june 23, 2015 the nasa engineering and safety center ...€¦ · the nasa engineering and safety...
TRANSCRIPT
Bill Prosser
June 23, 2015
Engineering Excellence 1
The NASA Engineering and Safety Center
Nondestructive Evaluation Technical Discipline Team
14th International Symposium on Nondestructive
Characterization of Materials
NASA Engineering and Safety Center
Bill Prosser
June 23, 2015
Engineering Excellence 2
Outline
• What is the NESC and the NESC NDE TDT?
• Examples of NDE Problems Addressed by NESC NDE TDT
– Shuttle
– ISS
– Orion
– Commercial Crew/Cargo
Bill Prosser
June 23, 2015
Engineering Excellence 3
NASA Engineering and Safety Center
• NESC created in wake of Columbia accident to provide independent assessment of technical issues for NASA programs and projects
• Scope
– Independent in-depth technical assessments
– Independent trend analysis
– Independent systems engineering analysis
– Mishap Investigations
– Design and Flight Readiness Reviews
– Support Programs
– Focus on High Risk Programs
Space Shuttle on Mobile Launch Platform
Bill Prosser
June 23, 2015
Engineering Excellence 4
NASA Engineering and Safety Center
• NESC comprised of:
– Principal Engineers located at NASA Langley
– NESC Chief Engineers (NCEs) located at each NASA Field Center
– Systems Engineers located across the Agency
– NESC Technical Fellows (TFs) for specific disciplines located across the Agency
• Fluids/Life Support/Thermal, Flight Sciences, Guidance Navigation & Control, Human Factors, Materials, Mechanical Analysis, Mechanical Systems, Non-Destructive Evaluation, Power & Avionics, Propulsion, Software, Structures
– Chief Scientist & Chief Astronaut
• TFs are the leaders of National teams of experts…called Technical Discipline Teams (TDTs)
– NDE TDT comprised of about 65 members
– NASA, Other Government Agencies, Industry and Academia
Bill Prosser
June 23, 2015
Engineering Excellence 5
Notable NESC Assessments
• Assistance to Chilean Miner Rescue
• Toyota Unintended Acceleration Assessment
• Shuttle – Cracked Stringer Investigation, STS-135 Risk Assessment
• ISS – Independent Review of MMOD Risk, Ultrasonic Background Noise
Assessment, Solar Array Tear Investigation, Review of In-Suit Light
Exercise Prebreathe Protocol, UPA and CMG issues
• Orion/Ares – Crew Module Water Landing Tests, Human Occupant Injury
Factor Assessments, SiC/CC Pintle Valve Assessment
• Robotic Missions –Review of JWST Cryocooler, Cross-track Infrared
Sounder (CrIS) Instrument Structural Frame Assessment
• Commercial Cargo and Crew – Review of Requirements Documents,
Taurus II Launch Pad Structural Assessment, Readiness for Crewed
Operations
Bill Prosser
June 23, 2015
Engineering Excellence 6
Shuttle Critical NDE Issues Resolved
High Pressure Hydrogen
Valve Poppet Failure
Radiator Flex Hose Cracking
Crawler-Transporter Shoe Failure
RCS Thruster Cracking Launch Pad Flame Trench Damage
Bill Prosser
June 23, 2015
Engineering Excellence 7
Shuttle ET Stringer Cracks
• Crack in ET TPS (foam) noted after launch scrub for STS-133
• Underlying structural cracks found in stringers
• CR and BSX used to inspect for additional cracks
• Contributing causes determined to be low toughness material and high assembly
stresses
• NDE TDT provided independent reviews
of radiographic images and performed x-ray diffraction measurements of residual
stress in stringers
• Also inspected ET-138 for STS-135
Bill Prosser
June 23, 2015
Engineering Excellence 8
Shuttle External Tank TPS NDE
• ET TPS (foam) inspection identified as critical need after Columbia accident
• Foam proved very difficult to inspect
– Low density and highly porous
– High attenuation for acoustic waves
– Poor thermal conductor
• NESC funded effort to develop and validate new NDE inspection methods
– Backscatter Radiography
– Terahertz Imaging
– ShearographyFoam Loss on STS-114
Bill Prosser
June 23, 2015
Engineering Excellence 9
ET Inspection System
9
LOX Feed Line
Overhead Crane
ET
Scanner
LH2 Tank
Bill Prosser
June 23, 2015
Engineering Excellence 10
