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1

X-33 Base Region Thermal Protection System Design Study  

NASA Technical Reports Server (NTRS)

The X-33 is an advanced technology demonstrator for validating critical technologies and systems required for an operational Single-Stage-to-Orbit (SSTO) Reusuable Launch Vehicle (RLV). Currently under development by a unique contractor/government team led by Lockheed- Martin Skunk Works (LMSW), and managed by Marshall Space Flight Center (MSFC), the X-33 will be the prototype of the first new launch system developed by the United States since the advent of the space shuttle. This paper documents a design trade study of the X-33 base region thermal protection system (TPS). Two candidate designs were evaluated for thermal performance and weight. The first candidate was a fully reusable metallic TPS using Inconel honeycomb panels insulated with high temperature fibrous insulation, while the second was an ablator/insulator sprayed on the metallic skin of the vehicle. The TPS configurations and insulation thickness requirements were determined for the predicted main engine plume heating environments and base region entry aerothermal environments. In addition to thermal analysis of the design concepts, sensitivity studies were performed to investigate the effect of variations in key parameters of the base TPS analysis.

Lycans, Randal W.

1998-01-01

2

Aerothermal Test of Thermal Protection Systems for X-33 Reusable Launch Vehicle  

NASA Technical Reports Server (NTRS)

An array of metallic Thermal Protection System (TPS) panels developed for the windward surface of the X-33 vehicle was tested in the 8-Foot High Temperature Tunnel at the NASA Langley Research Center. These tests were the first aerothermal tests of an X-33 TPS array and the test results will be used to validate the TPS for the X-33 flight program. Specifically, the tests evaluated the structural and thermal performance of the TPS, the effectiveness of the high temperature seals between adjacent panels and the durability of the TPS under realistic aerothermal flight conditions. The effect of varying panel-to-panel step heights, intentional damage to the seals between adjacent panels, and the use of secondary seals were also investigated during the test program. The metallic TPS developed for the windward surface of the X-33, the blanket TPS developed to protect the leeward surfaces of the X-33, and the test program in the 8-Foot High Temperature Tunnel are presented and discussed.

Sawyer, James Wayne; Hodge, Jefferson; Moore, Brad; Snyder, Kevin

1999-01-01

3

Thermal Management Design for the X-33 Lifting Body  

NASA Technical Reports Server (NTRS)

The X-33 Advantage Technology Demonstrator offers a rare and exciting opportunity in Thermal Protection System development. The experimental program incorporates the latest design innovation in re-useable, low life cycle cost, and highly dependable Thermal Protection materials and constructions into both ground based and flight test vehicle validations. The unique attributes of the X-33 demonstrator for design application validation for the full scale Reusable Launch Vehicle, (RLV), are represented by both the configuration of the stand-off aeroshell, and the extreme exposures of sub-orbital hypersonic re-entry simulation. There are several challenges of producing a sub-orbital prototype demonstrator of Single Stage to Orbit/Reusable Launch Vehicle (SSTO/RLV) operations. An aggressive schedule with budgetary constraints precludes the opportunity for an extensive verification and qualification program of vehicle flight hardware. However, taking advantage of off the shelf components with proven technologies reduces some of the requirements for additional testing. The effects of scale on thermal heating rates must also be taken into account during trajectory design and analysis. Described in this document are the unique Thermal Protection System (TPS) design opportunities that are available with the lifting body configuration of the X-33. The two principal objectives for the TPS are to shield the primary airframe structure from excessive thermal loads and to provide an aerodynamic mold line surface. With the relatively benign aeroheating capability of the lifting body, an integrated stand-off aeroshell design with minimal weight and reduced procurement and operational costs is allowed. This paper summarizes the design objectives of the X-33 TPS, the flight test requirements driven configuration, and design benefits. Comparisons are made of the X-33 flight profiles and Space Shuttle Orbiter, and lifting body Reusable Launch Vehicle aerothermal environments. The X-33 TPS is based on a design to cost configuration concept. Only RLV critical technologies are verified to conform to cost and schedule restrictions. The one-off prototype vehicle configuration has evolved to minimize the tooling costs by reducing the number of unique components. Low cost approaches such as a composite/blanket leeward aeroshell and the use of Shuttle technology are implemented where applicable. The success of the X-33 will overcome the ballistic re-entry TPS mindset. The X-33 TPS is tailored to an aircraft type mission while maintaining sufficient operational margins. The flight test program for the X-33 will demonstrate that TPS for the RLV is not simply a surface insulation but rather an integrated aeroshell system.

Bouslog, S.; Mammano, J.; Strauss, B.

1998-01-01

4

Task 4 supporting technology. Part 2: Detailed test plan for thermal seals. Thermal seals evaluation, improvement and test. CAN8-1, Reusable Launch Vehicle (RLV), advanced technology demonstrator: X-33. Leading edge and seals thermal protection system technology demonstration  

NASA Technical Reports Server (NTRS)

The objective is to develop the advanced thermal seals to a technology readiness level (TRL) of 6 to support the rapid turnaround time and low maintenance requirements of the X-33 and the future reusable launch vehicle (RLV). This program is divided into three subtasks: (1) orbiter thermal seals operation history review; (2) material, process, and design improvement; and (3) fabrication and evaluation of the advanced thermal seals.

Hogenson, P. A.; Lu, Tina

1995-01-01

5

Task 4 supporting technology. Part 2: Detailed test plan for thermal seals. Thermal seals evaluation, improvement and test. CAN8-1, Reusable Launch Vehicle (RLV), advanced technology demonstrator: X-33. Leading edge and seals thermal protection system technology demonstration  

NASA Astrophysics Data System (ADS)

The objective is to develop the advanced thermal seals to a technology readiness level (TRL) of 6 to support the rapid turnaround time and low maintenance requirements of the X-33 and the future reusable launch vehicle (RLV). This program is divided into three subtasks: (1) orbiter thermal seals operation history review; (2) material, process, and design improvement; and (3) fabrication and evaluation of the advanced thermal seals.

Hogenson, P. A.; Lu, Tina

1995-05-01

6

Cyclic Cryogenic Thermal-Mechanical Testing of an X-33/RLV Liquid Oxygen Tank Concept  

NASA Technical Reports Server (NTRS)

An important step in developing a cost-effective, reusable, launch vehicle is the development of durable, lightweight, insulated, cryogenic propellant tanks. Current cryogenic tanks are expendable so most of the existing technology is not directly applicable to future launch vehicles. As part of the X-33/Reusable Launch Vehicle (RLV) Program, an experimental apparatus developed at the NASA Langley Research Center for evaluating the effects of combined, cyclic, thermal and mechanical loading on cryogenic tank concepts was used to evaluate cryogenic propellant tank concepts for Lockheed-Martin Michoud Space Systems. An aluminum-lithium (Al 2195) liquid oxygen tank concept, insulated with SS-1171 and PDL-1034 cryogenic insulation, is tested under simulated mission conditions, and the results of those tests are reported. The tests consists of twenty-five simulated Launch/Abort missions and twenty-five simulated flight missions with temperatures ranging from -320 F to 350 F and a maximum mechanical load of 71,300 lb. in tension.

Rivers, H. Kevin

1999-01-01

7

Design, Development, And Testing of Umbilical System Mechanisms for the X-33 Advanced Technology Demonstrator  

NASA Technical Reports Server (NTRS)

The X-33 Advanced Technology Demonstrator is an un-piloted, vertical take-off, horizontal landing spacecraft. The purpose of the X-33 program is to demonstrate technologies that will dramatically lower the cost of access to space. The rocket-powered X-33 will reach an altitude of up to 100 km and speeds between Mach 13 and 15. Fifteen flight tests are planned, beginning in 2000. Some of the key technologies demonstrated will be the linear aerospike engine, improved thermal protection systems, composite fuel tanks and reduced operational timelines. The X-33 vehicle umbilical connections provide monitoring, power, cooling, purge, and fueling capability during horizontal processing and vertical launch operations. Two "rise-off" umbilicals for the X-33 have been developed, tested, and installed. The X-33 umbilical systems mechanisms incorporate several unique design features to simplify horizontal operations and provide reliable disconnect during launch.

Littlefield, Alan C.; Melton, Gregory S.

2000-01-01

8

[X-33 Systems  

NASA Technical Reports Server (NTRS)

Lockheed Martin Skunk Works has compiled an Annual Performance Report of the X-33/RLV Program. This report consists of individual reports from all industry team members, as well as NASA team centers. This portion of the report is comprised of a status report of Allied-Signal Aerospace's contribution to the program. The following is a summary of the work reviewed under their portion of the agreement: (1) Communication Systems; (2) Environmental Control Systems- Active Thermal Control System (ATCS), Purge and Vent System, Hydrogen Detection System (HDS), Avionics Bay Inerting System (ABIS), and Flush Air Data System (FADS); (2) Landing Systems; (3) Power Management and Generation Systems; (4) Flight Control Actuation System (FCAS)- Electric Power Control & Distribution System (EPCDS), and Battery Power System (BPS); and (5) Vehicle Management Systems (VMS)- VMS Hardware, VMS Software Development Activities, and System Integration Laboratory (SIL).

1999-01-01

9

X-33 Flight Visualization  

NASA Technical Reports Server (NTRS)

The X-33 flight visualization effort has resulted in the integration of high-resolution terrain data with vehicle position and attitude data for planned flights of the X-33 vehicle from its launch site at Edwards AFB, California, to landings at Michael Army Air Field, Utah, and Maelstrom AFB, Montana. Video and Web Site representations of these flight visualizations were produced. In addition, a totally new module was developed to control viewpoints in real-time using a joystick input. Efforts have been initiated, and are presently being continued, for real-time flight coverage visualizations using the data streams from the X-33 vehicle flights. The flight visualizations that have resulted thus far give convincing support to the expectation that the flights of the X-33 will be exciting and significant space flight milestones... flights of this nation's one-half scale predecessor to its first single-stage-to-orbit, fully-reusable launch vehicle system.

Laue, Jay H.

1998-01-01

10

X-33 Development History  

NASA Technical Reports Server (NTRS)

The problem of dealing with various types of proprietary documents, whether from the Lockheed Martin, the Skunk Works, McDonnell Douglas, Rockwell, and other corporations extant or extinct, remains unresolved. The computerized archive finding aid has over 100 records at present. These records consist of X-33 photographs, press releases, media clippings, and the small number of X-33 project records collected to date.

Butrica, Andrew J.

1997-01-01

11

Hypersonic Boundary-Layer Transition for X-33 Phase 2 Vehicle  

NASA Technical Reports Server (NTRS)

A status review of the experimental and computational work performed to support the X-33 program in the area of hypersonic boundary-layer transition is presented. Global transition fronts are visualized using thermographic phosphor measurements. Results are used to derive transition correlations for "smooth body" and discrete roughness data and a computational tool is developed to predict transition onset for X-33 using these results. The X-33 thermal protection system appears to be conservatively designed for transition effects based on these studies. Additional study is needed to address concerns related to surface waviness. A discussion of future test plans is included.

Thompson, Richard A.; Hamilton, Harris H., II; Berry, Scott A.; Horvath, Thomas J.; Nowak, Robert J.

1998-01-01

12

Aerothermal Test of Metallic TPS for X-33 Reusable Launch Vehicle  

NASA Technical Reports Server (NTRS)

An array of metallic Thermal Protection System (TPS) panels including the seals developed for the windward surface of the X-33 vehicle is being tested in the Eight Foot High Temperature Tunnel at the NASA Langley Research Center. These tests are the first aerothermal tests of an X-33 TPS array and will be used to validate the TPS for the X-33 flight program. Specifically, the tests will be used to evaluate the structural and thermal performance of the TPS, the effectiveness of the high temperature seals between adjacent tiles and the durability of the TPS under realistic aerothermal flight conditions. The effect of varying step heights, damage to the seals between adjacent panels, and the use of secondary seals will also be investigated during the test program. The metallic TPS developed for the windward surface of the X-33 and the test program in the Eight Foot High Temperature Tunnel is presented and discussed.

Sawyer, James Wayne; Hodge, Jefferson; Moore, Brad

1998-01-01

13

X-33. Phase 2  

NASA Technical Reports Server (NTRS)

In response to the Cooperative Agreement, Lockheed Martin Skunk Works has compiled an Annual Performance Report of the X-33/RLV Program. This report consists of individual reports from all industry team members, as well as NASA team centers. The first milestone was hand delivered to NASA MSFC. The second year has been one of significant accomplishment in which team members have demonstrated their ability to meet vital benchmarks while continuing on the technical adventure of the 20th century.

1998-01-01

14

X-33 Phase 2  

NASA Technical Reports Server (NTRS)

In response to Clause 17 of the Cooperative Agreement NCC8-115, Lockheed Martin Skunk Works has compiled an Annual Performance Report of the X-33/RLV Program. This report consists of individual reports from all industry team members, as well as NASA team centers. Contract award was announced on July 2, 1996 and the first milestone was hand delivered to NASA MSFC on July 17, 1996. The first year has been one of growth and progress as all team members staffed up and embarked on the technical adventure of the 20th century... the ultimate goal . . a Single Stage to Orbit (SSTO) Reuseable Launch Vehicle (RLV).

1997-01-01

15

The Lifting Body Legacy...X-33  

NASA Technical Reports Server (NTRS)

NASA has a technology program in place to enable the development of a next generation Reusable Launch Vehicle that will carry our future payloads into orbit at a much-reduced cost. The VentureStar, Lifting Body (LB) flight vehicle, is one of the potential reusable launch vehicle configurations being studied. A LB vehicle has no wings and derives its lift solely from the shape of its body, and has the unique advantages of superior volumetric efficiency, better aerodynamic efficiency at high angles-of-attack and hypersonic speeds, and reduced thermal protection system weight. Classically, in a ballistic vehicle, drag has been employed to control the level of deceleration in reentry. In the LB, lift enables the vehicle to decelerate at higher altitudes for the same velocity and defines the reentry corridor which includes a greater cross range. This paper outlines the flight stability and control aspects of our LB heritage which was utilized in the design of the VentureStar LB and its test version, the X-33. NASA and the U.S. Air Force have a rich heritage of LB vehicle design and flight experience. In the initial LB Program, eight LB's were built and over 225 LB test flights were conducted through 1975. Three LB series were most significant in the advancement of today's LB technolocy: the M2-F; the HL-10; and the X-24 series. The M2-F series was designed by NASA Ames Research Center, the HL-10 series by NASA Langley Research Center, and the X-24 series by the U. S. Air Force. LB vehicles are alive again today with the X- 33, X-38, and VentureStar.

Barret, Chris

1999-01-01

16

Artist concept of X-33 and Reusable Launch Vehicle (RLV)  

NASA Technical Reports Server (NTRS)

This artist's rendering depicts the NASA/Lockheed Martin X-33 technology demonstrator alongside the Venturestar, a Single-Stage-To-Orbit (SSTO) Reusable Launch Vehicle (RLV). The X-33, a half-scale prototype for the Venturestar, is scheduled to be flight tested in 1999. NASA's Dryden Flight Research Center, Edwards, California, plays a key role in the development and flight testing of the X-33. The RLV technology program is a cooperative agreement between NASA and industry. The goal of the RLV technology program is to enable signifigant reductions in the cost of access to space, and to promote the creation and delivery of new space services and other activities that will improve U.S. economic competitiveness. NASA Headquarter's Office of Space Access and Technology is overseeing the RLV program, which is being managed by the RLV Office at NASA's Marshall Space Flight Center, located in Huntsville, Alabama. The X-33 was a wedged-shaped subscale technology demonstrator prototype of a potential future Reusable Launch Vehicle (RLV) that Lockheed Martin had dubbed VentureStar. The company had hoped to develop VentureStar early this century. Through demonstration flight and ground research, NASA's X-33 program was to provide the information needed for industry representatives such as Lockheed Martin to decide whether to proceed with the development of a full-scale, commercial RLV program. A full-scale, single-stage-to-orbit RLV was to dramatically increase reliability and lower costs of putting a pound of payload into space, from the current figure of $10,000 to $1,000. Reducing the cost associated with transporting payloads in Low Earth Orbit (LEO) by using a commercial RLV was to create new opportunities for space access and significantly improve U.S. economic competitiveness in the world-wide launch marketplace. NASA expected to be a customer, not the operator, of the commercial RLV. The X-33 design was based on a lifting body shape with two revolutionary 'linear aerospike' rocket engines and a rugged metallic thermal protection system. The vehicle also had lightweight components and fuel tanks built to conform to the vehicle's outer shape. Time between X-33 flights was normally to have been seven days, but the program had hoped to demonstrate a two-day turnaround between flights during the flight-test phase of the program. The X-33 was to have been an unpiloted vehicle that took off vertically like a rocket and landed horizontally like an airplane. It was to have reached altitudes of up to 50 miles and high hypersonic speeds. The X-33 program was managed by the Marshall Space Flight Center and was to have been launched at a special launch site on Edwards Air Force Base. Due to technical problems with the liquid hydrogen tank, and the resulting cost increase and time delay, the X-33 program was cancelled in February 2001.

1997-01-01

17

X-33 Experimental Aeroheating at Mach 6 Using Phosphor Thermography  

NASA Technical Reports Server (NTRS)

The goal of the NASA Reusable Launch Vehicle (RLV) technology program is to mature and demonstrate essential, cost effective technologies for next generation launch systems. The X-33 flight vehicle presently being developed by Lockheed Martin is an experimental Single Stage to Orbit (SSTO) demonstrator that seeks to validate critical technologies and insure applicability to a full scale RLV. As with the design of any hypersonic vehicle, the aeroheating environment is an important issue and one of the key technologies being demonstrated on X-33 is an advanced metallic Thermal Protection System (TPS). As part of the development of this TPS system, the X-33 aeroheating environment is being defined through conceptual analysis, ground based testing, and computational fluid dynamics. This report provides an overview of the hypersonic aeroheating wind tunnel program conducted at the NASA Langley Research Center in support of the ground based testing activities. Global surface heat transfer images, surface streamline patterns, and shock shapes were measured on 0.013 scale (10-in.) ceramic models of the proposed X-33 configuration in Mach 6 air. The test parametrics include angles of attack from -5 to 40 degs, unit Reynolds numbers from 1x106 to 8x106/ft, and body flap deflections of 0, 10, and 20 deg. Experimental and computational results indicate the presence of shock/shock interactions that produced localized heating on the deflected flaps and boundary layer transition on the canted fins. Comparisons of the experimental data to laminar and turbulent predictions were performed. Laminar windward heating data from the wind tunnel was extrapolated to flight surface temperatures and generally compared to within 50 deg F of flight prediction along the centerline. When coupled with the phosphor technique, this rapid extrapolation method would serve as an invaluable TPS design tool.

Horvath, Thomas J.; Berry, Scott A.; Hollis, Brian R.; Liechty, Derek S.; Hamilton, H. Harris, II; Merski, N. Ronald

1999-01-01

18

Thermal insulation protection means  

NASA Technical Reports Server (NTRS)

A system for providing thermal insulation for portions of a spacecraft which do not exceed 900 F during ascent or reentry relative to the earth's atmosphere is described. The thermal insulation is formed of relatively large flexible sheets of needled Nomex felt having a flexible waterproof coating. The thickness of the felt is sized to protect against projected temperatures and is attached to the structure by a resin adhesive. Vent holes in the sheets allow ventilation while maintaining waterproofing. The system is heat treated to provide thermal stability.

Dotts, R. L.; Smith, J. A.; Strouhal, G. (inventors)

1979-01-01

19

X-33 Linear Aerospike Engine  

NASA Technical Reports Server (NTRS)

In July of 1999 two linear aerospike rocket engines will power the first flight of NASA's X-33 advanced technology demonstrator. A successful X-33 flight test program will validate the aerospike nozzle concept, a key technical feature of Lockheed Martin's VentureStar(trademark) reusable launch vehicle. The aerospike received serious consideration for NASA's current space shuttle, but was eventually rejected in 1969 in favor of high chamber pressure bell engines, in part because of perceived technical risk. The aerospike engine (discussed below) has several performance advantages over conventional bell engines. However, these performance advantages are difficult to validate by ground test. The space shuttle, a multibillion dollar program intended to provide all of NASA's future space lift could not afford the gamble of choosing a potentially superior though unproven aerospike engine over a conventional bell engine. The X-33 demonstrator provides an opportunity to prove the aerospike's performance advantage in flight before commiting to an operational vehicle.

Vinson, John

1998-01-01

20

Thermal Protection and Control  

NASA Technical Reports Server (NTRS)

During all phases of a spacecraft's mission, a Thermal Protection System (TPS) is needed to protect the vehicle and structure from extreme temperatures and heating. When designing TPS, low weight and cost while ensuring the protection of the vehicle is highly desired. There are two main types of TPS, ablative and reusable. The Apollo missions needed ablators due to the high heat loads from lunar reentry. However, when the desire for a reusable space vehicle emerged, the resultant_ Space Shuttle program propelled a push for the development of reusable TPS. With the growth of reqsable TPS, the need for ablators declined, triggering a drop off of the ablator industry. As a result, the expertise was not heavily maintained within NASA or the industry. When the Orion Program initiated a few years back, a need. for an ablator reemerged. Yet, due to of the lack of industry capability, redeveloping the ablator material took several years and came at a high cost. As NASA looks towards the future with both the Orion and Commercial Crew Programs, a need to preserve reusable, ablative, and other TPS technologies is essential. Research of the different TPS materials alongside their properties, capabilities, and manufacturing process was performed, and the benefits of the materials were analyzed alongside the future of TPS. Knowledge of the different technologies has the ability to help us know what expertise to maintain and ensure a lack in the industry does not occur again.

Greene, Effie E.

2013-01-01

21

Thermal protection apparatus  

DOEpatents

An apparatus for thermally protecting heat sensitive components of tools. The apparatus comprises a Dewar for holding the heat sensitive components. The Dewar has spaced-apart inside and outside walls, an open top end and a bottom end. An insulating plug is located in the top end. The inside wall has portions defining an inside wall aperture located at the bottom of the Dewar and the outside wall has portions defining an outside wall aperture located at the bottom of the Dewar. A bottom connector has inside and outside components. The inside component sealably engages the inside wall aperture and the outside component sealably engages the outside wall aperture. The inside component is operatively connected to the heat sensitive components and to the outside component. The connections can be made with optical fibers or with electrically conducting wires.

Bennett, Gloria A. (Los Alamos, NM); Moore, Troy K. (Los Alamos, NM)

1988-01-01

22

Thermal Protection Materials  

NASA Technical Reports Server (NTRS)

Thermal protection materials and systems (TPS) are required to protect a vehicle returning from space or entering an atmosphere. The selection of the material depends on the heat flux, heat load, pressure, and shear and other mechanical loads imposed on the material, which are in turn determined by the vehicle configuration and size, location on the vehicle, speed, a trajectory, and the atmosphere. In all cases the goal is to use a material that is both reliable and efficient for the application. Reliable materials are well understood and have sufficient test data under the appropriate conditions to provide confidence in their performance. Efficiency relates to the behavior of a material under the specific conditions that it encounters TPS that performs very well at high heat fluxes may not be efficient at lower heat fluxes. Mass of the TPS is a critical element of efficiency. This talk will review the major classes of TPS, reusable or insulating materials and ablators. Ultra high temperature ceramics for sharp leading edges will also be reviewed. The talk will focus on the properties and behavior of these materials.

Johnson, Sylvia M.

2011-01-01

23

X-33 Flight Operations Center  

NASA Technical Reports Server (NTRS)

In response to Clause 17 of the Cooperative Agreement NCC8-115, Lockheed Martin Skunk Works has compiled an Annual Performance Report of the X-33/RLV Program. This report consists of individual reports from all industry team members, as well as NASA team centers. Contract award was announced on July 2, 1996 and the first milestone was hand delivered to NASA MSFC on July 17, 1996. With the dedication of the launch site, and continuing excellence in technological achievement, the third year of the Cooperative Agreement has been one of outstanding accomplishment and excitement.

1999-01-01

24

X-33 Leading the Way to VentureStar(Trademark) in this Decade  

NASA Technical Reports Server (NTRS)

The X-33, reusable space plane technology demonstrator is on course to begin the flights of the X-33 by the end of 2002 that will serve as a basis for industry and government decisions that could lead to VentureStar(Trademark). Lockheed Martin has placed the VentureStar(Trademark) LLC in it's Space Company and is now competing in an industry wide effort that will permit NASA to select a Second Generation RLV source by 2005. This move provides the focus for firm business planning needed to enable the decision by the time X-33 flies in mid 2002 and possibly with upgraded technologies a year or so later. Since the IAF 50th Congress in Amsterdam, most of the major hardware elements of X-33 have been through their assembly and test. The flight liquid oxygen tank was the first major element to complete final assembly. Aerospike Engine qualification testing has progressed successfully through its test objectives and the two flight engines are in preparation to be delivered to the Assembly Facility in Palmdale. All Thermal Protection System (TPS) metallic panels have completed qualification testing and have been delivered to Palmdale and all remaining TPS elements have been assembled and are ready for delivery. Flight Software and Avionics have been delivered and are in integration testing. In November 1999, the first graphite composite liquid hydrogen tank experienced a debond between the tank inner skin and the honeycomb core in testing. This tank had completed its third successful cryogenic and loads testing at MSFC. Replacement liquid hydrogen tanks have completed design and are in fabrication. The resulting delay from this change of design for the liquid hydrogen tank will be approximately two years.

Austin, Robert E.; Rising, Jerry J.

2000-01-01

25

Unpowered thermal memory protection for circuit breakers  

Microsoft Academic Search

The National Fire Protection Association (NFPA) 70, National Electrical Code contains extensive information and requirements for overcurrent protection and temperature limitations of conductors. Thermal-magnetic trip units in circuit breakers provide protection for overloads and short circuit faults in electrical distribution systems. The magnetic element protects against short circuit faults and a bimetal element protects against overloaded thermal conditions. Electronic trip

James Lagree; Christopher Walker

2010-01-01

26

Shell tile thermal protection system  

NASA Technical Reports Server (NTRS)

A reusable, externally applied thermal protection system for use on aerospace vehicles subject to high thermal and mechanical stresses utilizes a shell tile structure which effectively separates its primary functions as an insulator and load absorber. The tile consists of structurally strong upper and lower metallic shells manufactured from materials meeting the thermal and structural requirements incident to tile placement on the spacecraft. A lightweight, high temperature package of insulation is utilized in the upper shell while a lightweight, low temperature insulation is utilized in the lower shell. Assembly of the tile which is facilitated by a self-locking mechanism, may occur subsequent to installation of the lower shell on the spacecraft structural skin.

Macconochie, I. O.; Lawson, A. G.; Kelly, H. N. (inventors)

1984-01-01

27

Testing the Preliminary X-33 Navigation System  

NASA Technical Reports Server (NTRS)

The X-33 Reusable Launch Vehicle (RLV) must meet the demanding requirements of landing autonomously on a narrow landing strip following a flight that reaches an altitude of up to 200,000 feet and a speed in excess of Mach 9 with significant in-flight energy bleed-off maneuvers. To execute this flight regimen a highly reliable avionics system has been designed that includes three LN-100G Inertial Navigation System/Global Positioning System (INS/GPS) units as the primary navigation system for the X-33. NASA's Marshall Space Flight Center (MSFC) tested an INS/GPS system in real-time simulations to determine the ability of this navigation suite to meet the in flight and autonomous landing requirements of the X-33 RLV. A total of sixty-one open loop tests were performed to characterize the navigation accuracy of the LN-100G. Twenty-seven closed-loop tests were also performed to evaluate the performance of the X-33 Guidance, Navigation and Control (GN&C) algorithms with the real navigation hardware. These closed-loop tests were also designed to expose any integration or operational issues with the real-time X-33 vehicle simulation. Dynamic road tests of the INS/GPS were conducted by Litton to assess the performance of differential and nondifferential INS/GPS hybrid navigation solutions. The results of the simulations and road testing demonstrate that this novel solution is capable of meeting the demanding requirements of take-off, in-flight navigation, and autonomous landing of the X-33 RLV. This paper describes the test environment developed to stimulate the LN-100G and discusses the results of this test effort. This paper also presents recommendations for a navigation system suitable to an operational RLV system.

Lomas, James J.; Mitchell, Daniel W.; Freestone, Todd M.; Lee, Charles; Lessman, Craig; Foster, Lee D. (Technical Monitor)

2001-01-01

28

The X-33 range Operations Control Center  

NASA Technical Reports Server (NTRS)

This paper describes the capabilities and features of the X-33 Range Operations Center at NASA Dryden Flight Research Center. All the unprocessed data will be collected and transmitted over fiber optic lines to the Lockheed Operations Control Center for real-time flight monitoring of the X-33 vehicle. By using the existing capabilities of the Western Aeronautical Test Range, the Range Operations Center will provide the ability to monitor all down-range tracking sites for the Extended Test Range systems. In addition to radar tracking and aircraft telemetry data, the Telemetry and Radar Acquisition and Processing System is being enhanced to acquire vehicle command data, differential Global Positioning System corrections and telemetry receiver signal level status. The Telemetry and Radar Acquisition Processing System provides the flexibility to satisfy all X-33 data processing requirements quickly and efficiently. Additionally, the Telemetry and Radar Acquisition Processing System will run a real-time link margin analysis program. The results of this model will be compared in real-time with actual flight data. The hardware and software concepts presented in this paper describe a method of merging all types of data into a common database for real-time display in the Range Operations Center in support of the X-33 program. All types of data will be processed for real-time analysis and display of the range system status to ensure public safety.

Shy, Karla S.; Norman, Cynthia L.

1998-01-01

29

Thermal protection system ablation sensor  

NASA Technical Reports Server (NTRS)

An isotherm sensor tracks space vehicle temperatures by a thermal protection system (TPS) material during vehicle re-entry as a function of time, and surface recession through calibration, calculation, analysis and exposed surface modeling. Sensor design includes: two resistive conductors, wound around a tube, with a first end of each conductor connected to a constant current source, and second ends electrically insulated from each other by a selected material that becomes an electrically conductive char at higher temperatures to thereby complete an electrical circuit. The sensor conductors become shorter as ablation proceeds and reduced resistance in the completed electrical circuit (proportional to conductor length) is continually monitored, using measured end-to-end voltage change or current in the circuit. Thermocouple and/or piezoelectric measurements provide consistency checks on local temperatures.

Gorbunov, Sergey (Inventor); Martinez, Edward R. (Inventor); Scott, James B. (Inventor); Oishi, Tomomi (Inventor); Fu, Johnny (Inventor); Mach, Joseph G. (Inventor); Santos, Jose B. (Inventor)

2011-01-01

30

Current Technology for Thermal Protection Systems  

NASA Technical Reports Server (NTRS)

Interest in thermal protection systems for high-speed vehicles is increasing because of the stringent requirements of such new projects as the Space Exploration Initiative, the National Aero-Space Plane, and the High-Speed Civil Transport, as well as the needs for improved capabilities in existing thermal protection systems in the Space Shuttle and in turbojet engines. This selection of 13 papers from NASA and industry summarizes the history and operational experience of thermal protection systems utilized in the national space program to date, and also covers recent development efforts in thermal insulation, refractory materials and coatings, actively cooled structures, and two-phase thermal control systems.

Scotti, Stephen J. (compiler)

1992-01-01

31

VentureStar(trademark) Reaping the Benefits of the X-33 Program  

NASA Technical Reports Server (NTRS)

Major X-33 flight hardware has been delivered, and assembly of the vehicle is well underway in anticipation of its flight test program commencing in the summer of 1999. Attention has now turned to the operational VentureStar(trademark), the first single-stage-to-orbit (SSTO) reusable launch vehicle. Activities are grouped under two broad categories: (1) vehicle development and (2) market/business planning, each of which is discussed. The mission concept is presented for direct payload delivery to the International Space Station and to low Earth orbit, as well as payload delivery with an upper stage to Geosynchronous Transfer Orbit (GTO) and other high energy orbits. System requirements include flight segment and ground segment. Vehicle system sizing and design status is provided including the application of X-33 traceability and lessons learned. Technology applications to the VentureStar(trademark) are described including the structure, propellant tanks, thermal protection system, aerodynamics, subsystems, payload bay and propulsion. Developing a market driven low cost launch services system for the 21 st Century requires traditional and non-traditional ways of being able to forecast the evolution of the potential market. The challenge is balancing both the technical and financial assumptions of the market. This involves the need to provide a capability to meet market segments that in some cases are very speculative, while at the same time providing the financial community with a credible revenue stream.

Sumrall, J.; Lane, C.

1998-01-01

32

X-33 HYPERSONIC BOUNDARY LAYER TRANSITION  

Microsoft Academic Search

Boundary layer and aeroheating characteristics of several X-33 configurations have been experimentally examinedin the Langley 20-Inch Mach 6 Air Tunnel. Global surface heat transfer distributions, surface streamlinepatterns, and shock shapes were measured on 0.013-scale models at Mach 6 in air. Parametric variations includeangles-of-attack of 20-deg, 30-deg, and 40-deg; Reynolds numbers based on model length of 0.9 to 6.6 million; andbody-flap

Scott A. Berry; Thomas J. Horvath; Brian R. Hollis; Richard A. Thompson; H. Harris Hamilton

1999-01-01

33

Computer graphic of Lockheed Martin X-33 Reusable Launch Vehicle (RLV) mounted on NASA 747 ferry air  

NASA Technical Reports Server (NTRS)

This is an artist's conception of the NASA/Lockheed Martin X-33 Advanced Technology Demonstrator being carried on the back of the 747 Shuttle Carrier Aircraft. This was a concept for moving the X-33 from its landing site back to NASA's Dryden Flight Research Center, Edwards, California. The X-33 was a technology demonstrator vehicle for the Reusable Launch Vehicle (RLV). The RLV technology program was a cooperative agreement between NASA and industry. The goal of the RLV technology program was to enable significant reductions in the cost of access to space, and to promote the creation and delivery of new space services and other activities that will improve U.S. economic competitiveness. NASA Headquarter's Office of Space Access and Technology oversaw the RLV program, which was being managed by the RLV Office at NASA's Marshall Space Flight Center, located in Huntsville, Alabama. Responsibilities of other NASA Centers included: Johnson Space Center, Houston, Texas, guidance navigation and control technology, manned space systems, and health technology; Ames Research Center, Mountain View, CA., thermal protection system testing; Langley Research Center, Langley, Virginia, wind tunnel testing and aerodynamic analysis; and Kennedy Space Center, Florida, RLV operations and health management. Lockheed Martin's industry partners in the X-33 program are: Astronautics, Inc., Denver, Colorado, and Huntsville, Alabama; Engineering & Science Services, Houston, Texas; Manned Space Systems, New Orleans, LA; Sanders, Nashua, NH; and Space Operations, Titusville, Florida. Other industry partners are: Rocketdyne, Canoga Park, California; Allied Signal Aerospace, Teterboro, NJ; Rohr, Inc., Chula Vista, California; and Sverdrup Inc., St. Louis, Missouri.

1997-01-01

34

Development of Processing Techniques for Advanced Thermal Protection Materials  

NASA Technical Reports Server (NTRS)

Thermal Protection Materials Branch (TPMB) has been involved in various research programs to improve the properties and structural integrity of the existing aerospace high temperature materials. Specimens from various research programs were brought into the analytical laboratory for the purpose of obtaining and refining the material characterization. The analytical laboratory in TPMB has many different instruments which were utilized to determine the physical and chemical characteristics of materials. Some of the instruments that were utilized by the SJSU students are: Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), X-ray Diffraction Spectrometer (XRD), Fourier Transform-Infrared Spectroscopy (FTIR), Ultra Violet Spectroscopy/Visible Spectroscopy (UV/VIS), Particle Size Analyzer (PSA), and Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). The above mentioned analytical instruments were utilized in the material characterization process of the specimens from research programs such as: aerogel ceramics (I) and (II), X-33 Blankets, ARC-Jet specimens, QUICFIX specimens and gas permeability of lightweight ceramic ablators. In addition to analytical instruments in the analytical laboratory at TPMB, there are several on-going experiments. One particular experiment allows the measurement of permeability of ceramic ablators. From these measurements, physical characteristics of the ceramic ablators can be derived.

Selvaduray, Guna; Cox, Michael; Srinivasan, Vijayakumar

1997-01-01

35

X-33/RLV Program Aerospike Engines  

NASA Technical Reports Server (NTRS)

Substantial progress was made during the past year in support of the X-33/RLV program. X-33 activity was directed towards completing the remaining design work and building hardware to support test activities. RLV work focused on the nozzle ramp and powerpack technology tasks and on supporting vehicle configuration studies. On X-33, the design activity was completed to the detail level and the remainder of the drawings were released. Component fabrication and engine assembly activity was initiated, and the first two powerpacks and the GSE and STE needed to support powerpack testing were completed. Components fabrication is on track to support the first engine assembly schedule. Testing activity included powerpack testing and component development tests consisting of thrust cell single cell testing, CWI system spider testing, and EMA valve flow and vibration testing. Work performed for RLV was divided between engine system and technology development tasks. Engine system activity focused on developing the engine system configuration and supporting vehicle configuration studies. Also, engine requirements were developed, and engine performance analyses were conducted. In addition, processes were developed for implementing reliability, mass properties, and cost controls during design. Technology development efforts were divided between powerpack and nozzle ramp technology tasks. Powerpack technology activities were directed towards the development of a prototype powerpack and a ceramic turbine technology demonstrator (CTTD) test article which will allow testing of ceramic turbines and a close-coupled gas generator design. Nozzle technology efforts were focused on the selection of a composite nozzle supplier and on the fabrication and test of composite nozzle coupons.

1999-01-01

36

Flutter Analysis of the X-33  

NASA Technical Reports Server (NTRS)

Flutter analysis performed in support of the X33 Advanced Technology Demonstrator is described. Analysis was conducted over a range of flow regimes using several different analysis codes. The finite element and aerodynamic models used in the analysis have undergone several years of development and refinement resulting in a high degree of model detail. The flutter analysis focuses on the area of three critical points within the vehicle's design trajectory at which full sets of external loads have previously been developed. A comparison between several different aerodynamic models is also made for the selected trajectory points.

Fowler, Samuel B.

2000-01-01

37

The X-33/VentureStar Program  

NASA Technical Reports Server (NTRS)

The VentureStar reusable launch vehicle is discussed in this viewgraph presentation. The objectives of the VentureStar program are reviewed: (1) expendables cost too much, (2) commercial space market is growing (3) meets NASA's goals, (4) Users want fast ground turnaround, (5) users want quick access to space, (6) the offline payload processing saves time, (7) low cost access to space will enable new markets. Flight tests of the X-33, which was designed to test the technology and is pictured in several slides, built credibility for VentureStar. One slide shows the dimensions, weight, length, LEO payload capacity, and the propulsion, in comparison for the X-33, the VentureStar, the Space Shuttle, the Proton D-1e, and the Ariane V. Yet other slides outline the vehicle's features, the plan for the operation of the vehicle, from the runway, to the pad, to orbit. The planned containerized payload operation will allow for a 7 day turnaround for the system, which will allow for the planned 40 flights per year.

Laube, J.

1998-01-01

38

X-33 Hypersonic Boundary Layer Transition  

NASA Technical Reports Server (NTRS)

Boundary layer and aeroheating characteristics of several X-33 configurations have been experimentally examined in the Langley 20-Inch Mach 6 Air Tunnel. Global surface heat transfer distributions, surface streamline patterns, and shock shapes were measured on 0.013-scale models at Mach 6 in air. Parametric variations include angles-of-attack of 20-deg, 30-deg, and 40-deg; Reynolds numbers based on model length of 0.9 to 6.6 million; and body-flap deflections of 0, 10 and 20-deg. The effects of discrete and distributed roughness elements on boundary layer transition, which included trip height, size, location, and distribution, both on and off the windward centerline, were investigated. The discrete roughness results on centerline were used to provide a transition correlation for the X-33 flight vehicle that was applicable across the range of reentry angles of attack. The attachment line discrete roughness results were shown to be consistent with the centerline results, as no increased sensitivity to roughness along the attachment line was identified. The effect of bowed panels was qualitatively shown to be less effective than the discrete trips; however, the distributed nature of the bowed panels affected a larger percent of the aft-body windward surface than a single discrete trip.

Berry, Scott A.; Horvath, Thomas J.; Hollis, Brian R.; Thompson, Richard A.; Hamilton, H. Harris, II

1999-01-01

39

Current technology for thermal protection systems  

SciTech Connect

Interest in thermal protection systems for high-speed vehicles is increasing because of the stringent requirements of such new projects as the Space Exploration Initiative, the National Aero-Space Plane, and the High-Speed Civil Transport, as well as the needs for improved capabilities in existing thermal protection systems in the Space Shuttle and in turbojet engines. This selection of 13 papers from NASA and industry summarizes the history and operational experience of thermal protection systems utilized in the national space program to date, and also covers recent development efforts in thermal insulation, refractory materials and coatings, actively cooled structures, and two-phase thermal control systems. Separate abstracts were prepared for papers of this report.

Scotti, S.J.

1992-10-01

40

Current Technology for Thermal Protection Systems  

Microsoft Academic Search

Interest in thermal protection systems for high-speed vehicles is increasing because of the stringent requirements of such new projects as the Space Exploration Initiative, the National Aero-Space Plane, and the High-Speed Civil Transport, as well as the needs for improved capabilities in existing thermal protection systems in the Space Shuttle and in turbojet engines. This selection of 13 papers from

Stephen J. Scotti

1992-01-01

41

Large thermal protection system panel  

NASA Technical Reports Server (NTRS)

A protective panel for a reusable launch vehicle provides enhanced moisture protection, simplified maintenance, and increased temperature resistance. The protective panel includes an outer ceramic matrix composite (CMC) panel, and an insulative bag assembly coupled to the outer CMC panel for isolating the launch vehicle from elevated temperatures and moisture. A standoff attachment system attaches the outer CMC panel and the bag assembly to the primary structure of the launch vehicle. The insulative bag assembly includes a foil bag having a first opening shrink fitted to the outer CMC panel such that the first opening and the outer CMC panel form a water tight seal at temperatures below a desired temperature threshold. Fibrous insulation is contained within the foil bag for protecting the launch vehicle from elevated temperatures. The insulative bag assembly further includes a back panel coupled to a second opening of the foil bag such that the fibrous insulation is encapsulated by the back panel, the foil bag, and the outer CMC panel. The use of a CMC material for the outer panel in conjunction with the insulative bag assembly eliminates the need for waterproofing processes, and ultimately allows for more efficient reentry profiles.

Myers, Franklin K. (Inventor); Weinberg, David J. (Inventor); Tran, Tu T. (Inventor)

2003-01-01

42

System Identification of X-33 Neural Network  

NASA Technical Reports Server (NTRS)

Modern flight control research has improved spacecraft survivability as its goal. To this end we need to have a failure detection system on board. In case the spacecraft is performing imperfectly, reconfiguration of control is needed. For that purpose we need to have parameter identification of spacecraft dynamics. Parameter identification of a system is called system identification. We treat the system as a black box which receives some inputs that lead to some outputs. The question is: what kind of parameters for a particular black box can correlate the observed inputs and outputs? Can these parameters help us to predict the outputs for a new given set of inputs? This is the basic problem of system identification. The X33 was supposed to have the onboard capability of evaluating the current performance and if needed to take the corrective measures to adapt to desired performance. The X33 is comprised of both rocket and aircraft vehicle design characteristics and requires, in general, analytical methods for evaluating its flight performance. Its flight consists of four phases: ascent, transition, entry and TAEM (Terminal Area Energy Management). It spends about 200 seconds in ascent phase, reaching an altitude of about 180,000 feet and a speed of about 10 to 15 Mach. During the transition phase which lasts only about 30 seconds, its altitude may increase to about 190,000 feet but its speed is reduced to about 9 Mach. At the beginning of this phase, the Main Engine is Cut Off (MECO) and the control is reconfigured with the help of aerosurfaces (four elevons, two flaps and two rudders) and reaction control system (RCS). The entry phase brings down the altitude of X33 to about 90,000 feet and its speed to about Mach 3. It spends about 250 seconds in this phase. Main engine is still cut off and the vehicle is controlled by complex maneuvers of aerosurfaces. The last phase TAEM lasts for about 450 seconds and the altitude and speed, both are reduced to zero. The present attempt, as a start, focuses only on the entry phase. Since the main engine remains cut off in this phase, there is no thrust acting on the system. This considerably simplifies the equations of motion. We introduce another simplification by assuming the system to be linear after some non-linearities are removed analytically from our consideration. Under these assumptions, the problem could be solved by Classical Statistics by employing the least sum of squares approach. Instead we chose to use the Neural Network method. This method has many advantages. It is modern, more efficient, can be adapted to work even when the assumptions are diluted. In fact, Neural Networks try to model the human brain and are capable of pattern recognition.

Aggarwal, Shiv

2003-01-01

43

49 CFR 193.2057 - Thermal radiation protection.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Thermal radiation protection. 193.2057 Section 193...Requirements § 193.2057 Thermal radiation protection. Each LNG container...following exceptions: (a) The thermal radiation distances must be calculated...

2013-10-01

44

49 CFR 193.2057 - Thermal radiation protection.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Thermal radiation protection. 193.2057 Section 193...Requirements § 193.2057 Thermal radiation protection. Each LNG container...following exceptions: (a) The thermal radiation distances must be calculated...

2012-10-01

45

49 CFR 193.2057 - Thermal radiation protection.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Thermal radiation protection. 193.2057 Section 193...Requirements § 193.2057 Thermal radiation protection. Each LNG container...following exceptions: (a) The thermal radiation distances must be calculated...

2011-10-01

46

Improved Thermal-Switch Disks Protect Batteries  

NASA Technical Reports Server (NTRS)

Improved thermal-switch disks help protect electrical batteries against high currents like those due to short circuits or high demands for power in circuits supplied by batteries. Protects batteries against excessive temperatures. Centered by insulating fiberglass washer. Contains conductive polymer that undergoes abrupt increase in electrical resistance when excessive current raises its temperature above specific point. After cooling, polymer reverts to low resistance. Disks reusable.

Darcy, Eric; Bragg, Bobby

1990-01-01

47

Toughened Thermal Blanket for MMOD Protection  

NASA Technical Reports Server (NTRS)

Thermal blankets are used extensively on spacecraft to provide passive thermal control of spacecraft hardware from thermal extremes encountered in space. Toughened thermal blankets have been developed that greatly improve protection from hypervelocity micrometeoroid and orbital debris (MMOD) impacts. These blankets can be outfitted if so desired with a reliable means to determine the location, depth and extent of MMOD impact damage by incorporating an impact sensitive piezoelectric film. Improved MMOD protection of thermal blankets was obtained by adding selective materials at various locations within the thermal blanket. As given in Figure 1, three types of materials were added to the thermal blanket to enhance its MMOD performance: (1) disrupter layers, near the outside of the blanket to improve breakup of the projectile, (2) standoff layers, in the middle of the blanket to provide an area or gap that the broken-up projectile can expand, and (3) stopper layers, near the back of the blanket where the projectile debris is captured and stopped. The best suited materials for these different layers vary. Density and thickness is important for the disrupter layer (higher densities generally result in better projectile breakup), whereas a highstrength to weight ratio is useful for the stopper layer, to improve the slowing and capture of debris particles.

Christiansen, Eric L.; Lear, Dana M.

2014-01-01

48

Thermal protection systems for hypersonic transport vehicles  

Microsoft Academic Search

Thermal protection systems (TPS) for hypersonic transport vehicles are described and evaluated. During the flight through the atmosphere moderate to high aerodynamic heating rates with corresponding high surface temperatures are generated. Therefore, a reliable light-weight but effective TPS is required, that limits the heat transfer into the central fuselage with the liquid hydrogen tank and that prevents the penetration of

G. Reich; J. Hinger; M. Huchler

1990-01-01

49

Thermal Materials Protect Priceless, Personal Keepsakes  

NASA Technical Reports Server (NTRS)

NASA astronaut Scott Parazynski led the development of materials and techniques for the inspection and repair of the shuttle’s thermal protection system. Parazynski later met Chris Shiver of Houston-based DreamSaver Enterprises LLC and used concepts from his work at Johnson Space Center to develop an enclosure that can withstand 98 percent of residential fires.

2014-01-01

50

Thermal Protection Materials for Reentry Applications  

NASA Technical Reports Server (NTRS)

Thermal protection materials and systems (IRS) are used to protect spacecraft during reentry into Earth's atmosphere or entry into planetary atmospheres. As such, these materials are subject to severe environments with high heat fluxes and rapid heating. Catalytic effects can increase the temperatures substantially. These materials are also subject to impact damage from micrometeorites or other debris during ascent, orbit, and descent, and thus must be able to withstand damage and to function following damage. Thermal protection materials and coatings used in reusable launch vehicles will be reviewed, including the needs and directions for new materials to enable new missions that require faster turnaround and much greater reusability. The role of ablative materials for use in high heat flux environments, especially for non-reusable applications and upcoming planetary missions, will be discussed. New thermal protection system materials may enable the use of sharp nose caps and leading edges on future reusable space transportation vehicles. Vehicles employing this new technology would have significant increases in maneuverability and out-of-orbit cross range compared to current vehicles, leading to increased mission safety in the event of the need to abort during ascent or from orbit. Ultrahigh temperature ceramics, a family of materials based on HfB2 and ZrB2 with SiC, will be discussed. The development, mechanical and thermal properties, and uses of these materials will be reviewed.

