134 results on '"Space Shuttle"'
Search Results
2. Simulation of RCC Crack Growth Due to Carbon Oxidation in High-Temperature Gas Environments.
- Author
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Titov, E. V., Jiaqiang Zhong, Levin, D. A., and Picetti, Donald J.
- Subjects
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GAS dynamics , *CARBON , *PHYSIOLOGICAL effects of heat , *HIGH temperatures , *HYPERSONIC aerodynamics - Abstract
High temperature gas dynamic computational techniques are employed to study microflows in expanding crack channels caused by the oxidation of the channel carbon walls. Wall regression rates for three reinforced carbon-carbon (RCC) samples that were tested in a high enthalpy arcjet environment were modeled. The test geometries and flow conditions span flow regimes from the transitional to the continuum, therefore kinetic (direct simulation Monte Carlo) and continuum (Navier-Stokes) gas dynamic approaches were used. The same mechanism for wall material loss, atomic oxygen reaction with bare carbon, was utilized in all three cases regardless of the computational techniques. The predicted wall regression rates were found to agree with arcjet measurements. Local gas flowfield results were found to affect the oxidation rate in a manner that cannot be predicted by previous mass loss correlations. The method holds promise for future modeling of materials gas-dynamic interactions for hypersonic flight. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
3. SOURCES OF AND REMEDIES FOR REMOVING UNWANTED REFLECTIONS IN MILLIMETER WAVE IMAGES OF COMPLEX SOFI-COVERED SPACE SHUTTLE STRUCTURES.
- Author
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Kharkovsky, S., Zoughi, R., and Hepburn, F. L.
- Subjects
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SPACE shuttles , *IMAGING systems , *MICROWAVES , *OPTOELECTRONIC devices , *SCANNING systems , *ELECTRONIC equipment - Abstract
In the recent years, continuous-wave near-field and lens-focused millimeter wave imaging systems have been effectively used to demonstrate their utility for producing high-resolution images of metallic structures covered with spay on foam insulation (SOFI) such as the Space Shuttle external fuel tank. However, for some specifc structures a certain interference pattern may be superimposed on the produced images. There are methods by which the influence of this unwanted interference can be reduced, such as the incorporation of an incidence angle and the proper use of signal polarization. This paper presents the basics of this problem and describes the use of the methods for reducing this unwanted influence through specific examples. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
4. SIMULTANEOUS NON-CONTACT PRECISION IMAGING OF MICROSTRUCTUAL AND THICKNESS VARIATION IN DIELECTRIC MATERIALS USING TERAHERTZ ENERGY.
- Author
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Roth, D. J., Seebo, J. P., and Winfree, William P.
- Subjects
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IMAGING systems , *DIELECTRICS , *TERAHERTZ spectroscopy , *ELECTROMAGNETIC measurements , *SPACE shuttles - Abstract
This article describes a non-contact single-sided terahertz electromagnetic measurement and imaging method that simultaneously characterizes microstructural (e.g. spatially-lateral density) and thickness variation in dielectric (insulating) materials. The method was demonstrated for Space Shuttle External Tank sprayed-on foam insulation. It is believed that this method can be used for applications where microstructural and/or thickness variation in dielectric materials require precision mapping. Scale-up to more complex shapes such as cylindrical structures and structures with beveled regions would appear to be feasible. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
5. ANALYSIS OF EDDY CURRENT CAPABILITIES FOR THE DETECTION OF OUTER DIAMETER CRACKING IN SMALL BORE METALLIC STRUCTURES.
- Author
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Wincheski, Buzz, Williams, Phillip, and Simpson, John
- Subjects
- *
EDDY currents (Electric) , *ELECTRIC currents , *FINITE element method , *DIMENSIONS , *SPACE shuttles , *AERONAUTICS - Abstract
The use of eddy current techniques for the detection of outer diameter damage in tubing and many complex aerospace structures often requires the use of an inner diameter probe due to a lack of access to the outside of the part. In small bore structures the probe size and orientation are constrained by the inner diameter of the part, complicating the optimization of the inspection technique. Detection of flaws through a significant remaining wall thickness becomes limited not only by the standard depth of penetration, but also geometrical aspects of the probe. Recently, an orthogonal eddy current probe was developed for detection of such flaws in space shuttle primary reaction control system (PRCS) thrusters. In this case, the detection of deeply buried intergranular cracking by an inner diameter eddy current probe was sought. Probe optimization was performed based upon the limiting spatial dimensions, flaw orientation, and required detection sensitivity. Analysis of the probe/flaw interaction was performed through the use of finite element modeling techniques. Experimental data for the flaw detection capabilities, including a probability of detection study, will be presented along with the simulation data. The results of this work have led to the successful deployment of an inspection system for the detection of intergranular cracking in PRCS thrusters. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
6. High Resolution Millimeter Wave Detection of Vertical Cracks in the Space Shuttle External Tank Spray-on-Foam Insulation (SOFI).
- Author
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Kharkovsky, S., Zoughi, R., and Hepburn, F.
- Subjects
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SPACE shuttles , *FOAM , *INSULATION contractors , *COATING processes , *NONDESTRUCTIVE testing , *MILLIMETER waves - Abstract
Space Shuttle Columbia’s catastrophic failure, the separation of a piece of spray-on-foam insulation (SOFI) from the external tank (ET) in the Space Shuttle Discovery’s flight in 2005 and crack detected in its ET foam prior to its successful launch in 2006 emphasize the need for effective nondestructive methods for inspecting the shuttle ET SOFI. Millimeter wave nondestructive testing methods have been considered as potential and effective inspection tools for evaluating the integrity of the SOFI. This paper presents recent results of an investigation for the purpose of detecting vertical cracks in SOFI panels using a focused millimeter wave (150 GHz) reflectometer. The presented images of the SOFI panels show the capability of this reflectometer for detecting tight vertical cracks (also as a function of crack opening dimension) in exposed SOFI panels and while covered by a piece of SOFI ramp simulating a more realistic and challenging situation. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
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7. Signal Processing Approaches for Terahertz Data Obtained from Inspection of the Shuttle External Tank Thermal Protection System Foam.
- Author
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Roth, D. J., Seebo, J. P., Trinh, L. B., Walker, J. L., and Aldrin, J. C.
- Subjects
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SPACE shuttles , *THERMAL insulation , *FOAMED materials , *SIGNAL processing , *TERAHERTZ technology , *ELECTROMAGNETIC devices - Abstract
Foam shedding from the shuttle external tank remains a critical problem regarding Shuttle orbiter safety. Flaws present in the foam can result in initiation sites for foam loss, and NASA is continuing to look at improving existing NDE methods for foam inspection as well as developing new methods. Terahertz NDE, greatly enhanced over the last several years with respect to its use for external tank foam inspection, has been a focus for continued improvement through signal and image processing improvements. In this study, results from various signal processing approaches to improve terahertz image flaw resolution for external tank foam are described. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
8. The National Aeronautics and Space Administration Nondestructive Evaluation Program for Safe and Reliable Operations.
- Author
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Generazio, Ed
- Subjects
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NONDESTRUCTIVE testing , *ENGINEERING inspection , *RELIABILITY in engineering , *ORGANIZATIONAL change - Abstract
The National Aeronautics and Space Administration (NASA) Nondestructive Evaluation (NDE) Program is presented. As a result of the loss of seven astronauts and the Space Shuttle Columbia on February 1, 2003, NASA has undergone many changes in its organization. NDE is one of the key areas that are recognized by the Columbia Accident Investigation Board (CAIB) that needed to be strengthened by warranting NDE as a discipline with Independent Technical Authority (iTA). The current NASA NDE system and activities are presented including the latest developments in inspection technologies being applied to the Space Transportation System (STS). The unfolding trends and directions in NDE for the future are discussed as they apply to assuring safe and reliable operations. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
