Proprietary BalloonWinds Cracks Under Pressure Jim Ryan University of New Hampshire

Proprietary BalloonWinds Instrument Overview Size: 8  8  12’ Gondola Mass: 5500 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)

Proprietary BalloonWinds Integrated Instrument

Proprietary Flight Timeline 1.Liftoff - System Startup 2.Emit Laser and Signal Fiber Alignment 3.Flight Altitude Checkout 4.Eight-Hour Data Collection 5.Extended Data Collection (resources/weather) 6.Descent 1.Liftoff - System Startup 2.Emit Laser and Signal Fiber Alignment 3.Flight Altitude Checkout 4.Eight-Hour Data Collection 5.Extended Data Collection (resources/weather) 6.Descent

Proprietary Mission Objectives 1.Measure wind velocity profiles with accuracy limited by photometric return and instrument technology. 2.Confirm instrument/atmosphere model for a space-like instrument. 3.Assess subsystem scalability for space. 4.Adapt model to a space-borne instrument and compare to data requirements.

Proprietary Previous BalloonWinds Schedule ActivityDate Crane Test04 Jan 07 Pre-Env. Functional Test30 Mar 07 Thermal-Vacuum Test02 Apr 07 First Launch14 May 07 Second Launch04 Jun 07 Return to UNH15 Jun 07

Proprietary Thermal-Vacuum Test 5 April 2007 at Kirtland AFB Phillips Lab Catastrophic failure occurred during initial backfill Damage assessment, failure analysis, redesign, and chamber reviews initiated

Proprietary External Pressure Vacuum at 3:30 Target P at 3:51 Backfill at 3:55 Internal Pressure Pressurized at 2:05 Failure at 3:50 Tracks External P

Proprietary External Pressure Linear decrease from pumping Pressure wave from explosion measured at 3:50:22 Internal Pressure 1.21 bar initial Rupture at 3:50: bar final 1.07 bar differential

Proprietary Laser Chamber Pre-Failure Cross-supports 29  47  ½-inch lid (0.35-inch eff. thickness)

Proprietary Laser Chamber Post-Failure I Cross-supports Lid bottom Secondary fractures from gondola impact Thermal insulation (yellow)

Proprietary Laser Chamber Post-Failure II Cross-support Lid bottom Secondary fractures from pipe interference Fibertek Laser

Proprietary Laser Chamber Post-Failure III Reverse angle showing the disorder

Proprietary Laser Chamber Post-Failure IV Fragments at the bottom of the thermal-vacuum chamber

Proprietary Damage Assessment Laser chamber: Lid and walls GPS, attitude sensors and heaters mounted on lid were damaged External cooling lines were stressed Internal damage was minimal FiberTek laser and other key elements passed diagnostic testing 11 July 2007

Proprietary Failure Analysis Lid Support Structures Lid required additional supports to counter pressure load (19,000 lbs) Each cross-support was fastened to lid using 7 bolts Middle beam took 20-39% of total load, depending on load/lid deformation

Proprietary Failure Analysis Lid Deformation & Reaction Support beams much stiffer than lid Lid pushed against middle beam in range of lbs (calc.) Only the two end bolts were under tension countering this load: lbs each. Lid displacement contour acting against support beams

Proprietary Change of Lid Bolts Small gauge bolt with insert to thread into Al. New through-bolt fixation.

Proprietary Failure Analysis Pull-Out Strengths Pull-out force for ¼-28 bolt in MIC-6 calculated to be 2100 lbs Measurements on two samples reported 2100 & 2700 lbs These values are at the lower-end of the expected lbs load range Pull-Out Strength Measurements

Proprietary Pull Test Samples Threads did not hold. Too short Too small diameter.

Proprietary Failure Analysis Failure Sequence I Pull-out occurred at an end of the middle support beam Same-side bolts on neighboring beams let go Unsupported lid then fractured 4 end-bolts recovered with evidence of pull-out 5 th end bolt was released by a crack

Proprietary Failure Analysis Reconstructed Lid Fragments Pull-out locations Primary fracture line Secondary fractures GPS & Attitude plate (damaged)

Proprietary Failure Analysis Conclusions Material selection (cast aluminum) was the primary cause of the failure –Poor strength required additional support –3% elongation caused brittle fractures Inaccuracies in the stress analysis –Failed to predict inadequate lid strength, which lead to the addition of cross-supports –Failed to predict pull-out of the cross-support bolts