Johnson, Sylvia M.; Stackpoole, Mairead; Gusman, Mike; Loehman, Ron; Kotula, Paul; Ellerby, Donald; Arnold, James; Wercinski, Paul; Reuthers, James; Kontinos, Dean

2001-01-01

51

Sprayable Phase Change Coating Thermal Protection Material  

NASA Technical Reports Server (NTRS)

NASA has expressed a need for reusable, environmentally friendly, phase change coating that is capable of withstanding the heat loads that have historically required an ablative thermal insulation. The Space Shuttle Program currently relies on ablative materials for thermal protection. The problem with an ablative insulation is that, by design, the material ablates away, in fulfilling its function of cooling the underlying substrate, thus preventing the insulation from being reused from flight to flight. The present generation of environmentally friendly, sprayable, ablative thermal insulation (MCC-l); currently use on the Space Shuttle SRBs, is very close to being a reusable insulation system. In actual flight conditions, as confirmed by the post-flight inspections of the SRBs, very little of the material ablates. Multi-flight thermal insulation use has not been qualified for the Space Shuttle. The gap that would have to be overcome in order to implement a reusable Phase Change Coating (PCC) is not unmanageable. PCC could be applied robotically with a spray process utilizing phase change material as filler to yield material of even higher strength and reliability as compared to MCC-1. The PCC filled coatings have also demonstrated potential as cryogenic thermal coatings. In experimental thermal tests, a thin application of PCC has provided the same thermal protection as a much thicker and heavier application of a traditional ablative thermal insulation. In addition, tests have shown that the structural integrity of the coating has been maintained and phase change performance after several aero-thermal cycles was not affected. Experimental tests have also shown that, unlike traditional ablative thermal insulations, PCC would not require an environmental seal coat, which has historically been required to prevent moisture absorption by the thermal insulation, prevent environmental degradation, and to improve the optical and aerodynamic properties. In order to reduce the launch and processing costs of a reusable space vehicle to an affordable level, refurbishment costs must be substantially reduced. A key component of such a cost effective approach is the use of a reusable, phase change, thermal protection coating.

Richardson, Rod W.; Hayes, Paul W.; Kaul, Raj

2005-01-01

52

Aerogel Composites for Aerospace Thermal Protection  

NASA Technical Reports Server (NTRS)

Aerogel composites formed by infiltrating organic and/or inorganic aerogels into fiber matrix materials enable us to exploit the low thermal conductivity and low density of aerogels while maintaining the strength, structure and other useful properties of a porous fiber matrix. New materials for extreme heating ranges are needed to insulate future spacecraft against the extreme heat of planetary atmospheric entry, but the insulation mass must be minimized in order to maximize the payload. A reusable system passively insulates to survive heating unchanged for relatively low heating. Ablators, which sacrifice mass to control heating, are used to protect vehicles against more extreme heating for a single use thermal protection system (TPS). Aerogel composites were fabricated and tested for spacecraft thermal protection. The high-temperaturey high heat flux tests described in this paper were performed in NASA Ames arc-jet facilities to simulate spacecraft atmospheric entry, and include heating conditions predicted for the forebody and backshell of the Mars Science Lander (MSL) entry probe. The aerogel composites tested showed excellent thermal performance in the arc-jet tests, functioning both as reusuable insulation under lower heat fluxes, and as ablative aerogels under the extreme heating predicted for the MSL forebody.

White, Susan

2003-01-01

53

Advanced materials for thermal protection system  

Microsoft Academic Search

Reticulated open-cell ceramic foams (both vitreous carbon and silicon carbide) and ceramic composites (SiC-based, both monolithic and fiber-reinforced) were evaluated as candidate materials for use in a heat shield sandwich panel design as an advanced thermal protection system (TPS) for unmanned single-use hypersonic reentry vehicles. These materials were fabricated by chemical vapor deposition\\/infiltration (CVD\\/CVI) and evaluated extensively for their mechanical,

Sangvavann Heng; Andrew J. Sherman

1996-01-01

54

Penetration equations for thermal protection materials  

Microsoft Academic Search

NASA has developed a number of penetration equations for a broad range of thermal protection system (TPS) materials used on the Space Shuttle Orbiter and other spacecraft including low-density ceramic tiles, reinforced carbon-carbon, flexible ceramic insulation and multi-layer insulation (MLI). The penetration equations describe the penetration depth or damage extent to be expected from hypervelocity particles as a function of

Eric L. Christiansen; Larry Friesen

1997-01-01

55

Testing of the X-33 umbilical system at KSC  

NASA Technical Reports Server (NTRS)

At the Launch Equipment Test Facility, Greg Melton (left), a NASA engineer, and Will Reaves (right), with Lockheed Martin Technical Operations, look at components of the X-33 umbilical system that is undergoing testing. A team of Kennedy Space Center experts developed the umbilical system, comprising panels, valves and hoses that provide the means to load the X-33 with super-cold propellant. The X-33, under construction at Lockheed Martin Skunk Works in Palmdale, Calif., is a half-scale prototype of the planned operational reusable launch vehicle dubbed VentureStar.

1999-01-01

56

Testing of the X-33 umbilical system at KSC  

NASA Technical Reports Server (NTRS)

At the Launch Equipment Test Facility, Mike Solomon, with Lockheed Martin Technical Operations, studies a part of the X-33 umbilical system during testing. Pointing to the part is Will Reaves, also with Lockheed Martin Technical Operations. A team of Kennedy Space Center experts developed the umbilical system, comprising panels, valves and hoses that provide the means to load the X-33 with super-cold propellant. The X-33, under construction at Lockheed Martin Skunk Works in Palmdale, Calif., is a half-scale prototype of the planned operational reusable launch vehicle dubbed VentureStar.

1999-01-01

57

Testing of the X-33 umbilical system at KSC  

NASA Technical Reports Server (NTRS)

At the Launch Equipment Test Facility, Will Reaves (top of stand), with Lockheed Martin Technical Operations, looks over components of the X-33 umbilical system undergoing testing. A team of Kennedy Space Center experts developed the umbilical system, comprising panels, valves and hoses that provide the means to load the X-33 with super-cold propellant. The X-33, under construction at Lockheed Martin Skunk Works in Palmdale, Calif., is a half-scale prototype of the planned operational reusable launch vehicle dubbed VentureStar.

1999-01-01

58

Testing of the X-33 umbilical system at KSC  

NASA Technical Reports Server (NTRS)

At the Launch Equipment Test Facility, , Will Reaves and Mike Solomon (kneeling), both with Lockheed Martin Technical Operations, observe parts of the X-33 umbilical system during testing. A team of Kennedy Space Center experts developed the umbilical system, comprising panels, valves and hoses that provide the means to load the X-33 with super-cold propellant. The X-33, under construction at Lockheed Martin Skunk Works in Palmdale, Calif., is a half-scale prototype of the planned operational reusable launch vehicle dubbed VentureStar.

1999-01-01

59

Testing of the X-33 umbilical system at KSC  

NASA Technical Reports Server (NTRS)

At the Launch Equipment Test Facility, workers check results from testing the X-33 umbilical system. From left are Greg Melton (left), a NASA engineer; Will Reaves, with Lockheed Martin Technical Operations; and Scott Holcomb, also with Lockheed Martin Technical Operations. A team of Kennedy Space Center experts developed the umbilical system, comprising panels, valves and hoses that provide the means to load the X-33 with super-cold propellant. The X-33, under construction at Lockheed Martin Skunk Works in Palmdale, Calif., is a half-scale prototype of the planned operational reusable launch vehicle dubbed VentureStar.

1999-01-01

60

Testing of the X-33 umbilical system at KSC  

NASA Technical Reports Server (NTRS)

At the Launch Equipment Test Facility, Mike Ynclan, with Dynacs, and Greg Melton, a NASA engineer, look at measurements during testing of the X-33 umbilical system. A team of Kennedy Space Center experts developed the umbilical system, comprising panels, valves and hoses that provide the means to load the X-33 with super-cold propellant. The X-33, under construction at Lockheed Martin Skunk Works in Palmdale, Calif., is a half-scale prototype of the planned operational reusable launch vehicle dubbed VentureStar.

1999-01-01

61

Testing of the X-33 umbilical system at KSC  

NASA Technical Reports Server (NTRS)

At the Launch Equipment Test Facility, Mike Solomon (left) and Will Reaves (right), both with Lockheed Martin Technical Operations, move in for a close look at part of the X-33 umbilical system. A team of Kennedy Space Center experts developed the umbilical system, comprising panels, valves and hoses that provide the means to load the X-33 with super-cold propellant. The X-33, under construction at Lockheed Martin Skunk Works in Palmdale, Calif., is a half-scale prototype of the planned operational reusable launch vehicle dubbed VentureStar.

1999-01-01

62

Lightweight Thermal Protection System for Atmospheric Entry  

NASA Technical Reports Server (NTRS)

TUFROC (Toughened Uni-piece Fibrous Reinforced Oxidation-resistant Composite) has been developed as a new thermal protection system (TPS) material for wing leading edge and nose cap applications. The composite withstands temperatures up to 1,970 K, and consists of a toughened, high-temperature surface cap and a low-thermal-conductivity base, and is applicable to both sharp and blunt leading edge vehicles. This extends the possible application of fibrous insulation to the wing leading edge and/or nose cap on a hypersonic vehicle. The lightweight system comprises a treated carbonaceous cap composed of ROCCI (Refractory Oxidation-resistant Ceramic Carbon Insulation), which provides dimensional stability to the outer mold line, while the fibrous base material provides maximum thermal insulation for the vehicle structure.

Stewart, David; Leiser, Daniel

2007-01-01

63

Outer skin protection of columbium Thermal Protection System (TPS) panels  

NASA Technical Reports Server (NTRS)

A coated columbium alloy material system 0.04 centimeter thick was developed which provides for increased reliability to the load bearing character of the system in the event of physical damage to and loss of the exterior protective coating. The increased reliability to the load bearing columbium alloy (FS-85) was achieved by interposing an oxidation resistant columbium alloy (B-1) between the FS-85 alloy and a fused slurry silicide coating. The B-1 alloy was applied as a cladding to the FS-85 and the composite was fused slurry silicide coated. Results of material evaluation testing included cyclic oxidation testing of specimens with intentional coating defects, tensile testing of several material combinations exposed to reentry profile conditions, and emittance testing after cycling of up to 100 simulated reentries. The clad material, which was shown to provide greater reliability than unclad materials, holds significant promise for use in the thermal protection system of hypersonic reentry vehicles.

Culp, J. D.

1973-01-01

64

Redundancy Management for Navigation Functions on X-33  

NASA Technical Reports Server (NTRS)

This presentation focus on the navigational functions of the X-33 aircraft. It addresses the type of fault testing, additional tests during the operational launch vehicle, and the detailed characterization of sensor errors.

Abbott, Richard

1998-01-01

65

X-33, Stepping Stone ot Low Cost Access to Space  

NASA Technical Reports Server (NTRS)

In response to the Access to Space Study, which was conducted in 1993 through the Office of Space Systems Development, an advanced technology Reusable Launch Vehicle (RLV) was selected for demonstration. The X-33 was advanced as an demonstration project, to build and test a 53-percent scale prototype of an operational RLV, it would also demonstrate new technologies which would be required to assure the operation of the new RLV. This presentation reviews the progress of the X-33 development and supporting sites. The X-33 design has been completed and fabrication and assembly is progressing well. The X-33 launch site has been completed. The first LH2 tank and engine is in testing. This will lead to the full scale development of VentureStar(tm).

Naftel, J. Chris

2000-01-01

66

X-33 Integrated Test Facility Extended Range Simulation  

NASA Technical Reports Server (NTRS)

In support of the X-33 single-stage-to-orbit program, NASA Dryden Flight Research Center was selected to provide continuous range communications of the X-33 vehicle from launch at Edwards Air Force Base, California, through landing at Malmstrom Air Force Base Montana, or at Michael Army Air Field, Utah. An extensive real-time range simulation capability is being developed to ensure successful communications with the autonomous X-33 vehicle. This paper provides an overview of various levels of simulation, integration, and test being developed to support the X-33 extended range subsystems. These subsystems include the flight termination system, L-band command uplink subsystem, and S-band telemetry downlink subsystem.

Sharma, Ashley

1998-01-01

67

49 CFR 179.18 - Thermal protection systems.  

Code of Federal Regulations, 2010 CFR

...the tank car must have sufficient thermal resistance so that there will...fire for 30 minutes. (b) Thermal analysis. (1) Compliance...underframes, metal jackets, insulation, and thermal protection. A complete...

2010-10-01

68

49 CFR 179.18 - Thermal protection systems.  

Code of Federal Regulations, 2011 CFR

...tank car must have sufficient thermal resistance so that there will...fire for 30 minutes. (b) Thermal analysis. (1) Compliance...underframes, metal jackets, insulation, and thermal protection. A complete...

2011-10-01

69

49 CFR 179.18 - Thermal protection systems.  

Code of Federal Regulations, 2012 CFR

...tank car must have sufficient thermal resistance so that there will...fire for 30 minutes. (b) Thermal analysis. (1) Compliance...underframes, metal jackets, insulation, and thermal protection. A complete...

2012-10-01

70

49 CFR 179.18 - Thermal protection systems.  

Code of Federal Regulations, 2013 CFR

...tank car must have sufficient thermal resistance so that there will...fire for 30 minutes. (b) Thermal analysis. (1) Compliance...underframes, metal jackets, insulation, and thermal protection. A complete...

2013-10-01

71

Support to X-33/Resusable Launch Vehicle Technology Program  

NASA Technical Reports Server (NTRS)

The X-33 Guidance, Navigation, and Control (GN&C) Peer Review Team (PRT) was formed to assess the integrated X-33 vehicle GN&C system in order to identify any areas of disproportionate risk for initial flight. The eventual scope of the PRT assessment encompasses the GN&C algorithms, software, avionics, control effectors, applicable models, and testing. The initial (phase 1) focus of the PRT was on the GN&C algorithms and the Flight Control Actuation Subsystem (FCAS). The PRT held meetings during its phase 1 assessment at X-33 assembly facilities in Palmdale, California on May 17-18, 2000 and at Honeywell facilities in Tempe, Arizona on June 7, 2000. The purpose of these meetings was for the PRT members to get background briefings on the X-33 vehicle and for the PRT team to be briefed on the design basis and current status of the X-33 GN&C algorithms as well as the FCAS. The following material is covered in this PRT phase 1 final report. Some significant GN&C-related accomplishments by the X-33 development team are noted. Some topics are identified that were found during phase 1 to require fuller consideration when the PRT reconvenes in the future. Some new recommendations by the PRT to the X-33 program will likely result from a thorough assessment of these subjects. An initial list of recommendations from the PRT to the X-33 program is provided. These recommendations stem from topics that received adequate review by the PRT in phase 1. Significant technical observations by the PRT members as a result of the phase 1 meetings are detailed. (These are covered in an appendix.) There were many X-33 development team members who contributed to the technical information used by the PRT during the phase 1 assessment, who supported presentations to the PRT, and who helped to address the many questions posed by the PRT members at and after the phase 1 meetings. In all instances the interaction between the PRT and the X-33 development team members was cordial and very professional. The members of the PRT are grateful for the time and effort applied by all of these individuals and hope that the contents of this report will help to make the X-33 program a success.

2000-01-01

72

Reusable Metallic Thermal Protection Systems Development  

NASA Technical Reports Server (NTRS)

Metallic thermal protection systems (TPS) are being developed to help meet the ambitious goals of future reusable launch vehicles. Recent metallic TPS development efforts at NASA Langley Research Center are described. Foil-gage metallic honeycomb coupons, representative of the outer surface of metallic TPS were subjected to low speed impact, hypervelocity impact, rain erosion, and subsequent arcjet exposure. TPS panels were subjected to thermal vacuum, acoustic, and hot gas flow testing. Results of the coupon and panel tests are presented. Experimental and analytical tools are being developed to characterize and improve internal insulations. Masses of metallic TPS and advanced ceramic tile and blanket TPS concepts are compared for a wide range of parameters.

Blosser, Max L.; Martin, Carl J.; Daryabeigi, Kamran; Poteet, Carl C.

1998-01-01

73

Commercial application of thermal protection system technology  

NASA Technical Reports Server (NTRS)

The thermal protection system process technology is examined which is used in the manufacture of the External Tank for the Space Shuttle system and how that technology is applied by private business to create new products, new markets, and new American jobs. The term 'technology transfer' means different things to different people and has become one of the buzz words of the 1980s and 1990s. Herein, technology transfer is defined as a means of transferring technology developed by NASA's prime contractors to public and private sector industries.

Dyer, Gordon L.

1991-01-01

74

Thermal Protection System of the Space Shuttle  

NASA Technical Reports Server (NTRS)

The Thermal Protection System (TPS), introduced by NASA, continues to incorporate many of the advances in materials over the past two decades. A comprehensive, single-volume summary of the TPS, including system design rationales, key design features, and broad descriptions of the subsystems of TPS (E.g., reusable surface insulation, leading edge structural, and penetration subsystems) is provided. Details of all elements of TPS development and application are covered (materials properties, manufacturing, modeling, testing, installation, and inspection). Disclosures and inventions are listed and potential commercial application of TPS-related technology is discussed.

Cleland, John; Iannetti, Francesco

1989-01-01

75

Thermal Vacuum Facility for Testing Thermal Protection Systems  

NASA Technical Reports Server (NTRS)

A thermal vacuum facility for testing launch vehicle thermal protection systems by subjecting them to transient thermal conditions simulating re-entry aerodynamic heating is described. Re-entry heating is simulated by controlling the test specimen surface temperature and the environmental pressure in the chamber. Design requirements for simulating re-entry conditions are briefly described. A description of the thermal vacuum facility, the quartz lamp array and the control system is provided. The facility was evaluated by subjecting an 18 by 36 in. Inconel honeycomb panel to a typical re-entry pressure and surface temperature profile. For most of the test duration, the average difference between the measured and desired pressures was 1.6% of reading with a standard deviation of +/- 7.4%, while the average difference between measured and desired temperatures was 7.6% of reading with a standard deviation of +/- 6.5%. The temperature non-uniformity across the panel was 12% during the initial heating phase (t less than 500 sec.), and less than 2% during the remainder of the test.

Daryabeigi, Kamran; Knutson, Jeffrey R.; Sikora, Joseph G.

2002-01-01

76

Thermal protection materials: Thermophysical property data  

NASA Technical Reports Server (NTRS)

This publication presents a thermophysical property survey on materials that could potentially be used for future spacecraft thermal protection systems (TPS). This includes data that was reported in the 1960's as well as more current information reported through the 1980's. An attempt was made to cite the manufacturers as well as the data source in the bibliography. This volume represents an attempt to provide in a single source a complete set of thermophysical data on a large variety of materials used in spacecraft TPS analysis. The property data is divided into two categories: ablative and reusable. The ablative materials have been compiled into twelve categories that are descriptive of the material composition. An attempt was made to define the Arrhenius equation for each material although this data may not be available for some materials. In a similar manner, char data may not be available for some of the ablative materials. The reusable materials have been divided into three basic categories: thermal protection materials (such as insulators), adhesives, and structural materials.

Williams, S. D.; Curry, Donald M.

1992-01-01

77

Advanced Metallic Thermal Protection System Development  

NASA Technical Reports Server (NTRS)

A new Adaptable, Robust, Metallic, Operable, Reusable (ARMOR) thermal protection system (TPS) concept has been designed, analyzed, and fabricated. In addition to the inherent tailorable robustness of metallic TPS, ARMOR TPS offers improved features based on lessons learned from previous metallic TPS development efforts. A specific location on a single-stage-to-orbit reusable launch vehicle was selected to develop loads and requirements needed to design prototype ARMOR TPS panels. The design loads include ascent and entry heating rate histories, pressures, acoustics, and accelerations. Additional TPS design issues were identified and discussed. An iterative sizing procedure was used to size the ARMOR TPS panels for thermal and structural loads as part of an integrated TPS/cryogenic tank structural wall. The TPS panels were sized to maintain acceptable temperatures on the underlying structure and to operate under the design structural loading. Detailed creep analyses were also performed on critical components of the ARMOR TPS panels. A lightweight, thermally compliant TPS support system (TPSS) was designed to connect the TPS to the cryogenic tank structure. Four 18-inch-square ARMOR TPS panels were fabricated. Details of the fabrication process are presented. Details of the TPSS for connecting the ARMOR TPS panels to the externally stiffened cryogenic tank structure are also described. Test plans for the fabricated hardware are presented.

Blosser, M. L.; Chen, R. R.; Schmidt, I. H.; Dorsey, J. T.; Poteet, C. C.; Bird, R. K.

2002-01-01

78

Lightweight Nonmetallic Thermal Protection Materials Technology  

NASA Technical Reports Server (NTRS)

To fulfill President George W. Bush's "Vision for Space Exploration" (2004) - successful human and robotic missions to and from other solar system bodies in order to explore their atmospheres and surfaces - the National Aeronautics and Space Administration (NASA) must reduce the trip time, cost, and vehicle weight so that the payload and scientific experiments' capabilities can be maximized. The new project described in this paper will generate thermal protection system (TPS) product that will enable greater fidelity in mission/vehicle design trade studies, support risk reduction for material selections, assist in the optimization of vehicle weights, and provide materials and processes templates for use in the development of human-rated TPS qualification and certification plans.

Valentine, Peter G.; Lawrence, Timothy W.; Gubert, Michael K.; Milos, Frank S.; Levine, Stanley R.; Ohlhorst, Craig W.; Koenig, John R.

2005-01-01

79

On the cathodic protection of thermally insulated pipelines  

Microsoft Academic Search

Thermal insulation and corrosion protection of heated pipelines used in moving oil\\/gas and heated products are accomplished industry-wide by using protective and insulating coatings supplemented by cathodic protection to protect any defected coating areas. A series of tests are carried out to study how the resistivity of the applied insulating layer polyurethane (PUR) can be affected by its specific gravity

El-Sayed A. Rassoul; Abdou Abdel-Samad; Rashad El-Naqier

2009-01-01

80

X-33 Reusable Launch Vehicle Demonstrator, Spaceport and Range.  

National Technical Information Service (NTIS)

The X-33 was a suborbital reusable spaceplane demonstrator, in development from 1996 to early 2001. The intent of the demonstrator was to lower the risk of building and operating a full-scale reusable vehicle fleet. Reusable spaceplanes offered the potent...

G. F. Letchworth

2011-01-01

81

Development of the X-33 Aerodynamic Uncertainty Model  

NASA Technical Reports Server (NTRS)

An aerodynamic uncertainty model for the X-33 single-stage-to-orbit demonstrator aircraft has been developed at NASA Dryden Flight Research Center. The model is based on comparisons of historical flight test estimates to preflight wind-tunnel and analysis code predictions of vehicle aerodynamics documented during six lifting-body aircraft and the Space Shuttle Orbiter flight programs. The lifting-body and Orbiter data were used to define an appropriate uncertainty magnitude in the subsonic and supersonic flight regions, and the Orbiter data were used to extend the database to hypersonic Mach numbers. The uncertainty data consist of increments or percentage variations in the important aerodynamic coefficients and derivatives as a function of Mach number along a nominal trajectory. The uncertainty models will be used to perform linear analysis of the X-33 flight control system and Monte Carlo mission simulation studies. Because the X-33 aerodynamic uncertainty model was developed exclusively using historical data rather than X-33 specific characteristics, the model may be useful for other lifting-body studies.

Cobleigh, Brent R.

1998-01-01

82

Ceramic-Fibrous-Insulation Thermal-Protection System  

NASA Technical Reports Server (NTRS)

New composite thermal-protection system developed in which glass-ceramic impregnated into surface of fibrous insulation. Called TUFI for toughened unipiece fibrous insulation developed as replacement for tiles with reaction-cured-glass (RCG) coating. Impregnation of glass-ceramic results in thermal protection system with insulating properties comparable to existing system but with 20 to 100 times more resistance to impact.

Leiser, Daniel; Churchward, Rex; Katvala, Victor; Stewart, David; Balter, Aliza

1992-01-01

83

Thermal Protection Studies of Plastic Films and Fibrous Materials  

Microsoft Academic Search

An experimental method of radiant heating was used to study the thermal protection properties of certain film and woven materials. Samples of these, placed in front of fiberglass batting containing a phenolic resin, were exposed to a radiant heat flux of 5 W\\/cm2 and the resin mass loss as a function of time indicated the thermal protective effectiveness of the

Michel A. Saad; Robert L. Altman

1988-01-01

84

Intumescence: An in situ approach to thermal protection  

NASA Technical Reports Server (NTRS)

The thermal protection of flammable structures with intumescent protective coatings is discussed. Various materials which have demonstrated an ability to provide protection through intumecence are described. Materials tests for intumescent coatings are presented and physical properties of various materials are included.

Fohlen, G. M.; Parker, J. A.; Riccitiello, S. R.; Sawko, P. M.

1971-01-01

85

Full Envelope Reconfigurable Control Design for the X-33 Vehicle  

NASA Technical Reports Server (NTRS)

In the event of a control surface failure, the purpose of a reconfigurable control system is to redistribute the control effort among the remaining working surfaces such that satisfactory stability and performance are retained. An Off-line Nonlinear General Constrained Optimization (ONCO) approach was used for the reconfigurable X-33 control design method. Three example failures are shown using a high fidelity 6 DOF simulation (case I ascent with a left body flap jammed at 25 deg.; case 2 entry with a right inboard elevon jam at 25 deg.; and case 3, landing (TAEM) with a left rudder jam at -30 deg.) Failure comparisons between responses with the nominal controller and reconfigurable controllers show the benefits of reconfiguration. Single jam aerosurface failures were considered, and failure detection and identification is considered accomplished in the actuator controller. The X-33 flight control system will incorporate reconfigurable flight control in the baseline system.

Cotting, M. Christopher; Burken, John J.; Lee, Seung-Hee (Technical Monitor)

2001-01-01

86

The Control System for the X-33 Linear Aerospike Engine  

NASA Technical Reports Server (NTRS)

The linear aerospike engine is being developed for single-stage -to-orbit (SSTO) applications. The primary advantages of a linear aerospike engine over a conventional bell nozzle engine include altitude compensation, which provides enhanced performance, and lower vehicle weight resulting from the integration of the engine into the vehicle structure. A feature of this integration is the ability to provide thrust vector control (TVC) by differential throttling of the engine combustion elements, rather than the more conventional approach of gimballing the entire engine. An analysis of the X-33 flight trajectories has shown that it is necessary to provide +/- 15% roll, pitch and yaw TVC authority with an optional capability of +/- 30% pitch at select times during the mission. The TVC performance requirements for X-33 engine became a major driver in the design of the engine control system. The thrust level of the X-33 engine as well as the amount of TVC are managed by a control system which consists of electronic, instrumentation, propellant valves, electro-mechanical actuators, spark igniters, and harnesses. The engine control system is responsible for the thrust control, mixture ratio control, thrust vector control, engine health monitoring, and communication to the vehicle during all operational modes of the engine (checkout, pre-start, start, main-stage, shutdown and post shutdown). The methodology for thrust vector control, the health monitoring approach which includes failure detection, isolation, and response, and the basic control system design are the topic of this paper. As an additional point of interest a brief description of the X-33 engine system will be included in this paper.

Jackson, Jerry E.; Espenschied, Erich; Klop, Jeffrey

1998-01-01

87

X-33 LH2 Tank Failure Investigation Findings  

NASA Technical Reports Server (NTRS)

The X-33 liquid hydrogen tank failure investigation found the following: (1) The inner skin microcracked and hydrogen infiltrated into it; (2) The cracks grew larger under pressure; (3) When pressure was removed, the cracks closed slightly; (4) When the tank was drained and warmed, the cracks closed and blocked the leak path; (5) Foreign object debris (FOD) and debond areas provided an opportunity for a leak path; and (6) There is still hydrogen in the other three lobes today.

Niedermeyer, M.

2001-01-01

88

X-33 Environmental Impact Statement: A Fast Track Approach  

NASA Technical Reports Server (NTRS)

NASA is required by the National Environmental Policy Act (NEPA) to prepare an appropriate level environmental analysis for its major projects. Development of the X-33 Technology Demonstrator and its associated flight test program required an environmental impact statement (EIS) under the NEPA. The EIS process is consists of four parts: the "Notice of Intent" to prepare an EIS and scoping; the draft EIS which is distributed for review and comment; the final ETS; and the "Record of Decision." Completion of this process normally takes from 2 - 3 years, depending on the complexity of the proposed action. Many of the agency's newest fast track, technology demonstration programs require NEPA documentation, but cannot sustain the lengthy time requirement between program concept development to implementation. Marshall Space Flight Center, in cooperation with Kennedy Space Center, accomplished the NEPA process for the X-33 Program in 13 months from Notice of Intent to Record of Decision. In addition, the environmental team implemented an extensive public involvement process, conducting a total of 23 public meetings for scoping and draft EIS comment along with numerous informal meetings with public officials, civic organizations, and Native American Indians. This paper will discuss the fast track approach used to successfully accomplish the NEPA process for X-33 on time.

McCaleb, Rebecca C.; Holland, Donna L.

1998-01-01

89

77 FR 11598 - Thermal Overload Protection for Electric Motors on Motor-Operated Valves  

Federal Register 2010, 2011, 2012, 2013

...application of thermal overload protection devices that...the availability of information regarding this document...application of thermal overload protection devices...ensure that the thermal overload protection devices will...function. II. Further Information DG-1264, was...

2012-02-27

90

Composite Flexible Insulation for Thermal Protection of Space Vehicles.  

National Technical Information Service (NTIS)

A composite flexible blanket insulation (CFBI) system considered for use as a thermal protection system for space vehicles is described. This flexible composite insulation system consists of an outer layer of silicon carbide fabric, followed by alumina ma...

D. A. Kourtides, H. K. Tran, S. A. Chiu

1992-01-01

91

Composite Flexible Insulation for Thermal Protection of Space Vehicles.  

National Technical Information Service (NTIS)

A composite flexible blanket insulation (CFBI) system considered for use as a thermal protection system for space vehicles is described. This flexible composite insulation system consists of an outer layer of silicon carbide fabric, followed by alumina ma...

D. A. Kourtides, H. K. Tran, S. A. Chiu

1991-01-01

92

Principle of thermal insulation for permafrost protection  

Microsoft Academic Search

In permafrost regions, the measures of constructing embankments or installing thermal insulations are in common use to keep the permafrost table under the roadways stable. However, the effectiveness of these measures depends on their adjustment to the mean annual ground temperature and the temperature amplitude in the permafrost under the roadway. This paper explains the principle of thermal insulation for

Guodong Cheng; Jianming Zhang; Yu Sheng; Ji Chen

2004-01-01

93

Composite flexible insulation for thermal protection of space vehicles  

NASA Technical Reports Server (NTRS)

A composite flexible blanket insulation (CFBI) system considered for use as a thermal protection system for space vehicles is described. This flexible composite insulation system consists of an outer layer of silicon carbide fabric, followed by alumina mat insulation, and alternating layers of aluminized polyimide film and aluminoborosilicate scrim fabric. A potential application of this composite insulation would be as a thermal protection system for the aerobrake of the aeroassist space transfer vehicle (ASTV). It would also apply to other space vehicles subject to high convective and radiative heating during atmospheric entry. The thermal performance of this composite insulation as exposed to a simulated atmospheric entry environment in a plasma arc test facility is described. Other thermophysical properties which affect the thermal response of this composite insulation is included. It shows that this composite insulation is effective as a thermal protection system at total heating rates up to 30.6 W/sq cm.

Kourtides, Demetrius A.; Tran, Huy K.; Chiu, S. Amanda

1991-01-01

94

Space Shuttle Orbiter thermal protection system design and flight experience  

NASA Technical Reports Server (NTRS)

The Space Shuttle Orbiter Thermal Protection System materials, design approaches associated with each material, and the operational performance experienced during fifty-five successful flights are described. The flights to date indicate that the thermal and structural design requirements were met and that the overall performance was outstanding.

Curry, Donald M.

1993-01-01

95

An empirical analysis of thermal protective performance of fabrics used in protective clothing.  

PubMed

Fabric-based protective clothing is widely used for occupational safety of firefighters/industrial workers. The aim of this paper is to study thermal protective performance provided by fabric systems and to propose an effective model for predicting the thermal protective performance under various thermal exposures. Different fabric systems that are commonly used to manufacture thermal protective clothing were selected. Laboratory simulations of the various thermal exposures were created to evaluate the protective performance of the selected fabric systems in terms of time required to generate second-degree burns. Through the characterization of selected fabric systems in a particular thermal exposure, various factors affecting the performances were statistically analyzed. The key factors for a particular thermal exposure were recognized based on the t-test analysis. Using these key factors, the performance predictive multiple linear regression and artificial neural network (ANN) models were developed and compared. The identified best-fit ANN models provide a basic tool to study thermal protective performance of a fabric. PMID:25135076

Mandal, Sumit; Song, Guowen

2014-10-01

96

X-33 LH2 Tank Failure Investigation Findings  

NASA Technical Reports Server (NTRS)

This viewgraph presentation gives an overview of the X-33 LH2 tank failure investigation findings. The conclusions of the investigation include the following: (1) the inner skin microcracked and hydrogen infiltrated; (2) the cracks grew larger under pressure; (3) when pressure was removed, the cracks closed slightly; (4) when the tank was drained and warmed, the cracks closed and blocked the leak path; (5) FOD and debond areas provided an opportunity for a leak path; and (6) there is still hydrogen in the the other three lobes today.

Niedermeyer, Melinda; Munafo, Paul (Technical Monitor)

2002-01-01

97

Design Description of the X-33 Avionics Architecture  

NASA Technical Reports Server (NTRS)

In this paper, we provide a design description of the X-33 avionics architecture. The X-33 is an autonomous Single Stage to Orbit (SSTO) launch vehicle currently being developed by Lockheed Martin for NASA as a technology demonstrator for the VentureStar Reusable Launch Vehicle (RLV). The X-33 avionics provides autonomous control of die vehicle throughout takeoff, ascent, descent, approach, landing, rollout, and vehicle safing. During flight the avionics provides communication to the range through uplinked commands and downlinked telemetry. During pre-launch and post-safing activities, the avionics provides interfaces to ground support consoles that perform vehicle flight preparations and maintenance. The X-33 Avionics is a hybrid of centralized and distributed processing elements connected by three dual redundant Mil-Std 1553 data buses. These data buses are controlled by a central processing suite located in the avionics bay and composed of triplex redundant Vehicle Mission Computers (VMCs). The VMCs integrate mission management, guidance, navigation, flight control, subsystem control and redundancy management functions. The vehicle sensors, effectors and subsystems are interfaced directly to the centralized VMCs as remote terminals or through dual redundant Data Interface Units (DIUs). The DIUs are located forward and aft of the avionics bay and provide signal conditioning, health monitoring, low level subsystem control and data interface functions. Each VMC is connected to all three redundant 1553 data buses for monitoring and provides a complete identical data set to the processing algorithms. This enables bus faults to be detected and reconfigured through a voted bus control configuration. Data is also shared between VMCs though a cross channel data link that is implemented in hardware and controlled by AlliedSignal's Fault Tolerant Executive (FTE). The FTE synchronizes processors within the VMC and synchronizes redundant VMCs to each other. The FTE provides an output-voting plane to detect, isolate and contain faults due to internal hardware or software faults and reconfigures the VMCs to accommodate these faults. Critical data in the 1553 messages are scheduled and synchronized to specific processing frames in order to minimize data latency. In order to achieve an open architecture, military and commercial off-the-shelf equipment is incorporated using common processors, standard VME backplanes and chassis, the VxWorks operating system, and MartixX for automatic code generation. The use of off-the-shelf tools and equipment helps reduce development time and enables software reuse. The open architecture allows for technology insertion, while the distributed modular elements allow for expansion to increased redundancy levels to meet the higher reliability goals of future RLVs.

Reichenfeld, Curtis J.; Jones, Paul G.

1999-01-01

98

Thermal Management Coating As Thermal Protection System for Space Transportation System  

NASA Technical Reports Server (NTRS)

This paper presents viewgraphs on the development of a non-ablative thermal management coating used as the thermal protection system material for space shuttle rocket boosters and other launch vehicles. The topics include: 1) Coating Study; 2) Aerothermal Testing; 3) Preconditioning Environments; 4) Test Observations; 5) Lightning Strike Test Panel; 6) Test Panel After Impact Testing; 7) Thermal Testing; and 8) Mechanical Testing.

Kaul, Raj; Stuckey, C. Irvin

2003-01-01

99

Arcjet Testing of Micro-Meteoroid Impacted Thermal Protection Materials  

NASA Technical Reports Server (NTRS)

There are several harsh space environments that could affect thermal protection systems and in turn pose risks to the atmospheric entry vehicles. These environments include micrometeoroid impact, extreme cold temperatures, and ionizing radiation during deep space cruise, all followed by atmospheric entry heating. To mitigate these risks, different thermal protection material samples were subjected to multiple tests, including hyper velocity impact, cold soak, irradiation, and arcjet testing, at various NASA facilities that simulated these environments. The materials included a variety of honeycomb packed ablative materials as well as carbon-based non-ablative thermal protection systems. The present paper describes the results of the multiple test campaign with a focus on arcjet testing of thermal protection materials. The tests showed promising results for ablative materials. However, the carbon-based non-ablative system presented some concerns regarding the potential risks to an entry vehicle. This study provides valuable information regarding the capability of various thermal protection materials to withstand harsh space environments, which is critical to sample return and planetary entry missions.

Agrawal, Parul; Munk, Michelle M.; Glaab, Louis J.

2013-01-01

100

Assessment of Thermal Control and Protective Coatings  

NASA Technical Reports Server (NTRS)

This final report is concerned with the tasks performed during the contract period which included spacecraft coating development, testing, and applications. Five marker coatings consisting of a bright yellow handrail coating, protective overcoat for ceramic coatings, and specialized primers for composites (or polymer) surfaces were developed and commercialized by AZ Technology during this program. Most of the coatings have passed space environmental stability requirements via ground tests and/or flight verification. Marker coatings and protective overcoats were successfully flown on the Passive Optical Sample Assembly (POSA) and the Optical Properties Monitor (OPM) experiments flown on the Russian space station MIR. To date, most of the coatings developed and/or modified during this program have been utilized on the International Space Station and other spacecraft. For ISS, AZ Technology manufactured the 'UNITY' emblem now being flown on the NASA UNITY node (Node 1) that is docked to the Russian Zarya (FGB) utilizing the colored marker coatings (white, blue, red) developed by AZ Technology. The UNITY emblem included the US American flag, the Unity logo, and NASA logo on a white background, applied to a Beta cloth substrate.

Mell, Richard J.

2000-01-01

101

N-Factor Computations for the X-33 Vehicle  

NASA Technical Reports Server (NTRS)

N-Factor computations for the X-33 vehicle on the lower side of the body were per-formed. The transition prediction code e-Malik was used to compute the N-Factors and the meanflow field was computed using the CFD code LAURA. The computations are done at two angles of attack 30 and 40 degrees and the freestream Mach number and Reynolds number are M= 6 and Re = 7.7* 10(exp 6). The N-Factors obtained are very low in the range of 2-3 near the experimentally observed transition onset regions. The stability computations show that at 30 degrees angle of attack, the transition occurs due to crossflow instability and at higher angles of attack the transition occurs due to first mode inviscid instability.

Balakumar, P.; Hamilton, H. Harris (Technical Monitor)

2001-01-01

102

Support to X-33/Reusable Launch Vehicle Technology Program  

NASA Technical Reports Server (NTRS)

The Primary activities of Lee & Associates for the referenced Purchase Order has been in direct support of the X-33/Reusable Launch Vehicle Technology Program. An independent review to evaluate the X-33 liquid hydrogen fuel tank failure, which recently occurred after-test of the starboard tank has been provided. The purpose of the Investigation team was to assess the tank design modifications, provide an assessment of the testing approach used by MSFC (Marshall Space Flight Center) in determining the flight worthiness of the tank, assessing the structural integrity, and determining the cause of the failure of the tank. The approach taken to satisfy the objectives has been for Lee & Associates to provide the expertise of Mr. Frank Key and Mr. Wayne Burton who have relevant experience from past programs and a strong background of experience in the fields critical to the success of the program. Mr. Key and Mr. Burton participated in the NASA established Failure Investigation Review Team to review the development and process data and to identify any design, testing or manufacturing weaknesses and potential problem areas. This approach worked well in satisfying the objectives and providing the Review Team with valuable information including the development of a Fault Tree. The detailed inputs were made orally in real time in the Review Team daily meetings. The results of the investigation were presented to the MSFC Center Director by the team on February 15, 2000. Attached are four charts taken from that presentation which includes 1) An executive summary, 2) The most probable cause, 3) Technology assessment, and 4) Technology Recommendations for Cryogenic tanks.

2000-01-01

103

Study of skin model and geometry effects on thermal performance of thermal protective fabrics  

NASA Astrophysics Data System (ADS)

Thermal protective clothing has steadily improved over the years as new materials and improved designs have reached the market. A significant method that has brought these improvements to the fire service is the NFPA 1971 standard on structural fire fighters’ protective clothing. However, this testing often neglects the effects of cylindrical geometry on heat transmission in flame resistant fabrics. This paper deals with methods to develop cylindrical geometry testing apparatus incorporating novel skin bioheat transfer model to test flame resistant fabrics used in firefighting. Results show that fabrics which shrink during the test can have reduced thermal protective performance compared with the qualities measured with a planar geometry tester. Results of temperature differences between skin simulant sensors of planar and cylindrical tester are also compared. This test method provides a new technique to accurately and precisely characterize the thermal performance of thermal protective fabrics.

Zhu, Fanglong; Ma, Suqin; Zhang, Weiyuan

2008-05-01

104

Thermal Protection During Percutaneous Thermal Ablation Procedures: Interest of Carbon Dioxide Dissection and Temperature Monitoring  

SciTech Connect

Percutaneous image-guided thermal ablation of tumor is widely used, and thermal injury to collateral structures is a known complication of this technique. To avoid thermal damage to surrounding structures, several protection techniques have been reported. We report the use of a simple and effective protective technique combining carbon dioxide dissection and thermocouple: CO{sub 2} displaces the nontarget structures, and its low thermal conductivity provides excellent insulation; insertion of a thermocouple in contact with vulnerable structures achieves continuous thermal monitoring. We performed percutaneous thermal ablation of 37 tumors in 35 patients (4 laser, 10 radiofrequency, and 23 cryoablations) with protection of adjacent vulnerable structures by using CO{sub 2} dissection combined with continuous thermal monitoring with thermocouple. Tumor locations were various (19 intra-abdominal tumors including 4 livers and 9 kidneys, 18 musculoskeletal tumors including 11 spinal tumors). CO{sub 2} volume ranged from 10 ml (epidural space) to 1500 ml (abdominal). Repeated insufflations were performed if necessary, depending on the information given by the thermocouple and imaging control. Dissection with optimal thermal protection was achieved in all cases except two patients where adherences (one postoperative, one arachnoiditis) blocked proper gaseous distribution. No complication referred to this technique was noted. This safe, cost-effective, and simple method increases the safety and the success rate of percutaneous thermal ablation procedures. It also offers the potential to increase the number of tumors that can be treated via a percutaneous approach.

Buy, Xavier; Tok, Chung-Hong; Szwarc, Daniel; Bierry, Guillaume; Gangi, Afshin, E-mail: gangi@rad6.u-strasbg.f [University Hospital of Strasbourg, Department of Radiology B (France)

2009-05-15

105

Composite flexible insulation for thermal protection of space vehicles  

NASA Astrophysics Data System (ADS)

A composite flexible blanket insulation (CFBI) system considered for use as a thermal protection system for space vehicles is described. This flexible composite insulation system consists of an outer layer of silicon carbide fabric, followed by alumina mat insulation, and alternating layers of aluminized polyimide film and aluminoborosilicate scrim fabric. A potential application of this composite insulation would be as a thermal protection system for the aerobrake of the Aeroassist Space Transfer Vehicle (ASTV). It would also apply to other space vehicles subject to high convective and radiative heating during atmospheric entry. The thermal performance of this composite insulation as exposed to a simulated atmospheric entry environment in a plasma arc test facility is described. Other thermophysical properties which affect the thermal response of this system are also described. Analytical modeling describing the thermal performance of this composite insulation is included. It shows that this composite insulation is effective as a thermal protection system at total heating rates up to 30.6 W/sq cm.

Kourtides, Demetrius A.; Tran, Huy K.; Chiu, S. Amanda

1992-09-01

106

Composite flexible insulation for thermal protection of space vehicles  

NASA Technical Reports Server (NTRS)

A composite flexible blanket insulation (CFBI) system considered for use as a thermal protection system for space vehicles is described. This flexible composite insulation system consists of an outer layer of silicon carbide fabric, followed by alumina mat insulation, and alternating layers of aluminized polyimide film and aluminoborosilicate scrim fabric. A potential application of this composite insulation would be as a thermal protection system for the aerobrake of the Aeroassist Space Transfer Vehicle (ASTV). It would also apply to other space vehicles subject to high convective and radiative heating during atmospheric entry. The thermal performance of this composite insulation as exposed to a simulated atmospheric entry environment in a plasma arc test facility is described. Other thermophysical properties which affect the thermal response of this system are also described. Analytical modeling describing the thermal performance of this composite insulation is included. It shows that this composite insulation is effective as a thermal protection system at total heating rates up to 30.6 W/sq cm.

Kourtides, Demetrius A.; Tran, Huy K.; Chiu, S. Amanda

1992-01-01

107

Numerical Simulation for Thermal Shock Resistance of Thermal Protection Materials Considering Different Operating Environments  

PubMed Central

Based on the sensitivities of material properties to temperature and the complexity of service environment of thermal protection system on the spacecraft, ultrahigh-temperature ceramics (UHTCs), which are used as thermal protection materials, cannot simply consider thermal shock resistance (TSR) of the material its own but need to take the external constraint conditions and the thermal environment into full account. With the thermal shock numerical simulation on hafnium diboride (HfB2), a detailed study of the effects of the different external constraints and thermal environments on the TSR of UHTCs had been made. The influences of different initial temperatures, constraint strengths, and temperature change rates on the TSR of UHTCs are discussed. This study can provide a more intuitively visual understanding of the evolution of the TSR of UHTCs during actual operation conditions. PMID:23983628

Fang, Daining

2013-01-01

108

Thermal Protection Systems for Future NASA Space Vehicles  

NASA Technical Reports Server (NTRS)

The proposed first through fourth generation of future NASA Reusable Launch Vehicles (RLV) within NASA will be described, in general, along with their relative goals for improvement in performance (i.e., cost, safety, life, and turnaround time). A brief description of Spaceliner 100 activities representing a means to achieve those goals will be included. Some of the families of thermal protection materials with widely varying characteristics that are being developed for first generation space vehicles at Ames Research Center will be described as well as potential materials and composites for second and third generation applications as systems. These families of materials include functionally gradient material composites that are made from a variety of low-density substrates and moderate to fully dense surface treatments providing the resultant material with both toughness and higher temperature capability opening the envelope of Thermal Protection Systems (TPS) capabilities. Some of the materials truly represent enabling technologies that are required to achieve substantially enhanced thermal protection system performance thereby reducing vehicle risk. Finally the needs for integrated vehicle health monitoring (IVHM) of future vehicles thermal protection systems relative to achieving the goals for third generation reusable launch vehicles and for improving vehicle performance and capabilities reducing risk will be described along with the state of the art in TPS.

Leiser, Daniel B.; Rasky, Daniel; Arnold, James O. (Technical Monitor)

2000-01-01

109

Intelligent, Self-Diagnostic Thermal Protection System for Future Spacecraft  

NASA Technical Reports Server (NTRS)

The goal of this project is to provide self-diagnostic capabilities to the thermal protection systems (TPS) of future spacecraft. Self-diagnosis is especially important in thermal protection systems (TPS), where large numbers of parts must survive extreme conditions after weeks or years in space. In-service inspections of these systems are difficult or impossible, yet their reliability must be ensured before atmospheric entry. In fact, TPS represents the greatest risk factor after propulsion for any transatmospheric mission. The concepts and much of the technology would be applicable not only to the Crew Exploration Vehicle (CEV), but also to ablative thermal protection for aerocapture and planetary exploration. Monitoring a thermal protection system on a Shuttle-sized vehicle is a daunting task: there are more than 26,000 components whose integrity must be verified with very low rates of both missed faults and false positives. The large number of monitored components precludes conventional approaches based on centralized data collection over separate wires; a distributed approach is necessary to limit the power, mass, and volume of the health monitoring system. Distributed intelligence with self-diagnosis further improves capability, scalability, robustness, and reliability of the monitoring subsystem. A distributed system of intelligent sensors can provide an assurance of the integrity of the system, diagnosis of faults, and condition-based maintenance, all with provable bounds on errors.