9. Application of Eddy Current Techniques for Orbiter Reinforced Carbon-Carbon Structural Health Monitoring.
- Author
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Wincheski, Buzz and Simpson, John
- Subjects
- *
EDDY currents (Electric) , *ELECTRIC currents , *CARBON , *NONDESTRUCTIVE testing , *SPACE shuttles , *REUSABLE space vehicles - Abstract
The development and application of advanced nondestructive evaluation techniques for the Reinforced Carbon-Carbon (RCC) components of the Space Shuttle Orbiter Leading Edge Structural Subsystem (LESS) were identified as a crucial step toward returning the shuttle fleet to service. In order to help meet this requirement, eddy current techniques have been developed for application to RCC components. Eddy current technology has been found to be particularly useful for measuring the protective coating thickness over the reinforced carbon-carbon and for the identification of near surface cracking and voids in the RCC matrix. Testing has been performed on as manufactured and flown RCC components with both actual and fabricated defects representing impact and oxidation damage. Encouraging initial results have led to the development of two separate eddy current systems for in-situ RCC inspections in the orbiter processing facility. Each of these systems has undergone blind validation testing on a full scale leading edge panel, and recently transitioned to Kennedy Space Center to be applied as a part of a comprehensive RCC inspection strategy to be performed in the orbiter processing facility after each shuttle flight. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
10. Hypersonic gas dynamics of a Marco Polo reentry capsule
- Author
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M. C. Fadgyas, Mihai Leonida Niculescu, Mihai Victor Pricop, M. G. Cojocaru, M. G. Stoican, and Dumitru Pepelea
- Subjects
Shock wave ,Hypersonic speed ,Materials science ,business.industry ,Space Shuttle ,Gas dynamics ,Reentry ,Aerospace engineering ,business ,Endothermic process - Abstract
Earth reentry of capsules, space shuttles and meteors are characterized by the presence of very strong shock waves that generate huge temperatures (over 10 000 K). At these temperatures, powerful endothermic chemical reactions start to take place, thus decreasing the temperature field. Unfortunately, the mechanism of these chemical reactions that alleviate the task of thermal shield of reentry space vehicles is not very well understood. For this reason, the present paper deals with the application of two chemical reaction mechanisms to a Marco Polo reentry capsule.
- Published
- 2018
11. Glide back booster wind tunnel model testing
- Author
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C. I. Stoica, A. M. Neculaescu, M. V. Pricop, M. Boscoianu, Marius Gabriel Cojocaru, Mihai Leonida Niculescu, and A. G. Persinaru
- Subjects
Booster (rocketry) ,Computer science ,business.industry ,Model testing ,Space Shuttle ,National level ,Launch vehicle ,Aerodynamics ,Aerospace engineering ,Reuse ,business ,Simulation ,Wind tunnel - Abstract
Affordable space access requires partial or ideally full launch vehicle reuse, which is in line with clean environment requirement. Although the idea is old, the practical use is difficult, requiring very large technology investment for qualification. Rocket gliders like Space Shuttle have been successfullyoperated but the price and correspondingly the energy footprint were found not sustainable. For medium launchers, finally there is a very promising platform as Falcon 9. For very small launchers the situation is more complex, because the performance index (payload to start mass) is already small, versus medium and heavy launchers. For partial reusable micro launchers this index is even smaller. However the challenge has to be taken because it is likely that in a multiyear effort, technology is going to enable the performance recovery to make such a system economically and environmentally feasible. The current paper is devoted to a small unitary glide back booster which is foreseen to be assembled in a number of possible configurations. Although the level of analysis is not deep, the solution is analyzed from the aerodynamic point of view. A wind tunnel model is designed, with an active canard, to enablea more efficient wind tunnel campaign, as a national level premiere.
- Published
- 2017
12. Thermal conductivity of spray-on foam insulations for aerospace applications
- Author
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Steven W. Van Sciver, M. Barrios, and Mark H. Vanderlaan
- Subjects
Materials science ,business.product_category ,Launch pad ,business.industry ,Polyisocyanurate ,Space Shuttle ,law.invention ,Thermal conductivity ,law ,Thermal ,Composite material ,business ,Aerospace ,Ambient pressure - Abstract
A guarded-hot-plate apparatus [1] has been developed to measure the thermal conductivity of spray-on foam insulations (SOFI) at temperatures ranging from 30 K to 300 K. The foam tested in the present study is NCFI 24-124, a polyisocyanurate foam used on the External Tanks of the Space Shuttle. The foam was tested first in ambient pressure air, then evacuated and tested once more. These thermal conductivities were compared to the thermal conductivity taken from a sample immediately after being subjected to conditions similar to those experienced by the foam while on the launch pad at Kennedy Space Center. To mimic the conditions experienced on the launch pad, an apparatus was built to enclose one side of the foam sample in a warm, humid environment while the other side of the sample contacts a stainless steel surface held at 77 K. The thermal conductivity data obtained is also compared to data found in the literature.
- Published
- 2012
13. Terahertz computed tomography of NASA thermal protection system materials
- Author
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S. Reyes-Rodriguez, R. W. Rauser, D. J. Roth, W. W. Ussery, and D. A. Zimdars
- Subjects
Engineering ,medicine.diagnostic_test ,business.industry ,Terahertz radiation ,Acoustics ,Space Shuttle ,Fuel storage ,Computed tomography ,Optics ,Nondestructive testing ,Space Shuttle thermal protection system ,medicine ,Fuel tank ,Time domain ,business - Abstract
A terahertz (THz) axial computed tomography system has been developed that uses time domain measurements in order to form cross-sectional image slices and three dimensional volume renderings of terahertz-transparent materials. The system can inspect samples as large as 0.0283 m3 (1 ft3) with no safety concerns as for x-ray computed tomography. In this study, the THz-CT system was evaluated for its ability to detect and characterize 1) an embedded void in Space Shuttle external fuel tank thermal protection system (TPS) foam material and 2) impact damage in a TPS configuration under consideration for use in NASA's multi-purpose Orion crew module (CM). Micro-focus X-ray CT is utilized to characterize the flaws and provide a baseline for which to compare the THz CT results.
- Published
- 2012
14. BACKSCATTER X-RAY DEVELOPMENT FOR SPACE VEHICLE THERMAL PROTECTION SYSTEMS
- Author
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Bence B. Bartha, Dale Hope, Paul Vona, Martin Born, Tony Corak, Donald O. Thompson, and Dale E. Chimenti
- Subjects
Optics ,Materials science ,Backscatter X-ray ,business.industry ,Space Shuttle thermal protection system ,Nondestructive testing ,Detector ,Space Shuttle ,Image processing ,business ,Space vehicle ,Image resolution - Abstract
The Backscatter X‐Ray (BSX) imaging technique is used for various single sided inspection purposes. Previously developed BSX techniques for spray‐on‐foam insulation (SOFI) have been used for detecting defects in Space Shuttle External Tank foam insulation. The developed BSX hardware and techniques are currently being enhanced to advance Non‐Destructive Evaluation (NDE) methods for future space vehicle applications. Various Thermal Protection System (TPS) materials were inspected using the enhanced BSX imaging techniques, investigating the capability of the method to detect voids and other discontinuities at various locations within each material. Calibration standards were developed for the TPS materials in order to characterize and develop enhanced BSX inspection capabilities. The ability of the BSX technique to detect both manufactured and natural defects was also studied and compared to through‐transmission x‐ray techniques. The energy of the x‐ray, source to object distance, angle of x‐ray, focal spot size and x‐ray detector configurations were parameters playing a significant role in the sensitivity of the BSX technique to image various materials and defects. The image processing of the results also showed significant increase in the sensitivity of the technique. The experimental results showed BSX to be a viable inspection technique for space vehicle TPS systems.
