alarm
• Both chambers vented until O2 gt 19.5
• Sound pressure (Acoustic)
• Chamber SP source interlocked to door
• Anechoic chamber fire
• See above
• Dial 767-3333 (instead of 911) for emergencies
• Shock/sulfuric acid from UPSs in EGSE
• UPSs will be replaced if need be, not serviced
  or repaired

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Environmental Test Review
Hazard matrix
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