Hyers, Robert W.; SanSoucie, Michael P.; Pepyne, David; Hanlon, Alaina B.; Deshmukh, Abhijit

2005-01-01

110

Thermal Protection System for the Space Shuttle External Tank  

Microsoft Academic Search

The External Tank (ET) has two major roles-to contain and deliver quality cryogenic propellants to the Space Shuttle main engines and to serve as the structural backbone for the attachment of the orbiter and solid rocket boosters. The Thermal Protection System (TPS), composed of cryoprotective foam insula tion and ablator (a sacrificial heatshield material), is applied to the outer sur

L. Ronquillo; C. Williams

1984-01-01

111

"TPSX: Thermal Protection System Expert and Material Property Database"  

NASA Technical Reports Server (NTRS)

The Thermal Protection Branch at NASA Ames Research Center has developed a computer program for storing, organizing, and accessing information about thermal protection materials. The program, called Thermal Protection Systems Expert and Material Property Database, or TPSX, is available for the Microsoft Windows operating system. An "on-line" version is also accessible on the World Wide Web. TPSX is designed to be a high-quality source for TPS material properties presented in a convenient, easily accessible form for use by engineers and researchers in the field of high-speed vehicle design. Data can be displayed and printed in several formats. An information window displays a brief description of the material with properties at standard pressure and temperature. A spread sheet window displays complete, detailed property information. Properties which are a function of temperature and/or pressure can be displayed as graphs. In any display the data can be converted from English to SI units with the click of a button. Two material databases included with TPSX are: 1) materials used and/or developed by the Thermal Protection Branch at NASA Ames Research Center, and 2) a database compiled by NASA Johnson Space Center 9JSC). The Ames database contains over 60 advanced TPS materials including flexible blankets, rigid ceramic tiles, and ultra-high temperature ceramics. The JSC database contains over 130 insulative and structural materials. The Ames database is periodically updated and expanded as required to include newly developed materials and material property refinements.

Squire, Thomas H.; Milos, Frank S.; Rasky, Daniel J. (Technical Monitor)

1997-01-01

112

Damage Detection/Locating System Providing Thermal Protection  

NASA Technical Reports Server (NTRS)

A damage locating system also provides thermal protection. An array of sensors substantially tiles an area of interest. Each sensor is a reflective-surface conductor having operatively coupled inductance and capacitance. A magnetic field response recorder is provided to interrogate each sensor before and after a damage condition. Changes in response are indicative of damage and a corresponding location thereof.

Woodard, Stanley E. (Inventor); Jones, Thomas W. (Inventor); Taylor, Bryant D. (Inventor); Qamar, A. Shams (Inventor)

2010-01-01

113

Closed-pore Insulation Thermal Protection System Design Concept Development  

NASA Technical Reports Server (NTRS)

The development of a unique closed-pore ceramic foam insulation (CPI) produced from low cost fly ash cenospheres is reported for space shuttle external thermal protection. Two basic design approaches were developed: bonded and mechanically fastened. A description of the concepts is presented in addition to fabrication and test results.

Varisco, A.; Harris, H. G.

1973-01-01

114

Thermal modeling of a metallic thermal protection tile for entry vehicles  

NASA Technical Reports Server (NTRS)

The thermal Energy Flow Simulation (TEFS) computer program was developed to simulate transient heat transfer through composite solids and predict interfacial temperatures. The program and its usage are described. A simulation of the thermal response of a new thermal protection tile design for the Space Shuttle Orbiter is presented and graphically compared with actual data. An example is also provided which shows the program's usage as a design tool for theoretical models.

Wiese, M. R.

1986-01-01

115

Engineering Aerothermal Analysis for X-34 Thermal Protection System Design  

NASA Technical Reports Server (NTRS)

Design of the thermal protection system for any hypersonic flight vehicle requires determination of both the peak temperatures over the surface and the heating-rate history along the flight profile. In this paper, the process used to generate the aerothermal environments required for the X-34 Testbed Technology Demonstrator thermal protection system design is described as it has evolved from a relatively simplistic approach based on engineering methods applied to critical areas to one of detailed analyses over the entire vehicle. A brief description of the trajectory development leading to the selection of the thermal protection system design trajectory is included. Comparisons of engineering heating predictions with wind-tunnel test data and with results obtained using a Navier-Stokes flowfield code and an inviscid/boundary layer method are shown. Good agreement is demonstrated among all these methods for both the ground-test condition and the peak heating flight condition. Finally, the detailed analysis using engineering methods to interpolate the surface-heating-rate results from the inviscid/boundary layer method to predict the required thermal environments is described and results presented.

Wurster, Kathryn E.; Riley, Christopher J.; Zoby, E. Vincent

1998-01-01

116

Thermal performance evaluation of artificial protective coatings applied to steam surface condenser tubes.  

E-print Network

??ENGLISH ABSTRACT: The coating thermal conductivity, the effective coated-tube thermal conductivity and the coating factor of three artificial protective coatings (APCs) applied to condenser tubes… (more)

Goodenough, John L.

2013-01-01

117

Hypervelocity impact testing of Shuttle Orbiter thermal protection system tiles  

NASA Technical Reports Server (NTRS)

Results are presented from a series of 22 hypervelocity impact tests carried out on the thermal protection system (TPS) for the Shuttle Orbiter. Both coated and uncoated low-density (0.14 g/cu cm) LI-900 and high-density (0.35 g/cu cm) LI-2200 tiles were tested. The results are used to develop the penetration and damage correlations which can be used in meteoroid and debris hazard analyses for spacecraft with a ceramic tile TPS. It is shown that tile coatings act as a 'bumper' to fragment the impacting projectile, with thicker coating providing increased protection.

Christiansen, Eric L.; Ortega, Javier

1990-01-01

118

Investigation of Fundamental Modeling and Thermal Performance Issues for a Metallic Thermal Protection System Design  

NASA Technical Reports Server (NTRS)

A study was performed to develop an understanding of the key factors that govern the performance of metallic thermal protection systems for reusable launch vehicles. A current advanced metallic thermal protection system (TPS) concept was systematically analyzed to discover the most important factors governing the thermal performance of metallic TPS. A large number of relevant factors that influence the thermal analysis and thermal performance of metallic TPS were identified and quantified. Detailed finite element models were developed for predicting the thermal performance of design variations of the advanced metallic TPS concept mounted on a simple, unstiffened structure. The computational models were also used, in an automated iterative procedure, for sizing the metallic TPS to maintain the structure below a specified temperature limit. A statistical sensitivity analysis method, based on orthogonal matrix techniques used in robust design, was used to quantify and rank the relative importance of the various modeling and design factors considered in this study. Results of the study indicate that radiation, even in small gaps between panels, can reduce significantly the thermal performance of metallic TPS, so that gaps should be eliminated by design if possible. Thermal performance was also shown to be sensitive to several analytical assumptions that should be chosen carefully. One of the factors that was found to have the greatest effect on thermal performance is the heat capacity of the underlying structure. Therefore the structure and TPS should be designed concurrently.

Blosser, Max L.

2002-01-01

119

Intumescent-ablators as improved thermal protection materials  

NASA Technical Reports Server (NTRS)

Nitroaromatic amine-based intumescent coatings were improved with regard to their thermal protection ability by adding endothermic decomposing fillers with endotherms at or near the exothermic reaction of the intumescent agent, since the effectiveness of the intumescent coatings without fillers is reduced by the exothermic behavior of the coatings during thermal activation. Fillers were dispersed directly in the base coating. Potassium fluoborate, ammonium fluoborate, zinc borate, and ammonium oxalate function as endothermic ablative materials at specific temperature regions, and also enhance the char formation during the intumescent process.

Sawko, P. M.; Riccitiello, S. R.

1977-01-01

120

Development of processing techniques for advanced thermal protection materials  

NASA Technical Reports Server (NTRS)

The main purpose of this work has been in the development and characterization of materials for high temperature applications. Thermal Protection Systems (TPS) are constantly being tested, and evaluated for increased thermal shock resistance, high temperature dimensional stability, and tolerance to environmental effects. Materials development was carried out through the use of many different instruments and methods, ranging from extensive elemental analysis to physical attributes testing. The six main focus areas include: (1) protective coatings for carbon/carbon composites; (2) TPS material characterization; (3) improved waterproofing for TPS; (4) modified ceramic insulation for bone implants; (5) improved durability ceramic insulation blankets; and (6) ultra-high temperature ceramics. This report describes the progress made in these research areas during this contract period.

Selvaduray, Guna S.

1995-01-01

121

The Challenges of Credible Thermal Protection System Reliability Quantification  

NASA Technical Reports Server (NTRS)

The paper discusses several of the challenges associated with developing a credible reliability estimate for a human-rated crew capsule thermal protection system. The process of developing such a credible estimate is subject to the quantification, modeling and propagation of numerous uncertainties within a probabilistic analysis. The development of specific investment recommendations, to improve the reliability prediction, among various potential testing and programmatic options is then accomplished through Bayesian analysis.

Green, Lawrence L.

2013-01-01

122

Impact Testing of Orbiter Thermal Protection System Materials  

NASA Technical Reports Server (NTRS)

This viewgraph presentation reviews the impact testing of the materials used in designing the shuttle orbiter thermal protection system (TPS). Pursuant to the Columbia Accident Investigation Board recommendations a testing program of the TPS system was instituted. This involved using various types of impactors in different sizes shot from various sizes and strengths guns to impact the TPS tiles and the Leading Edge Structural Subsystem (LESS). The observed damage is shown, and the resultant lessons learned are reviewed.

Kerr, Justin

2006-01-01

123

46 CFR 199.214 - Immersion suits and thermal protective aids.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Immersion suits and thermal protective aids. 199.214 Section...Vessels § 199.214 Immersion suits and thermal protective aids. (a) Each passenger...section, each passenger vessel must carry a thermal protective aid approved under...

2010-10-01

124

Thermal Protective Coating for High Temperature Polymer Composites  

NASA Technical Reports Server (NTRS)

The central theme of this research is the application of carboxylate-alumoxane nanoparticles as precursors to thermally protective coatings for high temperature polymer composites. In addition, we will investigate the application of carboxylate-alumoxane nanoparticle as a component to polymer composites. The objective of this research was the high temperature protection of polymer composites via novel chemistry. The significance of this research is the development of a low cost and highly flexible synthetic methodology, with a compatible processing technique, for the fabrication of high temperature polymer composites. We proposed to accomplish this broad goal through the use of a class of ceramic precursor material, alumoxanes. Alumoxanes are nano-particles with a boehmite-like structure and an organic periphery. The technical goals of this program are to prepare and evaluate water soluble carboxylate-alumoxane for the preparation of ceramic coatings on polymer substrates. Our proposed approach is attractive since proof of concept has been demonstrated under the NRA 96-LeRC-1 Technology for Advanced High Temperature Gas Turbine Engines, HITEMP Program. For example, carbon and Kevlar(tm) fibers and matting have been successfully coated with ceramic thermally protective layers.

Barron, Andrew R.

1999-01-01

125

MMOD Protection and Degradation Effects for Thermal Control Systems  

NASA Technical Reports Server (NTRS)

Micrometeoroid and orbital debris (MMOD) environment overview Hypervelocity impact effects & MMOD shielding MMOD risk assessment process Requirements & protection techniques - ISS - Shuttle - Orion/Commercial Crew Vehicles MMOD effects on spacecraft systems & improving MMOD protection - Radiators Coatings - Thermal protection system (TPS) for atmospheric entry vehicles Coatings - Windows - Solar arrays - Solar array masts - EVA Handrails - Thermal Blankets Orbital Debris provided by JSC & is the predominate threat in low Earth orbit - ORDEM 3.0 is latest model (released December 2013) - http://orbitaldebris.jsc.nasa.gov/ - Man-made objects in orbit about Earth impacting up to 16 km/s average 9-10 km/s for ISS orbit - High-density debris (steel) is major issue Meteoroid model provided by MSFC - MEM-R2 is latest release - http://www.nasa.gov/offices/meo/home/index.html - Natural particles in orbit about sun Mg-silicates, Ni-Fe, others - Meteoroid environment (MEM): 11-72 km/s Average 22-23 km/s.

Christiansen, Eric

2014-01-01

126

Coated columbium thermal protection systems: An assessment of technological readiness  

NASA Technical Reports Server (NTRS)

Evaluation and development to date show that of the coated columbium alloys FS-85 coated with R512E shows significant promise for a reusable thermal protection system (TPS) as judged by environmental resistance and the retention of mechanical properties and structural integrity of panels upon repeated reentry simulation. Production of the alloy, the coating, and full-sized TPS panels is well within current manufacturing technology. Small defects which arise from impact damage or from local coating breakdown do not appear to have serious immediate consequences in the use environment anticipated for the space shuttle orbiter TPS.

Levine, S. R.; Grisaffe, S. J.

1973-01-01

127

MSFC Thermal Protection System Materials on MISSE-6  

NASA Technical Reports Server (NTRS)

The Lightweight Nonmetallic Thermal Protection Materials Technology (LNTPMT) program studied a number of ceramic matrix composites, ablator materials, and tile materials for durability in simulated space environment. Materials that indicated low atomic oxygen reactivity and negligible change in thermo-optical properties in ground testing were selected to fly on the Materials on International Space Station Experiment (MISSE)-6. These samples were exposed for 17 months to the low Earth orbit environment on both the ram and wake sides of MISSE-6B. Thermo-optical properties are discussed, along with any changes in mass.

Finckenor, Miria M.; Valentine, Peter G.; Gubert, Michael K.

2010-01-01

128

Fiber optic temperature profiling for thermal protection heat shields  

NASA Astrophysics Data System (ADS)

Reliable Thermal Protection System (TPS) sensors are needed to achieve better designs for spacecraft (probe) heatshields for missions requiring atmospheric aero-capture or entry/reentry. In particular, they will allow both reduced risk and heat-shield mass minimization, which will facilitate more missions and allow increased payloads and returns. For thermal measurements, Intelligent Fiber Optic Systems Corporation (IFOS) is providing a temperature monitoring system involving innovative lightweight, EMI-immune, high-temperature resistant Fiber Bragg Grating (FBG) sensors with a thermal mass near that of TPS materials together with fast FBG sensor interrogation. The IFOS fiber optic sensing technology is highly sensitive and accurate. It is also low-cost and lends itself to high-volume production. Multiple sensing FBGs can be fabricated as arrays on a single fiber for simplified design and reduced cost. In this paper, we provide experimental results to demonstrate the temperature monitoring system using multi-sensor FBG arrays embedded in small-size Super-Light Ablator (SLA) coupon, which was thermally loaded to temperatures in the vicinity of the SLA charring temperature. In addition, a high temperature FBG array was fabricated and tested for 1000°C operation.

Black, Richard J.; Costa, Joannes M.; Moslehi, Behzad; Zarnescu, Livia; Hackney, Drew; Peters, Kara

2014-04-01

129

Thermomechanical analysis of a damaged thermal protection system  

NASA Astrophysics Data System (ADS)

Research on the effects of damage on the thermomechanical performance and structural integrity of thermal protection systems (TPS) has been limited. The objective of this research is to address this need by conducting experiments and finite element (FE) analysis on damaged TPS. The TPS selected for study is the High-Temperature Reusable Insulation (HRSI) tiles that are used extensively on NASA's Space Shuttle Orbiter. The TPS considered, which consists of a LI-900 tile, the strain isolator pad and the underlying structure, is subjected to the thermal loading and re-entry static pressure of the Access to Space reference vehicle. The damage to the TPS emulates hypervelocity-impact-type damage, which is approximated in the current research by a cylindrical hole ending with a spherical cap. Preliminary FE analysis using several simplifying assumptions, was conducted to determine the accuracy of using an approximate axisymmetric model compared to a complete three-dimensional model for both heat transfer and thermal stress analyses. Temperature results from the two models were found to be reasonable close; however, thermal stress results displayed significant differences. The sensitivity of the FE results to the various simplifying assumptions was also examined and it was concluded that for reliable results, the simplifying assumptions were not acceptable. Subsequently, an exact three-dimensional model was developed and validated by comparison with experimental data. Re-entry static pressures and temperatures were simulated using a high-temperature experimental facility that consists of a quartz radiant heater and a vacuum chamber with appropriate instrumentation. This facility was developed during the course of this dissertation. Temperatures on the top and bottom surfaces of the TPS specimen as well as strains in the underlying structure were recorded for FE model validation. The validated FE model was then combined with improved thermal loads based on the interactions of hypersonic flow past a cavity representing the damage. Effects of damage on the TPS were assessed by comparing the thermal and structural response of damaged configuration to the undamaged TPS. Damage increases the thermal loads on the TPS and significantly reduces the heat rejection capability of the surface of the tile, resulting in elevated temperatures. The higher temperatures coupled with the stress concentrations introduced by the damage cause a substantial increase in thermal stresses. For the damage sizes considered, the elevated thermal stresses alone are not likely to cause material failure. However, a modest damage size of 0.5? is capable of raising temperatures in the tile to exceed its melting point.

Ng, Wei Heok

130

Ablation Modeling of Ares-I Upper State Thermal Protection System Using Thermal Desktop  

NASA Technical Reports Server (NTRS)

The thermal protection system (TPS) for the Ares-I Upper Stage will be based on Space Transportation System External Tank (ET) and Solid Rocket Booster (SRB) heritage materials. These TPS materials were qualified via hot gas testing that simulated ascent and re-entry aerothermodynamic convective heating environments. From this data, the recession rates due to ablation were characterized and used in thermal modeling for sizing the thickness required to maintain structural substrate temperatures. At Marshall Space Flight Center (MSFC), the in-house code ABL is currently used to predict TPS ablation and substrate temperatures as a FORTRAN application integrated within SINDA/G. This paper describes a comparison of the new ablation utility in Thermal Desktop and SINDA/FLUINT with the heritage ABL code and empirical test data which serves as the validation of the Thermal Desktop software for use on the design of the Ares-I Upper Stage project.

Sharp, John R.; Page, Arthur T.

2007-01-01

131

Ballistic Performance of Porous-Ceramic, Thermal Protection Systems  

NASA Technical Reports Server (NTRS)

Porous-ceramic, thermal protection systems are used heavily in current reentry vehicles like the Orbiter, and they are currently being proposed for the next generation of US manned spacecraft, Orion. These systems insulate reentry critical components of a spacecraft against the intense thermal environments of atmospheric reentry. Additionally, these materials are highly exposed to space environment hazards like solid particle impacts. This paper discusses impact studies up to 10 km/s on 8 lb/cu ft alumina-fiber-enhanced-thermal-barrier (AETB8) tiles coated with a toughened-unipiece-fibrous-insulation/ reaction-cured-glass layer (TUFI/RCG). A semi-empirical, first principals impact model that describes projectile dispersion is described that provides excellent agreement with observations over a broad range of impact velocities, obliquities and projectile materials. Model extensions to look at the implications of greater than 10 GPa equation of state is also discussed. Predicted penetration probabilities for a vehicle visiting the International Space Station is 60% lower for orbital debris and 95% lower for meteoroids with this model compared to an energy scaled approach.

Miller, J. E.; Bohl, W. E.; Christiansen, Eric C.; Davis, B. A.; Foreman, C. D.

2011-01-01

132

Ballistic Performance of Porous-Ceramic, Thermal Protection Systems  

NASA Astrophysics Data System (ADS)

Porous-ceramic, thermal protection systems are used heavily in current reentry vehicles like the Orbiter, and they are currently being proposed for the next generation of US manned spacecraft, Orion. These systems insulate reentry critical components of a spacecraft against the intense thermal environments of atmospheric reentry. Additionally, these materials are also highly exposed to space environment hazards like solid particle impacts. This paper discusses impact testing up to 9.65 km/s on one of these systems. The materials considered are 8 lb/ft^3 alumina-fiber-enhanced-thermal-barrier (AETB8) tiles coated with a toughened-unipiece-fibrous-insulation/reaction-cured-glass layer (TUFI/RCG). A semi-empirical, first principals impact model that describes projectile dispersion is described that provides excellent agreement with observations over a broad range of impact velocities, obliquities and projectile materials. A model extension to look at the implications of greater than 10 GPa equation of state measurements is also discussed. Predicted penetration probabilities for a vehicle visiting the International Space Station is 60% lower for orbital debris and 95% lower for meteoroids with this model compared to an energy scaled approach.

Miller, Joshua; Bohl, William; Christiansen, Eric; Davis, B. Alan; Foreman, Cory

2011-06-01

133

Ballistic performance of porous-ceramic, thermal protection systems  

NASA Astrophysics Data System (ADS)

Porous-ceramic, thermal protection systems are used heavily in current reentry vehicles like the Orbiter, and they are currently being proposed for the next generation of US manned spacecraft, Orion. These systems insulate reentry critical components of a spacecraft against the intense thermal environments of atmospheric reentry. Additionally, these materials are highly exposed to space environment hazards like solid particle impacts. This paper discusses impact studies up to 10 km/s on 8 lb/ft3 alumina-fiber-enhanced-thermal-barrier (AETB8) tiles coated with a toughened-unipiece-fibrousinsulation/ reaction-cured-glass layer (TUFI/RCG). A semi-empirical, first principles impact model that describes projectile dispersion is described that provides excellent agreement with observations over a broad range of impact velocities, obliquities and projectile materials. Model extensions to look at the implications of greater than 10 GPa equation of state is also discussed. Predicted penetration probabilities for a vehicle visiting the International Space Station is 60% lower for orbital debris and 95% lower for meteoroids with this model compared to an energy scaled approach.

Miller, Joshua E.; Bohl, William E.; Christiansen, Eric C.; Davis, Bruce A.; Foreman, Cory D.

2012-03-01

134

Heat flux instrumentation for HYFLITE thermal protection system  

NASA Technical Reports Server (NTRS)

Tasks performed in this project were defined in a September 9, 1994 meeting of representatives of Vatell, NASA Lewis and Virginia Tech. The overall objective agreed upon in the meeting was 'to demonstrate the viability of thin film techniques for heat flux and temperature sensing in HYSTEP thermal protection systems'. We decided to attempt a combination of NASA's and Vatell's best heat flux sensor technology in a sensor which would be tested in the Vortek facility at Lewis early in 1995. The NASA concept for thermocouple measurement of surface temperature was adopted, and Vatell methods for fabrication of sensors on small diameter substrates of aluminum nitride were used to produce a sensor. This sensor was then encapsulated in a NARloy-Z housing. Various improvements to the Vatell substrate design were explored without success. The basic NASA and Vatell sensor layouts were analyzed by finite element modeling, in an attempt to better understand the effects of material properties, dimensions and thermal differential element location on sensor symmetry, bandwidth and sensitivity. This analysis showed that, as long as the thermal resistivity of the thermal differential element material is much larger (10X) than that of the substrate material, the simplest arrangement of layer is best. During calibration of the sensor produced in this project, undesirable side-effects of combining the heat flux and temperature sensor return leads were observed. The sensor did not cleanly separate the heat flux and temperature signals, as sensors with four leads have consistently done before. Task 7 and 8 discussed in the meeting will be performed with a continuation of funding in 1995. The following is a discussion of each of the tasks performed as outlined in the statement of work dated september 26, 1994. Task 1A was added to cover further investigation into the NASA sensor concept.

Diller, T. E.

1994-01-01

135

On the thermal rupture of 1.9 m 3 propane pressure vessels with defects in their thermal protection system  

Microsoft Academic Search

This paper describes the results from a series of fire tests that were carried out to measure the effect of defects in thermal protection systems on fire engulfed propane pressure vessels.In North America thermal protection is used to protect dangerous goods rail tank-cars from accidental fire impingement. They are designed so that a tank-car will not rupture for 100min in

A. M. Birk; D. Poirier; C. Davison

2006-01-01

136

Terahertz Computed Tomography of NASA Thermal Protection System Materials  

NASA Technical Reports Server (NTRS)

A terahertz 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 cubic meters (1 cubic foot) with no safety concerns as for x-ray computed tomography. In this study, the system is evaluated for its ability to detect and characterize flat bottom holes, drilled holes, and embedded voids in foam materials utilized as thermal protection on the external fuel tanks for the Space Shuttle. X-ray micro-computed tomography was also performed on the samples to compare against the terahertz computed tomography results and better define embedded voids. Limits of detectability based on depth and size for the samples used in this study are loosely defined. Image sharpness and morphology characterization ability for terahertz computed tomography are qualitatively described.

Roth, D. J.; Reyes-Rodriguez, S.; Zimdars, D. A.; Rauser, R. W.; Ussery, W. W.

2011-01-01

137

Integrated Thermal Protection Systems and Heat Resistant Structures  

NASA Technical Reports Server (NTRS)

In the early stages of NASA's Exploration Initiative, Snecma Propulsion Solide was funded under the Exploration Systems Research & Technology program to develop integrated thermal protection systems and heat resistant structures for reentry vehicles. Due to changes within NASA's Exploration Initiative, this task was cancelled early. This presentation provides an overview of the work that was accomplished prior to cancellation. The Snecma team chose an Apollo-type capsule as the reference vehicle for the work. They began with the design of a ceramic aft heatshield (CAS) utilizing C/SiC panels as the capsule heatshield, a C/SiC deployable decelerator and several ablators. They additionally developed a health monitoring system, high temperature structures testing, and the insulation characterization. Though the task was pre-maturely cancelled, a significant quantity of work was accomplished.

Pichon, Thierry; Lacoste, Marc; Glass, David E.

2006-01-01

138

Effects of selected trajectory parameters on weight trends in the shuttle thermal protection system  

NASA Technical Reports Server (NTRS)

An empirical heating model, thermal protection system unit weight correlation, and trajectory analysis were used to develop a computation procedure for studying the sensitivity of thermal protection system weights to variations in pertinent trajectory parameters. The analytical techniques used in developing this computer program are described. Application of the analysis to a Space Shuttle Orbiter configuration was performed to demonstrate gross thermal protection system weight trends with selected entry trajectory parameters.

Curry, D. M.; Tolin, J. W., Jr.; Goodrich, W. D.

1974-01-01

139

75 FR 72653 - Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events...  

Federal Register 2010, 2011, 2012, 2013

...CFR Part 50 [NRC-2007-0008] RIN 3150-AI01 Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal...Regulations (10 CFR) part 50, section 61a to provide alternate fracture toughness requirements for protection against pressurized...

2010-11-26

140

A Study of the Effects of Altitude on Thermal Ice Protection System Performance  

NASA Technical Reports Server (NTRS)

Thermal ice protection systems use heat energy to prevent a dangerous buildup of ice on an aircraft. As aircraft become more efficient, less heat energy is available to operate a thermal ice protections system. This requires that thermal ice protection systems be designed to more exacting standards so as to more efficiently prevent a dangerous ice buildup without adversely affecting aircraft safety. While the effects of altitude have always beeing taked into account in the design of thermal ice protection systems, a better understanding of these effects is needed so as to enable more exact design, testing, and evaluation of these systems.

Addy, Harold E., Jr.; Oleskiw, Myron; Broeren, Andy P.; Orchard, Andy P.

2013-01-01

141

Hypervelocity Impact Test Results for a Metallic Thermal Protection System  

NASA Technical Reports Server (NTRS)

Hypervelocity impact tests have been performed on specimens representing metallic thermal protection systems (TPS) developed at NASA Langley Research Center for use on next-generation reusable launch vehicles (RLV). The majority of the specimens tested consists of a foil gauge exterior honeycomb panel, composed of either Inconel 617 or Ti-6Al-4V, backed with 2.0 in. of fibrous insulation and a final Ti-6Al-4V foil layer. Other tested specimens include titanium multi-wall sandwich coupons as well as TPS using a second honeycomb sandwich in place of the foil backing. Hypervelocity impact tests were performed at the NASA Marshall Space Flight Center Orbital Debris Simulation Facility. An improved test fixture was designed and fabricated to hold specimens firmly in place during impact. Projectile diameter, honeycomb sandwich material, honeycomb sandwich facesheet thickness, and honeycomb core cell size were examined to determine the influence of TPS configuration on the level of protection provided to the substructure (crew, cabin, fuel tank, etc.) against micrometeoroid or orbit debris impacts. Pictures and descriptions of the damage to each specimen are included.

Karr, Katherine L.; Poteet, Carl C.; Blosser, Max L.

2003-01-01

142

X-33 Attitude Control Using the XRS-2200 Linear Aerospike Engine  

NASA Technical Reports Server (NTRS)

The Vehicle Control Systems Team at Marshall Space Flight Center, Structures and Dynamics Laboratory, Guidance and Control Systems Division is designing, under a cooperative agreement with Lockheed Martin Skunkworks, the Ascent, Transition, and Entry flight attitude control systems for the X-33 experimental vehicle. Test flights, while suborbital, will achieve sufficient altitudes and Mach numbers to test Single Stage To Orbit, Reusable Launch Vehicle technologies. Ascent flight control phase, the focus of this paper, begins at liftoff and ends at linear aerospike main engine cutoff (MECO). The X-33 attitude control system design is confronted by a myriad of design challenges: a short design cycle, the X-33 incremental test philosophy, the concurrent design philosophy chosen for the X-33 program, and the fact that the attitude control system design is, as usual, closely linked to many other subsystems and must deal with constraints and requirements from these subsystems. Additionally, however, and of special interest, the use of the linear aerospike engine is a departure from the gimbaled engines traditionally used for thrust vector control (TVC) in launch vehicles and poses certain design challenges. This paper discusses the unique problem of designing the X-33 attitude control system with the linear aerospike engine, requirements development, modeling and analyses that verify the design.

Hall, Charles E.; Panossian, Hagop V.

1999-01-01

143

X-33 Model Tested In Langley's 20-Inch Mach 6 Tunnel  

NASA Technical Reports Server (NTRS)

Thomas Horvath of Langley's Aerothermodynamics Branch examines the surface of a model of the X-33 prior to testing in the 20-Inch Mach 6 Air Wind Tunnel at NASA Langley Research Center. The tests, held during the month of September 1997, were conducted to determine aeroheating characteristics of the X-33. The X-33 vehicle will consist of a lifting body airframe with two cryogenic propellant tanks (liquid hydrogen, LH2, and liquid oxygen, LOX) placed within the aeroshell. The vehicle will have two linear aerospike main engines. The X-33 Design and Flight Demonstration Program key objectives are to reduce business and technical risks to privately finance development and operation of a next-generation space transportation system through ground and flight tests of a spaceplane technology demonstrator, ensure that the X-33 design and major components are usable and scaleable to a full-scale, single-stage-orbit reusable launch vehicle (RLV), demonstrate autonomous capability from takeoff to landing, and verify operability and performance in 'real world' environments.

1997-01-01

144

X-33 Model Tested In Langley's 20-Inch Mach 6 Tunnel  

NASA Technical Reports Server (NTRS)

Thomas Horvath of Langley's Aerothermodynamics Branch uses digital instrumentation to set the angle of attack on a model of the X-33 prior to a wind tunnel test run in the 20-Inch Mach 6 Air Wind Tunnel at NASA Langley Research Center. The tests, held during the month of September 1997, were conducted to determine aeroheating characteristics of the X-33. The X-33 vehicle will consist of a lifting body airframe with two cryogenic propellant tanks (liquid hydrogen, LH2, and liquid oxygen, LOX) placed within the aeroshell. The vehicle will have two linear aerospike main engines. The X-33 Design and Flight Demonstration Program key objectives are to reduce business and technical risks to privately finance development and operation of a next-generation space transportation system through ground and flight tests of a spaceplane technology demonstrator, ensure that the X-33 design and major components are usable and scaleable to a full-scale, single-stage-orbit reusable launch vehicle (RLV), demonstrate autonomous capability from takeoff to landing, and verify operability and performance in 'real world' environments.

1997-01-01

145

Three-Dimensional Finite Element Ablative Thermal Response and Thermostructural Design of Thermal Protection Systems  

NASA Technical Reports Server (NTRS)

A finite element ablation and thermal response program is presented for simulation of three-dimensional transient thermostructural analysis. The three-dimensional governing differential equations and finite element formulation are summarized. A novel probabilistic design methodology for thermal protection systems is presented. The design methodology is an eight step process beginning with a parameter sensitivity study and is followed by a deterministic analysis whereby an optimum design can determined. The design process concludes with a Monte Carlo simulation where the probabilities of exceeding design specifications are estimated. The design methodology is demonstrated by applying the methodology to the carbon phenolic compression pads of the Crew Exploration Vehicle. The maximum allowed values of bondline temperature and tensile stress are used as the design specifications in this study.

Dec, John A.; Braun, Robert D.

2011-01-01

146

Design of metallic foams as insulation in thermal protection systems  

NASA Astrophysics Data System (ADS)

Metallic foams are novel materials that can be used as thermal insulation in many applications. The low volume fraction of solid, the small cell size and the low conductivity of enclosed gases limit the heat flow in foams. Varying the density, geometry and or material composition from point to point within the foam, one can produce functionally graded foams that may insulate more efficiently. The goal of this research is to investigate the use of functionally graded metal foam in thermal protection systems (TPS) for reusable launch vehicles. First, the effective thermal conductivity of the foam is derived based on a simple cubic unit cell model. Then two problems under steady state of heat transfer have been considered. The first one is the optimization of functionally graded foam insulation for minimum heat transmitted to the structure and the second is minimizing the mass of the functionally graded foam insulation for a given aerodynamic heating. In both cases optimality conditions are derived in closed-form, and numerical methods are used to solve the resulting differential equations to determine the optimal grading of the foam. In order to simplify the analysis the insulation was approximated by finite layers of uniform foams when studying the transient heat transfer case. The maximum structure temperature was minimized by varying the solidity profile for a given total thickness and mass. The principles that govern the design of TPS for transient conditions were identified. To take advantage of the load bearing ability of metallic foams, an integrated sandwich TPS/structure with metallic foam core is proposed. Such an integrated TPS will insulate the vehicle interior from aerodynamic heating as well as carry the primary vehicle loads. Thermal-structural analysis of integrated sandwich TPS panel subjected to transient heat conduction is developed to evaluate their performances. The integrated TPS design is compared with a conventional fibrous Safill TPS design. The weights of both designs are minimized subject to temperature constraints, stress constraints or both. Global buckling, shear crimping and face wrinkling are investigated for the integrated sandwich structure during the launch. It is found that for designs with variable insulation thickness, structure thickness and subjected to structure temperature constraint only, an integrated sandwich design tends to require as thick insulation as possible, while a Safill design requires thin structure. Shear crimping is most critical among all the three failure modes we studied in the integrated sandwich design.

Zhu, Huadong

147

A Strategy for Integrating a Large Finite Element Model: X-33 Lessons Learned  

NASA Technical Reports Server (NTRS)

The X-33 vehicle is an advanced technology demonstrator sponsored by NASA. For the past three years the Structural Dynamics & Loads Group of NASA's Marshall Space Flight Center has had the task of integrating the X-33 vehicle structural finite element model. In that time, five versions of the integrated vehicle model have been produced and a strategy has evolved that would benefit anyone given the task of integrating structural finite element models that have been generated by various modelers and companies. The strategy that has been presented here consists of six decisions that need to be made. These six decisions are: purpose of model, units, common material list, model numbering, interface control, and archive format. This strategy has been proved and expanded from experience on the X-33 vehicle.

McGhee, David S.

2000-01-01

148

Mars Science Laboratory Entry Capsule Aerothermodynamics and Thermal Protection System  

NASA Technical Reports Server (NTRS)

The Mars Science Laboratory (MSL) spacecraft is being designed to carry a large rover (greater than 800 kg) to the surface of Mars using a blunt-body entry capsule as the primary decelerator. The spacecraft is being designed for launch in 2009 and arrival at Mars in 2010. The combination of large mass and diameter with non-zero angle-of-attack for MSL will result in unprecedented convective heating environments caused by turbulence prior to peak heating. Navier-Stokes computations predict a large turbulent heating augmentation for which there are no supporting flight data1 and little ground data for validation. Consequently, an extensive experimental program has been established specifically for MSL to understand the level of turbulent augmentation expected in flight. The experimental data support the prediction of turbulent transition and have also uncovered phenomena that cannot be replicated with available computational methods. The result is that the flight aeroheating environments predictions must include larger uncertainties than are typically used for a Mars entry capsule. Finally, the thermal protection system (TPS) being used for MSL has not been flown at the heat flux, pressure, and shear stress combinations expected in flight, so a test program has been established to obtain conditions relevant to flight. This paper summarizes the aerothermodynamic definition analysis and TPS development, focusing on the challenges that are unique to MSL.

Edquist, Karl T.; Hollis, Brian R.; Dyakonov, Artem A.; Laub, Bernard; Wright, Michael J.; Rivellini, Tomasso P.; Slimko, Eric M.; Willcockson, William H.

2007-01-01

149

Mechanical Testing of Carbon Based Woven Thermal Protection Materials  

NASA Technical Reports Server (NTRS)

Three Dimensional Woven thermal protection system (TPS) materials are one of the enabling technologies for mechanically deployable hypersonic decelerator systems. These materials have been shown capable of serving a dual purpose as TPS and as structural load bearing members during entry and descent operations. In order to ensure successful structural performance, it is important to characterize the mechanical properties of these materials prior to and post exposure to entry-like heating conditions. This research focuses on the changes in load bearing capacity of woven TPS materials after being subjected to arcjet simulations of entry heating. Preliminary testing of arcjet tested materials [1] has shown a mechanical degradation. However, their residual strength is significantly more than the requirements for a mission to Venus [2]. A systematic investigation at the macro and microstructural scales is reported here to explore the potential causes of this degradation. The effects of heating on the sizing (an epoxy resin coating used to reduce friction and wear during fiber handling) are discussed as one of the possible causes for the decrease in mechanical properties. This investigation also provides valuable guidelines for margin policies for future mechanically deployable entry systems.

Pham, John; Agrawal, Parul; Arnold, James O.; Peterson, Keith; Venkatapathy, Ethiraj

2013-01-01

150

Effectiveness of Thermal-Pneumatic Airfoil-Ice-Protection System  

NASA Technical Reports Server (NTRS)

Icing and drag investigations were conducted in the NACA Lewis icing research tunnel employing a combination thermal-pneumatic de-icer mounted on a 42-inch-chord NACA 0018 airfoil. The de-icer consisted of a 3-inch-wide electrically heated strip symmetrically located about the leading edge with inflatable tubes on the upper and lower airfoil surfaces aft of the heated area. The entire de-icer extended to approximately 25 percent of chord. A maximum power density of 9.25 watts per square inch was required for marginal ice protection on the airfoil leading edge at an air temperature of 00 F and an airspeed of 300 miles per hour. Drag measurements indicated, that without icing, the de-icer installation increased the section drag to approximately 140 percent of that of the bare airfoil; with the tubes inflated, this value increased to a maximum of approximately 620 percent. A 2-minute tube-inflation cycle prevented excessive ice formation on the inflatable area although small scattered residual Ice formations remained after inflation and were removed intermittently during later cycles. Effects of the time lag of heater temperatures after initial application of power and the insulating effect of ice formations on heater temperatures were also determined.

Gowan, William H., Jr.; Mulholland, Donald R.

1951-01-01

151

Thermal Protection System (Heat Shield) Development - Advanced Development Project  

NASA Technical Reports Server (NTRS)

The Orion Thermal Protection System (TPS) ADP was a 3 1/2 year effort to develop ablative TPS materials for the Orion crew capsule. The ADP was motivated by the lack of available ablative TPS's. The TPS ADP pursued a competitive phased development strategy with succeeding rounds of development, testing and down selections. The Project raised the technology readiness level (TRL) of 8 different TPS materials from 5 different commercial vendors, eventual down selecting to a single material system for the Orion heat shield. In addition to providing a heat shield material and design for Orion on time and on budget, the Project accomplished the following: 1) Re-invigorated TPS industry & re-established a NASA competency to respond to future TPS needs; 2) Identified a potentially catastrophic problem with the planned MSL heat shield, and provided a viable, high TRL alternate heat shield design option; and 3) Transferred mature heat shield material and design options to the commercial space industry, including TPS technology information for the SpaceX Dragon capsule.

Kowal, T. John

2010-01-01

152

Heat flux instrumentation for Hyflite thermal protection system  

NASA Technical Reports Server (NTRS)

Using Thermal Protection Tile core samples supplied by NASA, the surface characteristics of the FRCI, TUFI, and RCG coatings were evaluated. Based on these results, appropriate methods of surface preparation were determined and tested for the required sputtering processes. Sample sensors were fabricated on the RCG coating and adhesion was acceptable. Based on these encouraging results, complete Heat Flux Microsensors were fabricated on the RCG coating. The issue of lead attachment was addressed with the annnealing and welding methods developed at NASA Lewis. Parallel gap welding appears to be the best method of lead attachment with prior heat treatment of the sputtered pads. Sample Heat Flux Microsensors were submitted for testing in the NASA Ames arc jet facility. Details of the project are contained in two attached reports. One additional item of interest is contained in the attached AIAA paper, which gives details of the transient response of a Heat Flux Microsensors in a shock tube facility at Virginia Tech. The response of the heat flux sensor was measured to be faster than 10 micro-s.

Diller, T. E.

1994-01-01

153

X-33 Attitude Control System Design for Ascent, Transition, and Entry Flight Regimes  

NASA Technical Reports Server (NTRS)

The Vehicle Control Systems Team at Marshall Space Flight Center, Systems Dynamics Laboratory, Guidance and Control Systems Division is designing under a cooperative agreement with Lockheed Martin Skunkworks, the Ascent, Transition, and Entry flight attitude control system for the X-33 experimental vehicle. Ascent flight control begins at liftoff and ends at linear aerospike main engine cutoff (NECO) while Transition and Entry flight control begins at MECO and concludes at the terminal area energy management (TAEM) interface. TAEM occurs at approximately Mach 3.0. This task includes not only the design of the vehicle attitude control systems but also the development of requirements for attitude control system components and subsystems. The X-33 attitude control system design is challenged by a short design cycle, the design environment (Mach 0 to about Mach 15), and the X-33 incremental test philosophy. The X-33 design-to-launch cycle of less than 3 years requires a concurrent design approach while the test philosophy requires design adaptation to vehicle variations that are a function of Mach number and mission profile. The flight attitude control system must deal with the mixing of aerosurfaces, reaction control thrusters, and linear aerospike engine control effectors and handle parasitic effects such as vehicle flexibility and propellant sloshing from the uniquely shaped propellant tanks. The attitude control system design is, as usual, closely linked to many other subsystems and must deal with constraints and requirements from these subsystems.

Hall, Charles E.; Gallaher, Michael W.; Hendrix, Neal D.

1998-01-01

154

Design and Calibration of the X-33 Flush Airdata Sensing (FADS) System  

NASA Technical Reports Server (NTRS)

This paper presents the design of the X-33 Flush Airdata Sensing (FADS) system. The X-33 FADS uses a matrix of pressure orifices on the vehicle nose to estimate airdata parameters. The system is designed with dual-redundant measurement hardware, which produces two independent measurement paths. Airdata parameters that correspond to the measurement path with the minimum fit error are selected as the output values. This method enables a single sensor failure to occur with minimal degrading of the system performance. The paper shows the X-33 FADS architecture, derives the estimating algorithms, and demonstrates a mathematical analysis of the FADS system stability. Preliminary aerodynamic calibrations are also presented here. The calibration parameters, the position error coefficient (epsilon), and flow correction terms for the angle of attack (delta alpha), and angle of sideslip (delta beta) are derived from wind tunnel data. Statistical accuracy of' the calibration is evaluated by comparing the wind tunnel reference conditions to the airdata parameters estimated. This comparison is accomplished by applying the calibrated FADS algorithm to the sensed wind tunnel pressures. When the resulting accuracy estimates are compared to accuracy requirements for the X-33 airdata, the FADS system meets these requirements.

Whitmore, Stephen A.; Cobleigh, Brent R.; Haering, Edward A.

1998-01-01

155

Investigation for thermal stability of U(sub 3)Si(sub 2) and protection methods.  

National Technical Information Service (NTIS)

The thermal stability of U(sub 3)Si(sub 2) in Ar, N(sub 2) and air, and the interaction between U(sub 3)Si(sub 2) and Al, Zr have been investigated by thermal analysis method. According to the results of thermal analysis, protection measures for various p...

Zhang Huiying Sun Jichang Sun Rongxian

1994-01-01

156

Cognitive function following treadmill exercise in thermal protective clothing.  

PubMed

Occupational injuries are common among firefighters who perform strenuous physical exertion in extreme heat. The thermal protective clothing (TPC) worn by firefighters inhibits normal thermoregulation, placing the firefighter at risk of hypohydration and hyperthermia that may result in cognitive decline. We tested whether cognitive function changes after treadmill exercise in TPC. In an initial study (Cog 1), ten healthy volunteers performed up to 50 min of treadmill exercise while wearing TPC in a heated room. A battery of neurocognitive tests evaluating short-term memory, sustained and divided attention, and reaction time was administered immediately before and after exercise. In a follow-up study (Cog 2), 19 healthy volunteers performed a similar exercise protocol with the battery of cognitive tests administered pre-exercise, immediately post-exercise, and serially up to 120 min after exercise. Subjects performed 46.4 ± 4.6 and 48.1 ± 3.6 min of exercise in the Cog 1 and Cog 2, respectively. In both studies heart rate approached age predicted maximum, body mass was reduced 1.0-1.5 kg, and body core temperature increased to levels similar to what is seen after fire suppression. Neurocognitive test scores did not change immediately after exercise. Recall on a memory test was reduced 60 and 120 min after exercise. The mean of the 10 slowest reaction times increased in the 120 min after exercise. Fifty minutes of treadmill exercise in TPC resulted in near maximal physiologic strain but alterations in neurocognitive performance were not noted until an hour or more following exercise in TPC. PMID:21892644

Morley, Julia; Beauchamp, Gillian; Suyama, Joe; Guyette, Francis X; Reis, Steven E; Callaway, Clifton W; Hostler, David

2012-05-01

157

Evaluation of Thermal Control Coatings for Flexible Ceramic Thermal Protection Systems  

NASA Technical Reports Server (NTRS)

This report summarizes the evaluation and testing of high emissivity protective coatings applied to flexible insulations for the Reusable Launch Vehicle technology program. Ceramic coatings were evaluated for their thermal properties, durability, and potential for reuse. One of the major goals was to determine the mechanism by which these coated blanket surfaces become brittle and try to modify the coatings to reduce or eliminate embrittlement. Coatings were prepared from colloidal silica with a small percentage of either SiC or SiB6 as the emissivity agent. These coatings are referred to as gray C-9 and protective ceramic coating (PCC), respectively. The colloidal solutions were either brushed or sprayed onto advanced flexible reusable surface insulation blankets. The blankets were instrumented with thermocouples and exposed to reentry heating conditions in the Ames Aeroheating Arc Jet Facility. Post-test samples were then characterized through impact testing, emissivity measurements, chemical analysis, and observation of changes in surface morphology. The results show that both coatings performed well in arc jet tests with backface temperatures slightly lower for the PCC coating than with gray C-9. Impact testing showed that the least extensive surface destruction was experienced on blankets with lower areal density coatings.

Kourtides, Demetrius; Carroll, Carol; Smith, Dane; Guzinski, Mike; Marschall, Jochen; Pallix, Joan; Ridge, Jerry; Tran, Duoc

1997-01-01

158

Evaluation of protective ensemble thermal characteristics through sweating hot plate, sweating thermal manikin, and human tests.  