- Published
- 2011
15. Projections for Future Funding of NASA And NASA Science Activities: Reassessing the Obama FY 2010 Budget Request
- Author
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C. N. Hartman and Glen A. Robertson
- Subjects
Finance ,Engineering ,business.industry ,Budget process ,Liberian dollar ,Event study ,Space Shuttle ,Operations management ,business - Abstract
This paper develops a novel approach for predicting future funding for the total NASA budget and for science activities within that budget. Although the budget process is inherently political, it is adequately characterized by analyzing the last thirty‐two years of NASA budgets, organized by the party of the President. Over the last thirty‐two years, Republicans have increased the buying power of the NASA budget while Democrats have decreased it, with significant differences in the rates. The President’s budget projections for NASA, available since 1990, are used to produce a model that may be applied to future budget projections. Before final conclusions are drawn from these results, the most significant NASA budgetary event of this decade is examined: the one billion dollar share of the American Recovery and Reinvestment Act of 2009. The hypothesis is that an unanticipated, significant, one‐year increase to the NASA budget can affect NASA’s funding profile for more than one year. This is tested with the only other similar event in NASA history, the unanticipated budget increase following the loss of Space Shuttle Challenger in 1986. An event study of the changes in NASA’s total budget before and after the loss of Challenger indicates that the one‐year spike in funding increased subsequent NASA growth rates for four years. These results are combined to predict future NASA top‐level and science budgets for FY 2011 and FY 2012.
- Published
- 2010
16. Transformational Technologies to Expedite Space Access and Development
- Author
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John D. G. Rather and Glen A. Robertson
- Subjects
Engineering ,Spacecraft ,business.industry ,Emerging technologies ,Systems engineering ,Space Shuttle ,Energy consumption ,Electric power ,Appropriate technology ,Aerospace engineering ,business ,StarTram ,Solar power - Abstract
Throughout history the emergence of new technologies has enabled unforeseen breakthrough capabilities that rapidly transformed the world. Some global examples from the twentieth century include AC electric power, nuclear energy, and turbojet engines. At the systems level, success of both Apollo and the Space Shuttle programs depended upon taming hydrogen propulsion and developing high‐temperature atmospheric reentry materials. Human space development now is stymied because of a great need for breakthrough technologies and strategies. It is believed that new capabilities exist within the present states‐of‐the‐art of superconducting technology that can be implemented to transform the future of human space development. This paper is an overview of three other papers presented within this forum, which summarizes the principles and consequences of StarTram, showing how the resulting breakthrough advantages can lead directly to safe space tourism and massive development of the moon, Mars and the outer solar system. StarTram can implement cost‐effective solar power from space, simple utilization of asteroid material to protect humans from ionizing radiation, and effective defense of the Earth from devastating cosmic impacts. Synergistically, StarTram technologies will revolutionize ground transportation on the Earth, leading to enormous reduction in energy consumption and creation of millions of jobs. High energy lasers will also be discussed because of their importance to power beaming applications.
- Published
- 2010
17. Space Environment Effects on Materials at Different Positions and Operational Periods of ISS
- Author
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Yugo Kimoto, Shoichi Ichikawa, Eiji Miyazaki, Koji Matsumoto, Junichiro Ishizawa, Hiroyuki Shimamura, Riyo Yamanaka, Mineo Suzuki, and Jacob I. Kleiman
- Subjects
Engineering ,Micrometeoroid ,business.industry ,Payload ,International Space Station ,Atomic oxygen ,Space Shuttle ,business ,Space research ,Aerospace ,Remote sensing ,Space environment - Abstract
A space materials exposure experiment was condcuted on the exterior of the Russian Service Module (SM) of the International Space Station (ISS) using the Micro‐Particles Capturer and Space Environment Exposure Device (MPAC&SEED) of the Japan Aerospace Exploration Agency (JAXA). Results reveal artificial environment effects such as sample contamination, attitude change effects on AO fluence, and shading effects of UV on ISS. The sample contamination was coming from ISS components. The particles attributed to micrometeoroids and/or debris captured by MPAC might originate from the ISS solar array. Another MPAC&SEED will be aboard the Exposure Facility of the Japanese Experiment Module, KIBO Exposure Facility (EF) on ISS. The JEM/MPAC&SEED is attached to the Space Environment Data Acquisition Equipment‐Attached Payload (SEDA‐AP) and is exposed to space. Actually, SEDA‐AP is a payload on EF to be launched by Space Shuttle flight 2J/A. In fact, SEDA‐AP has space environment monitors such as a high‐energy particle monitor, atomic oxygen monitor, and plasma monitor to measure in‐situ natural space environment data during JEM/MPAC&SEED exposure. Some exposure samples for JEM/MPAC&SEED are identical to SM/MPAC&SEED samples. Consequently, effects on identical materials at different positions and operation periods of ISS will be evaluated. This report summarizes results from space environment monitoring samples for atomic oxygen analysis on SM/MPAC&SEED, along with experimental plans for JEM/MPAC&SEED.
- Published
- 2009
18. Preliminary Flight Data From the Materials Exposure and Degradation experiment (MEDET)
- Author
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A. P. Tighe, M. van Eesbeek, S. Duzellier, M. Dinguirard, D. Falguere, C. Pons, V. Inguimbert, C. Durin, S. Gabriel, D. Goulty, G. Roberts, and Jacob I. Kleiman
- Subjects
Earth's orbit ,Engineering ,Low earth orbit ,business.industry ,Material Degradation ,Space exposure ,Space Shuttle ,Local pressure ,Aerospace engineering ,business ,Flight data ,Simulation ,Space environment - Abstract
The Materials Exposure and Degradation Experiment (MEDET) was recently launched to the ISS on Space Shuttle Flight IE, as part of the EuTEF payload on the external payload facility of ESA’s Columbus module. The experiment will operate in‐orbit for at least 1.5 years, and has the overall objectives of evaluating the effects of the complex low Earth orbit space environment on material properties, investigating material degradation due to contamination, characterising the local ISS environment and measuring the local micro‐particle flux. This paper gives a brief overview of the experiment function and the material samples which are being exposed, before presenting some of the early flight data. In this phase of the mission, all of the instruments are operating successfully, and continuously acquiring data. The preliminary results mainly concern the environmental sensors, which are operating at relatively high acquisition rates (e.g. one reading every few seconds). It has been shown that the docking of the Space Shuttle to the ISS has a significant effect on the local pressure environment. The more complex degradation experiments are acquiring at much slower rates (e.g. one reading per day) and several more months of space exposure will be required before sufficient data is generated to reach conclusions about the behaviour of the materials. However, preliminary data is presented.
- Published
- 2009
19. EDDY CURRENT SYSTEM FOR DETECTION OF CRACKING BENEATH BRAIDING IN CORRUGATED METAL HOSE
- Author
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Buzz Wincheski, John Simpson, George Hall, Donald O. Thompson, and Dale E. Chimenti
- Subjects
Engineering ,Fabrication ,Design analysis ,business.industry ,Space Shuttle ,Mechanical engineering ,Metal hose ,Image processing ,Structural engineering ,law.invention ,Cracking ,law ,Eddy current ,Radiator (engine cooling) ,business - Abstract
In this paper an eddy current system for the detection of partially-through-the-thickness cracks in corrugated metal hose is presented. Design criteria based upon the geometry and conductivity of the part are developed and applied to the fabrication of a prototype inspection system. Experimental data are used to highlight the capabilities of the system and an image processing technique is presented to improve flaw detection capabilities. A case study for detection of cracking damage in a space shuttle radiator retract flex hoses is also presented.