ISS Critical NDE Issues Resolved/In-work
• MMOD Impact/Leak Detection
• Inspection of Spacesuit Components
• Recommendation of UT system for on-orbit damage
assessment
• COPV’s
– New methods for inspection
– Data for stress rupture life assessment
Bill Prosser
June 23, 2015
Engineering Excellence 11
ISS MMOD Impact and Leak Detection
• No current impact detection capability available
• Limited leak detection capability
- Pressure sensors and hatch closing procedure
- Handheld ultrasonic leak detector
- Distributed Impact Detection System (DIDS)• Multiple structure borne (AE) sensors
• Battery powered data acquisition with wireless data transmission
• Ground testing on ISS Node 1 Structural Test Article, Flight Nodes 2 and 3, and Soyuz
– Background noise assessment
– Wave propagation studies
• Background ultrasonic noise measurements obtained on ISS
- Noise levels below required threshold for leak detection
- Successfully located noise sources
Bill Prosser
June 23, 2015
Engineering Excellence 12
Impact/Leak Detection System
Implementation
Bill Prosser
June 23, 2015
Engineering Excellence 13
Ultrasonic Background Noise Tests
Forward AftOverhead
Port
Starboard
Location of GLA
(General
Luminary
Assembly) on
LAB1OS1 panel
in hallway
Location of GLA
on LAB1OP3
panel in hallway
US Lab FEM Model
Note 1: Location Estimates for Sounds Recorded
between 12 AM and 3 AM GMT on May 15, 2013
Crew was active during this time period.
Note 2: Ultrasonic Background Noise Levels in the
US Lab are below critical leak sound levels.
Bill Prosser
June 23, 2015
Engineering Excellence 14
Spacesuit Water Leak
Bill Prosser
June 23, 2015
Engineering Excellence 15
NDE of Spacesuit Components
Neutron CT image of spacesuit
component showing contamination
Nuclear Reactor Neutron Ray Source
Bill Prosser
June 23, 2015
Engineering Excellence 16
Orion Critical NDE Issues
Resolved/In-Work
• Heat-Shield
– EFT-1 Cracking/Low Strength Root Cause Investigation
– NDE of Bondline for new Block Architecture
• Tube Weld Digital Radiography
• LAS Pintle Valve
• Window Inspection
Bill Prosser
June 23, 2015
Engineering Excellence 17
Orion Block Bond NDE Verification
• New Orion Heatshield Architecture Comprised of
Bonded Blocks of TPS Material
• Integrity of Bondline Critical
• Proposed Approach Includes Process Control, Proof Testing, and NDE
• Multiple NDE Methods
– THz for missing adhesive material
– UT for disbonds
– BSX for gap filler voids
Bill Prosser
June 23, 2015
Engineering Excellence 18
Orion Tube Weld Inspection
• Film radiography utilized for EFT-1
• Orion Chief Engineer requested NESC to evaluate digital radiographic methods as a replacement and if
applicable, to make recommendations on preferred
system to use
Bill Prosser
June 23, 2015
Engineering Excellence 19
Orion Window Inspection
• Verification of Minimal
Distortion of Spacecraft
Windows
• Optical Interferometer
Based Distortion
Measurement System
• Custom Scanning System
Forward window
composed of two fused
silica panes
and one acrylic pane
Bill Prosser
June 23, 2015
Engineering Excellence 20
Commercial Cargo/Crew
• COPV Failure – Scanning EC for Liner Inspection
• Visiting Vehicle TPS Damage Assessment/Inspection
• AJ-26 Failures
– Fuel line rupture
– SSC Test Stand NDE following engine failure during test
• SNC Dream-Chaser Composite Inspection
Bill Prosser
June 23, 2015
Engineering Excellence 21
COPV Liner Inspection
• On pad failure of COPV during engine test
• Need to inspect liners for smaller flaws and to be able to inspect post wrapping/autofrettage/proof testing
• Scanning eddy current system capable of external and internal liner inspection
– Thickness mapping
– Flaw detection
• Coupled with pre-existing laser profilometry inspection system
• System development and preliminary evaluation complete
• POD for flaw detection underway
Bill Prosser
June 23, 2015
Engineering Excellence 22
System Overview
ID Vertical Stage
Travel increased to
72 in
New OD Vertical Stage
60 in travel
Maximum Height: 162 in.