PubMed

The purpose of this study was to evaluate the predictive capability of fabric Total Heat Loss (THL) values on thermal stress that Personal Protective Equipment (PPE) ensemble wearers may encounter while performing work. A series of three tests, consisting of the Sweating Hot Plate (SHP) test on two sample fabrics and the Sweating Thermal Manikin (STM) and human performance tests on two single-layer encapsulating ensembles (fabric/ensemble A = low THL and B = high THL), was conducted to compare THL values between SHP and STM methods along with human thermophysiological responses to wearing the ensembles. In human testing, ten male subjects performed a treadmill exercise at 4.8 km and 3% incline for 60 min in two environmental conditions (mild = 22°C, 50% relative humidity (RH) and hot/humid = 35°C, 65% RH). The thermal and evaporative resistances were significantly higher on a fabric level as measured in the SHP test than on the ensemble level as measured in the STM test. Consequently the THL values were also significantly different for both fabric types (SHP vs. STM: 191.3 vs. 81.5 W/m(2) in fabric/ensemble A, and 909.3 vs. 149.9 W/m(2) in fabric/ensemble B (p < 0.001). Body temperature and heart rate response between ensembles A and B were consistently different in both environmental conditions (p < 0.001), which is attributed to significantly higher sweat evaporation in ensemble B than in A (p < 0.05), despite a greater sweat production in ensemble A (p < 0.001) in both environmental conditions. Further, elevation of microclimate temperature (p < 0.001) and humidity (p < 0.01) was significantly greater in ensemble A than in B. It was concluded that: (1) SHP test determined THL values are significantly different from the actual THL potential of the PPE ensemble tested on STM, (2) physiological benefits from wearing a more breathable PPE ensemble may not be feasible with incremental THL values (SHP test) less than approximately 150-200 W·m(2), and (3) the effects of thermal environments on a level of heat stress in PPE ensemble wearers are greater than ensemble thermal characteristics. PMID:24579755

Kim, Jung-Hyun; Powell, Jeffery B; Roberge, Raymond J; Shepherd, Angie; Coca, Aitor

2014-01-01

159

A Base Drag Reduction Experiment on the X-33 Linear Aerospike SR71 Experiment (LASRE) Flight Program  

Microsoft Academic Search

Drag reduction tests were conducted on the LASRE\\/ X-33 flight experiment. The LASRE experiment is a flight test of a roughly 20-percent scale model of an X-33 forebody with a single aerospike engine at the rear. The experiment apparatus is mounted on top of an SR-71 aircraft. This paper suggests a method for reducing base drag by adding surface roughness

Stephen A. Whitmore; Timothy R. Moes

1999-01-01

160

A photogrammetric on-orbit inspection for orbiter thermal protection system  

E-print Network

Due to the Columbia Space Shuttle Accident of February 2003, the Columbia Accident Investigation Board determined the need for an on-orbit inspection system for the Thermal Protection System that accurately determines damage depth to 0.25". NASA...

Gesting, Peter Paul

2006-04-12

161

An assessment of radiative metallic thermal protection systems for space shuttle  

NASA Technical Reports Server (NTRS)

The metallic thermal protection system technology program for the space shuttle is reviewed for the areas of environmental uncertainties, materials data base, TPS design concepts and heat-shield panel configurations, testing and evaluation of materials, panels, and complete systems.

Stein, B. A.; Bohon, H. L.; Rummler, D. R.

1972-01-01

162

Updated Results of Deterministic Reconfigurable Control Design for the X-33 Vehicle  

NASA Technical Reports Server (NTRS)

In the event of a control surface failure, the purpose of a reconfigurable control system is to redistribute the control effort among the remaining working surfaces such that satisfactory stability and performance are retained. An Off-line Nonlinear General Constrained Optimization approach was used for the reconfigurable X-33 control design method. Three examples of failure are shown using a high fidelity 6 DOF simulation (case 1: ascent with a left body flap jammed at 25 deg.; case 2: entry with a right inboard elevon jam at 25 deg. and case 3: landing (TAEM) (Terminal Area Energy Management) with a left rudder jam at -30 deg.) Failure comparisons between responses with the nominal controller and reconfigurable controllers show the benefits of reconfiguration. Single jam aerosurface failures were considered, and failure detection and identification is considered accomplished in the actuator controller. The X-33 flight control system will incorporate reconfigurable flight control in the baseline system.

Cotting, M. Christopher; Burken, John J.

1999-01-01

163

Including Aeroelastic Effects in the Calculation of X-33 Loads and Control Characteristics  

NASA Technical Reports Server (NTRS)

Up until now, loads analyses of the X-33 RLV have been done at Marshall Space Flight Center (MSFC) using aerodynamic loads derived from CFD and wind tunnel models of a rigid vehicle. Control forces and moments are determined using a rigid vehicle trajectory analysis and the detailed control load distributions for achieving the desired control forces and moments, again on the rigid vehicle, are determined by Lockheed Martin Skunk Works. However, static aeroelastic effects upon the load distributions are not known. The static aeroelastic effects will generally redistribute external loads thereby affecting both the internal structural loads as well as the forces and moments generated by aerodynamic control surfaces. Therefore, predicted structural sizes as well as maneuvering requirements can be altered by consideration of static aeroelastic effects. The objective of the present work is the development of models and solutions for including static aeroelasticity in the calculation of X-33 loads and in the determination of stability and control derivatives.

Zeiler, Thomas A.

1998-01-01

164

Development of X-33\\/X-34 Aerothermodynamic Data Bases: Lessons Learned and Future Enhancements  

Microsoft Academic Search

Summary: A synoptic of programmatic and technical lessons learned in the development of aerothermodynamic data bases for the X-33 and X-34 programs is presented in general terms and from the perspective of the NASA Langley Research Center Aerothermodynamics Branch. The format used is that of the Òaerothermodynamic chain,Ó the links of which are personnel, facilities, models\\/test articles, instrumentation, test techniques,

C. G. Miller

165

Numerical simulations of heat and moisture transport in thermal protective clothing under flash fire conditions.  

PubMed

A numerical model of heat and moisture transport in thermal protective clothing during exposure to a flash fire was introduced. The model was developed with the assumption that textiles are treated as porous media. The numerical model predictions were compared with experimental data from different fabric systems and configurations. Additionally, with the introduction of a skin model, the parameters that affect the performance of thermal protective clothing were investigated. PMID:18394330

Song, Guowen; Chitrphiromsri, Patirop; Ding, Dan

2008-01-01

166

Optimization of thermal protection systems for the space vehicle. Volume 2: User's manual  

NASA Technical Reports Server (NTRS)

The development of the computational techniques for the design optimization of thermal protection systems for the space shuttle vehicle are discussed. The resulting computer program was then used to perform initial optimization and sensitivity studies on a typical thermal protection system (TPS) to demonstrate its application to the space shuttle TPS design. The program was developed in FORTRAN IV for CDC 6400 computer, but it was subsequently converted to the FORTRAN V language to be used on the Univac 1108.

1972-01-01

167

Ascent, Transition, Entry, and Abort Guidance Algorithm Design for the X-33 Vehicle  

NASA Technical Reports Server (NTRS)

One of the primary requirements for X-33 is that it be capable of flying autonomously. That is, onboard computers must be capable of commanding the entire flight from launch to landing, including cases where a single engine failure abort occurs. Guidance algorithms meeting these requirements have been tested in simulation and have been coded into prototype flight software. These algorithms must be sufficiently robust to account for vehicle and environmental dispersions, and must issue commands that result in the vehicle operating, within all constraints. Continual tests of these algorithms (and modifications as necessary) will occur over the next year as the X-33 nears its first flight. This paper describes the algorithms in use for X-33 ascent, transition, and entry flight, as well as for the powered phase of PowerPack-out (PPO) aborts (equivalent in thrust impact to losing an engine). All following discussion refers to these phases of flight when discussing guidance. The paper includes some trajectory results and results of dispersion analysis.

Hanson, John M.; Coughlin, Dan J.; Dukeman, Gregory A.; Mulqueen, John A.; McCarter, James W.

1998-01-01

168

An Inviscid Computational Study of an X-33 Configuration at Hypersonic Speeds  

NASA Technical Reports Server (NTRS)

This report documents the results of a study conducted to compute the inviscid longitudinal aerodynamic characteristics of a simplified X-33 configuration. The major components of the X-33 vehicle, namely the body, the canted fin, the vertical fin, and the body-flap, were simulated in the CFD (Computational Fluid Dynamic) model. The rear-ward facing surfaces at the base including the aerospike engine surfaces were not simulated. The FELISA software package consisting of an unstructured surface and volume grid generator and two inviscid flow solvers was used for this study. Computations were made for Mach 4.96, 6.0, and 10.0 with perfect gas air option, and for Mach 10 with equilibrium air option with flow condition of a typical point on the X-33 flight trajectory. Computations were also made with CF4 gas option at Mach 6.0 to simulate the CF4 tunnel flow condition. An angle of attack range of 12 to 48 deg was covered. The CFD results were compared with available wind tunnel data. Comparison was good at low angles of attack; at higher angles of attack (beyond 25 deg) some differences were found in the pitching moment. These differences progressively increased with increase in angle of attack, and are attributed to the viscous effects. However, the computed results showed the trends exhibited by the wind tunnel data.

Prabhu, Ramadas K.

1999-01-01

169

THERMAL PROTECTION OF STRUCTURAL, PROPULSION, AND TEMPERATURE-SENSITIVE MATERIALS FOR HYPERSONIC AND SPACE FLIGHT. PART III. ANALYTICAL STUDIES OF PHENOMENA FOR THERMAL PROTECTION  

Microsoft Academic Search

The results are presented of both analytical and experi-mental ; investigations of the applicability of the mass transfer cooling phenomenon to ; the protection of materials subjected to severe thermal environments. Efforts to ; improve characterization of the experimental tbermal environment provided by the ; one-megawatt air-stabilized arc are summarized. These efforts include extended ; development of calorimetry to provide

W. P. Manos; D. E. Taylor

1960-01-01

170

Effectiveness of Using Summer Thermal Indices to Classify and Protect Brook Trout Streams in Northern Ontario  

Microsoft Academic Search

We tested five thermal indices for their ability to differentiate streams containing brook trout Salvelinus fontinalis from streams not containing brook trout in forested watersheds of the Precambrian Shield, northern Ontario, with the goal of identifying and protecting riparian areas of thermally sensitive trout streams during timber harvesting. Logistic regression was used to predict brook trout presence and absence, with

Chris R. Picard; Michael A. Bozek; Walter T. Momot

2003-01-01

171

Heat transfer in a multilayered thermal protection system under aerodynamic heating  

Microsoft Academic Search

Future generation reusable re-entry vehicles must be capable of sustaining consistent repeated aero-thermal loads without damage or deterioration. This means that such structures should be able to withstand high temperatures engendered by aero-thermal re-entry fluxes due to the establishment of a hypersonic regime over the body.Thermal Protection Systems (TPS) are used to maintain a reusable launch vehicle structural temperature within

M. Ferraiuolo; O. Manca

172

49 CFR 193.2057 - Thermal radiation protection.  

Code of Federal Regulations, 2010 CFR

...3.2 of NFPA 59A (incorporated by reference, see § 193.2013) with the following exceptions: (a) The thermal radiation...Model for LNG Fires (incorporated by reference, see § 193.2013). The use of other alternate models which take into...

2010-10-01

173

Review and research on carbon fiber reinforced quartz used as thermal protection shield  

SciTech Connect

An evaluation was done of the characteristics of fiber reinforced ceramics in radiation thermal protective structures acting as exterior radiation cover plates. Using as a basis typical mechanical environments and thermal environments associated with returnable spacecraft, experimental research was carried out with regard to carbon fiber reinforced quartz-- including such items as small plate reentry thermal simulation tests as well as room temperature vibration, room temperature shock, low temperature vibration, and low temperature shock associated with large scale thermal structural members, along with reentry heating, and so on. A series of tests clearly demonstrated that carbon fiber reinforced quartz not only retain%d ceramic resistance to high temperatures and good insulation characteristics, but also overcame inherent ceramic brittleness. As a result, it possesses considerable potential to act as thermal protective material on returnable spacecraft.

Wu, G.

1995-12-20

174

X-33 Telemetry Best Source Selection, Processing, Display, and Simulation Model Comparison  

NASA Technical Reports Server (NTRS)

The X-33 program requires the use of multiple telemetry ground stations to cover the launch, ascent, transition, descent, and approach phases for the flights from Edwards AFB to landings at Dugway Proving Grounds, UT and Malmstrom AFB, MT. This paper will discuss the X-33 telemetry requirements and design, including information on fixed and mobile telemetry systems, best source selection, and support for Range Safety Officers. A best source selection system will be utilized to automatically determine the best source based on the frame synchronization status of the incoming telemetry streams. These systems will be used to select the best source at the landing sites and at NASA Dryden Flight Research Center to determine the overall best source between the launch site, intermediate sites, and landing site sources. The best source at the landing sites will be decommutated to display critical flight safety parameters for the Range Safety Officers. The overall best source will be sent to the Lockheed Martin's Operational Control Center at Edwards AFB for performance monitoring by X-33 program personnel and for monitoring of critical flight safety parameters by the primary Range Safety Officer. The real-time telemetry data (received signal strength, etc.) from each of the primary ground stations will also be compared during each nu'ssion with simulation data generated using the Dynamic Ground Station Analysis software program. An overall assessment of the accuracy of the model will occur after each mission. Acknowledgment: The work described in this paper was NASA supported through cooperative agreement NCC8-115 with Lockheed Martin Skunk Works.

Burkes, Darryl A.

1998-01-01

175

Vacuum chamber thermal protection for the APS (Advanced Photon Source)  

SciTech Connect

The addition of undulators and wigglers into synchrotron storage rings created new problems in terms of protecting the integrity of the ring vacuum chamber. If the photon beam from these devices were missteered into striking an inadequately cooled section of the storage ring vacuum chamber, the structural strength might be reduced sufficiently that the vacuum envelope could be penetrated, resulting in long downtime of the storage ring. The new generation of high-energy synchrotron light sources will produce photon beams of such high power density that cooling of the vacuum chamber will not prevent a potential penetration of the vacuum envelope, and other methods of preventing this occurrence will be required. Since active methods will be used to ensure that the beams are delivered to beam lines for users during normal operation, there is a need for passive protection methods during non-routine operation, such as turning on new beam lines, injection, etc., when the active systems may be disabled. In addition, the passive methods could prevent the problem from arising and provide the rapid time response necessary for the highest power beams, a property that might not be easily and reliably provided by active methods during the early operation of these machines. This paper summarizes the results of a task group that studied the problem and outlines passive methods of protection for the Advanced Photon Source (APS). 2 refs., 3 figs., 1 tab.

Kramer, S.L.; Crosbie, E.A.; Kim, S.; Wehrle, R.; Yoon, M.

1989-01-01

176

Fabrication of prepackaged superalloy honeycomb Thermal Protection System (TPS) panels  

NASA Technical Reports Server (NTRS)

High temperature materials were surveyed, and Inconel 617 and titanium were selected for application to a honeycomb TPS configuration designed to withstand 2000 F. The configuration was analyzed both thermally and structurally. Component and full-sized panels were fabricated and tested to obtain data for comparison with analysis. Results verified the panel design. Twenty five panels were delivered to NASA Langley Research Center for additional evaluation.

Blair, W.; Meaney, J. E.; Rosenthal, H. A.

1985-01-01

177

Coating effects on thermal properties of carbon carbon and carbon silicon carbide composites for space thermal protection systems  

NASA Astrophysics Data System (ADS)

Many are the materials for hot structures, but the most promising one are the carbon based composites nowadays. This is because they have good characteristics with a high stability at high temperatures, preserving their mechanical properties. Unfortunately, carbon reacts rapidly with oxygen and the composites are subjected to oxidation degradation. From this point of view CC has to be modified in order to improve its thermal and oxidative resistance. The most common solutions are the use of silicon carbide into the carbon composites matrix (SiC composites) to make the thermal properties increase and the use of coating on the surface in order to protect the composite from the space plasma effects. Here is presented an experimental study on coating effects on these composites. Thermal properties of coated and non coated materials have been studied and the thermal impact on the matrix and surface degradation is analyzed by a SEM analysis.

Albano, M.; Morles, R. B.; Cioeta, F.; Marchetti, M.

2014-06-01

178

Multidimensional Testing of Thermal Protection Materials in the Arcjet Test Facility  

NASA Technical Reports Server (NTRS)

Many thermal protection system materials used for spacecraft heatshields have anisotropic thermal properties, causing them to display significantly different thermal characteristics in different directions, when subjected to a heating environment during flight or arcjet tests. The anisotropic effects are enhanced in the presence of sidewall heating. This paper investigates the effects of anisotropic thermal properties of thermal protection materials coupled with sidewall heating in the arcjet environment. Phenolic Impregnated Carbon Ablator (PICA) and LI-2200 materials (the insulation material of Shuttle tiles) were used for this study. First, conduction-based thermal response simulations were carried out, using the Marc.Mentat finite element solver, to study the effects of sidewall heating on PICA arcjet coupons. The simulation showed that sidewall heating plays a significant role in thermal response of these models. Arcjet tests at the Aerodynamic Heating Facility (AHF) at NASA Ames Research Center were performed later on instrumented coupons to obtain temperature history at sidewall and various radial locations. The details of instrumentation and experimental technique are the prime focus of this paper. The results obtained from testing confirmed that sidewall heating plays a significant role in thermal response of these models. The test results were later used to validate the two-dimensional ablation, thermal response, and sizing program, TITAN. The test data and model predictions were found to be in excellent agreement

Agrawal, Parul; Ellerby, Donald T.; Switzer, Matt R.; Squire, Thomas Howard

2010-01-01

179

Multidimensional Tests of Thermal Protection Materials in the Arcjet Test Facility  

NASA Technical Reports Server (NTRS)

Many thermal protection system materials used for spacecraft heatshields have anisotropic thermal properties, causing them to display significantly different thermal characteristics in different directions, when subjected to a heating environment during flight or arcjet tests. This paper investigates the effects of sidewall heating coupled with anisotropic thermal properties of thermal protection materials in the arcjet environment. Phenolic Impregnated Carbon Ablator (PICA) and LI-2200 materials (the insulation material of Shuttle tiles) were used for this study. First, conduction-based thermal response simulations were carried out, using the Marc.Mentat finite element solver, to study the effects of sidewall heating on PICA arcjet coupons. The simulation showed that sidewall heating plays a significant role in thermal response of these models. Arcjet tests at the Aerodynamic Heating Facility (AHF) at NASA Ames Research Center were performed later on instrumented coupons to obtain temperature history at sidewall and various radial locations. The details of instrumentation and experimental technique are the prime focus of this paper. The results obtained from testing confirmed that sidewall heating plays a significant role in thermal response of these models. The test results were later used to verify the two-dimensional ablation, thermal response, and sizing program, TITAN. The test data and model predictions were found to be in excellent agreement

Agrawal, Parul; Ellerby, Donald T.; Switzer, Mathew R.; Squire, Thomas H.

2010-01-01

180

Field repair of coated columbium Thermal Protection System (TPS)  

NASA Technical Reports Server (NTRS)

The requirements for field repair of coated columbian panels were studied, and the probable cause of damage were identified. The following types of repair methods were developed, and are ready for use on an operational system: replacement of fused slurrey silicide coating by a short processing cycle using a focused radiant spot heater; repair of the coating by a glassy matrix ceramic composition which is painted or sprayed over the defective area; and repair of the protective coating by plasma spraying molybdenum disilicide over the damaged area employing portable equipment.

Culp, J. D.

1972-01-01

181

The employment of a high density plasma jet for the investigation of thermal protection materials  

NASA Astrophysics Data System (ADS)

This paper describes the results of tests of thermal protection materials (TPM) at conditions that simulate the atmospheric re-entry of space vehicles, tested by means of a high velocity and enthalpy air plasma jet generated with a dc plasma torch. Such a high velocity and enthalpy air plasma jet allows us to investigate TPM by simulating heat flux values varying with time in accordance with real re-entry altitudes and trajectories. The main research interests include the measurements of plasma flow temperature and heat flux for the testing of materials used for thermal protection systems of space vehicles. The test results of investigations of light composite thermal protective system material and graphite are presented.

Kezelis, R.; Grigaitiene, V.; Levinskas, R.; Brinkiene, K.

2014-05-01

182

Thermal instability of protected end states in a one-dimensional topological insulator  

NASA Astrophysics Data System (ADS)

We have studied the dynamical thermal effects on the protected end states of a topological insulator (TI) when it is considered as an open quantum system in interaction with a noisy environment at a certain temperature T. As a result, we find that protected end states in a TI become unstable and decay with time. Very remarkably, the interaction with the thermal environment (fermion-boson) respects chiral symmetry, which is the symmetry responsible for the protection (robustness) of the end states in this TI when it is isolated from the environment. Therefore, this mechanism makes end states unstable while preserving their protecting symmetry. Our results have immediate practical implications in recently proposed simulations of TIs using cold atoms in optical lattices. Accordingly, we have computed lifetimes of topological end states for these physical implementations that are useful to make those experiments realistic.

Viyuela, O.; Rivas, A.; Martin-Delgado, M. A.

2012-10-01

183

Thermal Instability of Protected End States in a 1-D Topological Insulator  

E-print Network

We have studied the dynamical thermal effects on the protected end states of a topological insula- tor (TI) when it is considered as an open quantum system in interaction with a noisy environment at a certain temperature T . As a result, we find that protected end states in a TI become unstable and decay with time. Very remarkably, the interaction with the thermal environment (fermion-boson) respects chiral symmetry, which is the symmetry responsible for the protection (robustness) of the end states in this TI when it is isolated from the environment. Therefore, this mechanism makes end states unstable while preserving their protecting symmetry. Our results have immediate practical implications in recently proposed simulations of TI using cold atoms in optical lattices. Accordingly, we have computed lifetimes of topological end states for these physical implementations that are useful to make those experiments realistic.

O. Viyuela; A. Rivas; M. A. Martin-Delgado

2012-07-10

184

X-33 Computational Aeroheating/Aerodynamic Predictions and Comparisons With Experimental Data  

NASA Technical Reports Server (NTRS)

This report details a computational fluid dynamics study conducted in support of the phase II development of the X-33 vehicle. Aerodynamic and aeroheating predictions were generated for the X-33 vehicle at both flight and wind-tunnel test conditions using two finite-volume, Navier-Stokes solvers. Aerodynamic computations were performed at Mach 6 and Mach 10 wind-tunnel conditions for angles of attack from 10 to 50 with body-flap deflections of 0 to 20. Additional aerodynamic computations were performed over a parametric range of free-stream conditions at Mach numbers of 4 to 10 and angles of attack from 10 to 50. Laminar and turbulent wind-tunnel aeroheating computations were performed at Mach 6 for angles of attack of 20 to 40 with body-flap deflections of 0 to 20. Aeroheating computations were performed at four flight conditions with Mach numbers of 6.6 to 8.9 and angles of attack of 10 to 40. Surface heating and pressure distributions, surface streamlines, flow field information, and aerodynamic coefficients from these computations are presented, and comparisons are made with wind-tunnel data.

Hollis, Brian R.; Thompson, Richard A.; Berry, Scott A.; Horvath, Thomas J.; Murphy, Kelly J.; Nowak, Robert J.; Alter, Stephen J.

2003-01-01

185

Evaluation of GPS Coverage for the X-33 Michael-6 Trajectory  

NASA Technical Reports Server (NTRS)

The onboard navigational system for the X-33 test flights will be based on the use of measurements collected from the Embedded Global Positioning System (GPS)/INS system. Some of the factors which will affect the quality of the GPS contribution to the navigational solution will be the number of pseudorange measurements collected at any instant in time, the distribution of the GPS satellites within the field of view, and the inherent noise level of the GPS receiver. The distribution of GPS satellites within the field of view of the receiver's antenna will depend on the receiver's position, the time of day, pointing direction of the antenna, and the effective cone angle of the antenna. The number of pseudorange measurements collected will depend upon these factors as well as the time required to lock onto a GPS satellite signal once the GPS satellite comes into the field of view of the antenna and the number of available receiver channels. The objective of this study is to evaluate the GPS coverage resulting from the proposed antenna pointing directions, the proposed antenna cone angles, and the effects due to the time of day for the X-33 Michael-6 trajectory from launch at Edwards AFB, California, to the start of the Terminal Area Energy Management (TAEM) phase on approach to Michael AAF, Utah.

Lundberg, John B.

1998-01-01

186

Computational/Experimental Aeroheating Predictions for X-33. Phase 2; Vehicle  

NASA Technical Reports Server (NTRS)

Laminar and turbulent heating-rate calculations from an "engineering" code and laminar calculations from a "benchmark" Navier-Stokes code are compared with experimental wind-tunnel data obtained on several candidate configurations for the X-33 Phase 2 flight vehicle. The experimental data were obtained at a Mach number of 6 and a freestream Reynolds number ranging from 1 to 8 x 10(exp 6)/ft. Comparisons are presented along the windward symmetry plane and in a circumferential direction around the body at several axial stations at angles of attack from 20 to 40 deg. The experimental results include both laminar and turbulent flow. For the highest angle of attack some of the measured heating data exhibited a "non-laminar" behavior which caused the heating to increase above the laminar level long before "classical" transition to turbulent flow was observed. This trend was not observed at the lower angles of attack. When the flow was laminar, both codes predicted the heating along the windward symmetry plane reasonably well but under-predicted the heating in the chine region. When the flow was turbulent the LATCH code accurately predicted the measured heating rates. Both codes were used to calculate heating rates over the X-33 vehicle at the peak heating point on the design trajectory and they were found to be in very good agreement over most of the vehicle windward surface.

Hamilton, H. Harris, II; Weilmuenster, K. James; Horvath, Thomas J.; Berry, Scott A.

1998-01-01

187

Simulation of Foam Impact Effects on Components of the Space Shuttle Thermal Protection System. Chapter 7  

NASA Technical Reports Server (NTRS)

A series of three dimensional simulations has been performed to investigate analytically the effect of insulating foam impacts on ceramic tile and reinforced carbon-carbon components of the Space Shuttle thermal protection system. The simulations employed a hybrid particle-finite element method and a parallel code developed for use in spacecraft design applications. The conclusions suggested by the numerical study are in general consistent with experiment. The results emphasize the need for additional material testing work on the dynamic mechanical response of thermal protection system materials, and additional impact experiments for use in validating computational models of impact effects.

Fahrenthold, Eric P.; Park, Young-Keun

2004-01-01

188

Research progress on thermal protection materials and structures of hypersonic vehicles  

Microsoft Academic Search

Hypersonic vehicles represent future trends of military equipments and play an important role in future war. Thermal protection\\u000a materials and structures, which relate to the safety of hypersonic vehicles, are one of the most key techniques in design\\u000a and manufacture of hypersonic vehicles. Among these materials and structures, such as metallic temperature protection structure,\\u000a the temperature ceramics and carbon\\/carbon composites

Ya-zheng Yang; Jia-ling Yang; Dai-ning Fang

2008-01-01

189

Thermal analysis of the thermal protection system for the re-entry vehicle  

Microsoft Academic Search

Thermal analysis methods for re-entry vehicle structure are presented. At first CFD\\/FEM coupling thermal analysis and a joint component heat conduction analysis for Japanese hypersonic experimental vehicle are introduced. Then, the finite element modeling problem is treated. Two methods are applied to the heat conduction simulation of fastener jointed structural component.

Kunihiko Ohtake

1998-01-01

190

Flight Set 360L006 STS-34 field joint protection system, thermal protection system, and systems tunnel components, volume 4  

NASA Technical Reports Server (NTRS)

The performance of the thermal protection system, field joint protection system, and systems tunnel components of Flight Set 360L006, are documented, as evaluated by postflight hardware inspection. The condition of both motors was similar to previous flights. Sixteen aft edge hits were noted on the ground environment instrumentation thermal protection system. Each hit left a clean substrate, indicating that the damage was caused by nozzle severance debris and/or water impact. No National Space and Transporation System debris criteria for missing thermal protection system were violated. One 5.0 by 1.0 in. unbond was observed on the left hand center field joint K5NA closeout and was elevated to an in-flight anomaly (STS-34-M-4) by the NASA Ice/Debris team. Aft edge damage to the K5NA and an associated black streak indicate that burning debris from the nozzle severance system was the likely cause of the damage. Minor divots caused by debris were seen on previous flights, but this is the first occurrence of a K5NA unbond. Since the unbond occurred after booster separation there is no impact on flight safety and no corrective actions was taken. The right hand center field joint primary heater failed the dielectric withstanding voltage test after joint closeout. The heater was then disabled by opening the circuit breaker, and the redundant heater was used. The redundant heater performed nominally during the launch countdown. A similar condition occurred on Flight 4 when a secondary joint heater failed the dielectric withstanding voltage test.

Wilkinson, J. P.

1990-01-01

191

Mars transit vehicle thermal protection system: Issues, options, and trades  

NASA Technical Reports Server (NTRS)

A Mars mission is characterized by different mission phases. The thermal control of cryogenic propellant in a propulsive vehicle must withstand the different mission environments. Long term cryogenic storage may be achieved by passive or active systems. Passive cryo boiloff management features will include multilayer insulation, vapor cooled shield, and low conductance structural supports and penetrations. Active boiloff management incorporates the use of a refrigeration system. Key system trade areas include active verses passive system boiloff management (with respect to safety, reliability, and cost) and propellant tank insulation optimizations. Technology requirements include refrigeration technology advancements, insulation performance during long exposure, and cryogenic fluid transfer system for mission vehicle propellant tanking during vehicle buildip in LEO.

Brown, Norman

1986-01-01

192

Composite multilayer insulations for thermal protection of aerospace vehicles  

NASA Technical Reports Server (NTRS)

Composite flexible multilayer insulation systems (MLI), consisting of alternating layers of metal foil and scrim cloth or insulation quilted together using ceramic thread, were evaluated for thermal performance and compared with a silica fibrous (baseline) insulation system. The systems studied included: (1) alternating layers of aluminoborosilicate (ABS) scrim cloth and stainless steel foil, with silica, ABS, or alumina insulation; (2) alternating layers of scrim cloth and aluminum foil, with silica or ABS insulation; (3) alternating layers of aluminum foil and silica or ABS insulation; and (4) alternating layers of aluminum-coated polyimide placed on the bottom of the silica insulation. The MLIs containing aluminum were the most efficient, measuring as little as half the backface temperature increase of the baseline system.

Kourtides, Demetrius A.; Pitts, William C.

1989-01-01

193

Composite multilayer insulations for thermal protection of aerospace vehicles  

NASA Technical Reports Server (NTRS)

Composite flexible multilayer insulation systems (MLI), consisting of alternating layers of metal foil and scrim cloth or insulation quilted together using ceramic thread, were evaluated for thermal performance and compared with a silica fibrous (baseline) insulation system. The systems studied included: (1) alternating layers of aluminoborosilicate (ABS) scrim cloth and stainless steel foil, with silica, ABS, or alumina insulation; (2) alternating layers of scrim cloth and aluminum foil, with silica or ABS insulation; (3) alternating layers of alumininum foil and silica or ABS insulation; and (4) alternating layers of aluminum-coated polyimide placed on the bottom of the silica insulation. The MLIs containing aluminum were the most efficient, measuring as little as half the backface temperature increase of the baseline system.

Kourtides, D. A.; Pitts, W. C.

1989-01-01

194

Liquid Oxygen Propellant Densification Production and Performance Test Results With a Large-Scale Flight-Weight Propellant Tank for the X33 RLV  

NASA Technical Reports Server (NTRS)

This paper describes in-detail a test program that was initiated at the Glenn Research Center (GRC) involving the cryogenic densification of liquid oxygen (LO2). A large scale LO2 propellant densification system rated for 200 gpm and sized for the X-33 LO2 propellant tank, was designed, fabricated and tested at the GRC. Multiple objectives of the test program included validation of LO2 production unit hardware and characterization of densifier performance at design and transient conditions. First, performance data is presented for an initial series of LO2 densifier screening and check-out tests using densified liquid nitrogen. The second series of tests show performance data collected during LO2 densifier test operations with liquid oxygen as the densified product fluid. An overview of LO2 X-33 tanking operations and load tests with the 20,000 gallon Structural Test Article (STA) are described. Tank loading testing and the thermal stratification that occurs inside of a flight-weight launch vehicle propellant tank were investigated. These operations involved a closed-loop recirculation process of LO2 flow through the densifier and then back into the STA. Finally, in excess of 200,000 gallons of densified LO2 at 120 oR was produced with the propellant densification unit during the demonstration program, an achievement that s never been done before in the realm of large-scale cryogenic tests.

Tomsik, Thomas M.; Meyer, Michael L.

2010-01-01

195

Heat Shield Employing Cured Thermal Protection Material Blocks Bonded in a Large-Cell Honeycomb Matrix  

NASA Technical Reports Server (NTRS)

A document describes a new way to integrate thermal protection materials on external surfaces of vehicles that experience the severe heating environments of atmospheric entry from space. Cured blocks of thermal protection materials are bonded into a compatible, large-cell honeycomb matrix that can be applied on the external surfaces of the vehicles. The honeycomb matrix cell size, and corresponding thermal protection material block size, is envisioned to be between 1 and 4 in. (.2.5 and 10 cm) on a side, with a depth required to protect the vehicle. The cell wall thickness is thin, between 0.01 and 0.10 in. (.0.025 and 0.25 cm). A key feature is that the honeycomb matrix is attached to the vehicle fs unprotected external surface prior to insertion of the thermal protection material blocks. The attachment integrity of the honeycomb can then be confirmed over the full range of temperature and loads that the vehicle will experience. Another key feature of the innovation is the use of uniform-sized thermal protection material blocks. This feature allows for the mass production of these blocks at a size that is convenient for quality control inspection. The honeycomb that receives the blocks must have cells with a compatible set of internal dimensions. The innovation involves the use of a faceted subsurface under the honeycomb. This provides a predictable surface with perpendicular cell walls for the majority of the blocks. Some cells will have positive tapers to accommodate mitered joints between honeycomb panels on each facet of the subsurface. These tapered cells have dimensions that may fall within the boundaries of the uniform-sized blocks.

Zell, Peter

2012-01-01

196

Design of thermal protection system for 8 foot HTST combustor  

NASA Technical Reports Server (NTRS)

The combustor in the 8-foot high temperature structures tunnel at the NASA-Langley Research Center has encountered cracking over a period of 50-250 tunnel tests within a limited range of the required operating envelope. A program was conducted which analyzed the failed combustor liner hardware and determined that the mechanism of failure was vibratory fatigue. A vibration damper system using wave springs located axially between the liner T-bar and the liner support was designed as an intermediate solution to extend the life of the current two-pass regenerative air-cooled liner. The effects of liner wall thickness, cooling air passage height, stiffener ring geometry, reflective coatings, and liner material selection were investigated for these designs. Preliminary layout design arrangements including the external water-cooling system requirements, weight estimates, installation requirements and preliminary estimates of manufacturing costs were prepared for the most promissing configurations. A state-of-the-art review of thermal barrier coatings and an evaluation of reflective coatings for the gasside surface of air-cooled liners are included.

Moskowitz, S.

1973-01-01

197

NASA Earth-to-Orbit Engineering Design Challenges: Thermal Protection Systems  

ERIC Educational Resources Information Center

National Aeronautics and Space Administration (NASA) Engineers at Marshall Space Flight Center, Dryden Flight Research Center, and their partners at other NASA centers and in private industry are currently developing X-33, a prototype to test technologies for the next generation of space transportation. This single-stage-to-orbit reusable launch…

National Aeronautics and Space Administration (NASA), 2010

2010-01-01

198

Development of X-33/X-34 Aerothermodynamic Data Bases: Lessons Learned and Future Enhancements  

NASA Technical Reports Server (NTRS)

A synoptic of programmatic and technical lessons learned in the development of aerothermodynamic data bases for the X-33 and X-34 programs is presented in general terms and from the perspective of the NASA Langley Research Center Aerothermodynamics Branch. The format used is that of the "aerothermodynamic chain," the links of which are personnel, facilities, models/test articles, instrumentation, test techniques, and computational fluid dynamics (CFD). Because the aerodynamic data bases upon which the X-33 and X-34 vehicles will fly are almost exclusively from wind tunnel testing, as opposed to CFD, the primary focus of the lessons learned is on ground-based testing. The period corresponding to the development of X-33 and X-34 aerothermodynamic data bases was challenging, since a number of other such programs (e.g., X-38, X-43) competed for resources at a time of downsizing of personnel, facilities, etc., outsourcing, and role changes as NASA Centers served as subcontractors to industry. The impact of this changing environment is embedded in the lessons learned. From a technical perspective, the relatively long times to design and fabricate metallic force and moment models, delays in delivery of models, and a lack of quality assurance to determine the fidelity of model outer mold lines (OML) prior to wind tunnel testing had a major negative impact on the programs. On the positive side, the application of phosphor thermography to obtain global, quantitative heating distributions on rapidly fabricated ceramic models revolutionized the aerothermodynamic optimization of vehicle OMLs, control surfaces, etc. Vehicle designers were provided with aeroheating information prior to, or in conjunction with, aerodynamic information early in the program, thereby allowing trades to be made with both sets of input; in the past only aerodynamic data were available as input. Programmatically, failure to include transonic aerodynamic wind tunnel tests early in the assessment phase led to delays in the optimization phase, as OMLs required modification to provide adequate transonic aerodynamic performance without sacrificing subsonic and hypersonic performance. Funding schedules for industry, based on technical milestones, also presented challenges to aerothermodynamics seeking optimum flying characteristics across the subsonic to hypersonic speed regimes and minimum aeroheating. This paper is concluded with a brief discussion of enhancements in ground-based testing/CFD capabilities necessary to partially/fully satisfy future requirements.

Miller, C. G.

2000-01-01

199

Heat Shielding Characteristics and Thermostructural Performance of a Superalloy Honeycomb Sandwich Thermal Protection System (TPS)  

NASA Technical Reports Server (NTRS)

Heat-transfer, thermal bending, and mechanical buckling analyses have been performed on a superalloy "honeycomb" thermal protection system (TPS) for future hypersonic flight vehicles. The studies focus on the effect of honeycomb cell geometry on the TPS heat-shielding performance, honeycomb cell wall buckling characteristics, and the effect of boundary conditions on the TPS thermal bending behavior. The results of the study show that the heat-shielding performance of a TPS panel is very sensitive to change in honeycomb core depth, but insensitive to change in honeycomb cell cross-sectional shape. The thermal deformations and thermal stresses in the TPS panel are found to be very sensitive to the edge support conditions. Slight corrugation of the honeycomb cell walls can greatly increase their buckling strength.

Ko, William L.

2004-01-01

200

Combined chilled water thermal energy storage and fire protection storage systems  

Microsoft Academic Search

The re-emergence of thermal storage as a significant energy cost saving technology can be expected to continue as utility companies struggle to meet consumer energy needs without constructing new power plants. At the same time, the need for reliable water supplies for fire protection service can be expected to grow, with the requirement for sprinkler systems now imposed on most

Holness; G. V. R

1992-01-01

201

Permanent set of the Space Shuttle Thermal Protection System Reinforced Carbon–Carbon material  

Microsoft Academic Search

The objective of this paper is to provide an interpretation and understanding of the permanent set (or deformation) phenomenon observed from debris impacts on Space Shuttle Thermal Protection System (TPS) Reinforced Carbon–Carbon (RCC) panels. Deflection test results for static and dynamic loadings of RCC material will be presented. Permanent set has been observed for both the static and dynamic loading

Karen H. Lyle; Edwin L. Fasanella

2009-01-01

202

Identifying, Protecting, and Restoring (?) Fine-Scale Thermal Heterogeneity in Streams  

EPA Science Inventory

The functional role of thermal heterogeneity to fish in warm streams has been well recognized in the scientific literature, and is increasingly invoked as an important aspect of biodiversity conservation. Water temperature standards designed to protect cold-water taxa are also be...

203

Identifying, protecting and restoring fine-scale thermal heterogeneity in Oregon coastal streams  

EPA Science Inventory

The functional role of thermal heterogeneity to fish in warm streams has been well recognized in the scientific literature, and is increasingly invoked as an important aspect of biodiversity conservation. Water temperature standards designed to protect cold-water taxa are also be...

204

Robotic system for the servicing of the orbiter thermal protection system  

NASA Technical Reports Server (NTRS)

This paper describes the design and development of a mobile robotic system to process orbiter thermal protection system (TPS) tiles. This work was justified by a TPS automation study which identified tile rewaterproofing and visual inspection as excellent applications for robotic automation.

Graham, Todd; Bennett, Richard; Dowling, Kevin; Manouchehri, Davoud; Cooper, Eric; Cowan, Cregg

1994-01-01

205

Surface Catalytic Efficiency of Advanced Carbon Carbon Candidate Thermal Protection Materials for SSTO Vehicles  

NASA Technical Reports Server (NTRS)

The catalytic efficiency (atom recombination coefficients) for advanced ceramic thermal protection systems was calculated using arc-jet data. Coefficients for both oxygen and nitrogen atom recombination on the surfaces of these systems were obtained to temperatures of 1650 K. Optical and chemical stability of the candidate systems to the high energy hypersonic flow was also demonstrated during these tests.

Stewart, David A.

1996-01-01

206

The Relationship between Physical Activity and Thermal Protective Clothing on Functional Balance in Firefighters  

ERIC Educational Resources Information Center

We investigated the relationship between baseline physical training and the use of firefighting thermal protective clothing (TPC) with breathing apparatus on functional balance. Twenty-three male firefighters performed a functional balance test under four gear/clothing conditions. Participants were divided into groups by physical training status,…

Kong, Pui W.; Suyama, Joe; Cham, Rakie; Hostler, David

2012-01-01

207

Thermomechanical response of metal foam sandwich panels for structural thermal protection systems in hypersonic vehicles  

Microsoft Academic Search

Sandwich panels with metal foam cores are proposed for load-bearing structural components in actively cooled thermal protection systems for aerospace vehicles. Prototype acreage metal foam sandwich panels (MFSP's) are constructed and analyzed with the central goal of characterizing the thermomechanical response of the system. MFSP's are subjected to uniform temperature fields and equibiaxial loading in a novel experimental load frame.

Joseph F. Rakow

2005-01-01

208

Advances in hypersonic vehicle synthesis with application to studies of advanced thermal protection system  

Microsoft Academic Search

This report summarizes the work entitled 'Advances in Hypersonic Vehicle Synthesis with Application to Studies of Advanced Thermal Protection Systems.' The effort was in two areas: (1) development of advanced methods of trajectory and propulsion system optimization; and (2) development of advanced methods of structural weight estimation. The majority of the effort was spent in the trajectory area.

Mark D. Ardema

1995-01-01

209

Measuring the Thermal Conductive Property of Protective Fabrics to Radiant Heat Exposure  

Microsoft Academic Search

A novel experimental apparatus called thermal simulating box is designed to evaluate the heat transmission of protective fabrics subject to radiation\\/ convection heat flux representative of typical high temperature occupational environments. The cold side of the test sample is maintained around human body skin temperature as high as 36°C, however, the hot side was exposed to dry hot air. An

Zhu Fanglong; Zhang Weiyuan

2007-01-01

210

Stormwater and Streams A Collaboration to Protect the Thermal Regime in New England Streams  

E-print Network

Stormwater and Streams A Collaboration to Protect the Thermal Regime in New England Streams Dr) a jointly planned and led meeting with agency partners and stakeholders. In New England, our green economy streams in New England are highly sensitive to changes in temperature and their water temperature dictates

New Hampshire, University of

211

Performance of thermal control tape in the protection of composite materials to space environmental exposure  

NASA Technical Reports Server (NTRS)

Thermal control tape flown on the Long Duration Exposure Facility (LDEF) experiment A0171 has shown to be effective in protecting epoxy fiberglass composites from atomic oxygen and ultraviolet degradation. The tape adhesive performed well. The aluminum, however, appeared to have become embrittled by the 5.8 years of space radiation exposure.

Kamenetzky, R. R.; Whitaker, A. F.

1992-01-01

212

Validation of NASA Thermal Ice Protection Computer Codes. Part 1; Program Overview  

NASA Technical Reports Server (NTRS)

The Icing Technology Branch at NASA Lewis has been involved in an effort to validate two thermal ice protection codes developed at the NASA Lewis Research Center. LEWICE/Thermal (electrothermal deicing & anti-icing), and ANTICE (hot-gas & electrothermal anti-icing). The Thermal Code Validation effort was designated as a priority during a 1994 'peer review' of the NASA Lewis Icing program, and was implemented as a cooperative effort with industry. During April 1996, the first of a series of experimental validation tests was conducted in the NASA Lewis Icing Research Tunnel(IRT). The purpose of the April 96 test was to validate the electrothermal predictive capabilities of both LEWICE/Thermal, and ANTICE. A heavily instrumented test article was designed and fabricated for this test, with the capability of simulating electrothermal de-icing and anti-icing modes of operation. Thermal measurements were then obtained over a range of test conditions, for comparison with analytical predictions. This paper will present an overview of the test, including a detailed description of: (1) the validation process; (2) test article design; (3) test matrix development; and (4) test procedures. Selected experimental results will be presented for de-icing and anti-icing modes of operation. Finally, the status of the validation effort at this point will be summarized. Detailed comparisons between analytical predictions and experimental results are contained in the following two papers: 'Validation of NASA Thermal Ice Protection Computer Codes: Part 2- The Validation of LEWICE/Thermal' and 'Validation of NASA Thermal Ice Protection Computer Codes: Part 3-The Validation of ANTICE'

Miller, Dean; Bond, Thomas; Sheldon, David; Wright, William; Langhals, Tammy; Al-Khalil, Kamel; Broughton, Howard

1996-01-01

213

Thermal Growth and Performance of Manganese Cobaltite Spinel Protection Layers on Ferritic Stainless Steel SOFC Interconnects  

SciTech Connect

To protect solid oxide fuel cells (SOFCs) from chromium poisoning and improve metallic interconnect stability, manganese cobaltite spinel protection layers with a nominal composition of Mn1.5Co1.5O4 were thermally grown on Crofer22 APU, a ferritic stainless steel. Thermal, electrical and electrochemical investigations indicated that the spinel protection layers not only significantly decreased the contact area specific resistance (ASR) between a LSF cathode and the stainless steel interconnect, but also inhibited the sub-scale growth on the stainless steel by acting as a barrier to the inward diffusion of oxygen. A long-term thermal cycling test demonstrated excellent structural and thermomechanical stability of these spinel protection layers, which also acted as a barrier to outward chromium cation diffusion to the interconnect surface. The reduction in the contact ASR and prevention of Cr migration achieved by application of the spinel protection layers on ferritic stainless steel resulted in improved stability and electrochemical performance of SOFCs.

Yang, Zhenguo; Xia, Guanguang; Simner, Steven P.; Stevenson, Jeffry W.

2005-08-01

214

Reconfigurable Flight Control Designs With Application to the X-33 Vehicle  

NASA Technical Reports Server (NTRS)

Two methods for control system reconfiguration have been investigated. The first method is a robust servomechanism control approach (optimal tracking problem) that is a generalization of the classical proportional-plus-integral control to multiple input-multiple output systems. The second method is a control-allocation approach based on a quadratic programming formulation. A globally convergent fixed-point iteration algorithm has been developed to make onboard implementation of this method feasible. These methods have been applied to reconfigurable entry flight control design for the X-33 vehicle. Examples presented demonstrate simultaneous tracking of angle-of-attack and roll angle commands during failures of the right body flap actuator. Although simulations demonstrate success of the first method in most cases, the control-allocation method appears to provide uniformly better performance in all cases.

Burken, John J.; Lu, Ping; Wu, Zhenglu

1999-01-01

215

A Strategy for Integrating a Large Finite Element Model Using MSC NASTRAN/PATRAN: X-33 Lessons Learned  

NASA Technical Reports Server (NTRS)

The X-33 vehicle is an advanced technology demonstrator sponsored by NASA. For the past 3 years the Structural Dynamics and Loads Branch of NASA's Marshall Space Flight Center has had the task of integrating the X-33 vehicle structural finite element model. In that time, five versions of the integrated vehicle model have been produced and a strategy has evolved that would benefit anyone given the task of integrating structural finite element models that have been generated by various modelers and companies. The strategy that has been presented here consists of six decisions that need to be made: purpose of models, units, common materials list, model numbering, interface control, and archive format. This strategy has been proven and expanded from experience on the X-33 vehicle.

McGhee, D. S.

1999-01-01

216

Ablation, Thermal Response, and Chemistry Program for Analysis of Thermal Protection Systems  

NASA Technical Reports Server (NTRS)

In previous work, the authors documented the Multicomponent Ablation Thermochemistry (MAT) and Fully Implicit Ablation and Thermal response (FIAT) programs. In this work, key features from MAT and FIAT were combined to create the new Fully Implicit Ablation, Thermal response, and Chemistry (FIATC) program. FIATC is fully compatible with FIAT (version 2.5) but has expanded capabilities to compute the multispecies surface chemistry and ablation rate as part of the surface energy balance. This new methodology eliminates B' tables, provides blown species fractions as a function of time, and enables calculations that would otherwise be impractical (e.g. 4+ dimensional tables) such as pyrolysis and ablation with kinetic rates or unequal diffusion coefficients. Equations and solution procedures are presented, then representative calculations of equilibrium and finite-rate ablation in flight and ground-test environments are discussed.

Milos, Frank S.; Chen, Yih-Kanq

2010-01-01

217

Broadband thermal optical limiter for the protection of eyes and sensors  

NASA Astrophysics Data System (ADS)

A broadband thermal optical limiter for protecting a light sensitive object from intense laser beams at all near ultraviolet, visible and near infrared wavelengths is disclosed. The broadband thermal optical limiter comprises: a sample cell containing a solution of broadband absorber material dissolved in a thermal solvent; and a first optical device for converging an incident laser beam into the sample cell. The sample cell is responsive to a converged incident laser beam below a predetermined intensity level for passing therethrough the converged incident laser beam below the predetermined intensity level. The sample cell is also responsive to a converged incident laser beam at or above a predetermined intensity level for thermally defocusing substantially all of the converged incident laser beam in different directions and passing therethrough only a remaining small portion of the converged incident laser beam at or above the predetermined intensity level. The broadband thermal optical limiter further includes a second optical device for focusing substantially all of the laser beam passing through the sample cell into the light sensitive object to be protected.