- Published
- 2009
20. The Next Generation Advanced Video Guidance Sensor: Flight Heritage and Current Development
- Author
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Richard T. Howard, Thomas C. Bryan, and Glen A. Robertson
- Subjects
Engineering ,business.industry ,Video sensors ,Real-time computing ,Rendezvous ,Space Shuttle ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,First generation ,International Space Station ,Current sensor ,business ,Simulation ,Space rendezvous ,Constellation - Abstract
The Next Generation Advanced Video Guidance Sensor (NGAVGS) is the latest in a line of sensors that have flown four times in the last 10 years. The NGAVGS has been under development for the last two years as a long-range proximity operations and docking sensor for use in an Automated Rendezvous and Docking (AR&D) system. The first autonomous rendezvous and docking in the history of the U.S. Space Program was successfully accomplished by Orbital Express, using the Advanced Video Guidance Sensor (AVGS) as the primary docking sensor. That flight proved that the United States now has a mature and flight proven sensor technology for supporting Crew Exploration Vehicles (CEV) and Commercial Orbital Transport Systems (COTS) Automated Rendezvous and Docking (AR&D). NASA video sensors have worked well in the past: the AVGS used on the Demonstration of Autonomous Rendezvous Technology (DART) mission operated successfully in "spot mode" out to 2 km, and the first generation rendezvous and docking sensor, the Video Guidance Sensor (VGS), was developed and successfully flown on Space Shuttle flights in 1997 and 1998. This paper presents the flight heritage and results of the sensor technology, some hardware trades for the current sensor, and discusses the needs of future vehicles that may rendezvous and dock with the International Space Station (ISS) and other Constellation vehicles. It also discusses approaches for upgrading AVGS to address parts obsolescence, and concepts for minimizing the sensor footprint, weight, and power requirements. In addition, the testing of the various NGAVGS development units will be discussed along with the use of the NGAVGS as a proximity operations and docking sensor.
- Published
- 2009
21. MODELS IN THE DESIGN AND VALIDATION OF EDDY CURRENT INSPECTION FOR CRACKING IN THE SHUTTLE REACTION CONTROL SYSTEM THRUSTER
- Author
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John C. Aldrin, Phillip A. Williams, Buzz Wincheski, Donald O. Thompson, and Dale E. Chimenti
- Subjects
Engineering ,business.industry ,Space Shuttle ,Reaction control system ,law.invention ,Transducer ,Complex geometry ,law ,Nondestructive testing ,Eddy-current testing ,Eddy current ,Electronic engineering ,Aerospace engineering ,business ,Parametric statistics - Abstract
A case study is presented for using models in eddy current NDE design for crack detection in Shuttle Reaction Control System thruster components. Numerical methods were used to address the complex geometry of the part and perform parametric studies of potential transducer designs. Simulations were found to show agreement with experimental results. Accurate representation of the coherent noise associated with the measurement and part geometry was found to be critical to properly evaluate the best probe designs.
- Published
- 2009
22. THE NICMOS COOLING SYSTEM—5 YEARS OF SUCCESSFUL ON-ORBIT OPERATION
- Author
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W. L. Swift, F. X. Dolan, M. V. Zagarola, J. G. Weisend, John Barclay, Susan Breon, Jonathan Demko, Michael DiPirro, J. Patrick Kelley, Peter Kittel, Arkadiy Klebaner, Al Zeller, Mark Zagarola, Steven Van Sciver, Andrew Rowe, John Pfotenhauer, Tom Peterson, and Jennifer Lock
- Subjects
Physics ,Physics::Instrumentation and Detectors ,business.industry ,Bolometer ,Circulator ,Space Shuttle ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Cryogenics ,Cryocooler ,law.invention ,Telescope ,Optics ,law ,Heat exchanger ,Water cooling ,Astrophysics::Earth and Planetary Astrophysics ,Aerospace engineering ,business ,Astrophysics::Galaxy Astrophysics - Abstract
The NICMOS Cooling System consists of a closed-loop turbo-Brayton cryocooler coupled with a cryogenic circulator that provides refrigeration to the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope (HST). The cryocooler heat is rejected to space through a capillary pumped loop connected to radiators mounted on the side of the telescope. The system was deployed and integrated with NICMOS by astronauts during STS–109 (Space Shuttle Columbia) in March 2002. It has operated nearly continuously without performance degradation since that time, maintaining NICMOS detectors at a constant temperature of 77 K. Miniature, high-speed turbomachines are used in the cryocooler and the circulator loop to provide vibration-free, long-life operation. A small centrifugal compressor and miniature turboalternator are key elements of the closed loop cryocooler. A miniature cryogenic centrifugal circulator in a separate pressurized neon loop transports heat from the NICMOS instrument to the cryocooler interface heat exchanger. This paper describes the development of the system, key operational features, ground and orbital tests prior to its deployment, and operational results during its five-year operational history on orbit.
- Published
- 2008
23. An Exploration Perspective of Beamed Energy Propulsion
- Author
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John Cole and Andrew V. Pakhomov
- Subjects
Engineering ,Aeronautics ,Spacecraft propulsion ,business.industry ,In-space propulsion technologies ,Space Shuttle ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Technology readiness level ,Technology assessment ,Propulsion ,Space research ,business ,Space exploration - Abstract
The Vision for Exploration is currently focused on flying the Space Shuttle safely to complete our Space Station obligations, retiring the Shuttle in 2010, then returning humans to the Moon and learning how to proceed to Mars and beyond. The NASA budget still includes funds for science and aeronautics but the primary focus is on human exploration. Fiscal constraints have led to pursuing exploration vehicles that use heritage hardware, particularly existing boosters and engines, with the minimum modifications necessary to satisfy mission requirements. So, pursuit of immature technologies is not currently affordable by NASA. Beamed energy is one example of an immature technology, from a human exploration perspective, that may eventually provide significant benefits for human exploration of space, but likely not in the near future. Looking to the more distant future, this paper will examine some of the criteria that must be achieved by beamed energy propulsion to eventually contribute to human exploration of the solar system. The analysis focuses on some of the implications of increasing the payload fraction of a launch vehicle, with a quick look at trans-lunar injection. As one would expect, there is potential for benefit, and there are concerns. The analysis concludes with an assessment of the Technology Readiness Level (TRL) for some beamed energy propulsion components, indicating that TRL 2 is close to being completed.
- Published
- 2008
24. APPLICATION OF TERAHERTZ RADIATION TO THE DETECTION OF CORROSION UNDER THE SHUTTLE'S THERMAL PROTECTION SYSTEM
- Author
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Eric I. Madaras, Robert F. Anastasi, Stephen W. Smith, Jeffrey P. Seebo, James L. Walker, Janice K. Lomness, Paul E. Hintze, Catherine C. Kammerer, William P. Winfree, Richard W. Russell, Donald O. Thompson, and Dale E. Chimenti
- Subjects
animal structures ,Materials science ,genetic structures ,business.industry ,Terahertz radiation ,genetic processes ,Space Shuttle ,Ranging ,Terahertz nondestructive evaluation ,Structural engineering ,Corrosion ,Space Shuttle thermal protection system ,visual_art ,Nondestructive testing ,visual_art.visual_art_medium ,Optoelectronics ,natural sciences ,sense organs ,Tile ,business - Abstract
There is currently no method for detecting corrosion under Shuttle tiles except for the expensive process of tile removal and replacement; hence NASA is investigating new NDE methods for detecting hidden corrosion. Time domain terahertz radiation has been applied to corrosion detection under tiles in samples ranging from small lab samples to a Shuttle with positive results. Terahertz imaging methods have been able to detect corrosion at thicknesses of 5 mils or greater under 1” thick Shuttle tiles and 7‐12 mils or greater under 2” thick Shuttle tiles.
- Published
- 2008
25. MODELING OF TERAHERTZ RAY SIGNALS FOR NDE APPLICATIONS
- Author
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Chien-Ping Chiou, R. Bruce Thompson, James L. Blackshire, Donald O. Thompson, and Dale E. Chimenti
- Subjects
Flexibility (engineering) ,Materials science ,business.industry ,Terahertz radiation ,Point source ,Nondestructive testing ,Electronic engineering ,Space Shuttle ,Experimental data ,Spray foams ,Terahertz nondestructive evaluation ,Aerospace engineering ,business - Abstract
Recently, terahertz ray (T‐ray) imaging has emerged as one of the most promising new techniques for NDE applications. This technique, however, is still in its early development, and requires further studies. This work explores the use of state‐of‐the‐art computer modeling technologies to study T‐ray radiation in media. A series of point source synthesis models have been developed, using both the classic Fresnel‐Kirchhoff and the refined Rayleigh‐Sommerfeld formulations. The flexibility of these models enables us to investigate T‐ray propagation through interfaces of various geometry and morphology. That in turn allows us to simulate T‐ray interaction with flaws and hence to predict the flaw responses. In this paper, we present preliminary results of simulating T‐ray inspection of space shuttle's spray‐on foam insulation structure. Included are comparisons with experimental data of drilled holes embedded in foam sample.
