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BalloonWinds Update--Straight to Launch--

James M. Ryan

University of New Hampshire

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BalloonWindsInstrument Overview

Size: 8’x8’x12’

Gondola Mass: 6000 lbs

Power Requirements: 1300 W

Power System:

26 Lithium-Ion Batteries

Thermal Management:

Ice and Electric Heaters

Optical Systems:

Diode-Pumped Nd:YAG

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 ChamberMaterial 6061-T6 AluminumVolume (empty) 10 cubic feetDesign Pressure 18 psigTest Pressure (Hydrostatic) 28 psigAssembly Test Pressure (Pneumatic) 22.5 psig (1.5 MEOP)

Interferometer ChamberMaterial 304L Stainless SteelVolume 14 cubic feetDesign Pressure 16.5 psigAssembly Test Pressure (Pneumatic) 22.5 psig (1.5 MEOP)

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Chamber Reviews (cont.)

Coolant TankMaterial 304L Stainless SteelVolume (empty) 18 cubic feetDesign Pressure 18.75 psigTest Pressure (Hydrostatic) 28 psigAssembly Test Pressure (Pneumatic) 22.5 psig (1.5 MEOP)

Electronics ChamberMaterial 304L Stainless SteelVolume (empty) 30 cubic feetDesign Pressure 18.75 psigTest Pressure (Hydrostatic) 28 psigAssembly 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

• Gondola’s 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

1. Verification of thermal system operation• Heating/cooling capacities (duty cycles)• System performance (temperatures vs set points)• Time required to equilibrate at final altitude

2. 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.)

3. Estimation of Mission Duration• Battery power burn rate & “knee” shape

• Coolant system capacity & “knee” shape

• Pressure chamber leak rates

All impacted by risk mitigation effortsTest 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

1. 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

2. 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

3. 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

Activity Date

Arrive at Holloman 17 Sept 08

First Launch 8 Oct 08

Second Launch 5 Nov 08

Return to UNH 21 Nov 08

Report 31 Mar 09

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Additional

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Laser ChamberPre-Failure

Cross-supports

2947½-inch lid(0.35-inch eff. thickness)

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Laser ChamberPost-Failure I

Cross-supports

Lid bottom

Secondary fractures from gondola impact

Thermal insulation(yellow)

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Laser ChamberPost-Failure II

Cross-support

Lid bottom

Secondary fracturesfrom pipe interference

Fibertek Laser

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Laser ChamberPost-Failure III

Reverse angleshowing the disorder

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Laser ChamberPost-Failure IV

Fragments at thebottom of the

thermal-vacuum chamber