Justus, Brian L.; Huston, Alan L.; Campillo, Anthony J.

1994-05-01

218

Recession Curve Generation for the Space Shuttle Solid Rocket Booster Thermal Protection System Coatings  

NASA Technical Reports Server (NTRS)

Ablatable Thermal Protection System (TPS) coatings are used on the Space Shuttle Vehicle Solid Rocket Boosters in order to protect the aluminum structure from experiencing excessive temperatures. The methodology used to characterize the recession of such materials is outlined. Details of the tests, including the facility, test articles and test article processing are also presented. The recession rates are collapsed into an empirical power-law relation. A design curve is defined using a 95-percentile student-t distribution. based on the nominal results. Actual test results are presented for the current acreage TPS material used.

Kanner, Howard S.; Stuckey, C. Irvin; Davis, Darrell W.; Davis, Darrell (Technical Monitor)

2002-01-01

219

Atomic Oxygen Durability Evaluation of Protected Polymers Using Thermal Energy Plasma Systems  

NASA Technical Reports Server (NTRS)

The durability evaluation of protected polymers intended for use in low Earth orbit (LEO) has necessitated the use of large-area, high-fluence, atomic oxygen exposure systems. Two thermal energy atomic oxygen exposure systems which are frequently used for such evaluations are radio frequency (RF) plasma ashers and electron cyclotron resonance plasma sources. Plasma source testing practices such as ample preparation, effective fluence prediction, atomic oxygen flux determination, erosion measurement, operational considerations, and erosion yield measurements are presented. Issues which influence the prediction of in-space durability based on ground laboratory thermal energy plasma system testing are also addressed.

Banks, Bruce A.; Rutledge, Sharon K.; Degroh, Kim K.; Stidham, Curtis R.; Gebauer, Linda; Lamoreaux, Cynthia M.

1995-01-01

220

An atmosphere protection subsystem in the thermal power station automated process control system  

NASA Astrophysics Data System (ADS)

Matters concerned with development of methodical and mathematical support for an atmosphere protection subsystem in the thermal power station automated process control system are considered taking as an example the problem of controlling nitrogen oxide emissions at a gas-and-oil-fired thermal power station. The combined environmental-and-economic characteristics of boilers, which correlate the costs for suppressing emissions with the boiler steam load and mass discharge of nitrogen oxides in analytic form, are used as the main tool for optimal control. A procedure for constructing and applying environmental-and-economic characteristics on the basis of technical facilities available in modern instrumentation and control systems is presented.

Parchevskii, V. M.; Kislov, E. A.

2014-03-01

221

Multi-tube thermal fuse for nozzle protection from a flame holding or flashback event  

DOEpatents

A protection system for a pre-mixing apparatus for a turbine engine, includes: a main body having an inlet portion, an outlet portion and an exterior wall that collectively establish a fuel delivery plenum; and a plurality of fuel mixing tubes that extend through at least a portion of the fuel delivery plenum, each of the plurality of fuel mixing tubes including at least one fuel feed opening fluidly connected to the fuel delivery plenum; at least one thermal fuse disposed on an exterior surface of at least one tube, the at least one thermal fuse including a material that will melt upon ignition of fuel within the at least one tube and cause a diversion of fuel from the fuel feed opening to at least one bypass opening. A method and a turbine engine in accordance with the protection system are also provided.

Lacy, Benjamin Paul; Davis, Jr., Lewis Berkley; Johnson, Thomas Edward; York, William David

2012-07-03

222

Effects of natural environment on first generation solid rocket booster thermal protection system materials  

NASA Technical Reports Server (NTRS)

The effort to demonstrate, by real-time exposure, the effects of the natural environment at Kennedy Space Center, Florida, upon the Thermal Protection System (TPS) of the Solid Rocket Booster (SRB) is summarized, and that the overall SRB TPS configuration is verified to meet all requirements for resistance to the conditions associated with outdoor weathering, including: solar radiation; temperature; humidity; precipitation; wind; sand/dust abrasion; static electricity; salt spray; fungus; and atmospheric oxidants. The evaluation criterion for this project was based upon flatwise tensile properties, visual inspection, color change, and thermal performance. Based upon the evaluation of the changes in these properties, it is concluded that properly applied and topcoat-protected TPS can satisfactorily withstand the conditions of the natural environment at KSC for exposures up to six months.

Webb, D. D.

1988-01-01

223

Acoustic Characterization and Impact Sensing for Ceramic Thermal Protection Systems (TPS)  

NASA Astrophysics Data System (ADS)

A study was conducted to understand acoustic wave propagation characteristics in a ceramic matrix composite (CMC) wrapped tile thermal protection system (CMC+ Foam+ RTV+ SIP+ RTV+ Al) and ceramic foam. Sound velocities were measured in three orthogonal directions on the above material. The attenuation coefficients were also determined for a uncoated ceramic foam. Commercially available standard acoustic emission transducers, piezo-wafers and polymer based PVDF (polyvinylidiene fluoride) film were employed in the experiments to acquire the acoustic data. The performance characteristics of these sensors will be discussed in light of impact detection. Variation in the wave propagation characteristics along different directions and the role of processing in causing anisotropic acoustic properties in thermal protection systems will be discussed.

Kuhr, S. J.; Reibel, R.; Sathish, S.; Jata, K. V.

2006-03-01

224

Development and Verification of the Charring Ablating Thermal Protection Implicit System Solver  

NASA Technical Reports Server (NTRS)

The development and verification of the Charring Ablating Thermal Protection Implicit System Solver is presented. This work concentrates on the derivation and verification of the stationary grid terms in the equations that govern three-dimensional heat and mass transfer for charring thermal protection systems including pyrolysis gas flow through the porous char layer. The governing equations are discretized according to the Galerkin finite element method with first and second order implicit time integrators. The governing equations are fully coupled and are solved in parallel via Newton's method, while the fully implicit linear system is solved with the Generalized Minimal Residual method. Verification results from exact solutions and the Method of Manufactured Solutions are presented to show spatial and temporal orders of accuracy as well as nonlinear convergence rates.

Amar, Adam J.; Calvert, Nathan D.; Kirk, Benjamin S.

2010-01-01

225

Protection of alodine coatings from thermal aging by removable polymer coatings  

Microsoft Academic Search

Removable polymer coatings were evaluated as a means to suppress dehydration of Alodine chromate conversion coatings during thermal aging and thereby retain the corrosion protection afforded by Alodine. Two types of polymer coatings were applied to Alodine-treated panels of aluminum alloys 7075-T73 and 6061-T6 that were subsequently aged for 15 to 50 hours at temperatures between 135 F to 200

Brett R. Wagstaff; Robert W. Bradshaw; Whinnery LeRoy L. Jr

2006-01-01

226

Heath Monitoring of Thermal Protection Systems - Preliminary Measurements and Design Specifications  

NASA Technical Reports Server (NTRS)

The work reported here is the first stage of a project that aims to develop a health monitoring system for Thermal Protection Systems (TPS) that enables a vehicle to safely re-enter the Earth's atmosphere. The TPS health monitoring system is to be integrated into an existing acoustic emissions-based Concept Demonstrator, developed by CSIRO, which has been previously demonstrated for evaluating impact damage of aerospace systems.

Scott, D. A.; Price, D. C.

2007-01-01

227

Analysis of gap heating due to stepped tiles in the shuttle thermal protection system  

NASA Technical Reports Server (NTRS)

Analytical methods used to investigate entry gap heating in the Shuttle orbiter thermal protection system are described. Analytical results are given for a fuselage lower-surface location and a wing lower-surface location. These are locations where excessive gap heating occurred on the first flight of the Shuttle. The results of a study to determine the effectiveness of a half-height ceramic fiber gap filler in preventing hot-gas flow in the tile gaps are also given.

Petley, D. H.; Smith, D. M.; Edwards, C. L. W.; Carlson, A. B.

1983-01-01

228

A modernized high-pressure heater protection system for nuclear and thermal power stations  

NASA Astrophysics Data System (ADS)

Experience gained from operation of high-pressure heaters and their protection systems serving to exclude ingress of water into the turbine is analyzed. A formula for determining the time for which the high-pressure heater shell steam space is filled when a rupture of tubes in it occurs is analyzed, and conclusions regarding the high-pressure heater design most advisable from this point of view are drawn. A typical structure of protection from increase of water level in the shell of high-pressure heaters used in domestically produced turbines for thermal and nuclear power stations is described, and examples illustrating this structure are given. Shortcomings of components used in the existing protection systems that may lead to an accident at the power station are considered. A modernized protection system intended to exclude the above-mentioned shortcomings was developed at the NPO Central Boiler-Turbine Institute and ZioMAR Engineering Company, and the design solutions used in this system are described. A mathematical model of the protection system's main elements (the admission and check valves) has been developed with participation of specialists from the St. Petersburg Polytechnic University, and a numerical investigation of these elements is carried out. The design version of surge tanks developed by specialists of the Central Boiler-Turbine Institute for excluding false operation of the high-pressure heater protection system is proposed.

Svyatkin, F. A.; Trifonov, N. N.; Ukhanova, M. G.; Tren'kin, V. B.; Koltunov, V. A.; Borovkov, A. I.; Klyavin, O. I.

2013-09-01

229

Wireless Subsurface Sensors for Health Monitoring of Thermal Protection Systems on Hypersonic Vehicles  

NASA Technical Reports Server (NTRS)

Health diagnostics is an area where major improvements have been identified for potential implementation into the design of new reusable launch vehicles (RLVs) in order to reduce life cycle costs, to increase safety margins, and to improve mission reliability. NASA Ames is leading the effort to develop inspection and health management technologies for thermal protection systems. This paper summarizes a joint project between NASA Ames and industry partners to develop "wireless" devices that can be embedded in the thermal protection system to monitor temperature or other quantities of interest. These devices are sensors integrated with radio-frequency identification (RFID) microchips to enable non-contact communication of sensor data to an external reader that may be a hand-held scanner or a large portal. Both passive and active prototype devices have been developed. The passive device uses a thermal fuse to indicate the occurrence of excessive temperature. This device has a diameter under 0.13 cm. (suitable for placement in gaps between ceramic TPS tiles on an RLV) and can withstand 370 C for 15 minutes. The active device contains a small battery to provide power to a thermocouple for recording a temperature history during flight. The bulk of the device must be placed beneath the TPS for protection from high temperature, but the thermocouple can be placed in a hot location such as near the external surface.

Milos, Frank S.; Arnold, Jim (Technical Monitor)

2001-01-01

230

Development of Thermal Protection Materials for Future Mars Entry, Descent and Landing Systems  

NASA Technical Reports Server (NTRS)

Entry Systems will play a crucial role as NASA develops the technologies required for Human Mars Exploration. The Exploration Technology Development Program Office established the Entry, Descent and Landing (EDL) Technology Development Project to develop Thermal Protection System (TPS) materials for insertion into future Mars Entry Systems. An assessment of current entry system technologies identified significant opportunity to improve the current state of the art in thermal protection materials in order to enable landing of heavy mass (40 mT) payloads. To accomplish this goal, the EDL Project has outlined a framework to define, develop and model the thermal protection system material concepts required to allow for the human exploration of Mars via aerocapture followed by entry. Two primary classes of ablative materials are being developed: rigid and flexible. The rigid ablatives will be applied to the acreage of a 10x30 m rigid mid L/D Aeroshell to endure the dual pulse heating (peak approx.500 W/sq cm). Likewise, flexible ablative materials are being developed for 20-30 m diameter deployable aerodynamic decelerator entry systems that could endure dual pulse heating (peak aprrox.120 W/sq cm). A technology Roadmap is presented that will be used for facilitating the maturation of both the rigid and flexible ablative materials through application of decision metrics (requirements, key performance parameters, TRL definitions, and evaluation criteria) used to assess and advance the various candidate TPS material technologies.

Cassell, Alan M.; Beck, Robin A. S.; Arnold, James O.; Hwang, Helen; Wright, Michael J.; Szalai, Christine E.; Blosser, Max; Poteet, Carl C.

2010-01-01

231

Analysis of Linear Aerospike Plume Induced X-33 Base Heating Environment  

NASA Technical Reports Server (NTRS)

Computational analysis is conducted to study the effect of an linear aerospike engine plume on the X-33 base-heating environment during ascent flight. To properly account for the freestream-body interaction and to allow for potential plume-induced flow-separation, the thermo-flowfield of the entire vehicle at several trajectory points is computed. A sequential grid-refinement technique is used in conjunction with solution-adaptive, patched, and embedded grid methods to limit the model to a manageable size. The computational methodology is based on a three-dimensional, finite-difference, viscous flow, chemically reacting, pressure-based computational fluid dynamics formulation, and a three-dimensional, finite-volume, spectral-line based weighted-sum-of-gray-gases absorption, computational radiation heat transfer formulation. The computed forebody and afterbody surface pressure coefficients and base pressure characteristic curves are compared with those of a cold-flow test. The predicted convective and radiative base-heat fluxes, the effect of base-bleed, and the potential of plume-induced flow separation are presented.

Wang, Ten-See

1998-01-01

232

Performance Tests of a Liquid Hydrogen Propellant Densification Ground System for the X33/RLV  

NASA Technical Reports Server (NTRS)

A concept for improving the performance of propulsion systems in expendable and single-stage-to-orbit (SSTO) launch vehicles much like the X33/RLV has been identified. The approach is to utilize densified cryogenic liquid hydrogen (LH2) and liquid oxygen (LOX) propellants to fuel the propulsion stage. The primary benefit for using this relatively high specific impulse densified propellant mixture is the subsequent reduction of the launch vehicle gross lift-off weight. Production of densified propellants however requires specialized equipment to actively subcool both the liquid oxygen and liquid hydrogen to temperatures below their normal boiling point. A propellant densification unit based on an external thermodynamic vent principle which operates at subatmospheric pressure and supercold temperatures provides a means for the LH2 and LOX densification process to occur. To demonstrate the production concept for the densification of the liquid hydrogen propellant, a system comprised of a multistage gaseous hydrogen compressor, LH2 recirculation pumps and a cryogenic LH2 heat exchanger was designed, built and tested at the NASA Lewis Research Center (LeRC). This paper presents the design configuration of the LH2 propellant densification production hardware, analytical details and results of performance testing conducted with the hydrogen densifier Ground Support Equipment (GSE).

Tomsik, Thomas M.

1997-01-01

233

Thermal Protection Requirements for Near-Earth Aeroassisted Orbital Transfer Vehicle Missions  

NASA Technical Reports Server (NTRS)

The thermal protection required for decelerating and maneuvering spacecraft by aerodynamic forces is determined for return missions from geosynchronous to low Earth orbits. The effect of vehicle configuration on surface heating rates and selection of heat shield materials is analyzed. The effects of the current widespread estimates in the structure of atmospheric density are also evaluated. It is shown that nonequilibrium radiation can be a major source of surface heating during atmospheric entry and a significant factor for heat shielding requirements. It is also demonstrated that drag-brake concepts have application to a broad range of orbital transfer missions because of the favorable tradeoffs with aeromaneuvering vehicles in volumetric efficiency, retrothrust plane-change capability, and heat protection requirements. In addition, the results of this study indicate that the aeroassist technique produces acceptable penalties in vehicle payload capacity for drag-brake concepts, because of the system's heat protection requirements, and is highly attractive relative to all-propulsive orbital change maneuvers.

Menees, Gene P.

1985-01-01

234

Thermal Properties of Microstrain Gauges Used for Protection of Lithium-Ion Cells of Different Designs  

NASA Technical Reports Server (NTRS)

The purpose of this innovation is to use microstrain gauges to monitor minute changes in temperature along with material properties of the metal cans and pouches used in the construction of lithium-ion cells. The sensitivity of the microstrain gauges to extremely small changes in temperatures internal to the cells makes them a valuable asset in controlling the hazards in lithium-ion cells. The test program on lithium-ion cells included various cell configurations, including the pouch type configurations. The thermal properties of microstrain gauges have been found to contribute significantly as safety monitors in lithium-ion cells that are designed even with hard metal cases. Although the metal cans do not undergo changes in material property, even under worst-case unsafe conditions, the small changes in thermal properties observed during charge and discharge of the cell provide an observable change in resistance of the strain gauge. Under abusive or unsafe conditions, the change in the resistance is large. This large change is observed as a significant change in slope, and this can be used to prevent cells from going into a thermal runaway condition. For flexible metal cans or pouch-type lithium-ion cells, combinations of changes in material properties along with thermal changes can be used as an indication for the initiation of an unsafe condition. Lithium-ion cells have a very high energy density, no memory effect, and almost 100-percent efficiency of charge and discharge. However, due to the presence of a flammable electrolyte, along with the very high energy density and the capability of releasing oxygen from the cathode, these cells can go into a hazardous condition of venting, fire, and thermal runaway. Commercial lithium-ion cells have current and voltage monitoring devices that are used to control the charge and discharge of the batteries. Some lithium-ion cells have internal protective devices, but when used in multi-cell configurations, these protective devices either do not protect or are themselves a hazard to the cell due to their limitations. These devices do not help in cases where the cells develop high impedance that suddenly causes them to go into a thermal runaway condition. Temperature monitoring typically helps with tracking the performance of a battery. But normal thermistors or thermal sensors do not provide the accuracy needed for this and cannot track a change in internal cell temperatures until it is too late to stop a thermal runaway.

Jeevarajan, Judith

2011-01-01

235

Ballistic Performance of Porous-Ceramic, Thermal Protection Systems to 9 km/s  

NASA Technical Reports Server (NTRS)

Porous-ceramic, thermal protection systems are used heavily in current reentry vehicles like the Orbiter, and they are currently being proposed for the next generation of US manned spacecraft, Orion. These materials insulate the structural components and sensitive components of a spacecraft against the intense thermal environments of atmospheric reentry. These materials are also highly exposed to solid particle space environment hazards. This paper discusses recent impact testing up to 9.65 km/s on ceramic tiles similar to those used on the Orbiter. These tiles are a porous-ceramic insulator of nominally 8 lb/ft(exp 3) alumina-fiber-enhanced-thermal-barrier (AETB8) coated with a damage-resistant, toughened-unipiece-fibrous-insulation/reaction-cured-glass layer (TUFI/RCG).

Miller, Joshua E.; Bohl, William E.; Foreman, Cory D.; Christiansen, Eric C.; Davis, Bruce A.

2010-01-01

236

Electrochemical aging of humectant-treated thermal-sprayed zinc anodes for cathodic protection  

SciTech Connect

Humectants, substances that promote the retention of moisture, were studied to determine their effectiveness in improving the performance and extending the service life of both new and previously-aged thermal-sprayed Zn anodes used in impressed current (ICCP) and galvanic cathodic protection (GCP) systems for steel-reinforced concrete structures. Potassium acetate, lithium nitrate, and lithium bromide were applied to a series of thermal-sprayed Zn-coated concrete slabs before starting the ICCP or GCP experiment. All of the humectants altered the behavior of the thermal-sprayed Zn anodes. LiNO{sub 3} was the most beneficial for ICCP anodes and LiBr was the most beneficial for GCP anodes. Circuit resistances for ICCP anodes and galvanic current density for GCP anodes are compared on the basis of electrochemical aging, humidity, and type of humectant.

Covino, B.S. Jr.; Holcomb, G.R.; Bullard, S.J.; Russell, J.H.; Cramer, S.D.; Bennett, J.E.; Laylor, H.M.

1999-07-01

237

Protection of alodine coatings from thermal aging by removable polymer coatings.  

SciTech Connect

Removable polymer coatings were evaluated as a means to suppress dehydration of Alodine chromate conversion coatings during thermal aging and thereby retain the corrosion protection afforded by Alodine. Two types of polymer coatings were applied to Alodine-treated panels of aluminum alloys 7075-T73 and 6061-T6 that were subsequently aged for 15 to 50 hours at temperatures between 135 F to 200 F. The corrosion resistance of the thermally aged panels was evaluated, after stripping the polymer coatings, by exposure to a standard salt-fog corrosion test and the extent of pitting of the polymer-coated and untreated panels compared. Removable polymer coatings mitigated the loss of corrosion resistance due to thermal aging experienced by the untreated alloys. An epoxide coating was more effective than a fluorosilicone coating as a dehydration barrier.

Wagstaff, Brett R. (.); Bradshaw, Robert W.; Whinnery, LeRoy L., Jr. (.,; .)

2006-12-01

238

Ultrahigh Temperature Ceramics for Thermal Protection of Next Generation Space Vehicles  

NASA Technical Reports Server (NTRS)

Materials with improved properties are needed for thermal protection of next generation space vehicles. Sharp leading edges on these vehicles will have to withstand exposure to high temperatures (> 2200 C or 4000 F) and severe thermal cycling in both neutral and oxidizing environments. These extreme conditions will require materials that possess superior oxidation resistance, low creep, and excellent thermal shock properties. This presentation will first discuss the system requirements for thermal protection of advanced space vehicles and then show how they are driving development of new materials systems. The presentation will focus on ultrahigh temperature ceramics (UHTCs) that are promising candidates for such applications. ZrB2 and HfB2 and composites of those ceramics with SiC are two particular families of UHTCs that are currently under development for sharp leading edges. These ceramics are appealing because their melting temperatures are 3245 C (5873 F) for ZrB2 and 3380 C (6116 F) for HfB2 and because they may form protective, oxidation resistant coatings in use. The mechanical properties of the UHTCs are strongly dependent on phase purity and the processing route used to make them, both of which factors are being actively investigated. For example, oxide impurities could form glassy grain boundary phases that soften at high temperatures and make the ceramic susceptible to creep deformation. Results from scanning and transmission electron microscopic studies of the UHTCs have shown how their processing can be improved to give better properties. This presentation will discuss the UHTC characterization results in some detail, focusing particularly on the structure and composition of the ceramic grain boundaries. The presentation will conclude with some remarks on how the properties of these promising UHTCs can be further improved and how they might be made more economically.

Loehman, R. E.; Ellerby, D. T.; Gusman, M. I.; Stackpoole, M.; Johnson, S. M.; Arnold, James (Technical Monitor)

2001-01-01

239

Fabrication of protective over layer for enhanced thermal stability of zinc oxide based TCO films  

NASA Astrophysics Data System (ADS)

To prevent the loss of oxygen vacancies in aluminium doped zinc oxide (AZO) thin films at high temperature process, and to enhance the thermal stability a protective tin oxide (TO) over layer has been realized. To investigate the protective nature of doped tin oxide layer, fluorine doped tin oxide (FTO) and antimony doped tin oxide (ATO) layers have also been coated on AZO layer. Then, to confirm its stability of opto-electrical properties under high temperature process, structural, optical and electrical studies of AZO single layer, TO/AZO, FTO/AZO and ATO/AZO double layered films were carried out before and after annealing and the results are reported. The XRD results showed that the crystalline nature of double layered films remains unchanged, even after the heat treatment. The UV results depicted that, in all the double layer films the transmission spectra remain unchanged or changed negligibly after annealing, indicating the thermal stability of double layered films. The photoluminescence results also strongly supported the improvement in the thermal stability of double layered films. The electrical studies suggested that the double layered films exhibited better electrical resistivity with bare AZO films.

Ravichandran, K.; Ravikumar, P.; Sakthivel, B.

2013-12-01

240

Replacement of Ablators with Phase-Change Material for Thermal Protection of STS Elements  

NASA Technical Reports Server (NTRS)

As part of the research and development program to develop new Thermal Protection System (TPS) materials for aerospace applications at NASA's Marshall Space Flight Center (MSFC), an experimental study was conducted on a new concept for a non-ablative TPS material. Potential loss of TPS material and ablation by-products from the External Tank (ET) or Solid Rocket Booster (SRB) during Shuttle flight with the related Orbiter tile damage necessitates development of a non-ablative thermal protection system. The new Thermal Management Coating (TMC) consists of phase-change material encapsulated in micro spheres and a two-part resin system to adhere the coating to the structure material. The TMC uses a phase-change material to dissipate the heat produced during supersonic flight rather than an ablative material. This new material absorbs energy as it goes through a phase change during the heating portion of the flight profile and then the energy is slowly released as the phase-change material cools and returns to its solid state inside the micro spheres. The coating was subjected to different test conditions simulating design flight environments at the NASA/MSFC Improved Hot Gas Facility (IHGF) to study its performance.

Kaul, Raj K.; Stuckey, Irvin; Munafo, Paul M. (Technical Monitor)

2002-01-01

241

Study on corrosion protection of organic coatings using electrochemical techniques: Thermal property characterization, film thickness investigation, and coating performance evaluation  

Microsoft Academic Search

As an initial effort to establish a rapid, accurate, and comprehensive testing protocol for performance evaluation and lifetime prediction of corrosion protective coatings, the effects of coating thermal characteristics, coating application parameters, and coating formulation variations on corrosion protection have been explored. The study has been accomplished primarily through modern electrochemical techniques, such as Electrochemical Noise Methods (ENM) and Electrochemical

Junping Li

2002-01-01

242

Corrosion protection of Mg/Al alloys by thermal sprayed aluminium coatings  

NASA Astrophysics Data System (ADS)

The protective features of thermal sprayed Al-coatings applied on AZ31, AZ80 and AZ91D magnesium/aluminium alloys were evaluated in 3.5 wt.% NaCl solution by electrochemical and gravimetric measurements. The changes in the morphology and corrosion behaviour of the Al-coatings induced by a cold-pressing post-treatment were also examined. The specimens were characterized by scanning electron microscopy, energy dispersive X-ray analysis and low-angle X-ray diffraction. The as-sprayed Al-coatings revealed a high degree of porosity and poor corrosion protection, which resulted in galvanic acceleration of the corrosion of the magnesium substrates. The application of a cold-pressing post-treatment produced more compact Al-coatings with better bonding at the substrate/coating interface and higher corrosion resistance regardless of the nature of the magnesium alloy.

Pardo, A.; Casajús, P.; Mohedano, M.; Coy, A. E.; Viejo, F.; Torres, B.; Matykina, E.

2009-05-01

243

Measuring the spectral emissivity of thermal protection materials during atmospheric reentry simulation  

NASA Technical Reports Server (NTRS)

Hypersonic spacecraft reentering the earth's atmosphere encounter extreme heat due to atmospheric friction. Thermal Protection System (TPS) materials shield the craft from this searing heat, which can reach temperatures of 2900 F. Various thermophysical and optical properties of TPS materials are tested at the Johnson Space Center Atmospheric Reentry Materials and Structures Evaluation Facility, which has the capability to simulate critical environmental conditions associated with entry into the earth's atmosphere. Emissivity is an optical property that determines how well a material will reradiate incident heat back into the atmosphere upon reentry, thus protecting the spacecraft from the intense frictional heat. This report describes a method of measuring TPS emissivities using the SR5000 Scanning Spectroradiometer, and includes system characteristics, sample data, and operational procedures developed for arc-jet applications.

Marble, Elizabeth

1996-01-01

244

X-33 (Rev-F) Aeroheating Results of Test 6770 in NASA Langley 20-Inch Mach 6 Air Tunnel  

NASA Technical Reports Server (NTRS)

Aeroheating characteristics of the X-33 Rev-F configuration have been experimentally examined in the Langley 20-Inch Mach 6 Air Tunnel (Test 6770). Global surface heat transfer distributions, surface streamline patterns, and shock shapes were measured on a 0.013-scale model at Mach 6 in air. Parametric variations include angles-of-attack of 20-deg, 30-deg, and 40-deg; Reynolds numbers based on model length of 0.9 to 4.9 million; and body-flap deflections of 10-deg and 20-deg. The effects of discrete roughness elements on boundary layer transition, which included trip height, size, and location, both on and off the windward centerline, were investigated. This document is intended to serve as a quick release of preliminary data to the X-33 program; analysis is limited to observations of the experimental trends in order to expedite dissemination.

Berry, Scott A.; Horvath, Thomas J.; Kowalkowski, Matthew K.; Liechty, Derek S.

1999-01-01

245

Revitalizing the Space Shuttle's Thermal Protection System with Reverse Engineering and 3D Vision Technology  

NASA Technical Reports Server (NTRS)

The Space Shuttle is protected by a Thermal Protection System (TPS) made of tens of thousands of individually shaped heat protection tile. With every flight, tiles are damaged on take-off and return to earth. After each mission, the heat tiles must be fixed or replaced depending on the level of damage. As part of the return to flight mission, the TPS requirements are more stringent, leading to a significant increase in heat tile replacements. The replacement operation requires scanning tile cavities, and in some cases the actual tiles. The 3D scan data is used to reverse engineer each tile into a precise CAD model, which in turn, is exported to a CAM system for the manufacture of the heat protection tile. Scanning is performed while other activities are going on in the shuttle processing facility. Many technicians work simultaneously on the space shuttle structure, which results in structural movements and vibrations. This paper will cover a portable, ultra-fast data acquisition approach used to scan surfaces in this unstable environment.

Wilson, Brad; Galatzer, Yishai

2008-01-01

246

Monitoring of Thermal Protection Systems Using Robust Self-Organizing Optical Fiber Sensing Networks  

NASA Technical Reports Server (NTRS)

The general aim of this work is to develop and demonstrate a prototype structural health monitoring system for thermal protection systems that incorporates piezoelectric acoustic emission (AE) sensors to detect the occurrence and location of damaging impacts, and an optical fiber Bragg grating (FBG) sensor network to evaluate the effect of detected damage on the thermal conductivity of the TPS material. Following detection of an impact, the TPS would be exposed to a heat source, possibly the sun, and the temperature distribution on the inner surface in the vicinity of the impact measured by the FBG network. A similar procedure could also be carried out as a screening test immediately prior to re-entry. The implications of any detected anomalies in the measured temperature distribution will be evaluated for their significance in relation to the performance of the TPS during re-entry. Such a robust TPS health monitoring system would ensure overall crew safety throughout the mission, especially during reentry

Richards, Lance

2013-01-01

247

Evaluation of nondestructive testing techniques for the space shuttle nonmetallic thermal protection system  

NASA Technical Reports Server (NTRS)

A program was conducted to evaluate nondestructive analysis techniques for the detection of defects in rigidized surface insulation (a candidate material for the Space Shuttle thermal protection system). Uncoated, coated, and coated and bonded samples with internal defects (voids, cracks, delaminations, density variations, and moisture content), coating defects (holes, cracks, thickness variations, and loss of adhesion), and bondline defects (voids and unbonds) were inspected by X-ray radiography, acoustic, microwave, high-frequency ultrasonic, beta backscatter, thermal, holographic, and visual techniques. The detectability of each type of defect was determined for each technique (when applicable). A possible relationship between microwave reflection measurements (or X-ray-radiography density measurements) and the tensile strength was established. A possible approach for in-process inspection using a combination of X-ray radiography, acoustic, microwave, and holographic techniques was recommended.

Tiede, D. A.

1972-01-01

248

Moisture absorption characteristics of the Orbiter thermal protection system and methods used to prevent water ingestion  

NASA Technical Reports Server (NTRS)

The Space Shuttle Orbiter's silica tile Thermal Protection System (TPS) is beset by the moisture absorption problems inherently associated with low density, highly porous insulation systems. Attention is presently given to the comparative success of methods for the minimization and/or prevention of water ingestion by the TPS tiles, covering the development of water-repellent agents and their tile application techniques, flight test program results, and materials improvements. The use of external films for rewaterproofing of the TPS tiles after each mission have demonstrated marginal to unacceptable performance. By contrast, a tile interior waterproofing agent has shown promise.

Schomburg, C.; Dotts, R. L.; Tillian, D. J.

1983-01-01

249

Refurbishment cost study of the thermal protection system of a space shuttle vehicle, phase 2  

NASA Technical Reports Server (NTRS)

The labor costs and techniques associated with the refurbishment and maintenance of representative thermal protection system (TPS) components and their attachment concepts suitable for space shuttle application are defined, characterized, and evaluated from the results of an experimental test program. This program consisted of designing selected TPS concepts, fabricating and assembling test hardware, and performing a time and motion study of specific maintenance functions of the test hardware on a full-scale- mockup. Labor requirements and refurbishment techniques, as they relate to the maintenance functions of inspection, repair, removal, and replacement were identified.

Haas, D. W.

1972-01-01

250

The optimum levels of the thermal protection of residential buildings under climatic conditions of Russia  

NASA Astrophysics Data System (ADS)

The present paper reports the results of determining the optimum values of the resistance of building envelopes to heat transfer for both existing and newly constructed buildings for regions of Russia with different climatic conditions. An analysis for the sensitivity of obtained optimum solutions to changes in external factors has been made. The potential of energy saving in both the existing housing stock and in newly constructed buildings due to the improvement of thermal protection performance of buildings to the optimum level has been determined.

Filippov, S. P.; Dil'man, M. D.; Ionov, M. S.

2013-11-01

251

Position Paper External Tank Thermal Protection System (TPS) Manually Sprayed fly-as-is Foam Certification  

NASA Technical Reports Server (NTRS)

During manufacture of the existing External Tanks (ETs), the Thermal Protection System (TPS) foam manual spray application processes lacked the enhanced controls/procedures to ensure that defects produced were less than the critical size. Therefore the only remaining option to certify the "fly-as-is" foam is to verify ET120 tank hardware meets the new foam debris requirements. The ET project has undertaken a significant effort studying the existing "fly-as-is" TPS foam. This paper contains the findings of the study.

Stadler, John H.

2009-01-01

252

Design of Inorganic Water Repellent Coatings for Thermal Protection Insulation on an Aerospace Vehicle  

NASA Technical Reports Server (NTRS)

In this report, thin film deposition of one of the model candidate materials for use as water repellent coating on the thermal protection systems (TPS) of an aerospace vehicle was investigated. The material tested was boron nitride (BN), the water-repellent properties of which was detailed in our other investigation. Two different methods, chemical vapor deposition (CVD) and pulsed laser deposition (PLD), were used to prepare the BN films on a fused quartz substrate (one of the components of thermal protection systems on aerospace vehicles). The deposited films were characterized by a variety of techniques including X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The BN films were observed to be amorphous in nature, and a CVD-deposited film yielded a contact angle of 60 degrees with water, similar to the pellet BN samples investigated previously. This demonstrates that it is possible to use the bulk sample wetting properties as a guideline to determine the candidate waterproofing material for the TPS.

Fuerstenau, D. W.; Ravikumar, R.

1997-01-01

253

Survey of the supporting research and technology for the thermal protection of the Galileo Probe  

NASA Technical Reports Server (NTRS)

The Galileo Probe, which is scheduled to be launched in 1985 and to enter the hydrogen-helium atmosphere of Jupiter up to 1,475 days later, presents thermal protection problems that are far more difficult than those experienced in previous planetary entry missions. The high entry speed of the Probe will cause forebody heating rates orders of magnitude greater than those encountered in the Apollo and Pioneer Venus missions, severe afterbody heating from base-flow radiation, and thermochemical ablation rates for carbon phenolic that rival the free-stream mass flux. This paper presents a comprehensive survey of the experimental work and computational research that provide technological support for the Probe's heat-shield design effort. The survey includes atmospheric modeling; both approximate and first-principle computations of flow fields and heat-shield material response; base heating; turbulence modelling; new computational techniques; experimental heating and materials studies; code validation efforts; and a set of 'consensus' first-principle flow-field solutions through the entry maneuver, with predictions of the corresponding thermal protection requirements.

Howe, J. T.; Pitts, W. C.; Lundell, J. H.

1981-01-01

254

Ballistic Performance Model of Crater Formation in Monolithic, Porous Thermal Protection Systems  

NASA Technical Reports Server (NTRS)

Porous monolithic ablative systems insulate atmospheric reentry vehicles from reentry plasmas generated by atmospheric braking from orbital and exo-orbital velocities. Due to the necessity that these materials create a temperature gradient up to several thousand Kelvin over their thickness, it is important that these materials are near their pristine state prior to reentry. These materials may also be on exposed surfaces to space environment threats like orbital debris and meteoroids leaving a probability that these exposed surfaces will be below their prescribed values. Owing to the typical small size of impact craters in these materials, the local flow fields over these craters and the ablative process afford some margin in thermal protection designs for these locally reduced performance values. In this work, tests to develop ballistic performance models for thermal protection materials typical of those being used on Orion are discussed. A density profile as a function of depth of a typical monolithic ablator and substructure system is shown in Figure 1a.

Miller, J. E.; Christiansen, E. L.; Deighton, K. D.

2014-01-01

255

Development and test of the Shuttle/Centaur cryogenic tankage thermal protection system  

NASA Technical Reports Server (NTRS)

The Thermal Protection System (TPS) for the Shuttle/Centaur had to provide fail-safe thermal protection during prelaunch, launch ascent, and on-orbit operations as well as during potential abort where the Shuttle and Centaur would return to earth. The TPS selected used a helium-purged polyimide foam beneath three radiation shields for the liquid hydrogen (LH2) tank and radiation shields only for the liquid oxygen (LO2) tank (three shields on the tank sidewall and four on the aft bulkhead). An evacuated common intermediate bulkhead separated the two tanks. The LH2 tank had one 1.9-cm thick layer of foam on the forward bulkhead and two layers on the larger area side-wall. Full scale tests of the flight vehicle in a simulated Shuttle cargo bay, that was purged with gaseous nitrogen, gave total prelaunch heating rates of 25.9 kW and 12.9 kW for LH2 and LO2 tanks, respectively. Calorimeter tests on a representative LH2 tank sidewall TPS sample indicated that the measured unit heating rate would rapidly decrease from the prelaunch rate of 300 W/sq m to a desired rate of less than 4 W/sq m once on-orbit.

Knoll, R. H.; England, J. E.; Macneil, P. N.

1987-01-01

256

Design, development, and test of Shuttle/Centaur G-prime cryogenic tankage thermal protection systems  

NASA Technical Reports Server (NTRS)

The thermal protection systems (TPS) for the Shuttle/Centaur were designed to provide fail-safe thermal protection during prelaunch, launch ascent, and on-orbit operations as well as during potential abort, where the Shuttle and Centaur would return to earth. The TPS selected used a helium-purged polyimide foam beneath three radiation shields for the liquid-hydrogen (LH2) tank and radiation shields only for the liquid-oxygen (LO2) tank. A double-walled vacuum bulkhead separated the two tanks. The LH2 tank had one 1.9 cm-thick layer of foam on the forward bulkhead and two layers on the larger-area sidewall. Full scale tests of the flight vehicle in a simulated Shuttle cargo bay gave total prelaunch heating rates of 29.5 and 12.9 kW for the LH2 and LO2 tanks, respectively. Calorimeter tests on a representative sample of the LH2 tank sidewall TPS indicated that the measured unit heating one would rapidly decrease from the prelaunch rate of about 300 W/sq m to a desired rate less than 4 W/sq m once on-orbit.

Macneil, Peter N.; England, James E.; Knoll, Richard H.

1988-01-01

257

Overexpression of Hsp90 from grass carp (Ctenopharyngodon idella) increases thermal protection against heat stress.  

PubMed

With homologous DNA probes, we had screened a grass carp heat shock protein 90 gene (CiHsp90). The full sequence of CiHsp90 cDNA was 2793 bp, which could code a 798 amino acids peptide. The phylogenetic analysis demonstrated that CiHsp90 shared the high homology with Zebrafish Grp94. Quantitative RT-PCR analysis showed that CiHsp90 was ubiquitously expressed at lower levels in all detected tissues and up-regulated after heat shock at 34 °C or cold stress at 4 °C. To understand the function of CiHsp90 involving in thermal protection, an expression vector containing coding region cDNA was expressed in E. coli BL21 (DE3) plysS. Upon transfer from 37 °C to 42 °C, these cells that accumulated CiHsp90 peptides displayed greater thermoresistance than the control cells. While incubated at 4°C for different periods, it could also improve the cell viability. After transient transfected recombinant plasmid pcDNA3.1/CiHsp90 into mouse myeloma cell line SP2/0, we found that CiHsp90 could contribute to protecting cells against both thermal and cold extremes. On the contrary, the mutant construct ?N-CiHsp90 (256-798aa) could abolish the protection activity both in prokaryotic cells and eukaryotic cells. Additionally, both CiHsp90 and ?N-CiHsp90 peptides could reduce the level of citrate synthase aggregation at the high temperature. PMID:22510210

Wu, Chu-Xin; Zhao, Feng-Yun; Zhang, Yuan; Zhu, Yu-Jiao; Ma, Mei-Sheng; Mao, Hui-Ling; Hu, Cheng-Yu

2012-07-01

258

Space Shuttle Thermal Protection System Repair Flight Experiment Induced Contamination Impacts  

NASA Technical Reports Server (NTRS)

NASA s activities to prepare for Flight LF1 (STS-114) included development of a method to repair the Thermal Protection System (TPS) of the Orbiter s leading edge should it be damaged during ascent by impacts from foam, ice, etc . Reinforced Carbon-Carbon (RCC) is used for the leading edge TPS. The repair material that was developed is named Non- Oxide Adhesive eXperimental (NOAX). NOAX is an uncured adhesive material that acts as an ablative repair material. NOAX completes curing during the Orbiter s descent. The Thermal Protection System (TPS) Detailed Test Objective 848 (DTO 848) performed on Flight LF1 (STS-114) characterized the working life, porosity void size in a micro-gravity environment, and the on-orbit performance of the repairs to pre-damaged samples. DTO 848 is also scheduled for Flight ULF1.1 (STS-121) for further characterization of NOAX on-orbit performance. Due to the high material outgassing rates of the NOAX material and concerns with contamination impacts to optically sensitive surfaces, ASTM E 1559 outgassing tests were performed to determine NOAX condensable outgassing rates as a function of time and temperature. Sensitive surfaces of concern include the Extravehicular Mobility Unit (EMU) visor, cameras, and other sensors in proximity to the experiment during the initial time after application. This paper discusses NOAX outgassing characteristics, how the amount of deposition on optically sensitive surfaces while the NOAX is being manipulated on the pre-damaged RCC samples was determined by analysis, and how flight rules were developed to protect those optically sensitive surfaces from excessive contamination where necessary.

Smith, Kendall A.; Soares, Carlos E.; Mikatarian, Ron; Schmidl, Danny; Campbell, Colin; Koontz, Steven; Engle, Michael; McCroskey, Doug; Garrett, Jeff

2006-01-01

259

Cardiovascular and thermal consequences of protective clothing: a comparison of clothed and unclothed states.  

PubMed

We have undertaken a laboratory-based examination of the cardiovascular and thermal impact of wearing thermal (heat) protective clothing during fatiguing exercise in the heat. Seven males completed semi-recumbent, intermittent cycling (39.6 degrees C, 45% relative humidity) wearing either protective clothing or shorts (control). Mean core and skin temperatures, cardiac frequency (f(c)), stroke volume (Q), cardiac output (Q), arterial pressure, forearm blood flow (Q(f)), plasma volume change, and sweat rates were measured. In the clothed trials, subjects experienced significantly shorter times to fatigue (52.5 vs. 58.9 min), at lower peak work rates (204.3 vs. 277.4 W), and with higher core (37.9 degrees vs. 37.5 degrees C) and mean skin temperatures (37.3 degrees vs. 36.9 degrees C). There was a significant interaction between time and clothing on f(c), such that, over time, the clothing effect became more powerful. Clothing had a significant main affect on Q, but not Q, indicating the higher Q was chronotropically driven. Despite a greater sweat loss when clothed (923.0 vs. 547.1 g.m(-2) x h(-1); P<0.05), Q(f) and plasma volume change remained equivalent. Protective clothing reduced exercise tolerance, but did not affect overall cardiovascular function, at the point of volitional fatigue. It was concluded that, during moderately heavy, semi-recumbent exercise under hot, dry conditions, the strain on the unclothed body was already high, such that the additional stress imparted by the clothing ensemble represented a negligible, further impact upon cardiovascular stability. PMID:15370864

Fogarty, Alison; Armstrong, Karen; Gordon, Christopher; Groeller, Herbert; Woods, Brian; Stocks, Jodie; Taylor, Nigel

2004-08-15

260

On-Line Thermal Barrier Coating Monitoring for Real-Time Failure Protection and Life Maximization  

SciTech Connect

Under the sponsorship of the U. S. Department of Energy's National Energy Laboratory, Siemens Power Generation, Inc proposed a four year program titled, ''On-Line Thermal Barrier Coating (TBC) Monitor for Real-Time Failure Protection and Life Maximization'', to develop, build and install the first generation of an on-line TBC monitoring system for use on land-based advanced gas turbines (AGT). Federal deregulation in electric power generation has accelerated power plant owner's demand for improved reliability availability maintainability (RAM) of the land-based advanced gas turbines. As a result, firing temperatures have been increased substantially in the advanced turbine engines, and the TBCs have been developed for maximum protection and life of all critical engine components operating at these higher temperatures. Losing TBC protection can therefore accelerate the degradation of substrate components materials and eventually lead to a premature failure of critical component and costly unscheduled power outages. This program seeks to substantially improve the operating life of high cost gas turbine components using TBC; thereby, lowering the cost of maintenance leading to lower cost of electricity. Siemens Power Generation, Inc. has teamed with Indigo Systems, a supplier of state-of-the-art infrared camera systems, and Wayne State University, a leading research organization in the field of infrared non-destructive examination (NDE), to complete the program.

Dennis H. LeMieux

2005-10-01

261

On-Line Thermal Barrier Coating Monitoring for Real-Time Failure Protection and Life Maximization  

SciTech Connect

Under the sponsorship of the U. S. Department of Energy's National Energy Laboratory, Siemens Westinghouse Power Corporation proposes a four year program titled, ''On-Line Thermal Barrier Coating (TBC) Monitor for Real-Time Failure Protection and Life Maximization'', to develop, build and install the first generation of an on-line TBC monitoring system for use on land-based advanced gas turbines (AGT). Federal deregulation in electric power generation has accelerated power plant owner's demand for improved reliability availability maintainability (RAM) of the land-based advanced gas turbines. As a result, firing temperatures have been increased substantially in the advanced turbine engines, and the TBCs have been developed for maximum protection and life of all critical engine components operating at these higher temperatures. Losing TBC protection can therefore accelerate the degradation of substrate components materials and eventually lead to a premature failure of critical component and costly unscheduled power outages. This program seeks to substantially improve the operating life of high cost gas turbine components using TBC; thereby, lowering the cost of maintenance leading to lower cost of electricity. Siemens Westinghouse Power Corporation has teamed with Indigo Systems, a supplier of state-of-the-art infrared camera systems, and Wayne State University, a leading research organization in the field of infrared non-destructive examination (NDE), to complete the program.

Dennis H. LeMieux

2005-04-01

262

ON-LINE THERMAL BARRIER COATING MONITORING FOR REAL-TIME FAILURE PROTECTION AND LIFE MAXIMIZATION  

SciTech Connect

Under the sponsorship of the U. S. Department of Energy's National Energy Laboratory, Siemens Westinghouse Power Corporation proposes a four year program titled, ''On-Line Thermal Barrier Coating (TBC) Monitor for Real-Time Failure Protection and Life Maximization,'' to develop, build and install the first generation of an on-line TBC monitoring system for use on land-based advanced gas turbines (AGT). Federal deregulation in electric power generation has accelerated power plant owner's demand for improved reliability availability maintainability (RAM) of the land-based advanced gas turbines. As a result, firing temperatures have been increased substantially in the advanced turbine engines, and the TBCs have been developed for maximum protection and life of all critical engine components operating at these higher temperatures. Losing TBC protection can therefore accelerate the degradation of substrate components materials and eventually lead to a premature failure of critical component and costly unscheduled power outages. This program seeks to substantially improve the operating life of high cost gas turbine components using TBC; thereby, lowering the cost of maintenance leading to lower cost of electricity. Siemens Westinghouse Power Corporation has teamed with Indigo Systems, a supplier of state-of-the-art infrared camera systems, and Wayne State University, a leading research organization in the field of infrared non-destructive examination (NDE), to complete the program.

Dennis H. LeMieux

2002-04-01

263

ON-LINE THERMAL BARRIER COATING MONITORING FOR REAL-TIME FAILURE PROTECTION AND LIFE MAXIMIZATION  

SciTech Connect

Under the sponsorship of the U. S. Department of Energy's National Energy Laboratory, Siemens Westinghouse Power Corporation proposes a four year program titled, ''On-Line Thermal Barrier Coating (TBC) Monitor for Real-Time Failure Protection and Life Maximization,'' to develop, build and install the first generation of an on-line TBC monitoring system for use on land-based advanced gas turbines (AGT). Federal deregulation in electric power generation has accelerated power plant owner's demand for improved reliability, availability, and maintainability (RAM) of the land-based advanced gas turbines. As a result, firing temperatures have been increased substantially in the advanced turbine engines, and the TBCs have been developed for maximum protection and life of all critical engine components operating at these higher temperatures. Losing TBC protection can, therefore, accelerate the degradation of substrate component materials and eventually lead to a premature failure of critical components and costly unscheduled power outages. This program seeks to substantially improve the operating life of high cost gas turbine components using TBC; thereby, lowering the cost of maintenance leading to lower cost of electricity. Siemens Westinghouse Power Corporation has teamed with Indigo Systems, a supplier of state-of-the-art infrared camera systems, and Wayne State University, a leading research organization in the field of infrared non-destructive examination (NDE), to complete the program.