- Published
- 2008
26. ANALYSIS OF EDDY CURRENT CAPABILITIES FOR THE DETECTION OF OUTER DIAMETER CRACKING IN SMALL BORE METALLIC STRUCTURES
- Author
-
Buzz Wincheski, Phillip Williams, John Simpson, Donald O. Thompson, and Dale E. Chimenti
- Subjects
Materials science ,Orientation (computer vision) ,business.industry ,Acoustics ,Space Shuttle ,Structural engineering ,Intergranular corrosion ,Finite element method ,law.invention ,Cracking ,law ,Eddy-current testing ,Eddy current ,Sensitivity (control systems) ,business - Abstract
The use of eddy current techniques for the detection of outer diameter damage in tubing and many complex aerospace structures often requires the use of an inner diameter probe due to a lack of access to the outside of the part. In small bore structures the probe size and orientation are constrained by the inner diameter of the part, complicating the optimization of the inspection technique. Detection of flaws through a significant remaining wall thickness becomes limited not only by the standard depth of penetration, but also geometrical aspects of the probe. Recently, an orthogonal eddy current probe was developed for detection of such flaws in space shuttle primary reaction control system (PRCS) thrusters. In this case, the detection of deeply buried intergranular cracking by an inner diameter eddy current probe was sought. Probe optimization was performed based upon the limiting spatial dimensions, flaw orientation, and required detection sensitivity. Analysis of the probe/flaw interaction was performed through the use of finite element modeling techniques. Experimental data for the flaw detection capabilities, including a probability of detection study, will be presented along with the simulation data. The results of this work have led to the successful deployment of an inspection system for the detection of intergranular cracking in PRCS thrusters.
- Published
- 2008
27. SOURCES OF AND REMEDIES FOR REMOVING UNWANTED REFLECTIONS IN MILLIMETER WAVE IMAGES OF COMPLEX SOFI-COVERED SPACE SHUTTLE STRUCTURES
- Author
-
S. Kharkovsky, R. Zoughi, F. L. Hepburn, Donald O. Thompson, and Dale E. Chimenti
- Subjects
Engineering ,Optics ,business.industry ,Nondestructive testing ,Extremely high frequency ,High resolution ,Space Shuttle ,Fuel tank ,business ,Interference (wave propagation) ,Polarization (waves) ,Signal - Abstract
In the recent years, continuous‐wave near‐field and lens‐focused millimeter wave imaging systems have been effectively used to demonstrate their utility for producing high‐resolution images of metallic structures covered with spay on foam insulation (SOFI) such as the Space Shuttle external fuel tank. However, for some specifc structures a certain interference pattern may be superimposed on the produced images. There are methods by which the influence of this unwanted interference can be reduced, such as the incorporation of an incidence angle and the proper use of signal polarization. This paper presents the basics of this problem and describes the use of the methods for reducing this unwanted influence through specific examples.
- Published
- 2008
28. Where Space Comes Down to Earth: Test Facilities for Exploration Systems
- Author
-
Jeffrey M. Woytach, Brian P. Willis, Gerald A. Carek, Jeffrey A. Chambers, and Diane L. Linne
- Subjects
Engineering ,Space technology ,Spacecraft ,business.industry ,Space Shuttle ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Mars Exploration Program ,computer.software_genre ,Aerospace engineering ,Vision for Space Exploration ,business ,Space research ,Space simulator ,computer ,Research center - Abstract
The NASA Glenn Research Center’s (GRC’s) Plum Brook Station has a complement of unique, highly capable facilities that can test space flight hardware ranging from development testing at the component, subsystem and system levels up to environmental qualification of very large spacecraft and extraterrestrial surface systems. The facilities can simulate the conditions of free space or the surfaces of the Moon or Mars, including atmospheric pressure and content, temperature and day/night cycles. This paper presents information on the facilities at the Plum Brook Station as they apply to the development of space systems that support the Vision for Space Exploration, and cites specific examples of testing to illustrate those capabilities.
- Published
- 2007
29. High Resolution Millimeter Wave Detection of Vertical Cracks in the Space Shuttle External Tank Spray-on-Foam Insulation (SOFI)
- Author
-
Reza Zoughi, S. Kharkovsky, and Frank L. Hepburn
- Subjects
Engineering ,business.industry ,Catastrophic failure ,Acoustics ,Nondestructive testing ,Drop tank ,Extremely high frequency ,High resolution ,Space Shuttle ,Spray foams ,Structural engineering ,business - Abstract
Space Shuttle Columbia’s catastrophic failure, the separation of a piece of spray‐on‐foam insulation (SOFI) from the external tank (ET) in the Space Shuttle Discovery’s flight in 2005 and crack detected in its ET foam prior to its successful launch in 2006 emphasize the need for effective nondestructive methods for inspecting the shuttle ET SOFI. Millimeter wave nondestructive testing methods have been considered as potential and effective inspection tools for evaluating the integrity of the SOFI. This paper presents recent results of an investigation for the purpose of detecting vertical cracks in SOFI panels using a focused millimeter wave (150 GHz) reflectometer. The presented images of the SOFI panels show the capability of this reflectometer for detecting tight vertical cracks (also as a function of crack opening dimension) in exposed SOFI panels and while covered by a piece of SOFI ramp simulating a more realistic and challenging situation.
- Published
- 2007
30. Imaging and Modeling Techniques for Terahertz Inspection of NASA-SOFI
- Author
-
Vikram R. Melapudi, Naveen V. Nair, Satish S. Udpa, William P. Winfree, and Lalita Udpa
- Subjects
Profiling (computer programming) ,Engineering ,Microwave imaging ,business.industry ,Terahertz radiation ,Drop tank ,Nondestructive testing ,Electronic engineering ,Medical imaging ,Space Shuttle ,Ray tracing (graphics) ,Aerospace engineering ,business - Abstract
Short‐pulsed terahertz imaging techniques have found application in recent years especially in the areas of nondestructive evaluation, homeland security and biomedical imaging. One such application involves the inspection of bonding between spray on foam insulation (SOFI) and the external tank in the NASA space shuttle. This work discusses a suite of image enhancement techniques that was developed to improve the probability of detection of voids and disbands SOFI. Physics based defect detection and profiling methods are detailed along with initial results. In addition a ray‐tracing model was developed to simulate the inspection process. Results comparing the model and experimental images will also be presented.
- Published
- 2007
31. NASA Engineering and Safety Center NDE Super Problem Resolution Team
- Author
-
W. H. Prosser
- Subjects
Engineering ,Government ,business.industry ,media_common.quotation_subject ,Space Shuttle ,Problem resolution ,Engineering management ,Resource (project management) ,Excellence ,Agency (sociology) ,Systems engineering ,Center (algebra and category theory) ,business ,nesC ,media_common - Abstract
The NASA Engineering and Safety Center (NESC) is an independent organization, which was charted in the wake of the Space Shuttle Columbia accident to serve as an Agency‐wide technical resource focused on engineering excellence. The objective of the NESC is to improve safety by performing in‐depth independent engineering assessments, testing, and analysis to uncover technical vulnerabilities and to determine appropriate preventative and corrective actions for problems, trends or issues within NASA’s programs, projects and institutions. Critical to the NESC are teams of experts in a number of core disciplines including nondestructive evaluation (NDE). These teams, designated Super Problem Resolution Teams (SPRTs), draw upon the best engineering expertise from across the Agency and include partnerships with other government agencies, national laboratories, universities and industry. The NESC NDE SPRT provides a ready resource of NDE technical expertise to support NESC Independent Technical Assessments and In...