(including sensor)
22 inch dia. (300 L) liner
Or shorty 15 inch liner
Liner Rotation Stage
• Multi-purpose COPV NDE scanner
– Can scan COPV liners up to 22-in diameter
and 48-in long and internally and externally
map thickness variations, map surfaces, provide laser video and detect very fine flaws
– Highly accurate and calibrated internal
mapping allows mechanical response evaluation and provides high resolution
images of the vessel interior
– Allows flaw screening and analysis after wrapping and autofrettage addressing a long
standing technical concern over potential flaw
generation and liner thinning during this time
of plastic deformation
Bill Prosser
June 23, 2015
Engineering Excellence 23
COPV Liner Inspection Preliminary
Results
Thickness Mapping Flaw Detection
Bill Prosser
June 23, 2015
Engineering Excellence 24
ISS Visiting Vehicle Inspection
• TPS damage due to prolonged exposure
to MMOD while docked at ISS is the
number one contributor to LOC risk for
Soyuz, and future SpaceX Dragon and
Boeing CST-100 Commercial Crew
vehicles
• Assessing approaches to minimize risk
– Development of Damage Assessment and Decision Plan
– Evaluating various inspection/detection methodologies
• On-board impact detection
• Survey inspection using currently available ISS assets
• New technologies for focused inspections
2
Bill Prosser
June 23, 2015
Engineering Excellence 25
Soyuz Survey Inspection Assessment
Bill Prosser
June 23, 2015
Engineering Excellence 26
Soyuz Focused Inspection Assessment
Risk Addressed Effort to Achieve Other
ApplicationsImproved Sensors: MLI Thru Hole Backshell Cost & Sched Ops Effort
- Wrist/elbow add-on HD Too far away Use EHDC? SSRMS Ops Imagery
- CSA – DDVS on SSRMS IR and LIDAR Need BXray 2018 is late SSRMS Integ Comm Crew
- AS&E Mini-Z Xray BXray Testing
Needed
Thru hole in
substrate -
size needs to
be Validated
COTS - needs
interface dev
SSRMS
Integration on
FGB PDGF and
SPDM Ops
ISS & C.
Crew
- TEK-84 BXray System
- Nucsafe BXray - NAVAIR Miniaturize
Scanner cert- POC BXay – L.A. or LaRC
- IR Camera Tests needed -
ability to find
MLI thru-
holes
Aluminized
MLI
Blocks Energy
Development
Needed
ISS Radiator
- Millimeter Wave Image Tiled TPS
- Terrahertz Scanner
EVA-based
- Borescope Push thru hole COTS EVA not practical ISS&C. Crew
- Backscatter X-ray Hand-held COTS ISS&C. Crew
Free-flyer
- Japanese Robotic Arm
– no tether
Too Far Away Safety,
Reliability,
Comm & Nav
New
Infrastructure
Many
- SSRMS-based, no tether Too far Away Safety
- SSRMS-based - tether Mini B-Xray? BXray Dev
- “Independent” Mission Too Far Away Ext to Int
Damage
External Robots:
R2, JPL, SRI
Sensor
Dependent
Long Term
Investigation?
Intensive
Robotic Ops
Limited
locations
Bill Prosser
June 23, 2015
Engineering Excellence 27
Summary Comments
• NDE plays a crucial role in NASA spaceflight programs
• Often key aspect in providing flight rationale
• Will be increasingly important as NASA moves to
longer duration missions beyond low earth orbit
• Extend thanks to all that support the NESC NDE TDT
who provide a truly outstanding resource to the Agency to enable safe flight!