Dennis H. LeMieux

2003-07-01

264

ON-LINE THERMAL BARRIER COATING MONITORING FOR REAL-TIME FAILURE PROTECTION AND LIFE MAXIMIZATION  

SciTech Connect

Under the sponsorship of the U. S. Department of Energy's National Energy Laboratory, Siemens Westinghouse Power Corporation proposes a four year program titled, ''On-Line Thermal Barrier Coating (TBC) Monitor for Real-Time Failure Protection and Life Maximization,'' to develop, build and install the first generation of an on-line TBC monitoring system for use on land-based advanced gas turbines (AGT). Federal deregulation in electric power generation has accelerated power plant owner's demand for improved reliability, availability, and maintainability (RAM) of the land-based advanced gas turbines. As a result, firing temperatures have been increased substantially in the advanced turbine engines, and the TBCs have been developed for maximum protection and life of all critical engine components operating at these higher temperatures. Losing TBC protection can, therefore, accelerate the degradation of substrate component materials and eventually lead to a premature failure of critical components and costly unscheduled power outages. This program seeks to substantially improve the operating life of high cost gas turbine components using TBC; thereby, lowering the cost of maintenance leading to lower cost of electricity. Siemens Westinghouse Power Corporation has teamed with Indigo Systems, a supplier of state-of-the-art infrared camera systems, and Wayne State University, a leading research organization in the field of infrared non-destructive examination (NDE), to complete the program.

Dennis H. LeMieux

2003-10-01

265

On-Line Thermal Barrier Coating Monitoring for Real-Time Failure Protection and Life Maximization  

SciTech Connect

Under the sponsorship of the U. S. Department of Energy's National Energy Laboratory, Siemens Westinghouse Power Corporation proposes a four year program titled, ''On-Line Thermal Barrier Coating (TBC) Monitor for Real-Time Failure Protection and Life Maximization'', to develop, build and install the first generation of an on-line TBC monitoring system for use on land -based advanced gas turbines (AGT). Federal deregulation in electric power generation has accelerated power plant owner's demand for improved reliability availability maintainability (RAM) of the land-based advanced gas turbines. As a result, firing temperatures have been increased substantially in the advanced turbine engines, and the TBCs have been developed for maximum protection and life of all critical engine components operating at these higher temperatures. Losing TBC protection can therefore accelerate the degradation of substrate components materials and eventually lead to a premature failure of critical component and costly unscheduled power outages. This program seeks to substantially improve the operating life of high cost gas turbine components using TBC; thereby, lowering the cost of maintenance leading to lower cost of electricity. Siemens Westinghouse Power Corporation has teamed with Indigo Systems; a supplier of state-of-the-art infrared camera systems, and Wayne State University, a leading research organization.

Dennis H. LeMieux

2004-10-01

266

Development of Metallic Thermal Protection Systems for the Reusable Launch Vehicle  

NASA Technical Reports Server (NTRS)

A reusable Thermal Protection System (TPS) that is not only lightweight, but durable, operable and cost effective is one of the technologies required by the Reusable Launch Vehicle (RLV) to achieve the goal of drastically reducing the cost of delivering payload to orbit. Metallic TPS is one of the systems being developed to meet this challenge. Current efforts involve improving the superalloy honeycomb TPS concept, which consists of a foil-gage metallic box encapsulating a low density fibrous insulation, and evaluating it for RLV requirements. The superalloy honeycomb TPS concept is mechanically attached to the vehicle structure. Improvements include more efficient internal insulation, a simpler, lighter weight configuration, and a quick-release fastener system for easier installation and removal. Evaluation includes thermal and structural analysis, fabrication and testing of both coupons and TPS panels under conditions simulating RLV environments. Coupons of metallic honeycomb sandwich, representative of the outer TPS surface, were subjected to low speed impact, hypervelocity impact, and rain erosion testing as well as subsequent arcjet exposure. Arrays of TPS panels have been subjected to radiant heating in a thermal/vacuum facility, aerodynamic heating in an arcjet facility and acoustic loading.

Blosser, Max L.

1996-01-01

267

Evaluation of protective coatings under thermal insulation at high temperatures by the use of an innovative design  

SciTech Connect

In order to disseminate the existing information on protective systems that have given good performance results, NACE published Document 6H-189 through its technical groups working on coatings for carbon and stainless steels under insulation and corrosion under thermal insulation. This report is unique in its kind and, in the opinion of the authors of this paper, the next step should be the characterization of each of these systems in combination with different insulating materials. Based on NACE Document No. 6H-189, the design of a probe was developed to evaluate, in a salt chamber, the protective coatings which were supposed to work under thermal insulation at high temperatures (30--1,500 C) . This paper describes the results obtained with different combinations of protective coatings (Silicone-Aluminum, Zinc-Rich and Aluminum Metallizing), and thermal insulators (mineral wool, fiber glass and calcium silicate).

Lasarte, C. [PEQUIVEN, S.A., Maracaibo (Venezuela); Rincon, O.T. de; Montiel, A. [Univ. del Zulia, Maracaibo (Venezuela). Centro de Estudios de Corrosion

1994-12-31

268

High Temperature Damping Behavior of Plasma-Sprayed Thermal Barrier and Protective Coatings  

NASA Technical Reports Server (NTRS)

A high temperature damping test apparatus has been developed using a high heat flux CO 2 laser rig in conjunction with a TIRA S540 25 kHz Shaker and Polytec OFV 5000 Vibrometer system. The test rig has been successfully used to determine the damping performance of metallic and ceramic protective coating systems at high temperature for turbine engine applications. The initial work has been primarily focused on the microstructure and processing effects on the coating temperature-dependence damping behavior. Advanced ceramic coatings, including multicomponent tetragonal and cubic phase thermal barrier coatings, along with composite bond coats, have also been investigated. The coating high temperature damping mechanisms will also be discussed.

Zhu, Dongming; Miller, Robert A.; Duffy, Kirsten P.; Ghosn, Louis J.

2010-01-01

269

Micromechanical analysis and design of an integrated thermal protection system for future space vehicles  

NASA Astrophysics Data System (ADS)

Thermal protection systems (TPS) are the key features incorporated into a spacecraft's design to protect it from severe aerodynamic heating during high-speed travel through planetary atmospheres. The thermal protection system is the key technology that enables a spacecraft to be lightweight, fully reusable, and easily maintainable. Add-on TPS concepts have been used since the beginning of the space race. The Apollo space capsule used ablative TPS and the Space Shuttle Orbiter TPS technology consisted of ceramic tiles and blankets. Many problems arose from the add-on concept such as incompatibility, high maintenance costs, non-load bearing, and not being robust and operable. To make the spacecraft's TPS more reliable, robust, and efficient, we investigated Integral Thermal Protection System (ITPS) concept in which the load-bearing structure and the TPS are combined into one single component. The design of an ITPS was a challenging task, because the requirement of a load-bearing structure and a TPS are often conflicting. Finite element (FE) analysis is often the preferred method of choice for a structural analysis problem. However, as the structure becomes complex, the computational time and effort for an FE analysis increases. New structural analytical tools were developed, or available ones were modified, to perform a full structural analysis of the ITPS. With analytical tools, the designer is capable of obtaining quick and accurate results and has a good idea of the response of the structure without having to go to an FE analysis. A MATLABRTM code was developed to analytically determine performance metrics of the ITPS such as stresses, buckling, deflection, and other failure modes. The analytical models provide fast and accurate results that were within 5% difference from the FEM results. The optimization procedure usually performs 100 function evaluations for every design variable. Using the analytical models in the optimization procedure was a time saver, because the optimization time to reach an optimum design was reached in less than an hour, where as an FE optimization study would take hours to reach an optimum design. Corrugated-core structures were designed for ITPS applications with loads and boundary conditions similar to that of a Space Shuttle-like vehicle. Temperature, buckling, deflection and stress constraints were considered for the design and optimization process. An optimized design was achieved with consideration of all the constraints. The ITPS design obtained from the analytical solutions was lighter (4.38 lb/ft2) when compared to the ITPS design obtained from a finite element analysis (4.85 lb/ft 2). The ITPS boundary effects added local stresses and compressive loads to the top facesheet that was not able to be captured by the 2D plate solutions. The inability to fully capture the boundary effects lead to a lighter ITPS when compared to the FE solution. However, the ITPS can withstand substantially large mechanical loads when compared to the previous designs. Truss-core structures were found to be unsuitable as they could not withstand the large thermal gradients frequently encountered in ITPS applications.

Martinez, Oscar

270

Impacts of Space Shuttle thermal protection system tile on F-15 aircraft vertical tile  

NASA Technical Reports Server (NTRS)

Impacts of the space shuttle thermal protection system (TPS) tile on the leading edge and the side of the vertical tail of the F-15 aircraft were analyzed under different TPS tile orientations. The TPS tile-breaking tests were conducted to simulate the TPS tile impacts. It was found that the predicted tile impact forces compare fairly well with the tile-breaking forces, and the impact forces exerted on the F-15 aircraft vertical tail were relatively low because a very small fraction of the tile kinetic energy was dissipated in the impact, penetration, and fracture of the tile. It was also found that the oblique impact of the tile on the side of the F-15 aircraft vertical tail was unlikely to dent the tail surface.

Ko, W. L.

1985-01-01

271

The relationship between physical activity and thermal protective clothing on functional balance in firefighters.  

PubMed

We investigated the relationship between baseline physical training and the use of firefighting thermal protective clothing (TPC) with breathing apparatus on functional balance. Twenty-three male firefighters performed a functional balance test under four gear/clothing conditions. Participants were divided into groups by physical training status, and task performance was analyzed. There was an effect of equipment and training status on performance with the group reporting both aerobic and resistance training performing better than the group reporting no physical training. In conclusion, firefighters walk more slowly as a strategy to maintain balance when wearing TPC, which may be suboptimal given the emergent nature of fire suppression. This result was most prominent in the group reporting no physical training. PMID:23367817

Kong, Pui W; Suyama, Joe; Cham, Rakié; Hostler, David

2012-12-01

272

GRP78 from grass carp (Ctenopharyngodon idella) provides cytoplasm protection against thermal and Pb2+ stress.  

PubMed

Glucose regulated protein (GRP) located in endoplasmic reticulum (ER) was a member of heat shock protein (Hsp) family. The protective mechanism adapted to ER stimuli was closely related to GRP. GRP78, known as BiP, was one of central regulator responded to stress in ER. Grass carp (Ctenopharyngodon idella) GRP78 (CiGRP78) was up-regulated in almost tissues, especially in liver, under heat shock (34 °C), cold stress (4 °C) or lead nitrate (0.25 mmol/L) stress. In order to understand the function of CiGRP78 in cellular protection, CiGRP78 ORF cDNA was inserted into the plasmid of pET-32a(+) or pEGFP-C1 respectively, then the recombinant plasmids were transformed or transfected into Escherichia coli cells, mouse myeloma cells (SP2/0) or grass carp kidney cells (CIK). In the cells, CiGRP78 was over-expressed following thermal, cold or Pb(2+) stress. Results showed that CiGRP78 not only contributed to protecting prokaryotic cells against thermal or cold extremes, but also played the same role in SP2/0 and CIK cells. After treatment with heat stress at 42 °C for 1 h, although the viability of the cells declined a lot, CIK cells with pEGFP-C1/CiGRP78 exhibited a higher survival rate (28%) than wild-type cells (7%) or cells with only pEGFP-C1 (5.1%). When the time lag extended to 2.5 h, the survival rates were 19%, 5.7%, 4.8% respectively. In addition, CiGRP78 would also provide a transient cytoplasm protection against Pb(2+) stress in a dose- and time-dependent manner. After treatment with lead nitrate at concentration of 10 ?mol/L for 12 h, 24 h or 36 h, the survival rates of cells with pEGFP-C1 or wild-type cells were 46.7% or 46.7% (12 h), 25% or 22% (24 h), 10% or 11% (36 h) respectively. When the cells were treated with lead nitrate at the concentration of 25 ?mol/L, the survival rates of cells with pEGFP-C1 or wild-type cells were 45.5% or 30% (12 h), 16.7% or 25% (24 h), 6.5% or 8% (36 h), respectively. CiGRP78 provided a distinct protection in CIK cells at the low concentration for 24 h. The survival rates of CIK cells with pEGFP-C1/CiGRP78 treated with lead nitrate at concentration of 10 ?mol/L or 25 ?mol/L were 65.9% or 58.8% respectively. When the cells were treated with lead nitrate at concentration of 50 ?mol/L for 24 h, the survival rate of the CIK cells was only about 30%. If the process-time was extended to 36 h, CiGRP78 could not provide any cytoplasm protection for CIK cells. PMID:23274159

Zhu, Yujiao; Fan, Qidi; Mao, Huiling; Liu, Yong; Hu, Chengyu

2013-02-01

273

Improving Metallic Thermal Protection System Hypervelocity Impact Resistance Through Design of Experiments Approach  

NASA Technical Reports Server (NTRS)

A design of experiments approach has been implemented using computational hypervelocity impact simulations to determine the most effective place to add mass to an existing metallic Thermal Protection System (TPS) to improve hypervelocity impact protection. Simulations were performed using axisymmetric models in CTH, a shock-physics code developed by Sandia National Laboratories, and validated by comparison with existing test data. The axisymmetric models were then used in a statistical sensitivity analysis to determine the influence of five design parameters on degree of hypervelocity particle dispersion. Several damage metrics were identified and evaluated. Damage metrics related to the extent of substructure damage were seen to produce misleading results, however damage metrics related to the degree of dispersion of the hypervelocity particle produced results that corresponded to physical intuition. Based on analysis of variance results it was concluded that the most effective way to increase hypervelocity impact resistance is to increase the thickness of the outer foil layer. Increasing the spacing between the outer surface and the substructure is also very effective at increasing dispersion.

Poteet, Carl C.; Blosser, Max L.

2001-01-01

274

CHAP III- CHARRING ABLATOR PROGRAM FOR ADVANCED INVESTIGATION OF THERMAL PROTECTION SYSTEMS FOR ENTRY  

NASA Technical Reports Server (NTRS)

The transient response of a thermal protection material to heat applied to the surface can be calculated using the CHAP III computer program. CHAP III can be used to analyze pyrolysis gas chemical kinetics in detail and examine pyrolysis reactions-indepth. The analysis includes the deposition of solid products produced by chemical reactions in the gas phase. CHAP III uses a modelling technique which can approximate a wide range of ablation problems. The energy equation used in CHAP III incorporates pyrolysis (both solid and gas reactions), convection, conduction, storage, work, kinetic energy, and viscous dissipation. The chemically reacting components of the solid are allowed to vary as a function of position and time. CHAP III employs a finite difference method to approximate the energy equations. Input values include specific heat, thermal conductivity, thermocouple locations, enthalpy, heating rates, and a description of the chemical reactions expected. The output tabulates the temperature at locations throughout the ablator, gas flow within the solid, density of the solid, weight of pyrolysis gases, and rate of carbon deposition. A sample case is included, which analyzes an ablator material containing several pyrolysis reactions subjected to an environment typical of entry at lunar return velocity. CHAP III is written in FORTRAN IV for batch execution and has been implemented on a CDC CYBER 170 series computer operating under NOS with a central memory requirement of approximately 102K (octal) of 60 bit words. This program was developed in 1985.

Stroud, C. W.

1994-01-01

275

Increasing refiner production by using motor thermal capacity for protection and control  

SciTech Connect

Industrial motors are typically controlled and operated by closely monitoring the stator winding temperatures and limiting the phase currents within the motor manufacturer`s full-load ampacity rating. A different approach to motor operation and control was implemented at the Blue Ridge Lumber medium density fiberboard (MDF) plant at Whitecourt, Alta., Canada. The capacity control of the refiner is based on using the remaining thermal capacity of the motor as the primary control parameter. In this installation, a 4,000-hp totally enclosed water air cooled (TEWAC) squirrel-cage induction motor is continuously operating above the manufacturer`s rated full-load current, but is being controlled by maintaining thermal capacity at 50%. Temporary current loadings well above this are permitted for up to several minutes to accommodate variations in the wood feed stock to the refiner. This was implemented by installing a modern motor protection relay, communication with a programmable logic controller (PLC) system, and the development of operator interface displays to provide plant operators with the necessary information to monitor the motor parameters. Factors which needed to be considered were the electrical power system limitations, the motor cooling effectiveness, and mechanical limitations imposed by the refiner shaft design.

Grainger, L.G. [Grainger Electrical Research Ltd., Edmonton, Alberta (Canada)] [Grainger Electrical Research Ltd., Edmonton, Alberta (Canada); McDonald, M.C. [Alberta Energy Co., Calgary, Alberta (Canada)] [Alberta Energy Co., Calgary, Alberta (Canada)

1997-05-01

276

Parametric Weight Comparison of Current and Proposed Thermal Protection System (TPS) Concepts  

NASA Technical Reports Server (NTRS)

A parametric weight assessment of advanced metallic panel, ceramic blanket, and ceramic tile thermal protection systems (TPS) was conducted using an implicit, one-dimensional (1 -D) thermal finite element sizing code. This sizing code contained models to ac- count for coatings, fasteners, adhesives, and strain isolation pads. Atmospheric entry heating profiles for two vehicles, the Access to Space (ATS) rocket-powered single-stage-to-orbit (SSTO) vehicle and a proposed Reusable Launch Vehicle (RLV), were used to ensure that the trends were not unique to a particular trajectory. Eight TPS concepts were compared for a range of applied heat loads and substructural heat capacities to identify general trends. This study found the blanket TPS concepts have the lightest weights over the majority of their applicable ranges, and current technology ceramic tiles and metallic TPS concepts have similar weights. A proposed, state-of-the-art metallic system which uses a higher temperature alloy and efficient multilayer insulation was predicted to be significantly lighter than the ceramic tile systems and approaches blanket TPS weights for higher integrated heat loads.

Myers, David E.; Martin, Carl J.; Blosser, Max L.

1999-01-01

277

Monitoring of Thermal Protection Systems and MMOD using Robust Self-Organizing Optical Fiber Sensing Networks  

NASA Technical Reports Server (NTRS)

The general aim of this work is to develop and demonstrate a prototype structural health monitoring system for thermal protection systems that incorporates piezoelectric acoustic emission (AE) sensors to detect the occurrence and location of damaging impacts, such as those from Micrometeoroid Orbital Debris (MMOD). The approach uses an optical fiber Bragg grating (FBG) sensor network to evaluate the effect of detected damage on the thermal conductivity of the TPS material. Following detection of an impact, the TPS would be exposed to a heat source, possibly the sun, and the temperature distribution on the inner surface in the vicinity of the impact measured by the FBG network. A similar procedure could also be carried out as a screening test immediately prior to re-entry. The implications of any detected anomalies in the measured temperature distribution will be evaluated for their significance in relation to the performance of the TPS during reentry. Such a robust TPS health monitoring system would ensure overall crew safety throughout the mission, especially during reentry.

Richards, Lance

2014-01-01

278

Final analysis and design of a thermal protection system for 8-foot HTST combustor  

NASA Technical Reports Server (NTRS)

The cylindrical shell combustor with T-bar supports in the 8-foot HTST at the NASA-Langley Research Center encountered vibratory fatigue cracking over a period of 50-250 tunnel tests within a limited range of the required operating envelope. A preliminary design study provided several suitable thermal protection system designs for the combustor, one of which was a two-pass regenerative type air-cooled omega-shaped segment liner. A final design layout of the omega segment liner was prepared and analyzed for steady-state and transient conditions. The design of a support system for the fuel spray bar assembly was also included. Detail drawings suitable for fabrication purposes were also prepared. Liner design problems defined during the preliminary study included (1) the ingress of gas into the attachment bulb section of the omega segment, (2) the large thermal gradient along the leg of the omega bulb attachment section and, (3) the local peak metal temperature at the radius between the liner ID and the leg of the bulb attachment. These were resolved during the final design task. Analyses of the final design of the omega segment liner indicated that all design goals were met and the design provided the capability of operating over the required test envelope with a life expectancy substantially above the goal of 1500 cycles.

Moskowitz, S.

1973-01-01

279

Design of an integral thermal protection system for future space vehicles  

NASA Astrophysics Data System (ADS)

Thermal protection systems (TPS) are the features incorporated into a spacecraft's design to protect it from severe aerodynamic heating during high-speed travel through planetary atmospheres. The ablative TPS on the space capsule Apollo and ceramic tiles and blankets on the Space Shuttle Orbiter were designed as add-ons to the main load-bearing structure of the vehicles. They are usually incompatible with the structure due to mismatch in coefficient of thermal expansion and as a result the robustness of the external surface of the spacecraft is compromised. This could potentially lead to catastrophic consequences because the TPS forms the external surface of the vehicle and is subjected to numerous other loads like aerodynamic pressure loads, small object high-speed impacts and handling damages during maintenance. In order to make the spacecraft external surface robust, an Integral Thermal Protection System (ITPS) concept has been proposed in this research in which the load-bearing structure and the TPS are combined into one single structure. The design of an ITPS is a formidable task because the requirement of a load-bearing structure and a TPS are often contradictory to one another. The design process has been formulated as an optimization problem with mass per unit area of the ITPS as the objective function and the various functions of the ITPS were formulated as constraints. This is a multidisciplinary design optimization problem involving heat transfer and structural analysis fields. The constraints were expressed as response surface approximations obtained from a large number of finite element analyses, which were carried out with combinations of design variables obtained from an optimized Latin-Hypercube sampling scheme. A MATLABRTM code has been developed to carry out these FE analyses automatically in conjunction with ABAQUSRTM . Corrugated-core structures were designed for ITPS applications with loads and boundary conditions similar to that of a Space Shuttle-like vehicle. Temperature, buckling, deflection and stress constraints were considered for the design process. An optimized mass ranging between 3.5--5 lb/ft2 was achieved by the design. This is considerably heavier when compared to conventional TPS designs. However, the ITPS can withstand substantially large mechanical loads when compared to the conventional TPS. Truss-core geometries used for ITPS design in this research were found to be unsuitable as they could not withstand large thermal gradients frequently encountered in ITPS applications. The corrugated-core design was used for further studying the influence of the various input parameters on the final design weight of the ITPS. It was observed that boundary conditions not only significantly influence the ITPS design but also have a major impact on the effect of various input parameters. It was found that even a small amount of heat loss from bottom face sheet leads to significant reduction in ITPS weight. Aluminum and Beryllium are the most suitable materials for bottom face sheet with Beryllium having considerable advantages in terms of heat capacity, stiffness and density. Although ceramic matrix composites have many superior properties when compared to metal alloys (Titanium alloys and Inconel), their low tensile strength presents difficulties in ITPS applications.

Bapanapalli, Satish Kumar

280

Aerothermal and structural performance of a cobalt-base superalloy thermal protection system at Mach 6.6  

NASA Technical Reports Server (NTRS)

A flightweight, metallic thermal protection system (TPS) applicable to reentry and hypersonic vehicles was subjected to multiple cycles of both radiant and aerothermal heating in order to evaluate its aerothermal performance and structural integrity. Good structural integrity and thermal performance were demonstrated by the TPS under both a radiant and aerothermal heating environment typical of a shuttle entry. The shingle-slip joints effectively allowed for thermal expansion of the panel without allowing any appreciable hot gas flow into the TPS cavity. The TPS also demonstrated good structural ruggedness.

Sawyer, J. W.

1977-01-01

281

Thermomechanical response of metal foam sandwich panels for structural thermal protection systems in hypersonic vehicles  

NASA Astrophysics Data System (ADS)

Sandwich panels with metal foam cores are proposed for load-bearing structural components in actively cooled thermal protection systems for aerospace vehicles. Prototype acreage metal foam sandwich panels (MFSP's) are constructed and analyzed with the central goal of characterizing the thermomechanical response of the system. MFSP's are subjected to uniform temperature fields and equibiaxial loading in a novel experimental load frame. The load frame exploits the mismatch of coefficients of thermal expansion and allows for thermostructural experimentation without the endemic conflict of thermal and mechanical boundary conditions. Back-to-back strain gages and distributed thermocouples capture the in-plane response of the panels, including buckling and elastic-plastic post-buckling. The out-of-plane response is captured via moire interferometry, which provides a visualization of evolving mode shapes throughout the post-buckling regime. The experimental results agree with an analytical prediction for critical temperatures in sandwich panels based on a Rayleigh-Ritz minimization of the energy functional for a Reissner-Mindlin plate. In addition, a three-dimensional finite element model of the non-linear thermomechanical response of the panel-frame experimental system is developed and the results are shown to agree well with the experimentally identified response of MFSP's. Central to analytical and numerical characterization of MFSP's is an understanding of the response of metal foam under shear loading. The shear response of metal foam is captured experimentally, providing density-dependent relationships for material stiffness, strength, and energy absorption. Speckle photography is employed to identify microstructural size effects in the distribution of strain throughout metal foam under shear loading. In addition, a micromechanical model is established for the density-dependent shear modulus of metal foam, which allows for the coupling of cell-level imperfections with unit cell response. Through experiments, MFSP's are subjected to dynamic through-the-thickness thermal gradients, constrained deformation, and active cooling. In capturing the response of the cooled and uncooled panels, control and actuation of thermostructural deformation in actively cooled MFSP's is demonstrated. The finite element model of the panel-frame system is extended to the actively cooled experiments and is shown to agree well with the experimental results.

Rakow, Joseph F.

282

Thermal Protection System Cavity Heating for Simplified and Actual Geometries Using Computational Fluid Dynamics Simulations with Unstructured Grids  

NASA Technical Reports Server (NTRS)

Thermal Protection System (TPS) Cavity Heating is predicted using Computational Fluid Dynamics (CFD) on unstructured grids for both simplified cavities and actual cavity geometries. Validation was performed using comparisons to wind tunnel experimental results and CFD predictions using structured grids. Full-scale predictions were made for simplified and actual geometry configurations on the Space Shuttle Orbiter in a mission support timeframe.

McCloud, Peter L.

2010-01-01

283

Results of tests of Insta-Foam Thermal Protection System (TPS) material for protection of equipment inside the SRB aft skirt  

NASA Technical Reports Server (NTRS)

The objective of these tests was to determine whether Insta-Foam can be used successfully to protect items inside the solid rocket booster aft skirt during reentry. On some of the early Space Shuttle flights the aft skirt heat shield curtain failed during reentry. This allowed the hot gases to damage some of the equipment, etc., inside the skirt. For example, some of the propellant lines were overheated and ruptured and some of the NSI (nozzle severance) cables were damaged. It was suggested that the Insta-Foam thermal protection system be sprayed over these lines, etc., to protect them during future flights in case of a curtain failure. The tests presented were devised and run to check out the feasibility of this idea.

Dean, W. G.

1982-01-01

284

Coating Layer and Corrosion Protection Characteristics in Sea Water with Various Thermal Spray Coating Materials for STS304  

NASA Astrophysics Data System (ADS)

We investigated the optimal method of application and the anticorrosive abilities of Zn, Al, and Zn + 15%Al spray coatings in protecting stainless steel 304 (STS304) in sea water. If a defect such as porosity or an oxide layer, causes STS304 to be exposed to sea water, and the thermal spray coating material will act as the cathode and anode, respectively. The Tafel experiments revealed that Al-coated specimens among applied coating methods had the lowest corrosion current densities. As the corrosion potential decreases with increasing corrosion current density, we estimated the characteristics and lifetime of the protective thermal spray coating layer in the galvanic cell formed by the thermal spray coating layer and STS304.

Kim, Seong-Jong; Woo, Yong-Bin

285

Study on corrosion protection of organic coatings using electrochemical techniques: Thermal property characterization, film thickness investigation, and coating performance evaluation  

NASA Astrophysics Data System (ADS)

As an initial effort to establish a rapid, accurate, and comprehensive testing protocol for performance evaluation and lifetime prediction of corrosion protective coatings, the effects of coating thermal characteristics, coating application parameters, and coating formulation variations on corrosion protection have been explored. The study has been accomplished primarily through modern electrochemical techniques, such as Electrochemical Noise Methods (ENM) and Electrochemical Impedance Spectroscopy (EIS), with the aid of traditional thermal analysis, surface characterization, and appearance inspection. The employed electrochemical techniques have exhibited usefulness as powerful testing tools that have provided valuable results in good agreement with field observations and other measures by traditional methods. Thermal property characterization on fusion bonded epoxy (FBE) pipeline coatings has shown that coating electrical resistances decreased as temperature rose with a distinct thermal transition point corresponding to glass transition temperature (Tg) of the immersed coatings. The change in coating capacitance with temperature revealed the irreversible process of water ingress and the effects of electrolyte plasticization in the coating films. Film thickness investigation on marine coating systems has demonstrated that film thickness has significant influences on coating corrosion protection. Better performance is expected for a coating system with thicker film thickness as well as with more coating layers when applied at a constant film thickness. The results indicate that there was a possible critical minimum film thickness above which coating protective performance was greatly enhanced and that there was also a maximum limiting film thickness above which increasing film thickness made little contribution to corrosion protection. Coating performance evaluation on aircraft coating systems has offered accurate performance ranking and reasonable lifetime prediction for high-quality, anticorrosive coatings. The mechanisms of corrosion protection by several coating systems with various types of polymers and pigment volume concentrations (PVC) have been discovered. Future work will consider a broader selection of materials, different test conditions, and a greater variety of characterization techniques. More sophisticated data analysis methods also need to be developed.

Li, Junping

2002-08-01

286

Comparative Thermal Requirements of Westslope Cutthroat Trout and Rainbow Trout: Implications for Species Interactions and Development of Thermal Protection Standards  

Microsoft Academic Search

Water temperature appears to play a key role in determining population persistence of westslope cutthroat trout Oncorhynchus clarkii lewisi, but specific thermal performance and survival criteria have not been defined. We used the acclimated chronic exposure laboratory method to determine upper thermal tolerances and growth optima of westslope cutthroat trout and rainbow trout O. mykiss, a potential nonnative competitor that

Elizabeth A. Bear; Thomas E. McMahon; Alexander V. Zale

2007-01-01

287

Thermal Aggregation of Recombinant Protective Antigen: Aggregate Morphology and Growth Rate  

PubMed Central

The thermal aggregation of the biopharmaceutical protein recombinant protective antigen (rPA) has been explored, and the associated kinetics and thermodynamic parameters have been extracted using optical and environmental scanning electron microscopies (ESEMs) and ultraviolet light scattering spectroscopy (UV-LSS). Visual observations and turbidity measurements provided an overall picture of the aggregation process, suggesting a two-step mechanism. Microscopy was used to examine the structure of aggregates, revealing an open morphology formed by the clustering of the microscopic aggregate particles. UV-LSS was used and developed to elucidate the growth rate of these particles, which formed in the first stage of the aggregation process. Their growth rate is observed to be high initially, before falling to converge on a final size that correlates with the ESEM data. The results suggest that the particle growth rate is limited by rPA monomer concentration, and by obtaining data over a range of incubation temperatures, an approach was developed to model the aggregation kinetics and extract the rate constants and the temperature dependence of aggregation. In doing so, we quantified the susceptibility of rPA aggregation under different temperature and environmental conditions and moreover demonstrated a novel use of UV spectrometry to monitor the particle aggregation quantitatively, in situ, in a nondestructive and time-resolved manner. PMID:23476645

Belton, Daniel J.; Miller, Aline F.

2013-01-01

288

Optimization of thermal protection systems for the space shuttle vehicle. Volume 1: Final report  

NASA Technical Reports Server (NTRS)

A study performed to continue development of computational techniques for the Space Shuttle Thermal Protection System is reported. The resulting computer code was used to perform some additional optimization studies on several TPS configurations. The program was developed in Fortran 4 for the CDC 6400, and it was converted to Fortran 5 to be used for the Univac 1108. The computational methodology is developed in modular fashion to facilitate changes and updating of the techniques and to allow overlaying the computer code to fit into approximately 131,000 octal words of core storage. The program logic involves subroutines which handle input and output of information between computer and user, thermodynamic stress, dynamic, and weight/estimate analyses of a variety of panel configurations. These include metallic, ablative, RSI (with and without an underlying phase change material), and a thermodynamic analysis only of carbon-carbon systems applied to the leading edge and flat cover panels. Two different thermodynamic analyses are used. The first is a two-dimensional, explicit precedure with variable time steps which is used to describe the behavior of metallic and carbon-carbon leading edges. The second is a one-dimensional implicity technique used to predict temperature in the charring ablator and the noncharring RSI. The latter analysis is performed simply by suppressing the chemical reactions and pyrolysis of the TPS material.

1972-01-01

289

Parametric Weight Comparison of Advanced Metallic, Ceramic Tile, and Ceramic Blanket Thermal Protection Systems  

NASA Technical Reports Server (NTRS)

A parametric weight assessment of advanced metallic panel, ceramic blanket, and ceramic tile thermal protection systems (TPS) was conducted using an implicit, one-dimensional (I-D) finite element sizing code. This sizing code contained models to account for coatings fasteners, adhesives, and strain isolation pads. Atmospheric entry heating profiles for two vehicles, the Access to Space (ATS) vehicle and a proposed Reusable Launch Vehicle (RLV), were used to ensure that the trends were not unique to a certain trajectory. Ten TPS concepts were compared for a range of applied heat loads and substructural heat capacities to identify general trends. This study found the blanket TPS concepts have the lightest weights over the majority of their applicable ranges, and current technology ceramic tiles and metallic TPS concepts have similar weights. A proposed, state-of-the-art metallic system which uses a higher temperature alloy and efficient multilayer insulation was predicted to be significantly lighter than the ceramic tile stems and approaches blanket TPS weights for higher integrated heat loads.

Myers, David E.; Martin, Carl J.; Blosser, Max L.

2000-01-01

290

In-flight load testing of advanced shuttle thermal protection systems  

NASA Technical Reports Server (NTRS)

NASA Ames Research Center has conducted in-flight airload testing of some advanced thermal protection systems (TPS) at the Dryden Flight Research Center. The two flexible TPS materials tested, felt reusable surface insulation (FRSI) and advanced flexible reusable surface insulation (AFRSI), are currently certified for use on the Shuttle orbiter. The objectives of the flight tests were to evaluate the performance of FRSI and AFRSI at simulated launch airloads and to provide a data base for future advanced TPS flight tests. Five TPS configurations were evaluated in a flow field which was representative of relatively flat areas without secondary flows. The TPS materials were placed on a fin, the Flight Test fixture (FTF), that is attached to the underside of the fuselage of an F-104 aircraft. This paper describes the test approach and techniques used and presents the results of the advanced TPS flight test. There were no failures noted during post-flight inspections of the TPS materials which were exposed to airloads 40 percent higher than the design launch airloads.

Trujillo, B. M.; Meyer, R., Jr.; Sawko, P. M.

1983-01-01

291

Metallic Thermal Protection System Technology Development: Concepts, Requirements and Assessment Overview  

NASA Technical Reports Server (NTRS)

A technology development program was conducted to evolve an earlier metallic thermal protection system (TPS) panel design, with the goals of: improving operations features, increasing adaptability (ease of attaching to a variety of tank shapes and structural concepts), and reducing weight. The resulting Adaptable Robust Metallic Operable Reusable (ARMOR) TPS system incorporates a high degree of design flexibility (allowing weight and operability to be traded and balanced) and can also be easily integrated with a large variety of tank shapes, airframe structural arrangements and airframe structure/material concepts. An initial attempt has been made to establish a set of performance based TPS design requirements. A set of general (FARtype) requirements have been proposed, focusing on defining categories that must be included for a comprehensive design. Load cases required for TPS design must reflect the full flight envelope, including a comprehensive set of limit loads, However, including additional loads. such as ascent abort trajectories, as ultimate load cases, and on-orbit debris/micro-meteoroid hypervelocity impact, as one of the discrete -source -damage load cases, will have a significant impact on system design and resulting performance, reliability and operability. Although these load cases have not been established, they are of paramount importance for reusable vehicles, and until properly included, all sizing results and assessments of reliability and operability must be considered optimistic at a minimum.

Dorsey, John T.; Poteet, Carl C.; Chen, Roger R.; Wurster, Kathryn E.

2002-01-01

292

Silicate-Based Thermal Spray Coatings for Environmental Protection of Silicon Carbide  

NASA Astrophysics Data System (ADS)

Environmental barrier coatings are a key technology for implementing ceramics in high-temperature, high-moisture environments. One such ceramic, silicon carbide, is a material that can be used in gas turbines. However, silicon carbide oxidizes into silicon dioxide with exposure to oxygen, carbon dioxide, and water vapor and would normally provide protection for the silicon carbide. However, silicon dioxide volatilizes in a gas turbine environment, which leads to the degradation of its mechanical properties, making it unfit for use in a gas turbine. Materials like yttria-monosilicate and barium-strontium doped aluminosilicate (BSAS) both have good environmental coating properties. However, sintered yttria-monosilicate does not bond well to silicon carbide, and thermally sprayed BSAS transforms very slowly from a metastable hexacelsian phase to the desired celsian phase that is necessary for it to bond well to silicon carbide. Coatings of these materials have been produced by plasma spray with some additional work using HVOF. Phase identification has been done by x-ray diffraction, and microstructural analysis has been done using scanning electron microscopy.

Sagiv, Ari Isaac

293

Flutter Analysis of the Thermal Protection Layer on the NASA HIAD  

NASA Technical Reports Server (NTRS)

A combination of classical plate theory and a supersonic aerodynamic model is used to study the aeroelastic flutter behavior of a proposed thermal protection system (TPS) for the NASA HIAD. The analysis pertains to the rectangular configurations currently being tested in a NASA wind-tunnel facility, and may explain why oscillations of the articles could be observed. An analysis using a linear flat plate model indicated that flutter was possible well within the supersonic flow regime of the wind tunnel tests. A more complex nonlinear analysis of the TPS, taking into account any material curvature present due to the restraint system or substructure, indicated that significantly greater aerodynamic forcing is required for the onset of flutter. Chaotic and periodic limit cycle oscillations (LCOs) of the TPS are possible depending on how the curvature is imposed. When the pressure from the base substructure on the bottom of the TPS is used as the source of curvature, the flutter boundary increases rapidly and chaotic behavior is eliminated.

Goldman, Benjamin D.; Dowell, Earl H.; Scott, Robert C.

2013-01-01

294

Investigation of Post-Flight Solid Rocket Booster Thermal Protection System  

NASA Technical Reports Server (NTRS)

After every Shuttle mission, the Solid Rocket Boosters (SRBs) are recovered and observed for missing material. Most of the SRB is covered with a cork-based thermal protection material (MCC-l). After the most recent shuttle mission, STS-114, the forward section of the booster appeared to have been impacted during flight. The darkened fracture surfaces indicated that this might have occurred early in flight. The scope of the analysis included microscopic observations to assess the degree of heat effects and locate evidence of the impact source as well as chemical analysis of the fracture surfaces and recovered foreign material using Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy/Energy Dispersive Spectroscopy. The amount of heat effects and presence of soot products on the fracture surface indicated that the material was impacted prior to SRB re-entry into the atmosphere. Fragments of graphite fibers found on these fracture surfaces were traced to slag inside the Solid Rocket Motor (SRM) that forms during flight as the propellant is spent and is ejected throughout the descent of the SRB after separation. The direction of the impact mark matches with the likely trajectory of SRBs tumbling prior to re-entry.

Nelson, Linda A.

2006-01-01

295

Methodology for Flight Relevant Arc-Jet Testing of Flexible Thermal Protection Systems  

NASA Technical Reports Server (NTRS)

A methodology to correlate flight aeroheating environments to the arc-jet environment is presented. For a desired hot-wall flight heating rate, the methodology provides the arcjet bulk enthalpy for the corresponding cold-wall heating rate. A series of analyses were conducted to examine the effects of the test sample model holder geometry to the overall performance of the test sample. The analyses were compared with arc-jet test samples and challenges and issues are presented. The transient flight environment was calculated for the Hypersonic Inflatable Aerodynamic Decelerator (HIAD) Earth Atmospheric Reentry Test (HEART) vehicle, which is a planned demonstration vehicle using a large inflatable, flexible thermal protection system to reenter the Earth's atmosphere from the International Space Station. A series of correlations were developed to define the relevant arc-jet test environment to properly approximate the HEART flight environment. The computed arcjet environments were compared with the measured arc-jet values to define the uncertainty of the correlated environment. The results show that for a given flight surface heat flux and a fully-catalytic TPS, the flight relevant arc-jet heat flux increases with the arc-jet bulk enthalpy while for a non-catalytic TPS the arc-jet heat flux decreases with the bulk enthalpy.

Mazaheri, Alireza; Bruce, Walter E., III; Mesick, Nathaniel J.; Sutton, Kenneth

2013-01-01

296

A Collaborative Analysis Tool for Thermal Protection Systems for Single Stage to Orbit Launch Vehicles  

NASA Technical Reports Server (NTRS)

Presented is a design tool and process that connects several disciplines which are needed in the complex and integrated design of high performance reusable single stage to orbit (SSTO) vehicles. Every system is linked to every other system and in the case of SSTO vehicles with air breathing propulsion, which is currently being studied by the National Aeronautics and Space Administration (NASA); the thermal protection system (TPS) is linked directly to almost every major system. The propulsion system pushes the vehicle to velocities on the order of 15 times the speed of sound in the atmosphere before pulling up to go to orbit which results high temperatures on the external surfaces of the vehicle. Thermal protection systems to maintain the structural integrity of the vehicle must be able to mitigate the heat transfer to the structure and be lightweight. Herein lies the interdependency, in that as the vehicle's speed increases, the TPS requirements are increased. And as TPS masses increase the effect on the propulsion system and all other systems is compounded. To adequately determine insulation masses for a vehicle such as the one described above, the aeroheating loads must be calculated and the TPS thicknesses must be calculated for the entire vehicle. To accomplish this an ascent or reentry trajectory is obtained using the computer code Program to Optimize Simulated Trajectories (POST). The trajectory is then used to calculate the convective heat rates on several locations on the vehicles using the Miniature Version of the JA70 Aerodynamic Heating Computer Program (MINIVER). Once the heat rates are defined for each body point on the vehicle, then insulation thicknesses that are required to maintain the vehicle within structural limits are calculated using Systems Improved Numerical Differencing Analyzer (SINDA) models. If the TPS masses are too heavy for the performance of the vehicle the process may be repeated altering the trajectory or some other input to reduce the TPS mass. The problem described is an example of the need for collaborative design and analysis. Analysis tools are being developed to facilitate these collaborative efforts. RECIPE is a cross-platform application capable of hosting a number of engineers and designers across the Internet for distributed and collaborative engineering environments. Such integrated system design environments allow for collaborative team design analysis for performing individual or reduced team studies. The analysis tools mentioned earlier are commonly run on different platforms and are usually run by different people. To facilitate the larger number of potential runs that may need to be made, RECIPE connects the computer codes that calculate the trajectory data, heat rate data, and TPS masses so that the output from each tool is easily transferred to the model input files that need it. This methodology is being applied to solve launch vehicle thermal design problems to shorten the design cycle, and enable the project team to evaluate design options. Results will be presented indicating the effectiveness of this as a collaborative design tool.

Alexander, Reginald A.; Stanley, Thomas Troy

1999-01-01

297

High-Temperature Structures, Adhesives, and Advanced Thermal Protection Materials for Next-Generation Aeroshell Design  

NASA Technical Reports Server (NTRS)

The next generation of planetary exploration vehicles will rely heavily on robust aero-assist technologies, especially those that include aerocapture. This paper provides an overview of an ongoing development program, led by NASA Langley Research Center (LaRC) and aimed at introducing high-temperature structures, adhesives, and advanced thermal protection system (TPS) materials into the aeroshell design process. The purpose of this work is to demonstrate TPS materials that can withstand the higher heating rates of NASA's next generation planetary missions, and to validate high-temperature structures and adhesives that can reduce required TPS thickness and total aeroshell mass, thus allowing for larger science payloads. The effort described consists of parallel work in several advanced aeroshell technology areas. The areas of work include high-temperature adhesives, high-temperature composite materials, advanced ablator (TPS) materials, sub-scale demonstration test articles, and aeroshell modeling and analysis. The status of screening test results for a broad selection of available higher-temperature adhesives is presented. It appears that at least one (and perhaps a few) adhesives have working temperatures ranging from 315-400 C (600-750 F), and are suitable for TPS-to-structure bondline temperatures that are significantly above the traditional allowable of 250 C (482 F). The status of mechanical testing of advanced high-temperature composite materials is also summarized. To date, these tests indicate the potential for good material performance at temperatures of at least 600 F. Application of these materials and adhesives to aeroshell systems that incorporate advanced TPS materials may reduce aeroshell TPS mass by 15% - 30%. A brief outline is given of work scheduled for completion in 2006 that will include fabrication and testing of large panels and subscale aeroshell test articles at the Solar-Tower Test Facility located at Kirtland AFB and operated by Sandia National Laboratories. These tests are designed to validate aeroshell manufacturability using advanced material systems, and to demonstrate the maintenance of bondline integrity at realistically high temperatures and heating rates. Finally, a status is given of ongoing aeroshell modeling and analysis efforts which will be used to correlate with experimental testing, and to provide a reliable means of extrapolating to performance under actual flight conditions. The modeling and analysis effort includes a parallel series of experimental tests to determine TSP thermal expansion and other mechanical properties which are required for input to the analysis models.

Collins, Timothy J.; Congdon, William M.; Smeltzer, Stanley S.; Whitley, Karen S.

2005-01-01

298

75 FR 10410 - Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events...  

Federal Register 2010, 2011, 2012, 2013

...NRC-2007-0008] RIN 3150-AI01 Alternate Fracture Toughness Requirements for Protection...NRC's regulations to provide alternate fracture toughness requirements for protection...as follows: Sec. 50.61a Alternate fracture toughness requirements for...

2010-03-08

299

PESTICIDE SPRAY PENETRATION AND THERMAL COMFORT OF PROTECTIVE APPAREL FOR PESTICIDE APPLICATORS  

EPA Science Inventory

The use of protective apparel to serve as a barrier from dermal exposure is considered vital for providing some measure of protection for those who work with and around pesticides. his research is aimed at ultimately providing recommendations for types of protective apparel for p...

300

Remote Sensing of Thermal Radiation from an Aircraft--An Analysis and Evaluation of Crop-Freeze Protection Methods.  

NASA Astrophysics Data System (ADS)

Thermal images from an aircraft-mounted scanner are used to evaluate the effectiveness of crop-freeze protection devices. Data from flights made while using fuel oil heaters, a wind machine and an undercanopy irrigation system are compared. Results show that the overall protection provided by irrigation (2°C) is comparable to the less energy-efficient heater-wind machine combination. Protection provided by the wind machine alone (1°C) was found to decrease linearly with distance from the machine by 1°C (100 m)1. The flights were made over a 1.5 hectare citrus grove at an altitude of 450 m with an 8-14 m detector. General meteorological conditions during the experiments, conducted during the nighttime, were cold ( 6°C) and calm with clear skies.

Sutherland, R. A.; Hannah, H. E.; Cook, A. F.; Martsolf, J. D.

1981-07-01

301

Today`s thermal imaging systems: Background and applications for civilian law enforcement and military force protection  

SciTech Connect

Thermal (infrared) imagers can solve many security assessment problems associated with the protection of high-value assets at military bases, secure installations, or commercial facilities. Thermal imagers can provide surveillance video from security areas or perimeters both day and night without expensive security lighting. In the past, thermal imagers required cryogenic cooling to operate. The high cost and maintenance requirements restricted their use. However, recent developments in reliable, linear drive cryogenic coolers and uncooled infrared imagers have dramatically reduced system cost. These technology developments are resulting in greater accessibility and practicality for military as well as civilian security and force protection applications. This paper discusses recent advances in thermal imaging technology including uncooled and cryo-cooled. Applications of Forward Looking InfraRed (FLIR) systems are also discussed, including integration with a high-speed pan/tilt mount and remote control, video frame storage and recall, low-cost vehicle-mounted systems, and hand-held devices. Other facility installation topics will be discussed, such as site layout, assessment ranges, imager positioning, fields-of-view, sensor and alarm reporting systems, and communications links.

Bisbee, T.L.; Pritchard, D.A.

1997-10-01

302

Heat shock protein hsp70 protects cells from thermal stress even after deletion of its ATP-binding domain.  