- Published
- 2007
32. Processing Terahertz Ray Data in Space Shuttle Inspection
- Author
-
Jeffrey P. Seebo, Chien-Ping Chiou, R. Bruce Thompson, William P. Winfree, and Eric I. Madaras
- Subjects
Naive Bayes classifier ,Probabilistic neural network ,Signal processing ,Engineering ,Microwave imaging ,business.industry ,Nondestructive testing ,Real-time computing ,Electronic engineering ,Space Shuttle ,Image processing ,Context (language use) ,business - Abstract
Terahertz ray imaging is one of the most capable techniques to inspect the space shuttle external tank foam insulation. This technique, however, is limited in its current inspection protocol using indirect substrate reflections. An alternate signal processing approach, working directly on the flaw responses, was lately demonstrated to be able to overcome some of these limitations. In this paper, we report recent progresses made by utilizing this alternate signal processing procedure in additional samples to detect flaws that were missed by the current protocol. We also present a new detection approach using the probabilistic neural network in the context of Bayesian classification. Preliminary results showed that the new Bayesian classification approach can achieve even greater improvement over the alternate signal processing approach.
- Published
- 2007
33. Microwave and Millimeter Wave Imaging of the Space Shuttle External Fuel Tank Spray on Foam Insulation (SOFI) Using Synthetic Aperture Focusing Techniques (SAFT)
- Author
-
Sergey Kharkovsky, Reza Zoughi, Joseph T. Case, J T Robbins, and Frank L. Hepburn
- Subjects
Engineering ,Optics ,business.industry ,Thermal insulation ,Acoustics ,Nondestructive testing ,Drop tank ,Extremely high frequency ,Space Shuttle ,Spray foams ,Fuel tank ,business ,Microwave - Abstract
The Space Shuttle Columbia s catastrophic failure is thought to have been caused by a dislodged piece of external tank spray on foam insulation (SOFI) striking the left wing of the orbiter causing significant damage to some of the reinforced carbodcarbon leading edge wing panels. Microwave and millimeter wave nondestructive evaluation methods have shown great potential for inspecting SOFI for the purpose of detecting anomalies such as small air voids that may cause separation of the SOFI from the external tank during a launch. These methods are capable of producing relatively high-resolution images of the interior of SOFI particularly when advanced imaging algorithms are incorporated into the overall system. To this end, synthetic aperture focusing techniques (SAFT) are being developed. This paper presents some of the preliminary results of this investigation using SAFT-based methods and microwave holography at relatively low frequencies illustrating their potential capabilities for operation at millimeter wave frequencies.
- Published
- 2006
34. Thermal Characterization of TPS Tiles
- Author
-
K. V. Jata, K. J. LaCivita, C. J. Kacmar, and S. Sathish
- Subjects
Materials science ,visual_art ,Space Shuttle thermal protection system ,Thermal ,Thermography ,visual_art.visual_art_medium ,Space Shuttle ,Ceramic ,Composite material ,Damage tolerance ,Durability ,Characterization (materials science) - Abstract
The Thermal Protection System (TPS) used on space shuttles protects the metallic structure from the large amounts of heat created during travel through the atmosphere, both on takeoff and reentry. The shuttle experiences high thermo‐acoustic loading and impact damage from micro‐meteorites, which can cause disbonds, delaminations, chips, cracks, and other defects to the TPS system. To enhance durability and damage tolerance, new TPS tiles with an added protective ceramic‐matrix‐composite layer are being developed. This paper explores the use of pulsed thermography as a quick, diverse, non‐destructive technique, to characterize the TPS system. The pulsed thermography images obtained are presented and analyzed.
- Published
- 2006
35. Roles of Hydrogen in Space Explorations
- Author
-
Robert C. Bowman
- Subjects
Hydrogen ,Chemistry ,business.industry ,Hydrogen economy ,Hydrogen fuel ,chemistry.chemical_element ,Space Shuttle ,Hydrogen technologies ,Scramjet ,Cryogenics ,Aerospace engineering ,business ,Space exploration - Abstract
The various roles of hydrogen in space technology are identified and discussed. The preeminent position of hydrogen as rocket fuel in launch vehicles is explained and illustrated for the NASA Space Shuttle. The history of hydrogen in launching space vehicles is also briefly summarized. The cryogenic aspects of hydrogen for cooling instruments during flight missions are covered for several past and current systems. The technology of Nickel‐Hydrogen batteries is covered. The storage of cryogenic hydrogen to operate fuel cells and to provide potable water is described for the NASA Apollo and Shuttle Missions. Other less well‐known applications of hydrogen and metal hydrides such as gas gap heat switches, fueling hypersonic scramjet flights to Mach 10 speeds, in‐situ resource utilization on lunar or Martian surfaces, and providing ultrapure reference hydrogen to scientific instruments are also described. Finally, some possible future roles for hydrogen in space exploration are identified.
- Published
- 2006
36. The National Aeronautics and Space Administration Nondestructive Evaluation Program for Safe and Reliable Operations
- Author
-
Ed Generazio
- Subjects
Engineering ,Aeronautics ,business.industry ,Accident investigation ,Nondestructive testing ,International Space Station ,Space Shuttle ,Space (commercial competition) ,business ,Space Transportation System ,Administration (government) - Abstract
The National Aeronautics and Space Administration (NASA) Nondestructive Evaluation (NDE) Program is presented. As a result of the loss of seven astronauts and the Space Shuttle Columbia on February 1, 2003, NASA has undergone many changes in its organization. NDE is one of the key areas that are recognized by the Columbia Accident Investigation Board (CAIB) that needed to be strengthened by warranting NDE as a discipline with Independent Technical Authority (iTA). The current NASA NDE system and activities are presented including the latest developments in inspection technologies being applied to the Space Transportation System (STS). The unfolding trends and directions in NDE for the future are discussed as they apply to assuring safe and reliable operations.
- Published
- 2006
37. Structural Health Monitoring of the Space Shuttle’s Wing Leading Edge
- Author
-
William H. Prosser, Eric I. Madaras, Steven M. Ziola, Michael R. Gorman, and George Studor
- Subjects
Engineering ,Leading edge ,Wing ,Aeronautics ,business.industry ,Large array ,Space Shuttle ,Structural health monitoring ,Aerospace engineering ,business ,Sensing system ,Structural acoustics ,First generation - Abstract
In a response to the Columbia Accident Investigation Board’s recommendations following the loss of the Space Shuttle Columbia in 2003, NASA developed methods to monitor the orbiters while in flight so that on‐orbit repairs could be made before reentry if required. One method that NASA investigated was an acoustic based impact detection system. A large array of ground tests successfully demonstrated the capability to detect and localize impact events on the Shuttle’s wing structure. Subsequently, a first generation impact sensing system was developed and deployed on the Shuttle Discovery, the first Shuttle scheduled for return to flight.
- Published
- 2006
38. Modeling and Processing of Terahertz Imaging in Space Shuttle External Tank Foam Inspection
- Author
-
Eric I. Madaras, Jeffrey P. Seebo, William P. Winfree, Chien-Ping Chiou, and R. Bruce Thompson
- Subjects
Signal processing ,Engineering ,Terahertz radiation ,business.industry ,Drop tank ,Electronic engineering ,Spray foams ,Experimental data ,Space Shuttle ,Terahertz nondestructive evaluation ,Image processing ,business ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
Recently, terahertz ray (T‐ray) imaging emerged as one of the most promising techniques to inspect the space shuttle external tank foam insulation. This paper demonstrates the application of state‐of‐the‐art computer processing and modeling technologies to assist in further refinement of this new technology. The current protocol of T‐ray inspection and its limitations are first reviewed. New strategies of using signal processing and modeling are then proposed to improve on the flaw detection. Preliminary results are presented on a series of multi‐dimensional signal processing operations of T‐ray signals. The use of models and their comparisons with experimental data from foam samples are also included.