Proprietary Laser Chamber Redesign Thinking outside the box… Rectangular Cylindrical Feasible Feasible Aluminum Steel Lighter Stronger Reuse mounting schemeGondola interference Simpler implementation Easier access Engineering costs Schedule

Proprietary Laser Chamber Redesign Design Comparison I

Proprietary Laser Chamber Redesign Design Comparison II Material:Cast Aluminum MIC6Wrought Aluminum 6061-T6 Ultimate Strength: 166 MPa310 MPa Yield Strength:105 MPa275 MPa Elongation at Break: 3% 12% Lid thickness (M/R)0.5  (0.065  )2.25  (0.25  ) Lid/base attachmentInserted threadsThrough bolts Weight~200 lbs~400 lbs

Proprietary Chamber Reviews Coolant Tank Material 304L Stainless Steel Volume (empty)18 cubic feet Design Pressure18.75 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 Pressure18.75 psig Test Pressure (Hydrostatic)28 psig Assembly Test Pressure (Pneumatic)22.5 psig (1.5  MEOP) Interferometer Chamber Material 304L Stainless Steel Volume14 cubic feet Design Pressure16.5 psig Assembly Test Pressure (Pneumatic)22.5 psig (1.5  MEOP)

Proprietary Revised BalloonWinds Schedule ActivityStart Date Laser Chamber CDR01 Aug 07 Re-Integration29 Oct 07 Leave UNH17 Mar 08 Thermal-Vacuum Test27 Mar 08 First Launch05 May 08 Second Launch27 May 08 Return to UNH09 Jun 08

Proprietary Thermal Chamber Design ASME Pressure Vessel Code used Design validated using COMPress Software Material 304L Stainless Steel 24” Diameter 10 GA shell (.1345”) ASME Flanged and Dished heads Volume (empty)18 cubic feet Design Pressure18.75 psig Maximum Expected Operating Pressure (MEOP) ~15psig Fabrication Welded cylinder, Flanges and Heads Festival City Fabricators, Stratford ONT, CA Code approved pressure vessel manufacturer

Proprietary Thermal Chamber Testing Proof/Leak Test (Hydrostatic) 28 psig Functional/Leak testing UNH (Pneumatic) 16.5 psig (1.1 MEOP) 3 Complete pressure cycles to date.

Proprietary Electronics Chamber Design ASME Pressure Vessel Code used Design validated using COMPress Software Material 304L Stainless Steel 36  Diameter 10 GA shell (.1345”) ASME Flanged and Dished heads Volume (empty)30 cubic feet Design Pressure18.75 psig Maximum Expected Operating Pressure (MEOP) ~15psig Fabrication Welded cylinder, Flanges and Heads Festival City Fabricators, Stratford ONT, CA Code approved pressure vessel manufacturer

Proprietary Electronics Chamber Testing Proof/Leak Test (Hydrostatic) 28 psig Functional/Leak testing UNH (Pneumatic) psig (1.1 MEOP) 3 Complete pressure cycles to date.

Proprietary Interferometer Chamber Design Material 304L Stainless Steel 20  Diameter 12 GA shell (.105”) Flat Heads with weight relief.625  thick Volume (empty)18 cubic feet Design Pressure16.5 psig ** Maximum Expected Operating Pressure (MEOP) ~15psig Fabrication Welded cylinder and flanges Shell made by Hollis Line Machining Hollis NH Code approved pressure vessel manufacturer Heads made by Advance Group Ann Arbor MI Testing Leak Test (Helium and Nitrogen) 16.3 psig Functional/Leak testing UNH (Pneumatic) 16.5 psig (1.1 MEOP) **Verified by mathematical analysis and OptiVessel Code

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Proprietary Laser Chamber Design Material MIC 6 Aluminum (Cast) Beams (added after initial lid deformation) 6061T6 Rectangular29  x 45  x 13  Volume (empty)9.5 cubic feet Design Pressure? Maximum Expected Operating Pressure (MEOP) ~15psig Fabrication Welded side walls and O-ring seal top and bottom Advance Group Ann Arbor MI Testing Leak Test (Helium and Nitrogen) psig Functional/Leak testing UNH (Pneumatic) 16.2 psig Failure Lid failed in TVAC at a differential pressure of 16.5 psig

Proprietary Laser Chamber Failure Analysis