PubMed Central

Retroviral-mediated gene transfer experiments show that rodent cells become heat resistant when stably and constitutively expressing a cloned human gene encoding an intact human 70-kDa heat shock protein (hsp70). Cells expressing higher levels of the hsp70 protein generally tolerate thermal stress better, whereas cells expressing either of two mutated hsp70-encoding genes, one with a 4-base pair out-of-frame deletion and one with an in-frame deletion of codons 438-618, are heat sensitive. These results provide strong evidence that expression of hsp70 leads directly to thermal tolerance. Surprisingly, cells expressing a mutant hsp70 of a human gene missing codons 120-428 are, nevertheless, heat resistant. Because the deleted region of this mutant contains the ATP-binding domain of human hsp70, this domain appears dispensable in the hsp70-mediated protection of cells from thermal stress. Images PMID:1549562

Li, G C; Li, L; Liu, R Y; Rehman, M; Lee, W M

1992-01-01

303

Thermal Stress Induced Aggregation of Aquaporin 0 (AQP0) and Protection by ?-Crystallin via Its Chaperone Function  

PubMed Central

Aquaporin 0 (AQP0) formerly known as membrane intrinsic protein (MIP), is expressed exclusively in the lens during terminal differentiation of fiber cells. AQP0 plays an important role not only in the regulation of water content but also in cell-to-cell adhesion of the lens fiber cells. We have investigated the thermal stress-induced structural alterations of detergent (octyl glucoside)-solubilized calf lens AQP0. The results show an increase in the amount of AQP0 that aggregated as the temperature increased from 40°C to 65°C. ?-Crystallin, molecular chaperone abundantly present in the eye lens, completely prevented the AQP0 aggregation at a 1?1 (weight/weight) ratio. Since ?-crystallin consists of two gene products namely ?A- and ?B-crystallins, we have tested the recombinant proteins on their ability to prevent thermal-stress induced AQP0 aggregation. In contrast to the general observation made with other target proteins, ?A-crystallin exhibited better chaperone-like activity towards AQP0 compared to ?B-crystallin. Neither post-translational modifications (glycation) nor C-terminus truncation of AQP0 have any appreciable effect on its thermal aggregation properties. ?-Crystallin offers similar protection against thermal aggregation as in the case of the unmodified AQP0, suggesting that ?crystallin may bind to either intracellular loops or other residues of AQP0 that become exposed during thermal stress. Far-UV circular dichroism studies indicated a loss of ?helical structures when AQP0 was subjected to temperatures above 45°C, and the presence of ?-crystallin stabilized these secondary structures. We report here, for the first time, that ?-crystallin protects AQP0 from thermal aggregation. Since stress-induced structural perturbations of AQP0 may affect the integrity of the lens, presence of the molecular chaperone, ?-crystallin (particularly ?A-crystallin) in close proximity to the lens membrane is physiologically relevant. PMID:24312215

Swamy-Mruthinti, Satyanarayana; Srinivas, Volety; Hansen, John E.; Rao, Ch Mohan

2013-01-01

304

Thermal stress induced aggregation of aquaporin 0 (AQP0) and protection by ?-crystallin via its chaperone function.  

PubMed

Aquaporin 0 (AQP0) formerly known as membrane intrinsic protein (MIP), is expressed exclusively in the lens during terminal differentiation of fiber cells. AQP0 plays an important role not only in the regulation of water content but also in cell-to-cell adhesion of the lens fiber cells. We have investigated the thermal stress-induced structural alterations of detergent (octyl glucoside)-solubilized calf lens AQP0. The results show an increase in the amount of AQP0 that aggregated as the temperature increased from 40°C to 65°C. ?-Crystallin, molecular chaperone abundantly present in the eye lens, completely prevented the AQP0 aggregation at a 1?1 (weight/weight) ratio. Since ?-crystallin consists of two gene products namely ?A- and ?B-crystallins, we have tested the recombinant proteins on their ability to prevent thermal-stress induced AQP0 aggregation. In contrast to the general observation made with other target proteins, ?A-crystallin exhibited better chaperone-like activity towards AQP0 compared to ?B-crystallin. Neither post-translational modifications (glycation) nor C-terminus truncation of AQP0 have any appreciable effect on its thermal aggregation properties. ?-Crystallin offers similar protection against thermal aggregation as in the case of the unmodified AQP0, suggesting that ?crystallin may bind to either intracellular loops or other residues of AQP0 that become exposed during thermal stress. Far-UV circular dichroism studies indicated a loss of ?helical structures when AQP0 was subjected to temperatures above 45°C, and the presence of ?-crystallin stabilized these secondary structures. We report here, for the first time, that ?-crystallin protects AQP0 from thermal aggregation. Since stress-induced structural perturbations of AQP0 may affect the integrity of the lens, presence of the molecular chaperone, ?-crystallin (particularly ?A-crystallin) in close proximity to the lens membrane is physiologically relevant. PMID:24312215

Swamy-Mruthinti, Satyanarayana; Srinivas, Volety; Hansen, John E; Rao, Ch Mohan

2013-01-01

305

Integrated Sensing and Material Damage Identification in Metallic and Ceramic Thermal Protection Systems Using Vibration and Wave Propagation Data  

SciTech Connect

Global thermal and impact material damage mechanisms in metallic and ceramic thermal protection systems are detected, located, and quantified using four complementary methods for sensing and data interrogation. First, spatial-temporal beamforming algorithms are used to process active elastic waves measured from remote sensor arrays in two different equilibrium positions of a gamma Ti-Al sheet to localize simulated thermal damage. Damage is located even when it is behind the sensor array and on the edge of the panel; results are shown to be dependent on the equilibrium position considered. Second, an active virtual force method is implemented in a honeycomb Al-Al sandwich panel instrumented with a distributed piezo sensor and actuator array to identify impact and thermal damage using frequency response inversion. Damage is quantified and is similarly diagnosed regardless of the excitation location. Third, passive acoustic transmission measurements through a homogeneous baffled Al panel subject to launch-type sound pressure variations are used to detect and locate material damage. The frequency range with highest transmission is shown to be optimal for damage detection. Fourth, thermal damage in a wrapped ceramic tile with a mock strain isolation pad is identified using active propagating waves. Remote actuation and sensing on the bulkhead and the tile backside are shown to be sufficient for detection even when variability is present in the data.

Sundararaman, S.; White, J.; Jiang, H.; Adams, D. [Purdue University, Ray W. Herrick Laboratories, W. Lafayette, IN 47907-2031 (United States); Jata, K. [AFRL/MLL, NDE Branch, 2230 Tenth St., Wright Patterson AFB, OH, 45433 (United States)

2006-03-06

306

Fluxing of protective oxide scales on superalloys via a thermal surface tension gradient  

Microsoft Academic Search

An oxide fluxing model involving continuous dissolution and reprecipitation of oxide scales via a thermal surface tension effect is postulated to explain hot corrosion of high teperature alloys and coatings in gas turbines. It is demonstrated that due to the existence of a thermal surface tension gradient, a molten alkali salt film condensed on a turbine vane or blade can

S. K. Lau; S. C. Singhal

1983-01-01

307

Improvement of Thermal Stability of Magnetoresistive Random Access Memory Device with SiN Protective Film Deposited by High-Density Plasma Chemical Vapor Deposition  

Microsoft Academic Search

Embedded magnetoresistive random access memory (MRAM) with multi-level interconnects necessitates that magnetic tunnel junction (MTJ) devices have a thermal stability of 350 °C or higher during fabrication. We have improved thermal stability of MRAM devices using SiN protective film deposited by high-density plasma chemical vapor deposition (HDP-CVD) at 200 °C. The MTJ devices with HDP-CVD SiN protective film did not

Katsumi Suemitsu; Yuichi Kawano; Hiroaki Utsumi; Hiroaki Honjo; Ryusuke Nebashi; Shinsaku Saito; Norikazu Ohshima; Tadahiko Sugibayashi; Hiromitsu Hada; Tatsuhiko Nohisa; Tadashi Shimazu; Masahiko Inoue; Naoki Kasai

2008-01-01

308

SO2 protects the amino nitrogen metabolism of Saccharomyces cerevisiae under thermal stress  

PubMed Central

Summary Thermal stress conditions during alcoholic fermentation modify yeasts' plasma membrane since they become more hyperfluid, which results in a loss of bilayer integrity. In this study, the influence of elevated temperatures on nitrogen metabolism of a Saccharomyces cerevisiae strain was studied, as well as the effect of different concentrations of SO2 on nitrogen metabolism under thermal stress conditions. The results obtained revealed that amino nitrogen consumption was lower in the fermentation sample subjected to thermal stress than in the control, and differences in amino acid consumption preferences were also detected, especially at the beginning of the fermentation. Under thermal stress conditions, among the three doses of SO2 studied (0, 35, 70?mg?l?1 SO2), the highest dose was observed to favour amino acid utilization during the fermentative process, whereas sugar consumption presented higher rates at medium doses. PMID:22452834

Ancin-Azpilicueta, Carmen; Barriuso-Esteban, Blanca; Nieto-Rojo, Rodrigo; Aristizabal-Lopez, Nerea

2012-01-01

309

MMOD testing of C-SiC based Rigid External Insulation of the CRV Thermal Protection System  

NASA Astrophysics Data System (ADS)

is to provide protection to the vehicle during the reentry, it also has to resist Micro Meteoroids and Orbital Debris (MMOD) aggression during the required 3 years in orbit stay of the CRV. composite panels that are fixed to the metallic airframe. An innovative approach for the thermal protection is to use a Rigid External Insulation composed of a C-SiC panel, an internal light insulation, attachment system and seal directly fixed on the metallic airframe. includes firstly a preliminary TPS design based on CRV specifications, then a comparison of the proposed REI design with the current tile. impacts, generic test articles have been designed and manufactured then exposed to MMOD testing. design of the TPS, the manufacturing of the test items, MMOD testing and results.

Copéret, Hervé; Soyris, Philippe; Lacoste, Marc

2002-01-01

310

Non-thermal plasma processing for environmental protection: decomposition of dilute VOCs in air  

Microsoft Academic Search

Non-thermal plasma processing is one of the most hopeful air-cleaning technologies to remove toxic gas contaminants in air. The historical background of the non-thermal plasma related with the electrostatics is described and the fundamental experimental system including the reactor designs and their power supplies is introduced. Some experimental results suggested the high potential of the plasma processing to decompose those

T. Oda

2003-01-01

311

Development and Design Application of Rigidized Surface Insulation Thermal Protection Systems, Volume 1. [for the space shuttle  

NASA Technical Reports Server (NTRS)

Materials and design technology of the all-silica LI-900 rigid surface insulation (RSI) thermal protection system (TPS) concept for the shuttle spacecraft is presented. All results of contract development efforts are documented. Engineering design and analysis of RSI strain arrestor plate material selections, sizing, and weight studies are reported. A shuttle prototype test panel was designed, analyzed, fabricated, and delivered. Thermophysical and mechanical properties of LI-900 were experimentally established and reported. Environmental tests, including simulations of shuttle loads represented by thermal response, turbulent duct, convective cycling, and chemical tolerance tests are described and results reported. Descriptions of material test samples and panels fabricated for testing are included. Descriptions of analytical sizing and design procedures are presented in a manner formulated to allow competent engineering organizations to perform rational design studies. Results of parametric studies involving material and system variables are reported. Material performance and design data are also delineated.

1972-01-01

312

Intelligent process development of foam molding for the Thermal Protection System (TPS) of the space shuttle external tank  

NASA Technical Reports Server (NTRS)

A knowledge based system to assist process engineers in evaluating the processability and moldability of poly-isocyanurate (PIR) formulations for the thermal protection system of the Space Shuttle external tank (ET) is discussed. The Reaction Injection Molding- Process Development Advisor (RIM-PDA) is a coupled system which takes advantage of both symbolic and numeric processing techniques. This system will aid the process engineer in identifying a startup set of mold schedules and in refining the mold schedules to remedy specific process problems diagnosed by the system.

Bharwani, S. S.; Walls, J. T.; Jackson, M. E.

1987-01-01

313

A design assessment of multiwall, metallic stand-off, and RSI reusable thermal protection systems including space shuttle application  

NASA Technical Reports Server (NTRS)

The design and assessment of reusable surface insulation (RSI), metallic stand off and multiwall thermal protection systems (TPS) is discussed. Multiwall TPS is described in some detail, and analyses useful for design of multiwall are included. Results indicate that multiwall has the potential to satisfy the TPS design goals better than the other systems. The total mass of the stand-off TPS and of the metallic systems require less primary structure mass than the RSI system, since the nonbuckling skin criteria required for RSI may be removed. Continued development of multiwall TPS is required to verify its potential and to provide the necessary data base for design.

Jackson, L. R.; Dixon, S. C.

1980-01-01

314

Aerothermal performance and structural integrity of a Rene 41 thermal protection system at Mach 6.6  

NASA Technical Reports Server (NTRS)

A flightweight panel based on a metallic thermal-protection-system concept for hypersonic and reentry vehicles was subjected repeatedly to thermal cycling by quartz-lamp radiant heating using a thermal history representative of a reentry heat pulse and to aerodynamic heating at heating rates required to sustain a surface temperature of 1089 K (1960 R). The panel consisted of a corrugated heat shield and support members of 0.05-cm (0.02-in.) thick Rene 41 of riveted construction and 5.08-cm (2-in.) thick silica fibrous insulation packages covered by Rene 41 foil and inconel screening. All tests were conducted in the Langley 8-foot high-temperature structures tunnel with the heat shield corrugations alined in the stream direction. The panel sustained 5.33 hr of intermittent radiant heating and 6.5 min of intermittent aerodynamic heating of up to 1-min duration for differential pressures up to 6.2 kPa (0.9 psi) with no apparent degradation of thermal or structural integrity, as indicated by temperature distributions and results from load deflection tests and vibration surveys of natural frequencies.

Deveikis, W. D.; Miserentino, R.; Weinstein, I.; Shideler, J. L.

1975-01-01

315

Mechanisms Underpinning Degradation of Protective Oxides and Thermal Barrier Coatings in High Hydrogen Content (HHC) - Fueled Turbines  

SciTech Connect

The overarching goal of this research program has been to evaluate the potential impacts of coal-derived syngas and high-hydrogen content fuels on the degradation of turbine hot-section components through attack of protective oxides and thermal barrier coatings. The primary focus of this research program has been to explore mechanisms underpinning the observed degradation processes, and connections to the combustion environments and characteristic non-combustible constituents. Based on the mechanistic understanding of how these emerging fuel streams affect materials degradation, the ultimate goal of the program is to advance the goals of the Advanced Turbine Program by developing materials design protocols leading to turbine hot-section components with improved resistance to service lifetime degradation under advanced fuels exposures. This research program has been focused on studying how: (1) differing combustion environments – relative to traditional natural gas fired systems – affect both the growth rate of thermally grown oxide (TGO) layers and the stability of these oxides and of protective thermal barrier coatings (TBCs); and (2) how low levels of fuel impurities and characteristic non-combustibles interact with surface oxides, for instance through the development of molten deposits that lead to hot corrosion of protective TBC coatings. The overall program has been comprised of six inter-related themes, each comprising a research thrust over the program period, including: (i) evaluating the role of syngas and high hydrogen content (HHC) combustion environments in modifying component surface temperatures, heat transfer to the TBC coatings, and thermal gradients within these coatings; (ii) understanding the instability of TBC coatings in the syngas and high hydrogen environment with regards to decomposition, phase changes and sintering; (iii) characterizing ash deposition, molten phase development and infiltration, and associated corrosive/thermo-chemical attack mechanisms; (iv) developing a mechanics-based analysis of the driving forces for crack growth and delamination, based on molten phase infiltration, misfit upon cooling, and loss of compliance; (v) understanding changes in TGO growth mechanisms associated with these emerging combustion product streams; and (vi) identifying degradation resistant alternative materials (including new compositions or bi-layer concepts) for use in mitigating the observed degradation modes. To address the materials stability concerns, this program integrated research thrusts aimed at: (1) Conducting tests in simulated syngas and HHC environments to evaluate materials evolution and degradation mechanisms; assessing thermally grown oxide development unique to HHC environmental exposures; carrying out high-resolution imaging and microanalysis to elucidate the evolution of surface deposits (molten phase formation and infiltration); exploring thermo-chemical instabilities; assessing thermo-mechanical drivers and thermal gradient effects on degradation; and quantitatively measuring stress evolution due to enhanced sintering and thermo-chemical instabilities induced in the coating. (2) Executing experiments to study the melting and infiltration of simulated ash deposits, and identifying reaction products and evolving phases associated with molten phase corrosion mechanisms; utilizing thermal spray techniques to fabricate test coupons with controlled microstructures to study mechanisms of instability and degradation; facilitating thermal gradient testing; and developing new materials systems for laboratory testing; (3) Correlating information on the resulting combustion environments to properly assess materials exposure conditions and guide the development of lab-scale simulations of material exposures; specification of representative syngas and high-hydrogen fuels with realistic levels of impurities and contaminants, to explore differences in heat transfer, surface degradation, and deposit formation; and facilitating combustion rig testing of materials test coupons.

Mumm, Daniel

2013-08-31

316

Development and evaluation of an ablative closeout material for solid rocket booster thermal protection system  

NASA Technical Reports Server (NTRS)

A trowellable closeout/repair material designated as MTA-2 was developed and evaluated for use on the Solid Rocket Booster. This material is composed of an epoxy-polysulfide binder and is highly filled with phenolic microballoons for density control and ablative performance. Mechanical property testing and thermal testing were performed in a wind tunnel to simulate the combined Solid Rocket Booster trajectory aeroshear and heating environments. The material is characterized by excellent thermal performance and was used extensively on the Space Shuttle STS-1 and STS-2 flight hardware.

Patterson, W. J.

1979-01-01

317

Using gas-thermal coatings for high-temperature protection of steel  

Microsoft Academic Search

High-temperature gas corrosion on slab heating in a furnace atmosphere containing oxygen leads to loss of metal in scale and in burning, increase in size of surface casting defects, and decarburization and gas saturation of the metal surface. To improve the efficiency of sheet production, it is expedient to create protective coatings by diffusional saturation of the surface layer with

A. G. Radyuk; A. E. Titlyanov; Yu. Z. Kul’mamet’eva

2007-01-01

318

Low-density polybenzimidazole foams for thermal insulation and fire protection  

NASA Technical Reports Server (NTRS)

Fire-resistant and nonsmoking foam can be prepared in desirable density range of 24 to 50 kg/cu m by controlled thermal crosslinking of polybenzimidazole prepolymer. Reproducible foams of specific density can be produced by controlling volative content and melting temperature of prepolymer.

Kourtides, D.; Parker, J. A.; Deland, C.; Milligan, R.

1975-01-01

319

Thermal protection with liquid film in turbulent mixed convection channel flows  

Microsoft Academic Search

In this numerical study, a channel flow of turbulent mixed convection of heat and mass transfer with film evaporation has been conducted. The turbulent hot air flows downward of the vertical channel and is cooled by the laminar liquid film on both sides of the channel with thermally insulated walls. The effect of gas–liquid phase coupling, variable thermophysical properties and

Jer-Huan Jang; Wei-Mon Yan

2006-01-01

320

Large modular graphite radiant heaters for testing space shuttle thermal protection systems  

NASA Technical Reports Server (NTRS)

A graphite radiant heating array, capable of heating a 5-ft span of shuttle wing leading edge or a 4 x 8 ft flat panel through an entry thermal profile up to 3200 G, has been designed and built by McDonnell Douglas Corporation for NASA-Johnson Space Center. The unique, interchangeable, self-contained heather modules and their versatile support structure/coolant manifold are discussed along with the extensive thermal analysis that accompanied the design effort. A complete description of the geometric capabilities of the array, as well as the design details of the individual modules, is presented. The complete performance envelope of the array is discussed, including maximum temperature and gradients, heating uniformity, and the required utilities and support equipment.

Cox, B. G.; Christensen, H. E.

1975-01-01

321

Evaluation of coated columbium alloy heat shields for space shuttle thermal protection system application  

NASA Technical Reports Server (NTRS)

A three-phase program to develop and demonstrate the feasibility of a metallic heat shield suitable for use on Space Shuttle Orbiter class vehicles at operating surface temperatures of up to 1590 K (2400 F) is summarized. An orderly progression of configuration studies, material screening tests, and subscale structural tests was performed. Scale-up feasibility was demonstrated in the final phase when a sizable nine-panel array was fabricated and successfully tested. The full-scale tests included cyclic testing at reduced air pressure to 1590 K (2400 F) and up to 158 dB overall sound pressure level. The selected structural configuration and design techniques succesfully eliminated thermal induced failures. The thermal/structural performance of the system was repeatedly demonstrated. Practical and effective field repair methods for coated columbium alloys were demonstrated. Major uncertainties of accessibility, refurbishability, and durability were eliminated.

Black, W. E.

1977-01-01

322

Arc Jet Testing of the TIRS Cover Thermal Protection System for Mars Exploration Rover  

NASA Technical Reports Server (NTRS)

This paper summarizes the arc jet test results of the Mars Exploration Rover (MER) Silicone Impregnated Reusable Ceramic Ablator (SIRCA) Transverse Impulse Rocket System (TIRS) Cover test series in the Panel Test Facility (PTF) at NASA Ames Research Center (ARC). NASA ARC performed aerothermal environment analyses, TPS sizing and thermal response analyses, and arc jet testing to evaluate the MER SIRCA TIRS Cover design and interface to the aeroshell structure. The primary objective of this arc jet test series was to evaluate specific design details of the SIRCA TIRS Cover interface to the MER aeroshell under simulated atmospheric entry heating conditions. Four test articles were tested in an arc jet environment with various sea] configurations. The test condition was designed to match the predicted peak flight heat load at the gap region between the SIRCA and the backshell TPS material, SLA-561S, and resulted in an over-test (with respect to heat flux and heat load) for the apex region of the SIRCA TIRS Cover. The resulting pressure differential was as much as twenty times that predicted for the flight case, depending on the location, and there was no post-test visual evidence of over-heating or damage to the seal, bracket, or backshell structure. The exposed titanium bolts were in good condition at post-test and showed only a small amount of oxidation at the leading edge locations. Repeatable thermocouple data were obtained and SIRCA thermal response analyses were compared to applicable thermocouple data. For the apex region of the SIRCA TIRS Cover, a one-dimensional thermal response prediction proved overly conservative, as there were strong multi-dimensional conduction effects evident from the thermocouple data. The one-dimensional thermal response prediction compared well with the thermocouple data for the leading edge "lip" region at the bolt location. In general, the test results yield confidence in the baseline seal design to prevent hot gas ingestion at the bracket and composite aeroshell structure interface.

Szalai, Christine E.; Chen, Y.-K.; Loomis, Mark; Hui, Frank; Scrivens, Larry

2002-01-01

323

Inorganic Water Repellent Coatings for Thermal Protection Insulation on an Aerospace Vehicle  

NASA Technical Reports Server (NTRS)

The objective of this research was two-fold: first, to identify and test inorganic water-repellent materials that would be hydrophobic even after thermal cycling to temperatures above 600 C and, second, to develop a model that would link hydrophobicity of a material to the chemical properties of its constituent atoms. Four different materials were selected for detailed experimental study, namely, boron nitride, talc, molybdenite, and pyrophyllite, all of which have a layered structure made up of ionic/covalent bonds within the layers but with van der Waals bonds between the layers. The materials tested could be considered hydrophobic for a nonporous surface but none of the observed contact angles exceeded the necessary 90 degrees required for water repellency of porous materials. Boron nitride and talc were observed to retain their water-repellency when heated in air to temperatures that did not exceed 800 C, and molybdenite was found to be retain its hydrophobicity when heated to temperatures up to 600 C. For these three materials, oxidation and decomposition were identified to be the main cause for the breakdown of water repellency after repeated thermal cycling. Pyrophyllite shows the maximum promise as a potential water-repellent inorganic material, which, when treated initially at 900 C, retained its shape and remained hydrophobic for two thermal cycles where the maximum retreatment temperature is 900 C. A model was developed for predicting materials that might exhibit hydrophobicity by linking two chemical properties, namely, that the constituent ions of the compound belong to the soft acid-base category and that the fractional ionic character of the bonds be less than about 20 percent.

Fuerstenau, D. W.; Huang, P.; Ravikumar, R.

1997-01-01

324

Techniques for aerothermal tests of large, flightweight thermal protection panels in a Mach 7 wind tunnel  

NASA Technical Reports Server (NTRS)

Recently developed experimental techniques permit evaluating thermal performance and structural integrity of full-scale panel concepts applicable to reentry and hypersonic vehicles in the Langley 8-foot high-performance structures tunnel. Rate and magnitude of surface heating and differential-pressure loading are independently controlled. Realistic temperature distributions are radiantly preheated into the panel prior to aerodynamic heating, and stream conditions are preselected to sustain the preheat surface heating input during aerodynamic exposure. During tunnel start and shutdown, panels are shielded outside the stream from potentially damaging transient acoustics and buffeting and are then rapidly inserted into the hypersonic flow. Infrared radiometry provides detailed surveys of surface temperatures.

Deveikis, W. D.; Bruce, W. E., Jr.; Karns, J. R.

1974-01-01

325

Development and validation of purged thermal protection systems for liquid hydrogen fuel tanks of hypersonic vehicles  

NASA Technical Reports Server (NTRS)

An economical, lightweight, safe, efficient, reliable, and reusable insulation system was developed for hypersonic cruise vehicle hydrogen fuel tanks. Results indicate that, a nitrogen purged, layered insulation system with nonpermeable closed-cell insulation next to the cryogenic tank and a high service temperature fibrous insulation surrounding it, is potentially an attractive solution to the insulation problem. For the postulated hypersonic flight the average unit weight of the purged insulation system (including insulation, condensate and fuel boil off) is 6.31 kg/sq m (1.29 psf). Limited cyclic tests of large specimens of closed cell polymethacrylimide foam indicate it will withstand the expected thermal cycle.

Helenbrook, R. D.; Colt, J. Z.

1977-01-01

326

Gap heating with pressure gradients. [for Shuttle Orbiter thermal protection system tiles  

NASA Technical Reports Server (NTRS)

The heating rate distribution and temperature response on the gap walls of insulating tiles is analyzed to determine significant phenomena and parameters in flows where there is an external surface pressure gradient. Convective heating due to gap flow, modeled as fully developed pipe flow, is coupled with a two-dimensional thermal model of the tiles that includes conduction and radiative heat transfer. To account for geometry and important environmental parameters, scale factors are obtained by curve-fitting measured temperatures to analytical solutions. These scale factors are then used to predict the time-dependent gap heat flux and temperature response of tile gaps on the Space Shuttle Orbiter during entry.

Scott, C. D.; Maraia, R. J.

1979-01-01

327

Methods and systems to thermally protect fuel nozzles in combustion systems  

DOEpatents

A method of assembling a gas turbine engine is provided. The method includes coupling a combustor in flow communication with a compressor such that the combustor receives at least some of the air discharged by the compressor. A fuel nozzle assembly is coupled to the combustor and includes at least one fuel nozzle that includes a plurality of interior surfaces, wherein a thermal barrier coating is applied across at least one of the plurality of interior surfaces to facilitate shielding the interior surfaces from combustion gases.

Helmick, David Andrew; Johnson, Thomas Edward; York, William David; Lacy, Benjamin Paul

2013-12-17

328

Reusable Surface Insulation Tile Thermal Protection Materials: Past, Present and the Future  

NASA Technical Reports Server (NTRS)

Silica (LI-900) Reusable Surface Insulation (RSI) tile have been used on the majority of the Shuttle since its initial flight. Its overall performance with Reaction Cured Glass (RCG) coating applied will be reviewed. Improvements in insulations, Fibrous Refractory Composite Insulation (FRCI-12) and Alumina Enhanced Thermal Barrier (AETB-8) and coatings/surface treatments such as Toughened Uni-Piece Fibrous Insulation (TUFI) have been developed and successfully applied. The performance of these enhancements on the Shuttle Orbiters over the past few years along with the next version of tile materials, High Efficiency Tantalum-based Ceramic (HETC) with even broader applicability will also be discussed.

Leiser, Daniel B.; Stewart, David A.; Venkatapathy, Ethiras (Technical Monitor)

2002-01-01

329

Ocean thermal conversion (OTEC) project bottom cable protection study: environmental characteristics and hazards analysis  

SciTech Connect

Seafloor cable-protection criteria and technology as applied to the four proposed OTEC plant sites and cable routes at Hawaii, Puerto Rico, Guam and Florida were examined. Study of environmental characteristics for each site covered: (A) natural factors of location, tide and currents, wind and wave, bottom soil type and seafloor movement; and (B) man-made factors such as ship traffic, fishing activities, ocean mining, government regulations. These characteristics were studied to determine the hazards which are potential sources of damage to a cable system. Hazards include: chafe and corrosion, hydrodynamic forces due to wave and current action, mudslides, earthquakes, trawler and/or dredge action and ship anchors. An analysis of the history of submarine-cable failures was conducted. Included are the probabilities of damage related to water depth. Probabilities become minimal for all hazards in water depths of 1500 feet and more. Chafe and corrosion had the highest probability of causing damage to a seafloor cable compared to the other hazards. Because of the hazards present at all sites, cable burial is recommended as the best means of protection.

Chern, C.; Tudor, W.

1981-10-01

330

Topologically protected measurement-based quantum computation on the thermal state of a nearest-neighbor two-body Hamiltonian with spin-3/2 particles  

E-print Network

Recently, Li {\\it et al.} [Phys. Rev. Lett. {\\bf 107}, 060501 (2011)] have demonstrated that topologically protected measurement-based quantum computation can be implemented on the thermal state of a nearest-neighbor two-body Hamiltonian with spin-2 and spin-3/2 particles provided that the temperature is smaller than a critical value, namely, threshold temperature. Here we show that the thermal state of a nearest-neighbor two-body Hamiltonian, which consists of only spin-3/2 particles, allows us to perform topologically protected measurement-based quantum computation. The threshold temperature is calculated and turns out to be comparable to that with the spin-2 and spin-3/2 system. Furthermore, we generally show that a cluster state of high connectivity can be efficiently generated from the thermal state of the spin-3/2 system without severe thermal noise accumulation.

Keisuke Fujii; Tomoyuki Morimae

2011-11-03

331

The Application of Infrared Thermographic Inspection Techniques to the Space Shuttle Thermal Protection System  

NASA Technical Reports Server (NTRS)

The Nondestructive Evaluation Sciences Branch at NASA s Langley Research Center has been actively involved in the development of thermographic inspection techniques for more than 15 years. Since the Space Shuttle Columbia accident, NASA has focused on the improvement of advanced NDE techniques for the Reinforced Carbon-Carbon (RCC) panels that comprise the orbiter s wing leading edge. Various nondestructive inspection techniques have been used in the examination of the RCC, but thermography has emerged as an effective inspection alternative to more traditional methods. Thermography is a non-contact inspection method as compared to ultrasonic techniques which typically require the use of a coupling medium between the transducer and material. Like radiographic techniques, thermography can be used to inspect large areas, but has the advantage of minimal safety concerns and the ability for single-sided measurements. Principal Component Analysis (PCA) has been shown effective for reducing thermographic NDE data. A typical implementation of PCA is when the eigenvectors are generated from the data set being analyzed. Although it is a powerful tool for enhancing the visibility of defects in thermal data, PCA can be computationally intense and time consuming when applied to the large data sets typical in thermography. Additionally, PCA can experience problems when very large defects are present (defects that dominate the field-of-view), since the calculation of the eigenvectors is now governed by the presence of the defect, not the "good" material. To increase the processing speed and to minimize the negative effects of large defects, an alternative method of PCA is being pursued where a fixed set of eigenvectors, generated from an analytic model of the thermal response of the material under examination, is used to process the thermal data from the RCC materials. Details of a one-dimensional analytic model and a two-dimensional finite-element model will be presented. An overview of the PCA process as well as a quantitative signal-to-noise comparison of the results of performing both embodiments of PCA on thermographic data from various RCC specimens will be shown. Finally, a number of different applications of this technology to various RCC components will be presented.

Cramer, K. E.; Winfree, W. P.

2005-01-01

332

Post-flight Analysis of Mars Science Laboratory Entry Aerothermal Environment and Thermal Protection System Response  

NASA Technical Reports Server (NTRS)

The Mars Science Laboratory successfully landed on the Martian surface on August 5th, 2012. The rover was protected from the extreme heating environments of atmospheric entry by an ablative heatshield. This Phenolic Impregnated Carbon Ablator heatshield was instrumented with a suite of embedded thermocouples, isotherm sensors, and pressure transducers. The sensors monitored the in-depth ablator response, as well as the surface pressure at discrete locations throughout the hypersonic deceleration. This paper presents a comparison of the flight data with post-entry estimates. An assessment of the aerothermal environments, as well as the in-depth response of the heatshield material is made, and conclusions regarding the overall performance of the ablator at the suite locations are presented.

White, Todd Richard; Mahazari, Milad; Bose, Deepak; Santos, Jose Antonio

2013-01-01

333

A Thermal Physiological Comparison of Two HazMat Protective Ensembles With and Without Active Convective Cooling  

NASA Technical Reports Server (NTRS)

Wearing impermeable garments for hazardous materials clean up can often present a health and safety problem for the wearer. Even short duration clean up activities can produce heat stress injuries in hazardous materials workers. It was hypothesized that an internal cooling system might increase worker productivity and decrease likelihood of heat stress injuries in typical HazMat operations. Two HazMat protective ensembles were compared during treadmill exercise. The different ensembles were created using two different suits: a Trelleborg VPS suit representative of current HazMat suits and a prototype suit developed by NASA engineers. The two life support systems used were a current technology Interspiro Spirolite breathing apparatus and a liquid air breathing system that also provided convective cooling. Twelve local members of a HazMat team served as test subjects. They were fully instrumented to allow a complete physiological comparison of their thermal responses to the different ensembles. Results showed that cooling from the liquid air system significantly decreased thermal stress. The results of the subjective evaluations of new design features in the prototype suit were also highly favorable. Incorporation of these new design features could lead to significant operational advantages in the future.

Williamson, Rebecca; Carbo, Jorge; Luna, Bernadette; Webbon, Bruce W.

1998-01-01

334

Computational techniques for design optimization of thermal protection systems for the space shuttle vehicle. Volume 1: Final report  

NASA Technical Reports Server (NTRS)

Computational techniques were developed and assimilated for the design optimization. The resulting computer program was then used to perform initial optimization and sensitivity studies on a typical thermal protection system (TPS) to demonstrate its application to the space shuttle TPS design. The program was developed in Fortran IV for the CDC 6400 but was subsequently converted to the Fortran V language to be used on the Univac 1108. The program allows for improvement and update of the performance prediction techniques. The program logic involves subroutines which handle the following basic functions: (1) a driver which calls for input, output, and communication between program and user and between the subroutines themselves; (2) thermodynamic analysis; (3) thermal stress analysis; (4) acoustic fatigue analysis; and (5) weights/cost analysis. In addition, a system total cost is predicted based on system weight and historical cost data of similar systems. Two basic types of input are provided, both of which are based on trajectory data. These are vehicle attitude (altitude, velocity, and angles of attack and sideslip), for external heat and pressure loads calculation, and heating rates and pressure loads as a function of time.

1971-01-01

335

Analytical modeling of intumescent coating thermal protection system in a JP-5 fuel fire environment  

NASA Technical Reports Server (NTRS)

The thermochemical response of Coating 313 when exposed to a fuel fire environment was studied to provide a tool for predicting the reaction time. The existing Aerotherm Charring Material Thermal Response and Ablation (CMA) computer program was modified to treat swelling materials. The modified code is now designated Aerotherm Transient Response of Intumescing Materials (TRIM) code. In addition, thermophysical property data for Coating 313 were analyzed and reduced for use in the TRIM code. An input data sensitivity study was performed, and performance tests of Coating 313/steel substrate models were carried out. The end product is a reliable computational model, the TRIM code, which was thoroughly validated for Coating 313. The tasks reported include: generation of input data, development of swell model and implementation in TRIM code, sensitivity study, acquisition of experimental data, comparisons of predictions with data, and predictions with intermediate insulation.

Clark, K. J.; Shimizu, A. B.; Suchsland, K. E.; Moyer, C. B.

1974-01-01

336

Low-Cost Protective Layer Coatings on Thermal Barrier Coatings via CCVD. Final Report  

SciTech Connect

MicroCoating Technologies, Inc., investigated the use of the Combustion Chemical Vapor Deposition (CCVD) process to deposit oxygen or sintering barrier coatings for thermal barrier coating (TBC) applications. In addition, it looked at the use of its nanopowders by the NanoSpray process for developing smoothing layers on TBCs. Testing and analysis of coated substrates included heat treatments, scanning electron microscopy, x-ray diffraction and profilometry. Coatings on TBC-coated superalloy coupons were tested by an outside collaborator. Results from the investigations indicated that the thin film coatings were not well-suited as barrier layers on the rough bond coat or TBC. Subsequent investigations considered smoothing layers on the TBC, as suggested by the collaborator, using nanopowder-based coatings. Smoothing of substrate surfaces by 50% was observed by profilometry.

Hendrick, Michelle

2003-09-18

337

Dual Heat Pulse, Dual Layer Thermal Protection System Sizing Analysis and Trade Studies for Human Mars Entry Descent and Landing  

NASA Technical Reports Server (NTRS)

NASA has been recently updating design reference missions for the human exploration of Mars and evaluating the technology investments required to do so. The first of these started in January 2007 and developed the Mars Design Reference Architecture 5.0 (DRA5). As part of DRA5, Thermal Protection System (TPS) sizing analysis was performed on a mid L/D rigid aeroshell undergoing a dual heat pulse (aerocapture and atmospheric entry) trajectory. The DRA5 TPS subteam determined that using traditional monolithic ablator systems would be mass expensive. They proposed a new dual-layer TPS concept utilizing an ablator atop a low thermal conductivity insulative substrate to address the issue. Using existing thermal response models for an ablator and insulative tile, preliminary hand analysis of the dual layer concept at a few key heating points indicated that the concept showed potential to reduce TPS masses and warranted further study. In FY09, the followon Entry, Descent and Landing Systems Analysis (EDL-SA) project continued by focusing on Exploration-class cargo or crewed missions requiring 10 to 50 metric tons of landed payload. The TPS subteam advanced the preliminary dual-layer TPS analysis by developing a new process and updated TPS sizing code to rapidly evaluate mass-optimized, full body sizing for a dual layer TPS that is capable of dual heat pulse performance. This paper describes the process and presents the results of the EDL-SA FY09 dual-layer TPS analyses on the rigid mid L/D aeroshell. Additionally, several trade studies were conducted with the sizing code to evaluate the impact of various design factors, assumptions and margins.

McGuire, Mary Kathleen

2011-01-01

338

Mount Protects Thin-Walled Glass or Ceramic Tubes from Large Thermal and Vibration Loads  

NASA Technical Reports Server (NTRS)

The design allows for the low-stress mounting of fragile objects, like thin walled glass, by using particular ways of compensating, isolating, or releasing the coefficient of thermal expansion (CTE) differences between the mounted object and the mount itself. This mount profile is lower than true full kinematic mounting. Also, this approach enables accurate positioning of the component for electrical and optical interfaces. It avoids the higher and unpredictable stress issues that often result from potting the object. The mount has been built and tested to space-flight specifications, and has been used for fiber-optic, optical, and electrical interfaces for a spaceflight mission. This mount design is often metal and is slightly larger than the object to be mounted. The objects are optical or optical/electrical, and optical and/or electrical interfaces are required from the top and bottom. This requires the mount to be open at both ends, and for the object s position to be controlled. Thin inside inserts at the top and bottom contact the housing at defined lips, or edges, and hold the fragile object in the mount. The inserts can be customized to mimic the outer surface of the object, which further reduces stress. The inserts have the opposite CTE of the housing material, partially compensating for the CTE difference that causes thermal stress. A spring washer is inserted at one end to compensate for more CTE difference and to hold the object against the location edge of the mount for any optical position requirements. The spring also ensures that any fiber-optic or optic interface, which often requires some pressure to ensure a good interface, does not overstress the fragile object. The insert thickness, material, and spring washer size can be traded against each other to optimize the mount and stresses for various thermal and vibration load ranges and other mounting requirements. The alternate design uses two separate, unique features to reduce stress and hold the object. A release agent is applied to the inside surface of the mount just before the binding potting material is injected in the mount. This prevents the potting material from bonding to the mount, and thus prevents stress from being applied, at very low temperatures, to the fragile object being mounted. The potting material mixing and curing is temperature- and humidity-controlled. The mount has radial grooves cut in it that the potting material fills, thus controlling the vertical position of the mounted object. The design can easily be used for long and thin objects, short and wide objects, and any shape in between. The design s advantages are amplified for long and thin fragile objects. The general testing range was 45 to +45 C, but multiple mounts were successfully tested down to 60 and up to 50 C and the design can be adjusted for larger ranges.

Amato, Michael; Schmidt, Stephen; Marsh. James; Dahya, Kevin

2011-01-01

339

Thermal Spray Coatings for High-Temperature Corrosion Protection in Biomass Co-Fired Boilers  

NASA Astrophysics Data System (ADS)

There are over 1000 biomass boilers and about 500 plants using waste as fuel in Europe, and the numbers are increasing. Many of them encounter serious problems with high-temperature corrosion due to detrimental elements such as chlorides, alkali metals, and heavy metals. By HVOF spraying, it is possible to produce very dense and well-adhered coatings, which can be applied for corrosion protection of heat exchanger surfaces in biomass and waste-to-energy power plant boilers. Four HVOF coatings and one arc sprayed coating were exposed to actual biomass co-fired boiler conditions in superheater area with a probe measurement installation for 5900 h at 550 and 750 °C. The coating materials were Ni-Cr, IN625, Fe-Cr-W-Nb-Mo, and Ni-Cr-Ti. CJS and DJ Hybrid spray guns were used for HVOF spraying to compare the corrosion resistance of Ni-Cr coating structures. Reference materials were ferritic steel T92 and nickel super alloy A263. The circulating fluidized bed boiler burnt a mixture of wood, peat and coal. The coatings showed excellent corrosion resistance at 550 °C compared to the ferritic steel. At higher temperature, NiCr sprayed with CJS had the best corrosion resistance. IN625 was consumed almost completely during the exposure at 750 °C.

Oksa, M.; Metsäjoki, J.; Kärki, J.

2014-09-01

340

To cite this document: Bennani , Lokman and Villedieu, Philippe and Salan, Michel Two Dimensional Model of an Electro-Thermal Ice Protection System. (2013) In: 5th  

E-print Network

a possible candidate is the electro-thermal ice protection system, which relies on cyclic heater mat The system we are trying to model is composed of heater mats installed within a multi-layered material shall focus on the main governing equations and building blocks of the M.A.D (Anti-icing Deicing

Mailhes, Corinne

341

Improvement of Thermal Stability of Magnetoresistive Random Access Memory Device with SiN Protective Film Deposited by High-Density Plasma Chemical Vapor Deposition  

NASA Astrophysics Data System (ADS)

Embedded magnetoresistive random access memory (MRAM) with multi-level interconnects necessitates that magnetic tunnel junction (MTJ) devices have a thermal stability of 350 °C or higher during fabrication. We have improved thermal stability of MRAM devices using SiN protective film deposited by high-density plasma chemical vapor deposition (HDP-CVD) at 200 °C. The MTJ devices with HDP-CVD SiN protective film did not degrade after post-annealing at 350 °C, which suggests that the HDP-CVD process reduced oxide metal on the etched surface of the MTJ devices and that the SiN film blocked H2O diffusion from the interlayer dielectric film during post-annealing at 350 °C. We also fabricated a 1-kbit MRAM array and experimentally demonstrated thermal stability at 350 °C.

Suemitsu, Katsumi; Kawano, Yuichi; Utsumi, Hiroaki; Honjo, Hiroaki; Nebashi, Ryusuke; Saito, Shinsaku; Ohshima, Norikazu; Sugibayashi, Tadahiko; Hada, Hiromitsu; Nohisa, Tatsuhiko; Shimazu, Tadashi; Inoue, Masahiko; Kasai, Naoki

2008-04-01

342

Chemical and thermal unfolding of glypican-1: protective effect of heparan sulfate against heat-induced irreversible aggregation.  

PubMed

Glypicans are cell-surface heparan sulfate proteoglycans that influence Wnt, hedgehog, decapentaplegic, and fibroblast growth factor activity via their heparan sulfate chains. However, recent studies have shown that glypican core proteins also have a role in growth factor signaling. Here, we expressed secreted recombinant human glypican-1 in eukaryotic cells. Recombinant glypican-1 was expressed as two glycoforms, one as proteoglycan substituted with heparan sulfate chains and one as the core protein devoid of glycosaminoglycans. Far-UV circular dichroism (CD) analysis of glypican-1 isolated under native conditions showed that the glypican-1 core protein is predominantly alpha-helical in structure, with identical spectra for the core protein and the proteoglycan form. The conformational stability of glypican-1 core protein to urea and guanidine hydrochloride denaturation was monitored by CD and fluorescence spectroscopy and showed a single unfolding transition at high concentrations of the denaturant (5.8 and 2.6 M, respectively). Renaturation from guanidine hydrochloride gave far-UV CD and fluorescence spectra identical to the spectra of native glypican-1. Thermal denaturation monitored by CD and differential scanning calorimetry (DSC) showed a single structural transition at a temperature of approximately 70 degrees C. Refolding of the heat-denatured glypican-1 core protein was dependent on protein concentration, suggesting that intermolecular interactions are involved in irreversible denaturation. However, refolding was concentration-independent for the proteoglycan form, suggesting that O-glycosylation protects the protein from irreversible aggregation. In summary, we have shown that the glypican-1 core protein is a stable alpha-helical protein and that the proteoglycan form of glypican-1 is protected from heat-induced aggregation. PMID:19775117

Svensson, Gabriel; Linse, Sara; Mani, Katrin

2009-10-27

343

Thermal and overcharge abuse analysis of a redox shuttle for overcharge protection of LiFePO4  

NASA Astrophysics Data System (ADS)

This work investigated the performance and abuse tolerance of cells protected using the redox shuttle 1,4-bis(2-methoxyethoxy)-2,5-di-tert-butylbenzene. The thermal efficiencies were evaluated using isothermal battery calorimetry. Cells containing the overcharge shuttle were observed to reach a steady state value of approximately 3.8 V, with a small variance in direct proportion to the applied current. In all cases the heat output from the cells was measured to reach ?90% of the total input power. The heat output was also measured using isothermal calorimetry. At higher rates of overcharge, the data shows that the cell containing the shuttle rapidly reaches a steady state voltage, while the temperature increases until a moderately high steady state temperature is reached. The control cell meanwhile rapidly increases in both applied voltage and cell temperature until cell failure. Two cells in series were taken deliberately out of balance individually, then charged as a single pack to observe the time needed to bring the cells into balance with one another.

Lamb, Joshua; Orendorff, Christopher J.; Amine, Khalil; Krumdick, Gregory; Zhang, Zhengcheng; Zhang, Lu; Gozdz, Antoni S.

2014-02-01

344

Nonlinear dynamic response of a uni-directional model for the tile/pad space shuttle thermal protection system  

NASA Technical Reports Server (NTRS)

A unidirectional analysis of the nonlinear dynamic behavior of the space shuttle tile/pad thermal protection system is developed and examined for imposed sinusoidal and random motions of the shuttle skin and/or applied tile pressure. The analysis accounts for the highly nonlinear stiffening hysteresis and viscous behavior of the pad which joins the tile to the shuttle skin. Where available, experimental data are used to confirm the validity of the analysis. Both analytical and experimental studies reveal that the system resonant frequency is very high for low amplitude oscillations but decreases rapidly to a minimum value with increasing amplitude. Analytical studies indicate that with still higher amplitude the resonant frequency increases slowly. The nonlinear pad is also responsible for the analytically and experimentally observed distorted response wave shapes having high sharp peaks when the system is subject to sinusoidal loads. Furthermore, energy dissipation in the pad is studied analytically and it is found that the energy dissipated is sufficiently high to cause rapid decay of dynamic transients. Nevertheless, the sharp peaked nonlinear responses of the system lead to higher magnification factors than would be expected in such a highly damped linear system.

Housner, J. M.; Edighoffer, H. H.; Park, K. C.