- Published
- 2006
39. Application of Eddy Current Techniques for Orbiter Reinforced Carbon-Carbon Structural Health Monitoring
- Author
-
Buzz Wincheski and John Simpson
- Subjects
Materials science ,business.industry ,Reinforced carbon–carbon ,Full scale ,Space Shuttle ,Structural engineering ,law.invention ,Orbiter ,law ,Eddy-current testing ,Nondestructive testing ,Eddy current ,Structural health monitoring ,Aerospace engineering ,business - Abstract
The development and application of advanced nondestructive evaluation techniques for the Reinforced Carbon-Carbon (RCC) components of the Space Shuttle Orbiter Leading Edge Structural Subsystem (LESS) was identified as a crucial step toward returning the shuttle fleet to service. In order to help meet this requirement, eddy current techniques have been developed for application to RCC components. Eddy current technology has been found to be particularly useful for measuring the protective coating thickness over the reinforced carbon-carbon and for the identification of near surface cracking and voids in the RCC matrix. Testing has been performed on as manufactured and flown RCC components with both actual and fabricated defects representing impact and oxidation damage. Encouraging initial results have led to the development of two separate eddy current systems for in-situ RCC inspections in the orbiter processing facility. Each of these systems has undergone blind validation testing on a full scale leading edge panel, and recently transitioned to Kennedy Space Center to be applied as a part of a comprehensive RCC inspection strategy to be performed in the orbiter processing facility after each shuttle flight.
- Published
- 2006
40. Consideration of Lower Allowable Impact Temperature for DOP-26 Iridium Alloy Fueled Clads
- Author
-
Emanuel A. Skrabek
- Subjects
Engineering ,Spacecraft ,business.industry ,Nuclear engineering ,General Purpose Heat Source ,Space Shuttle ,Parking orbit ,Radioisotope thermoelectric generator ,GPHS-RTG ,Ductility ,business ,Space research ,Simulation - Abstract
The current DOE General Purpose Heat Source (GPHS) was developed specifically for a SiGe Radioisotope Thermoelectric Generator (RTG) which was to be launched on a Space Shuttle. In such a launch, if the final stage of the deployed spacecraft failed to ignite, the spacecraft and RTG would reenter the atmosphere after about three months in a Shuttle parking orbit. The indium alloy clad containing the radioisotope fuel would have then been at about 1300° C for the entire time on orbit. This would lead to some grain growth in the clad material, which would tend to decrease its ductility. Due to these constraints, it was concluded by the heat source community that safety considerations would require that the clads be maintained at a temperature of at least 930° C through impact. The safety testing for the GPHS RTG programs was therefore conducted with these conditions as guides. Within this set of guidelines, the heat source was shown to be able to safely handle all credible launch and reentry accident events ...
- Published
- 2005
41. Technology and Applications of Terahertz Imaging Non-Destructive Examination: Inspection of Space Shuttle Sprayed On Foam Insulation
- Author
-
Jeffrey S. White, G. Stuk, William P. Winfree, David Zimdars, Eric I. Madaras, J. A. Valdmanis, and S. Williamson
- Subjects
Optical fiber ,Materials science ,Terahertz radiation ,business.industry ,Spray foams ,Space Shuttle ,Terahertz nondestructive evaluation ,law.invention ,law ,Nondestructive testing ,visual_art ,Electronic engineering ,visual_art.visual_art_medium ,Optoelectronics ,Ceramic ,business ,Electromagnetic pulse - Abstract
The implementation of terahertz (THz) imaging for non‐destructive evaluation shows great promise in 2 and 3 dimensional non‐contact inspection of non‐conductive materials such as plastics, foam, composites, ceramics, paper, wood and glass. THz imaging employs safe low power non‐ionizing electromagnetic pulses, which produce images with lateral resolution
- Published
- 2005
42. DSMC Simulations in Support of the STS-107 Accident Investigation
- Author
-
Katie A. Boyles, Gerald J. LeBeau, and Michael A. Gallis
- Subjects
Physics ,Leading edge ,business.industry ,Monte Carlo method ,Space Shuttle ,Aerodynamics ,Aerobraking ,law.invention ,Orbiter ,law ,Heat transfer ,Astrophysics::Earth and Planetary Astrophysics ,Direct simulation Monte Carlo ,Aerospace engineering ,business - Abstract
Three‐dimensional Direct Simulation Monte Carlo simulations of Columbia Shuttle Orbiter flight STS‐107 are presented. The aim of this work is to determine the aerodynamic and heating behavior of the Orbiter during aerobraking maneuvers and to provide piecewise integration of key scenario events to assess the plausibility of the candidate failure scenarios. The flight of the Orbiter is examined at two altitudes: 350 kft and 300 kft. The flow field around the Orbiter and the heat transfer to it are calculated for the undamaged configuration. The flow inside the wing for an assumed damage to the leading edge in the form of a 10‐inch hole is studied.
- Published
- 2005
43. Innovative Robot Archetypes for In-Space Construction and Maintenance
- Author
-
Brett Austin Kennedy, Robert O. Ambrose, S. Michael Goza, Myron A. Diftler, Fredrik Rehnmark, Nicolaus A. Radford, Joshua S. Mehling, Christopher Culbert, and Lyndon Bridgwater
- Subjects
Engineering ,business.industry ,Space Shuttle ,Robotics ,Maintenance engineering ,Remote manipulator ,International Space Station ,Systems engineering ,Robot ,Artificial intelligence ,Aerospace engineering ,Space Science ,business ,Space environment - Abstract
The space environment presents unique challenges and opportunities in the assembly, inspection and maintenance of orbital and transit spaceflight systems. While conventional Extra‐Vehicular Activity (EVA) technology, out of necessity, addresses each of the challenges, relatively few of the opportunities have been exploited due to crew safety and reliability considerations. Extra‐Vehicular Robotics (EVR) is one of the least‐explored design spaces but offers many exciting innovations transcending the crane‐like Space Shuttle and International Space Station Remote Manipulator System (RMS) robots used for berthing, coarse positioning and stabilization. Microgravity environments can support new robotic archetypes with locomotion and manipulation capabilities analogous to undersea creatures. Such diversification could enable the next generation of space science platforms and vehicles that are too large and fragile to launch and deploy as self‐contained payloads. Sinuous manipulators for minimally invasive inspection and repair in confined spaces, soft‐stepping climbers with expansive leg reach envelopes and free‐flying nanosatellite cameras can access EVA worksites generally not accessible to humans in spacesuits. These and other novel robotic archetypes are presented along with functionality concepts.
- Published
- 2005
44. Detection of Impact Damage on Space Shuttle Structures Using Acoustic Emission
- Author
-
William H. Prosser, Michael R. Gorman, and Eric I. Madaras
- Subjects
Materials science ,business.industry ,Spray foams ,Space Shuttle ,Terahertz nondestructive evaluation ,Structural engineering ,Acoustic emission ,Hypervelocity ,SPHERES ,sense organs ,Aerospace engineering ,business ,Structural acoustics ,Landing gear - Abstract
Studies of the acoustic signals originating from impact damage on Space Shuttle components were undertaken. Sprayed on foam insulation and small aluminum spheres were used as impactors. Shuttle reinforced carbon‐carbon panels, panels with Shuttle thermal protection tiles, and Shuttle main landing gear doors with tiles were targets. Ballistic speed and hypervelocity impacts over a wide range of impactor sizes, energies, and angles were tested. Additional tests were conducted to correlate the acoustic response of the test articles to actual Shuttle structures.
