BalloonWinds Update Straight to Launch

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BalloonWinds Update--Straight to Launch--

• James M. Ryan
• University of New Hampshire

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BalloonWindsInstrument Overview
Size 8x8x12 Gondola Mass 6000 lbs Power
Requirements 1300 W Power System 26 Lithium-Ion
Batteries Thermal Management Ice and Electric
Heaters Optical Systems Diode-Pumped
NdYAG ½-meter Telescope Direct-Detection
Receivers (2)
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Gondola and Control
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2007 TVAC Failure
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Chamber Reviews

• Laser Chamber
• Material 6061-T6 Aluminum
• Volume (empty) 10 cubic feet
• Design Pressure 18 psig
• Test Pressure (Hydrostatic) 28 psig
• Assembly Test Pressure (Pneumatic) 22.5 psig
  (1.5? MEOP)
• Interferometer Chamber
• Material 304L Stainless Steel
• Volume 14 cubic feet
• Design Pressure 16.5 psig
• Assembly Test Pressure (Pneumatic) 22.5 psig
  (1.5? MEOP)

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Chamber Reviews (cont.)

• Coolant Tank
• Material 304L Stainless Steel
• Volume (empty) 18 cubic feet
• Design Pressure 18.75 psig
• Test Pressure (Hydrostatic) 28 psig
• Assembly Test Pressure (Pneumatic) 22.5 psig
  (1.5? MEOP)
• Electronics Chamber
• Material 304L Stainless Steel
• Volume (empty) 30 cubic feet
• Design Pressure 18.75 psig
• Test Pressure (Hydrostatic) 28 psig
• Assembly Test Pressure (Pneumatic) 22.5 psig
  (1.5? MEOP)

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Schedule Delay

• AFRL postponed environmental tests
• Schedule slip by the preceding instrument
• Fixed schedule for the succeeding instrument
• Test window closed
• 6-month slip in launch schedule with rescheduled
  test date TBD

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Rescheduling Process

• 2-week window emerged in July-August
• New TVAC Facility cleanliness requirements
• Assessment began
• Flowdown from new requirements
• Risk risk reduction
• Impact of risk-mitigation
• Environmental test objectives

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TVAC Facility

• Large investment in facility for two optical
  payloads
• Class-100 inside TVAC chamber
• Class-100 outside TVAC chamber
• Select material list
• No particulates
• No liquids or volatiles
• No silicone-based materials

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Flowdown from New Requirements

• Meticulous cleaning of gondola
• Prepare comprehensive material list
• Removal or encapsulation of forbidden materials
• Vacuum grease
• Coolant
• Insulation
• Wood

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Risk Risk Reduction

• Facility contamination was primary risk
• Risk reduction measures included
• Bagging gondola
• Reduced altitude simulation
• Reduced temperature range (tropopause)
• All support equipment located outside facility
• No schedule or admittance guarantee after
  completion of all known requirements

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Impact of Risk-Mitigation

• Gondolas thermal properties different from
  flight configuration
• T-P profile not representative of flight profile
• Consumable state and burn rate not representative
  of flight
• Limited to one cycle. 2nd cycle logistically
  impractical.

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Environmental Test Objectives

• Verification of thermal system operation
• Heating/cooling capacities (duty cycles)
• System performance (temperatures vs set points)
• Time required to equilibrate at final altitude
• Revelation of impacts on opto-mechanical and
  detector systems
• Laser Power, seeding, frequency tuning
• Telescope Motor control of focus adjustment
• Interferometer Alignment, stability, motor
  control
• Detectors Chip temperature, Gain, read noise

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Environmental Test Objectives (cont.)

• Estimation of Mission Duration
• Battery power burn rate knee shape
• Coolant system capacity knee shape
• Pressure chamber leak rates
• All impacted by risk mitigation efforts
• Test no longer matched with objectives

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Straight to Launch

• The new facility requirements
• Increased resource requirements
• Increased associated risk
• Decreased benefit of test
• Hindered original test objectives
• Environmental tests were cancelled
• Environmental test objectives rolled into flight
  objectives

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Added Flight Objectives Procedures Impacts

• Verification of thermal system operation
• Monitor temperatures and heating/cooling duty
  cycles
• Modify temperature set points to counteract
  temperature and/or duty cycle issues
• Raw data will be unusable until thermal
  stead-state is attained and the interferometer is
  aligned

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Added Flight Objectives Procedures Impacts

• Revelation of impacts on opto-mechanical and
  detector systems
• Monitor laser power, spectral widths, optical
  transmissions, photometric return, etc
• Remote adjustments performed to reduce the impact
• Raw data black-outs will occur during such
  adjustments

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Added Flight Objectives Procedures Impacts

• Estimation of Mission Duration
• Capacity for an 8-hour mission will be assumed
• Monitor battery bus voltage, coolant temperature
  and chamber pressures
• Cut-down will be initiated if the following value
  estimates are reached
• Bus voltage limit- 25V
• Output manifold temperature- 4C
• Chamber pressure limit- 0.8 atm

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Advantages of Not Testing

• Schedule contingency
• Released resources
• Reduced risk of mishandling

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Revised BalloonWinds Schedule
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Additional
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Laser ChamberPre-Failure
Cross-supports
29?47?½-inch lid (0.35-inch eff. thickness)
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Laser ChamberPost-Failure I
Cross-supports
Secondary fractures from gondola impact
Lid bottom
Thermal insulation (yellow)
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Laser ChamberPost-Failure II
Cross-support
Secondary fractures from pipe interference
Lid bottom
Fibertek Laser
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Laser ChamberPost-Failure III
Reverse angle showing the disorder
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Laser ChamberPost-Failure IV
Fragments at the bottom of the thermal-vacuum
chamber