- Published
- 2005
45. Preliminary Analysis of ISS Maintenance History and Implications for Supportability of Future Missions
- Author
-
William W. Robbins and J. Kevin Watson
- Subjects
Engineering ,Aeronautics ,Corrective maintenance ,business.industry ,Human spaceflight ,International Space Station ,Maintainability ,Crew ,Space Shuttle ,Operations management ,business ,Preventive maintenance ,Maintenance engineering - Abstract
The International Space Station (ISS) enables the study of supportability issues associated with long-duration human spaceflight. The ISS is a large, complex spacecraft that must be maintained by its crew. In contrast to the Space Shuttle Orbiter vehicle, but similar to spacecraft that will be component elements of future missions beyond low-Earth orbit, ISS does not return to the ground for servicing and provisioning of spares is severely constrained by transportation limits. Although significant technical support is provided by ground personnel, all hands-on maintenance tasks are performed by the crew. It is expected that future missions to distant destinations will be further limited by lack of resupply opportunities and will, eventually, become largely independent of ground support. ISS provides an opportunity to begin learning lessons that will enable future missions to be successful. Data accumulated over the first several years of ISS operations have been analyzed to gain a better understanding of maintenance-related workload. This analysis addresses both preventive and corrective maintenance and includes all U.S segment core systems. Systems and tasks that are major contributors to workload are identified. As further experience accrues, lessons will be learned that will influence future system designs so that they require less maintenance and, when maintenance is required, it can be performed more efficiently. By heeding the lessons of ISS it will be possible to identify system designs that should be more robust and point towards advances in both technology and design that will offer the greatest return on investment.
- Published
- 2004
46. Neutron Diffraction Characterization of Residual Strain in Welded Inconel 718 for NASA Space Shuttle Flow Liners
- Author
-
Chandrasen Rameshlal Rathod, M. Femminineo, Mark A.M. Bourke, V. Livescu, Raj Vaidyanathan, Bjørn Clausen, and W. U. Notardonato
- Subjects
Materials science ,Neutron diffraction ,Metallurgy ,technology, industry, and agriculture ,Space Shuttle ,Cryogenics ,Welding ,respiratory system ,Residual ,Thermal expansion ,law.invention ,Residual stress ,law ,Inconel - Abstract
This work quantitatively assesses residual strains and stresses associated with the weld repair process used to repair cracks on NASA’s space shuttle flow liners. The coupons used in this investigation were made of the same INCONEL 718 alloy used for the flow liners. They were subjected to identical welding and certification procedures that were carried out on the space shuttle. Neutron diffraction measurements at Los Alamos National Laboratory determined residual strains at selected locations in a welded coupon at 293 K and 135 K. The weld repair process introduced Mises effective residual stresses of up to 555 MPa. On comparing the measurements at 293 K and 135 K, no significant change to the residual strain profile was noted at the low temperature. This indicated minimal mismatch in the coefficients of thermal expansion between the base metal and the weld.
- Published
- 2004
47. Business Context of Space Tourism
- Author
-
Harrison H. Schmitt
- Subjects
Marginal cost ,Service (business) ,Engineering ,business.industry ,Payload ,Space Shuttle ,Space (commercial competition) ,Computer security ,computer.software_genre ,Expendable launch system ,business ,Telecommunications ,Baseline (configuration management) ,computer ,Tourism - Abstract
Broadly speaking, two types of potential commercial activity in space can be defined. First, there are those activities that represent an expansion and improvement on services with broad existing commercial foundations such as telecommunications. The second type of potential commercial activity in space is one that may offer a type of service with few or any existing commercial foundations such as space‐based remote sensing. Space tourism clearly belongs in the first category of potential commercial activity in space. Roles in cooperation with the private sector that might be considered for NASA include 1) acceleration of the “Professional‐in Space” initiative, 2) research and technology developments related to a) a “Tourist Destination Module” for the Space Station, b) an “Extra Passengers Module” for the payload bay of the Space Shuttle, and c) a “Passenger‐rated Expendable Launch Vehicle,” 3) definition of criteria for qualifying candidate space tourists, and 4) initiatives to protect space tourism from unreasonable tort litigation. As baseline information for establishing fees, the cost of a possible tourist flight should be fully and objectively delineated. If it is correct that the marginal cost of each Space Shuttle flight to Earth‐orbit is about $100 million and the effective Shuttle payload is about 50,000 pounds, then the marginal cost would be roughly $2,000 per pound.
- Published
- 2003
48. NEPTranS; A Shuttle-Tended NEP Interplanetary Transportation System
- Author
-
John Elliott, Roy Y. Nakagawa, Thomas R. Spilker, Ronald J. Lipinski, David I. Poston, and Dean W. Moreland
- Subjects
Truck ,Engineering ,Ion thruster ,Spacecraft ,business.industry ,Software deployment ,Payload ,Rendezvous ,Space Shuttle ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Aerospace engineering ,business ,Interplanetary spaceflight - Abstract
Recently, a study was performed by a team from JPL and the DOE to develop a mission architecture for a reusable NEP Interplanetary Transfer Vehicle, a “Space Truck”. This vehicle is designed to be used for delivery of payloads from Earth to a variety of destinations, including Mars and Venus, dependent on mission needs. In addition to delivering payloads to the target bodies, the vehicle is designed to perform autonomous rendezvous and capture of sample return capsules at the destination for return to Earth. In order to maximize the utility of the vehicle, its design is optimized for servicing between missions with the Space Shuttle. Fuel tanks, ion thrusters, and Power Management and Distribution electronics are all on‐orbit replaceable units, located at the payload interface end of the spacecraft to ensure a minimal radiation dose to the Shuttle and crew during maintenance and resupply operations. Operational flexibility is maximized through the use of replaceable fuel tanks and thrusters, allowing tailoring of fuel load to any given destination and payload mass. This paper discusses the preliminary design developed for the NEP Interplanetary Transfer Vehicle, including its configuration and design features, and outlines the concept for mission design, including discussion of unique requirements for launch, deployment and operations with the Space Shuttle, and rendezvous and servicing by the Shuttle in Earth orbit following a return from each target destination.
- Published
- 2003
49. Flight Testing of the Capillary Pumped Loop 3 Experiment
- Author
-
Kwok Cheung, Robert W. Baldauff, Dan Butler, Triem T. Hoang, Laura Ottenstein, and Jentung Ku
- Subjects
Heat pipe ,Engineering ,Temperature control ,Continuous operation ,business.industry ,Nuclear engineering ,Radiator (engine cooling) ,Space Shuttle ,Sensitivity (control systems) ,Pressure regulator ,business ,Simulation ,Evaporator - Abstract
The Capillary Pumped Loop 3 (CAPL 3) experiment was a multiple evaporator capillary pumped loop experiment that flew in the Space Shuttle payload bay in December 2001 (STS‐108). The main objective of CAPL 3 was to demonstrate in micro‐gravity a multiple evaporator capillary pumped loop system, capable of reliable start‐up, reliable continuous operation, and heat load sharing, with hardware for a deployable radiator. Tests performed on orbit included start‐ups, power cycles, low power tests (100 W total), high power tests (up to 1447 W total), heat load sharing, variable/fixed conductance transition tests, and saturation temperature change tests. The majority of the tests were completed successfully, although the experiment did exhibit an unexpected sensitivity to shuttle maneuvers. This paper describes the experiment, the tests performed during the mission, and the test results.
- Published
- 2003
50. Electrochemical Evaluation of Alloys for Spaceport Design
- Author
-
Louis G. MacDowell, Rubiela Vinje, and Luz Marina Calle
- Subjects
Atmospheric exposure ,Materials science ,Test site ,Launch pad ,law ,Metallurgy ,Space Shuttle ,Corrosion ,law.invention ,Corrosion testing - Abstract
Corrosion studies began at the Kennedy Space Center (KSC) in 1966 during the Gemini/Apollo Programs with the evaluation of long‐term protective coatings for the corrosion protection of carbon steel. NASA’s KSC Beach Corrosion Test Site, which was established at that time, has been documented by the American Society of Materials (ASM) as one of the most corrosive naturally occurring environments in the world. With the introduction of the Space Shuttle in 1981, the already highly corrosive conditions at the launch pad were rendered even more severe by the acidic exhaust from the solid rocker boosters. In the years that followed, numerous studies have identified materials, coatings, and maintenance procedures for launch hardware and equipment exposed to the highly corrosive environment at the launch pad. The Corrosion Laboratory was established at KSC in 1985 and was outfitted with state‐of‐the‐art electrochemistry equipment to conduct research and materials characterization in many different corrosive environments. This paper will describe the application of electrochemistry in combination with atmospheric exposure to the selection of alloys in a spaceport environment.
- Published
- 2003
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