1980-01-01

345

In-Flight Aeroelastic Stability of the Thermal Protection System on the NASA HIAD, Part I: Linear Theory  

NASA Technical Reports Server (NTRS)

Conical shell theory and piston theory aerodynamics are used to study the aeroelastic stability of the thermal protection system (TPS) on the NASA Hypersonic Inflatable Aerodynamic Decelerator (HIAD). Structural models of the TPS consist of single or multiple orthotropic conical shell systems resting on several circumferential linear elastic supports. The shells in each model may have pinned (simply-supported) or elastically-supported edges. The Lagrangian is formulated in terms of the generalized coordinates for all displacements and the Rayleigh-Ritz method is used to derive the equations of motion. The natural modes of vibration and aeroelastic stability boundaries are found by calculating the eigenvalues and eigenvectors of a large coefficient matrix. When the in-flight configuration of the TPS is approximated as a single shell without elastic supports, asymmetric flutter in many circumferential waves is observed. When the elastic supports are included, the shell flutters symmetrically in zero circumferential waves. Structural damping is found to be important in this case. Aeroelastic models that consider the individual TPS layers as separate shells tend to flutter asymmetrically at high dynamic pressures relative to the single shell models. Several parameter studies also examine the effects of tension, orthotropicity, and elastic support stiffness.

Goldman, Benjamin D.; Dowell, Earl H.; Scott, Robert C.

2014-01-01

346

Evaluation of coated columbium alloy heat shields for space shuttle thermal protection system application. Volume 3, phase 3: Full size TPS evaluation  

NASA Technical Reports Server (NTRS)

The thermal protection system (TPS), designed for incorporation with space shuttle orbiter systems, consists of one primary heat shield thermally and structurally isolated from the test fixture by eight peripheral guard panels, all encompassing an area of approximately 12 sq ft. TPS components include tee-stiffened Cb 752/R-512E heat shields, bi-metallic support posts, panel retainers, and high temperature insulation blankets. The vehicle primary structure was simulated by a titanium skin, frames, and stiffeners. Test procedures, manufacturing processes, and methods of analysis are fully documented. For Vol. 1, see N72-30948; for Vol. 2, see N74-15660.

Baer, J. W.; Black, W. E.

1974-01-01

347

Thermal Performance of Fire Fighters' Protective Clothing. 3. Simulating a TPP Test for Single-Layered Fabrics.  

National Technical Information Service (NTIS)

Fabrics that are used in firefighter turnout gear are specifically designed to offer protection from various extreme conditions that may arise during fire exposures. Two optimize the design of these garments and understand the conditions for which protect...

S. Kukuck, K. Prasad

2003-01-01

348

Microstructure and solid particle erosion of carbon-based materials used for the protection of highly porous carbon–carbon composite thermal insulation  

Microsoft Academic Search

Multiparticle erosion tests were performed on candidate coating (colloidal graphite paints) and cladding (dense carbon–carbon\\u000a composites and graphite foil) materials employed to protect porous carbon–carbon composite thermal insulation in vacuum and\\u000a inert-gas furnaces that utilize inert gas quenching. The dependence of the erosion rate on the angle of incidence of the erodent\\u000a was examined and related to the microstructure and

R. I BAXTER; R. D. RAWLINGS

1997-01-01

349

The Evolution of Flexible Insulation as Thermal Protection Systems for Reusable Launch Vehicles: AFRSI (Advanced Flexible Reusable Surface Insulation) to CRI (Conformal Reusable Insulation)  

NASA Technical Reports Server (NTRS)

This viewgraph presentation gives an overview of the evolution of flexible insulation as a thermal protection system for reusable launch vehicles, Advanced Flexible Reusable Surface Insulation (AFRSI) to Conformal Reusable Insulation (CRI). Details are given on the approved use of AFRIS on the Shuttle Orbiter in June 1980, the first flight of AFRIS on STS-6, windward blanket development, composite flexible blanket insulation, and flight demonstrations.

Rezin, Marc; Oka, Kris; Arnold, Jim (Technical Monitor)

2001-01-01

350

Fe-Al Weld Overlay and High Velocity Oxy-Fuel Thermal Spray Coatings for Corrosion Protection of Waterwalls in Fossil Fired Plants with Low NOx Burners  

SciTech Connect

Iron-aluminum-chromium coatings were investigated to determine the best candidates for coatings of boiler tubes in Low NOx fossil fueled power plants. Ten iron-aluminum-chromium weld claddings with aluminum concentrations up to 10wt% were tested in a variety of environments to evaluate their high temperature corrosion resistance. The weld overlay claddings also contained titanium additions to investigate any beneficial effects from these ternary and quaternary alloying additions. Several High-Velocity Oxy-Fuel (HVOF) thermal spray coatings with higher aluminum concentrations were investigated as well. Gaseous corrosion testing revealed that at least 10wt%Al is required for protection in the range of environments examined. Chromium additions were beneficial in all of the environments, but additions of titanium were beneficial only in sulfur rich atmospheres. Similar results were observed when weld claddings were in contact with corrosive slag while simultaneously, exposed to the corrosive environments. An aluminum concentration of 10wt% was required to prevent large amounts of corrosion to take place. Again chromium additions were beneficial with the greatest corrosion protection occurring for welds containing both 10wt%Al and 5wt%Cr. The exposed thermal spray coatings showed either significant cracking within the coating, considerable thickness loss, or corrosion products at the coating substrate interface. Therefore, the thermal spray coatings provided the substrate very little protection. Overall, it was concluded that of the coatings studied weld overlay coatings provide superior protection in these Low NOx environments; specifically, the ternary weld composition of 10wt%Al and 5wt%Cr provided the best corrosion protection in all of the environments tested.

Regina, J.R.

2002-02-08

351

Development of ion-plated aluminide diffusion coatings for thermal cyclic oxidation and hot corrosion protection of a nickel-based superalloy and a stainless steel  

NASA Astrophysics Data System (ADS)

This project was carried out at the University of Toronto and Cametoid Ltd of Whitby, Ontario. Ohno continuous casting; a novel net shape casting technique, was used to generate, Al-Y, Al-Ce, Al-La, and Al-Si-Y, in form of 1.6 to 1.7 mm diameter alloy wires. These alloy wires exhibited suitable properties for use as feed materials to an Ion Vapor Deposition facility. The deposition parameters were optimized to provide coatings with a compact and cohesive columnar structure with reduced porosity and diffusion barriers that were essential to ensure the success of the diffusion process in the subsequent stage. Solid-state diffusion heat treatment processes were developed in order to form the stable aluminide phases, AlNi and FeAl, on IN738 and S310 substrates, respectively. Experiments simulating the coating service conditions and environments encountered during the prospective aerospace and fuel cell applications were conducted to evaluate the performance of each aluminide coating developed during this study. Thermal cyclic oxidation and molten sulfate corrosion studies were performed on coated IN738 pins at 1050°C and 900°C, respectively, simulating the service environment of turbine engine blades and other hot section components. Molten carbonate corrosion behavior was investigated for coated S310 coupons that were immersed in, or covered with a thin film of molten carbonate, at 650°C, in air plus 30%CO2, to simulate the operating conditions of the cathode-side separator plates of molten carbonate fuel cells. The behavior of the reactive elements, yttrium, cerium, lanthanum, and silicon in enhancing the adhesion of the protective aluminum oxide scale was determined by weight variation experiments, structural examination and compositional analysis. The influence of the base material elements, nickel, chromium, and iron, on the formation of protective oxides was investigated. All coatings were found to provide significant improvement for thermal cyclic oxidation and hot corrosion protection. For protection of IN738, Al-La coatings provided the greatest protection during oxidative thermal cycling, whereas Al-Ce coatings were found to be the most effective for protection against corrosive molten sulfate environments in aerospace applications. For protection of S310 against the corrosive environments of molten carbonate fuel cells, the effectiveness of the aluminide coatings were in the sequence, from the most to the least effective, Al-La, Al-Ce, Al-Y, and Al-Si-Y Mechanisms for Lanthanum and cerium protective behavior in high temperature aluminide diffusion coatings were suggested from the results of this study combined with literature information.

Elsawy, Abdel Raouf

352

Description of the manufacturing challenges in producing the high-temperature reusable surface insulation for the thermal protection system of the Space Shuttle  

NASA Technical Reports Server (NTRS)

The paper describes the high-temperature reusable surface insulation for the thermal protection system of the Space Shuttle. This system protects the Space Shuttle Orbiter on reentry and it is an externally attached, rigidized, fibrous silica, machined into 15 x 20 cm tiles. The tiles constitute the High-Temperature Reusable Surface Insulation (HRSI) system, and are used on over 70 percent of the exterior surface where peak temperatures range from 400 to 1260 C. Carbon-carbon leading edges are used in areas where peak temperatures exceed 1650 C, and a Nomex felt flexible insulation system is used in regions below 400 C. Approximately 32,000 tiles are used in the HRSI system, and due to vehicle configuration and aerodynamic requirements no two tiles are alike.

Forsberg, K.

1979-01-01

353

Multilayer SiC for thermal protection system of space vehicles: Manufacturing and testing under simulated re-entry conditions  

Microsoft Academic Search

Two types of laminated multilayer silicon carbide plates were processed by tape casting, de-binding and pressureless sintering. The specimens were subject to thermal re-entry testing under conditions as derived from the HERMES study: up to 100 combined thermal and air pressure cycles were performed. After the first cycle, all samples lost about 1.5% of their initial mass. This was caused

S. Biamino; V. Liedtke; C. Badini; G. Euchberger; I. Huertas Olivares; M. Pavese; P. Fino

2008-01-01

354

Thermal conductivities of naked and monolayer protected metal nanoparticle based nanofluids: Manifestation of anomalous enhancement and chemical effects  

Microsoft Academic Search

Thermal conductivities of two kinds of Au nanoparticles were measured in water and toluene media. The water soluble particles, 10-20 nm in mean diameter, made with citrate stabilization showed thermal conductivity enhancement of 5%-21% in the temperature range of 30-60 °C at a loading of 0.000 26 (by volume). The effect was 7%-14% for Au particles stabilized with a monolayer

Hrishikesh E. Patel; Sarit K. Das; T. Sundararajan; A. Sreekumaran Nair; Beena George; T. Pradeep

2003-01-01

355

A leading edge heating array and a flat surface heating array: Final design. [for testing the thermal protection system of the space shuttle  

NASA Technical Reports Server (NTRS)

A heating array is described for testing full-scale sections of the leading edge and lower fuselage surfaces of the shuttle. The heating array was designed to provide a tool for development and acceptance testing of leading edge segments and large flat sections of the main body thermal protection system. The array was designed using a variable length module concept to meet test requirements using interchangeable components from one test configuration in another configuration. Heat generating modules and heat absorbing modules were employed to achieve the thermal gradient around the leading edge. A support was developed to hold the modules to form an envelope around a variety of leading edges; to supply coolant to each module; the support structure and to hold the modules in the flat surface heater configuration. An optical pyrometer system mounted within the array was designed to monitor specimen surface temperatures without altering the test article's surface.

1975-01-01

356

Aerothermal loads analysis for high speed flow over a quilted surface configuration. [metallic Thermal Protection System panels simulation for Space Shuttle  

NASA Technical Reports Server (NTRS)

Attention is given to hypersonic laminar flow over a quilted surface configuration that simulates an array of Space Shuttle Thermal Protection System panels bowed in a spherical shape as a result of thermal gradients through the panel thickness. Pressure and heating loads to the surface are determined. The flow field over the configuration was mathematically modeled by means of time-dependent, three-dimensional conservation of mass, momentum, and energy equations. A boundary mapping technique was then used to obtain a rectangular, parallelepiped computational domain, and an explicit MacCormack (1972) explicit time-split predictor-corrector finite difference algorithm was used to obtain steady state solutions. Total integrated heating loads vary linearly with bowed height when this value does not exceed the local boundary layer thickness.

Olsen, G. C.; Smith, R. E.

1984-01-01

357

A New Way of Doing Business: Reusable Launch Vehicle Advanced Thermal Protection Systems Technology Development: NASA Ames and Rockwell International Partnership  

NASA Technical Reports Server (NTRS)

NASA Ames Research Center and Rockwell International are partners in a Cooperative Agreement (CA) for the development of Thermal Protection Systems (TPS) for the Reusable Launch Vehicle (RLV) Technology Program. This Cooperative Agreement is a 30 month effort focused on transferring NASA innovations to Rockwell and working as partners to advance the state-of-the-art in several TPS areas. The use of a Cooperative Agreement is a new way of doing business for NASA and Industry which eliminates the traditional customer/contractor relationship and replaces it with a NASA/Industry partnership.

Carroll, Carol W.; Fleming, Mary; Hogenson, Pete; Green, Michael J.; Rasky, Daniel J. (Technical Monitor)

1995-01-01

358

PART III DIVISION 7 PAGE 1 RUTGERS DESIGN STANDARDS MANUAL January 2012 DIVISION 7 -THERMAL AND MOISTURE PROTECTION  

E-print Network

designed to adhere to the wet concrete cast against it. 4. Positive side membranes must be protected from, these systems are not suitable for use under intensive green roofs. Positive drainage is a critical component (e.g. 110 pcf) concrete fill is preferred to obtain slope and mandatory over precast concrete. #12

359

High-temperature properties of ceramic fibers and insulations for thermal protection of atmospheric entry and hypersonic cruise vehicles  

NASA Technical Reports Server (NTRS)

Multilayer insulations (MIs) which will operate in the 500 to 1000 C temperature range are being considered for possible applications on aerospace vehicles subject to convective and radiative heating during atmospheric entry. The insulations described consist of ceramic fibers, insulations, and metal foils quilted together with ceramic thread. As these types of insulations have highly anisotropic properties, the total heat transfer characteristics must be determined. Data are presented on the thermal diffusivity and thermal conductivity of four types of MIs and are compared to the baseline Advanced Flexible Reusable Surface Insulation currently used on the Space Shuttle Orbiter. In addition, the high temperature properties of the fibers used in these MIs are discussed. The fibers investigated included silica and three types of aluminoborosilicate (ABS). Static tension tests were performed at temperatures up to 1200 C and the ultimate strain, tensile strength, and tensile modulus of single fibers were determined.

Kourtides, Demetrius A.; Pitts, William C.; Araujo, Myrian; Zimmerman, R. S.

1988-01-01

360

High temperature properties of ceramic fibers and insulations for thermal protection of atmospheric entry and hypersonic cruise vehicles  

NASA Technical Reports Server (NTRS)

Multilayer insulations (MIs) which will operate in the 500 to 1000 C temperature range are being considered for possible applications on aerospace vehicles subject to convective and radiative heating during atmospheric entry. The insulations described consist of ceramic fibers, insulations, and metal foils quilted together with ceramic thread. As these types of insulations have highly anisotropic properties, the total heat transfer characteristics must be determined. Data are presented on the thermal diffusivity and thermal conductivity of four types of MIs and are compared to the baseline Advanced Flexible Reusable Surface Insulation currently used on the Space Shuttle Orbiter. In addition, the high temperature properties of the fibers used in these MIs are discussed. The fibers investigated included silica and three types of aluminoborosilicate (ABS). Static tension tests were performed at temperatures up to 1200 C and the ultimate strain, tensile strength, and tensile modulus of single fibers were determined.

Kourtides, Demetrius A.; Pitts, William C.; Araujo, Myrian; Zimmerman, R. S.

1988-01-01

361

Effects of Thermal Spray Coating Composition and Microstructure on Coating Response and Substrate Protection at High Temperatures  

Microsoft Academic Search

Boiler tubes for fossil fuel-fired power plants typically are fabricated from low-alloy carbon steels, with chromium and molybdenum as the primary alloy additions. Three thermal spray coatings were subjected to high-temperature corrosion experiments to characterize the operative corrosion mechanism(s) and to examine the effects of coating composition and microstructure. Samples were placed in air and sulfur dioxide (SOâ) at 600

S. T. Bluni; A. R. Marder

1996-01-01

362

Thermal tolerance of contractile function in oxidative skeletal muscle: no protection by antioxidants and reduced tolerance with eicosanoid enzyme inhibition.  

PubMed

Mechanisms for the loss of muscle contractile function in hyperthermia are poorly understood. This study identified the critical temperature, resulting in a loss of contractile function in isolated diaphragm (thermal tolerance), and then tested the hypotheses 1) that increased reactive oxygen species (ROS) production contributes to the loss of contractile function at this temperature, and 2) eicosanoid metabolism plays an important role in preservation of contractile function in hyperthermia. Contractile function and passive force were measured in rat diaphragm bundles during and after 30 min of exposure to 40, 41, 42 or 43 degrees C. Between 40 and 42 degrees C, there were no effects of hyperthermia, but at 43 degrees C, a significant loss of active force and an increase in passive force were observed. Inhibition of ROS with the antioxidants, Tiron or Trolox, did not inhibit the loss of contractile force at 43 degrees C. Furthermore, treatment with dithiothreitol, a thiol (-SH) reducing agent, did not reverse the effects of hyperthermia. A variety of global lipoxygenase (LOX) inhibitors further depressed force during 43 degrees C and caused a significant loss of thermal tolerance at 42 degrees C. Cyclooxygenase (COX) inhibitors also caused a loss of thermal tolerance at 42 degrees C. Blockage of phospholipase with phospholipase A(2) inhibitors, bromoenol lactone or arachidonyltrifluoromethyl ketone failed to significantly prevent the loss of force at 43 degrees C. Overall, these data suggest that ROS do not play an apparent role in the loss of contractile function during severe hyperthermia in diaphragm. However, functional LOX and COX enzyme activities appear to be necessary for maintaining normal force production in hyperthermia. PMID:18768765

Oliver, S Ryan; Wright, Valerie P; Parinandi, Narasimham; Clanton, Thomas L

2008-11-01

363

Prediction and verification of creep behavior in metallic materials and components for the space shuttle thermal protection system. Volume 2: Phase 2 subsize panel cyclic creep predictions  

NASA Technical Reports Server (NTRS)

A method for predicting permanent cyclic creep deflections in stiffened panel structures was developed. The resulting computer program may be applied to either the time-hardening or strain-hardening theories of creep accumulation. Iterative techniques were used to determine structural rotations, creep strains, and stresses as a function of time. Deflections were determined by numerical integration of structural rotations along the panel length. The analytical approach was developed for analyzing thin-gage entry vehicle metallic-thermal-protection system panels subjected to cyclic bending loads at high temperatures, but may be applied to any panel subjected to bending loads. Predicted panel creep deflections were compared with results from cyclic tests of subsize corrugation and rib-stiffened panels. Empirical equations were developed for each material based on correlation with tensile cyclic creep data and both the subsize panels and tensile specimens were fabricated from the same sheet material. For Vol. 1, see N75-21431.

Cramer, B. A.; Davis, J. W.

1975-01-01

364

CAVE: A computer code for two-dimensional transient heating analysis of conceptual thermal protection systems for hypersonic vehicles  

NASA Technical Reports Server (NTRS)

A digital computer code CAVE (Conduction Analysis Via Eigenvalues), which finds application in the analysis of two dimensional transient heating of hypersonic vehicles is described. The CAVE is written in FORTRAN 4 and is operational on both IBM 360-67 and CDC 6600 computers. The method of solution is a hybrid analytical numerical technique that is inherently stable permitting large time steps even with the best of conductors having the finest of mesh size. The aerodynamic heating boundary conditions are calculated by the code based on the input flight trajectory or can optionally be calculated external to the code and then entered as input data. The code computes the network conduction and convection links, as well as capacitance values, given basic geometrical and mesh sizes, for four generations (leading edges, cooled panels, X-24C structure and slabs). Input and output formats are presented and explained. Sample problems are included. A brief summary of the hybrid analytical-numerical technique, which utilizes eigenvalues (thermal frequencies) and eigenvectors (thermal mode vectors) is given along with aerodynamic heating equations that have been incorporated in the code and flow charts.

Rathjen, K. A.

1977-01-01

365

Thermal protection of H13 steel by growth of (TiAl)N films by PAPVD pulsed arc technique  

SciTech Connect

(TiAl)N Films were grown on H13 steel by a plasma assisted repetitive pulsed arc discharge. To grow the coatings, a TiAl sintered cathode was used, 50% Ti-50% Al. The deposition system consists of a reaction chamber with two electrodes placed face to face. A pulsed power supply, which allows for control of parameters like time active arc, time between arcs, arc energy, and others, is used to generate the discharge. Thermal changes were carried out on H13 steel before and after growing the (TiAl)N films. X-ray diffraction (XRD) was employed to study the coatings, observing the H13 steel and (TiAl)N oxidation temperature. Morphological characteristics were analyzed by means of an Atomic Force Microscopy (AFM). Scanning electron microscopy (SEM) revealed the surface chemical composition of the films and morphological details of the samples.

Jimenez, H.; Devia, D.M.; Benavides, V. [Laboratorio de fisica del plasma, Universidad Nacional de Colombia, Sede Manizales.AA 127 (Colombia); Devia, A. [Laboratorio de fisica del plasma, Universidad Nacional de Colombia, Sede Manizales.AA 127 (Colombia)], E-mail: adevia@une.net.co; Arango, Y.C.; Arango, P.J. [Laboratorio de fisica del plasma, Universidad Nacional de Colombia, Sede Manizales.AA 127 (Colombia); Velez, J.M. [Facultad de Minas Medellin, Universidad Nacional de Colombia, Sede Medellin (Colombia)

2008-08-15

366

Conformal Ablative Thermal Protection System for Planetary and Human Exploration Missions: An Update of the Technology Maturation Effort  

NASA Technical Reports Server (NTRS)

This presentation will update the community on the development of conformal ablative TPS. As described at IPPW-10, in FY12, the CA-TPS element focused on establishing materials requirements based on MSL-type and COTS Low Earth orbit (LEO) conditions (q 250 Wcm2) to develop and deliver a conformal ablative TPS. This involved downselecting, manufacturing and testing two of the best candidate materials, demonstrating uniform infiltration of resins into baseline 2-cm thick carbon felt, selecting a primary conformal material formulation based on novel arc jet and basic material properties testing, developing and demonstrating instrumentation for felt-based materials and, based on the data, developing a low fidelity material response model so that the conformal ablator TPS thickness for missions could be established. In addition, the project began to develop Industry Partnerships. Since the nominal thickness of baseline carbon felts was only 2-cm, a partnership with a rayon felt developer was made in order to upgrade equipment, establish the processes required and attempt to manufacture 10-cm thick white goods. A partnership with a processing house was made to develop the methodology to carbonize large pieces of the white goods into 7.5-cm thick carbon felt.In FY13, more advanced testing and modeling of the downselected conformal material was performed. Material thermal properties tests and structural properties tests were performed. The first 3 and 4-point bend tests were performed on the conformal ablator as well as PICA for comparison and the conformal ablator had outstanding behavior compared to PICA. Arc jet testing was performed with instrumented samples of both the conformal ablator and standard PICA at heating rates ranging from 40 to 400 Wcm2 and shear as high as 600 Pa. The results from these tests showed a remarkable improvement in the thermal penetration through the conformal ablator when compared to PICAs response. The data from these tests were used to develop a mid-fidelity thermal response model. Additional arc jet testing in the same conditions on various seam designs were very successful in showing that the material could be joined with a minimum of adhesive and required no complicated gap and gap filler design for installation. In addition, the partnership with industry to manufacture thicker rayon felt was very successful. The vendor made a 2-m wide by 30-m long sample of 10-cm thick rayon felt. When carbonized, the resulting thickness was over 7.5-cm thick, nearly 4 times the thickest off-the-shelf carbon felt. In FY14, the project has initiated a partnership with another vendor to begin the scale-up manufacturing effort. This year, the vendor will duplicate the process and manufacture at the current scale for comparison with NASA-processed materials. Properties testing and arc jet testing will be performed on the vendor-processed materials. Planning for manufacturing large, 1-m x 1-m, panels will begin as well. In FY15, the vendor will then manufacture large panels and the project will build a 2-m x 2-m Manufacturing Demonstration Unit (MDU).

Beck, R.; Arnold, J.; Gasch, M.; Stackpoole, M.; Venkatapathy, E.

2014-01-01

367

Development of dispersion-strengthened Ni-Cr-ThOz alloys for the space shuttle thermal protection system  

NASA Technical Reports Server (NTRS)

Manufacturing processes were developed for TD-NiCr providing small sheet (45 x 90 cm), and larger sheet (60 x 150 cm) and foil. The alternate alloy, DS-NiCr, was produced by pack-chromizing Ni-ThO2 sheet. Formability criteria are being established for basic sheet forming processes, which are brake forming, corrugation forming, joggling, dimpling, and beading. Resistance spot welding (fusion and solid state), resistance seam welding, solid state diffusion welding, and brazing are included in the joining programs. Major emphasis is centered on an Al-modified Ni-Cr-ThO2 alloy development. These alloys, containing 3 to 5% Al, form the protective Al2O3 scale. This enhances oxidation resistance under reentry conditions. Both TD-NiCrAl and DS-NiCrAl alloys are included. A tentative composition of Ni-16Cr-3.5Al-2ThO2 was selected based on oxidation resistance and fabricability.

Blankenship, C. P.; Saunders, N. T.

1972-01-01

368

Thermally stable derivatives or propylenepolyamines as protective additives for lubricating oils used in compressors handling hydrogen sulfide-containing gas  

SciTech Connect

In the transmission of natural, associated, and petroleum gases containing hydrogen sulfide, carbon dioxide, water, and other corrosive impurities, problems are created by the saturation of the compressor lubricating oil with these impurities and failure of components of the lubricating and sealing system. Hydrogen sulfide is distinguished by the greatest affinity for oil and the highest corrosivity. Its solubility in oils may be as high as 10 g/liter under standard conditions. In the work reported here, we investigated the protective properties of salts and amides based on higher aliphatic, alkylaromatic, and unsaturated carboxylic acids with certain substituted propylenepolyamines. In synthesizing the additives, we used the following: a commercial C{sub 17} - C{sub 20} fraction of synthetic fatty acids (SFA): C{sub 25+} still bottoms; technical alkyl (C{sub 16} - C {sub 18}) salicylic acids; and oleic acid. From these materials, we obtained salts and amides of N,N-dimethylpropanediamine, N-benzylpropanediamine, N-cyanoethylpropanediamine, N,N,N`,N`-tetramethyldipropylenetriamine, and N,N-dimethyldipropylenetriamine.

Trofimov, V.A.; Panidi, I.S.; Spirkin, V.G. [and others

1995-09-01

369

FIRE PROTECTION ENGINEERING  

E-print Network

FIRE PROTECTION ENGINEERING FPE College of Engineering California Polytechnic State University San problems and develop fire safety design solutions in a variety of professional settings. Fire Protection Engineering Science � Apply concepts associated with the thermal sciences, to the analysis of fire protection

Sze, Lawrence

370

FIRE PROTECTION ENGINEERING  

E-print Network

FIRE PROTECTION ENGINEERING FPE College of Engineering California Polytechnic State University San and develop fire safety design solutions in a variety of professional settings. Fire Protection Engineering Science · Apply concepts associated with the thermal sciences, to the analysis of fire protection

Sze, Lawrence

371

A Collaborative Analysis Tool for Integrated Hypersonic Aerodynamics, Thermal Protection Systems, and RBCC Engine Performance for Single Stage to Orbit Vehicles  

NASA Technical Reports Server (NTRS)

Presented is a computer-based tool that connects several disciplines that are needed in the complex and integrated design of high performance reusable single stage to orbit (SSTO) vehicles. Every system is linked to every other system, as is the case of SSTO vehicles with air breathing propulsion, which is currently being studied by NASA. An RBCC propulsion system integrates airbreathing and rocket propulsion into a single engine assembly enclosed within a cowl or duct. A typical RBCC propulsion system operates as a ducted rocket up to approximately Mach 3. Then there is a transition to a ramjet mode for supersonic-to-hypersonic acceleration. Around Mach 8 the engine transitions to a scramjet mode. During the ramjet and scramjet modes, the integral rockets operate as fuel injectors. Around Mach 10-12 (the actual value depends on vehicle and mission requirements), the inlet is physically closed and the engine transitions to an integral rocket mode for orbit insertion. A common feature of RBCC propelled vehicles is the high degree of integration between the propulsion system and airframe. At high speeds the vehicle forebody is fundamentally part of the engine inlet, providing a compression surface for air flowing into the engine. The compressed air is mixed with fuel and burned. The combusted mixture must be expanded to an area larger than the incoming stream to provide thrust. Since a conventional nozzle would be too large, the entire lower after body of the vehicle is used as an expansion surface. Because of the high external temperatures seen during atmospheric flight, the design of an airbreathing SSTO vehicle requires delicate tradeoffs between engine design, vehicle shape, and thermal protection system (TPS) sizing in order to produce an optimum system in terms of weight (and cost) and maximum performance. To adequately determine the performance of the engine/vehicle, the Hypersonic Flight Inlet Model (HYFIM) module was designed to interface with the RBCC engine model. HYFIM performs the aerodynamic analysis of forebodies and inlet characteristics of RBCC powered SSTO launch vehicles. HYFIM is applicable to the analysis of the ramjet/scramjet engine operations modes (Mach 3-12), and provides estimates of parameters such as air capture area, shock-on-lip Mach number, design Mach number, compression ratio, etc., based on a basic geometry routine for modeling axisymmetric cones, 2-D wedge geometries. HYFIM also estimates the variation of shock layer properties normal to the forebody surface. The thermal protection system (TPS) is directly linked to determination of the vehicle moldline and the shaping of the trajectory. Thermal protection systems to maintain the structural integrity of the vehicle must be able to mitigate the heat transfer to the structure and be lightweight. Herein lies the interdependency, in that as the vehicle's speed increases, the TPS requirements are increased. And as TPS masses increase the effect on the propulsion system and all other systems is compounded. The need to analyze vehicle forebody and engine inlet is critical to be able to design the RBCC vehicle. To adequately determine insulation masses for an RBCC vehicle, the hypersonic aerodynamic environment and aeroheating loads must be calculated and the TPS thicknesses must be calculated for the entire vehicle. To accomplish this an ascent or reentry trajectory is obtained using the computer code Program to Optimize Simulated Trajectories (POST). The trajectory is then used to calculate the convective heat rates on several locations on the vehicles using the Miniature Version of the JA70 Aerodynamic Heating Computer Program (MINIVER). Once the heat rates are defined for each body point on the vehicle, then insulation thicknesses that are required to maintain the vehicle within structural limits are calculated using Systems Improved Numerical Differencing Analyzer (SINDA) models. If the TPS masses are too heavy for the performance of the vehicle the process may be repeated altering the trajectory or some other input to reduce the TPS mass.

Stanley, Thomas Troy; Alexander, Reginald; Landrum, Brian

2000-01-01

372

A title-gap flow model for use in aerodynamic loads assessment of space shuttle thermal protection system: Parallel gap faces  

NASA Technical Reports Server (NTRS)

The problem of predicting aerodynamic loads on the insulating tiles of the space shuttle thermal protection system (TPS) is discussed and seen to require a method for predicting pressure and mass flux in the gaps between tiles. A mathematical model of the tile-gap flow is developed, based upon a slow viscous (Stokes) flow analysis, and is verified against experimental data. The tile-gap pressure field is derived from a solution of the two-dimensional Laplace equation; the mass-flux vector is then calculated from the pressure gradient. The means for incorporating this model into a lumped-parameter network analogy for porous-media flow is given. The means for incorporating this model into a lumped-parameter network analogy for porous-media flow is given. The flow model shows tile-gap mass flux to be very sensitive to the gap width indicating a need for coupling the TPS flow and tile displacement calculation. Analytical and experimental work to improve TPS flow predictions and a possible shuttle TPS hardware modification are recommended.

Dwoyer, D. L.; Newman, P. A.; Thames, F. C.; Melson, N. D.

1981-01-01

373

Sun Protection  

MedlinePLUS

... Risks of Tanning Tanning Products Sun Protection Links Sun Protection Sun Protection Tips Protective Clothing Sunglasses Sunscreen ... for integrating sun protection into your daily routine. Sun Protection Tips Avoid overexposure to UV rays from ...

374

Prediction and verification of creep behavior in metallic materials and components for the space shuttle thermal protection system. Volume 3, phase 3: Full size heat shield data correlation and design criteria. [reentry  

NASA Technical Reports Server (NTRS)

Analysis methods for predicting cyclic creep deflection in stiffened metal panel structures, were applied to full size panels. Results were compared with measured deflections from cyclic tests of thin gage L605, Rene' 41, and TDNiCr full size corrugation stiffened panels. A design criteria was then formulated for metallic thermal protection panels subjected to creep. A computer program was developed to calculate creep deflections.

Cramer, B. A.; Davis, J. W.

1975-01-01

375

An Analysis of the Selected Materials Used in Step Measurements During Pre-Fits of Thermal Protection System Tiles and the Accuracy of Measurements Made Using These Selected Materials  

NASA Technical Reports Server (NTRS)

The goal of this research project was be to compare and contrast the selected materials used in step measurements during pre-fits of thermal protection system tiles and to compare and contrast the accuracy of measurements made using these selected materials. The reasoning for conducting this test was to obtain a clearer understanding to which of these materials may yield the highest accuracy rate of exacting measurements in comparison to the completed tile bond. These results in turn will be presented to United Space Alliance and Boeing North America for their own analysis and determination. Aerospace structures operate under extreme thermal environments. Hot external aerothermal environments in high Mach number flights lead to high structural temperatures. The differences between tile heights from one to another are very critical during these high Mach reentries. The Space Shuttle Thermal Protection System is a very delicate and highly calculated system. The thermal tiles on the ship are measured to within an accuracy of .001 of an inch. The accuracy of these tile measurements is critical to a successful reentry of an orbiter. This is why it is necessary to find the most accurate method for measuring the height of each tile in comparison to each of the other tiles. The test results indicated that there were indeed differences in the selected materials used in step measurements during prefits of Thermal Protection System Tiles and that Bees' Wax yielded a higher rate of accuracy when compared to the baseline test. In addition, testing for experience level in accuracy yielded no evidence of difference to be found. Lastly the use of the Trammel tool over the Shim Pack yielded variable difference for those tests.

Kranz, David William

2010-01-01

376

A Comparison between Shear Bond Strength of VMK Master Porcelain with Three Base-metal Alloys (Ni-cr-T3, VeraBond, Super Cast) and One Noble Alloy (X-33) in Metal-ceramic Restorations  

PubMed Central

Statement of Problem: The increase in the use of metal-ceramic restorations and a high prevalence of porcelain chipping entails introducing an alloy which is more compatible with porcelain and causes a stronger bond between the two. This study is to compare shear bond strength of three base-metal alloys and one noble alloy with the commonly used VMK Master Porcelain. Materials and Method: Three different groups of base-metal alloys (Ni-cr-T3, Super Cast, and VeraBond) and one group of noble alloy (X-33) were selected. Each group consisted of 15 alloy samples. All groups went through the casting process and change from wax pattern into metal disks. The VMK Master Porcelain was then fired on each group. All the specimens were put in the UTM; a shear force was loaded until a fracture occurred and the fracture force was consequently recorded. The data were analyzed by SPSS Version 16 and One-Way ANOVA was run to compare the shear strength between the groups. Furthermore, the groups were compared two-by-two by adopting Tukey test. Results: The findings of this study revealed shear bond strength of Ni-Cr-T3 alloy was higher than the three other alloys (94 MPa or 330 N). Super Cast alloy had the second greatest shear bond strength (80. 87Mpa or 283.87 N). Both VeraBond (69.66 MPa or 245 N) and x-33 alloys (66.53 MPa or 234 N) took the third place. Conclusion: Ni-Cr-T3 with VMK Master Porcelain has the greatest shear bond strength. Therefore, employment of this low-cost alloy is recommended in metal-ceramic restorations. PMID:24724144

Ahmadzadeh, A; Neshati, A; Mousavi, N; Epakchi, S; Dabaghi Tabriz, F; Sarbazi, AH

2013-01-01

377

Conformal Ablative Thermal Protection System for Planetary and Human Exploration Missions: Overview of the Technology Maturation Efforts Funded by NASA's Game Changing Development Program  

NASA Technical Reports Server (NTRS)

The Office of Chief Technologist (OCT), NASA has identified the need for research and technology development in part from NASA's Strategic Goal 3.3 of the NASA Strategic Plan to develop and demonstrate the critical technologies that will make NASA's exploration, science, and discovery missions more affordable and more capable. Furthermore, the Game Changing Development Program (GCDP) is a primary avenue to achieve the Agency's 2011 strategic goal to "Create the innovative new space technologies for our exploration, science, and economic future." In addition, recently released "NASA space Technology Roadmaps and Priorities," by the National Research Council (NRC) of the National Academy of Sciences stresses the need for NASA to invest in the very near term in specific EDL technologies. The report points out the following challenges (Page 2-38 of the pre-publication copy released on February 1, 2012): Mass to Surface: Develop the ability to deliver more payload to the destination. NASA's future missions will require ever-greater mass delivery capability in order to place scientifically significant instrument packages on distant bodies of interest, to facilitate sample returns from bodies of interest, and to enable human exploration of planets such as Mars. As the maximum mass that can be delivered to an entry interface is fixed for a given launch system and trajectory design, the mass delivered to the surface will require reduction in spacecraft structural mass; more efficient, lighter thermal protection systems; more efficient lighter propulsion systems; and lighter, more efficient deceleration systems. Surface Access: Increase the ability to land at a variety of planetary locales and at a variety of times. Access to specific sites can be achieved via landing at a specific location (s) or transit from a single designated landing location, but it is currently infeasible to transit long distances and through extremely rugged terrain, requiring landing close to the site of interest. The entry environment is not always guaranteed with a direct entry, and improving the entry system's robustness to a variety of environmental conditions could aid in reaching more varied landing sites."

Beck, Robin A.; Arnold, James O.; Gasch, Matthew J.; Stackpoole, Margaret M.; Fan, Wendy; Szalai, Christine E.; Wercinski, Paul F.; Venkatapathy, Ethiraj

2012-01-01

378

Quantitative characterization by asymmetrical flow field-flow fractionation of IgG thermal aggregation with and without polymer protective agents.  

PubMed

Complexes formed between poly(acrylates) and polyclonal immunoglobulin G (IgG) in its native conformation and after heat stress were characterized using asymmetric flow field-flow fractionation (AF4) coupled with on-line UV-Vis spectroscopy and multi-angle light-scattering detection (MALS). Mixtures of IgG and poly(acrylates) of increasing structural complexity, sodium poly(acrylate) (PAA), a sodium poly(acrylate) bearing at random 3 mol % n-octadecyl groups, and a random copolymer of sodium acrylate (35 mol %), N-n-octylacrylamide (25 mol %) and N-isopropylacrylamide (40 mol %), were fractionated in a sodium phosphate buffer (0.02 M, pH 6.8) in the presence, or not, of 0.1 M NaCl. The AF4 protocol developed allowed the fractionation of solutions containing free poly(acrylates), native IgG monomer and dimer, poly(acrylates)/IgG complexes made up of one IgG molecule and a few polymer chains, and/or larger poly(acrylates)/IgG aggregates. The molar mass and recovery of the soluble analytes were obtained for mixed solutions of poly(acrylates) and native IgG and for the same solutions incubated at 65 °C for 10 min. From the combined AF4 results, we concluded that in solutions of low ionic strength, the presence of PAA increased the recovery ratio of IgG after thermal stress because of the formation of electrostatically-driven PAA/IgG complexes, but PAA had no protective effect in the presence of 0.1 M NaCl. Poly(acrylates) bearing hydrophobic groups significantly increased IgG recovery after stress, independently of NaCl concentration, because of the synergistic effect of hydrophobic and electrostatic interactions. The AF4 results corroborate conclusions drawn from a previous study combining four analytical techniques. This study demonstrates that AF4 is an efficient tool for the analysis of protein formulations subjected to stress, an important achievement given the anticipated important role of proteins in near-future human therapies. PMID:25323742

Ma, Dewang; Martin, Nicolas; Tribet, Christophe; Winnik, Françoise M

2014-11-01

379

simulated service Thermal shock Testing  

E-print Network

conditions to evaluate mechanical and thermal integrity of insulation materials in real timeKeywords simulated service Testing Thermal shock Testing Cathodic disbondment Flexibility Testing for offshore Insulation and Corrosion Protection systems Simulated service insulation test samples being set up

Chapman, Clark R.

380

Thermal status of the noise- and heat-protective housing of a gas-turbine plant in a gas-pumping unit  

Microsoft Academic Search

The problem of the thermal status of the noise- and heat-insulating housing (NHH) of a gas-turbine plant (GTP) is examined.\\u000a Results are presented for an investigation of the thermal status of the space beneath the NHH and its walls with allowance\\u000a for heat transfer due to radiative emission of heated components of the structure. A mathematical model is proposed for

P. V. Trusov; D. A. Charntsev; A. M. Pechenkina

2010-01-01

381

X-33 Demonstrates Reusable Launch Vehicle Technologies  

NASA Technical Reports Server (NTRS)

NASA is developing advanced technologies that will revolutionize America's space launch capabilities and unleash the commercial potential of space. The challenge is to develop advanced technologies for affordable reusble launch vehicles. NASA's goal is to reduce the payload cost of access to space by an order of magnitude, from $10,000 to $1,000 per pound, within 10 years, and by an additional order of magnitude, to $100's per pound within 25 years. This research is part of NASA's Aeronautics and Space Transportation Technology (ASTT) Enterprise's strategy to sustain U.S. leadership in aeronautics and space. The Enterprise has set bold goals that are grouped into Three Pillars: Global Civil Aviation, Revolutionary Technology Leaps and Access to Space.

1998-01-01

382

Influence of sol-gel SiO2/TiO2 protective coatings on the optical and thermal properties of nickel-phosphorus selective surfaces  

NASA Astrophysics Data System (ADS)

A sol-gel coating was applied to an electroless acid-etched Ni-P spectrally selective surface in order to investigate its influence on the optical and thermal properties of the selective surface. The sol-gel process is a low-temperature preparation of glasses, which is of interest considering the lack of resistance of selective surfaces at the high temperatures generally needed to prepare glasses by the melting technique. The application of a glass coating on the Ni-P layer increases its oxidation resistance at high temperatures and improves the optical and thermal properties of this selective surface for heat treatments in air, up to 400 °C.

Papini, Marie

1991-07-01

383

Police protection - protecting whom?  

Microsoft Academic Search

Police protection (Children Act 1989, s.46) is a long-established police power allowing the removal or detention of children suffering or likely to suffer significant harm. This article outlines the findings of research into its use and discusses how it is viewed by the police and social workers. It explores how the use of the power affects relationships between parents and

Judith Masson

2002-01-01

384

Protective Role of Trehalose on Thermal Stability of Lactase in Relation to its Glass and Crystal Forming Properties and Effect of Delaying Crystallization  

Microsoft Academic Search

Thermal inactivation of ?-galactosidase was investigated in dried matrices of poly(vinyl)pyrrolidone (PVP), maltodextrin and trehalose. Significant lactase inactivation was observed in the polymeric matrices kept well below their glass transition temperature (Tg). The stability of the enzyme in the anhydrous glassy matrices of maltodextrin and PVPs heated at 70 °C was directly related to their Tg; i.e. systems with higher

Mar??a Florencia Mazzobre; Maria del Pilar Buera; Jorge Chirife

1997-01-01

385

Cermet composite thermal spray coatings for erosion and corrosion protection in combustion environments of advanced coal-fired boilers. Semiannual technical report, January 14, 1997--August 14, 1997  

SciTech Connect

Research is presently being conducted to determine the optimum ceramic/metal combination in thermally sprayed metal matrix composite coatings for erosion and corrosion resistance in new coal-fired boilers. The research will be accomplished by producing model cermet composites using powder metallurgy and electrodeposition methods in which the effect of ceramic/metal combination for the erosion and corrosion resistance will be determined. These results will provide the basis for determining the optimum hard phase constituent size and volume percent in thermal spray coatings. Thermal spray coatings will be applied by our industrial sponsor and tested in our erosion and corrosion laboratories. Bulk powder processed Ni-Al{sub 2}O{sub 3} composites were produced at Idaho National Engineering Laboratory. The composite samples contained 0, 21, 27, 37, and 45 volume percent Al{sub 2}O{sub 3} with an average particle size of 12 um. Also, to deposit model Ni-Al{sub 2}O{sub 3} coatings, an electrodeposition technique was developed and coatings with various volume fractions (0-35%) of Al{sub 2}O{sub 3} were produced. The powder and electrodeposition processing of Ni-Al{sub 2}O{sub 3} Composites provide the ability to produce two phase microstructure without changing the microstructure of the matrix material. Therefore, the effect of hard second phase particles size and volume fraction on erosion resistance could be analyzed.

Schorr, B.S.; Levin, B.F.; DuPont, J.N.; Marder, A.R.

1997-08-31

386

Bolt Inserts for Lightning Protection  

NASA Technical Reports Server (NTRS)

Stainless steel bolt fasteners have adequate grounding paths for protection of structures against lightning strikes. Fasteners particularly useful in sections where insulating material required, such as thermal panels of external storage tank.

Hambrock, K. O.

1985-01-01

387

Thermal Clothing  

NASA Technical Reports Server (NTRS)

Gateway Technologies, Inc. is marketing and developing textile insulation technology originally developed by Triangle Research and Development Corporation. The enhanced thermal insulation stems from Small Business Innovation Research contracts from NASA's Johnson Space Center and the U.S. Air Force. The effectiveness of the insulation comes from the microencapsulated phase-change materials originally made to keep astronauts gloved hands warm. The applications for the product range from outer wear, housing insulation, and blankets to protective firefighting gear and scuba diving suits. Gateway has developed and begun marketing thermal regulating products under the trademark, OUTLAST. Products made from OUTLAST are already on the market, including boot and shoe liners, winter headgear, hats and caps for hunting and other outdoor sports, and a variety of men's and women's ski gloves.

1997-01-01

388

Native and Thermally Modified Protein-Polyphenol Coassemblies: Lactoferrin-Based Nanoparticles and Submicrometer Particles as Protective Vehicles for (-)-Epigallocatechin-3-gallate.  

PubMed

The interactions between native, thermally modified lactoferrin (LF) and (-)-epigallocatechin-3-gallate (EGCG) at pH 3.5, 5.0, and 6.5 were investigated. Turbidity, particle size, and charge of LF-EGCG complexes were mainly dominated by pH value and secondary structure of protein. At pH 3.5 and 5.0, LF-EGCG complexes were nanoparticles which had high ?-potential, small size, and soluble state. At pH 6.5, they were submicrometer particles which exhibited low ?-potential, large size, and insoluble state. The infrared spectra of freeze-dried LF-EGCG complexes showed that they were different from LF and EGCG alone. Far-UV CD results indicated that heat denaturation might irreversibly alter the secondary structure of LF and EGCG induced a progressive increase in the proportion of ?-helix structure at the cost of ?-sheet and unordered coil structure of LF at pH 3.5, 5.0, and 6.5. EGCG exhibited a strong affinity for native LF but a weak affinity for thermally modified LF at pH 5.0 and 6.5. An inverse result was observed at pH 3.5. These results could have potential for the development of food formulations based on LF as a carrier of bioactive compounds. PMID:25310084

Yang, Wei; Xu, Chenqi; Liu, Fuguo; Yuan, Fang; Gao, Yanxiang

2014-11-01

389

SRB thermal curtain design support  

Microsoft Academic Search

Improvements in SRB Thermal Curtain were identified by thermal design featuring: selection of materials capable of thermal protection and service temperatures by tri-layering quartz, S2 glass, and Kevlar in thinner cross section; weaving in single piece (instead of 24 sections) to achieve improved strength; and weaving to reduce manufacturing cost with angle interlock construction.

Carl A. Dixon; Wayne E. Lundblad; John R. Koenig

1992-01-01

390

Thermal Response Of Composite Insulation  

NASA Technical Reports Server (NTRS)

Engineering model gives useful predictions. Pair of reports presents theoretical and experimental analyses of thermal responses of multiple-component, lightweight, porous, ceramic insulators. Particular materials examined destined for use in Space Shuttle thermal protection system, test methods and heat-transfer theory useful to chemical, metallurgical, and ceramic engineers needing to calculate transient thermal responses of refractory composites.

Stewart, David A.; Leiser, Daniel B.; Smith, Marnell; Kolodziej, Paul

1988-01-01

391

The Application of Principal Component Analysis Using Fixed Eigenvectors to the Infrared Thermographic Inspection of the Space Shuttle Thermal Protection System  

NASA Technical Reports Server (NTRS)

The Nondestructive Evaluation Sciences Branch at NASA s Langley Research Center has been actively involved in the development of thermographic inspection techniques for more than 15 years. Since the Space Shuttle Columbia accident, NASA has focused on the improvement of advanced NDE techniques for the Reinforced Carbon-Carbon (RCC) panels that comprise the orbiter s wing leading edge. Various nondestructive inspection techniques have been used in the examination of the RCC, but thermography has emerged as an effective inspection alternative to more traditional methods. Thermography is a non-contact inspection method as compared to ultrasonic techniques which typically require the use of a coupling medium between the transducer and material. Like radiographic techniques, thermography can be used to inspect large areas, but has the advantage of minimal safety concerns and the ability for single-sided measurements. Principal Component Analysis (PCA) has been shown effective for reducing thermographic NDE data. A typical implementation of PCA is when the eigenvectors are generated from the data set being analyzed. Although it is a powerful tool for enhancing the visibility of defects in thermal data, PCA can be computationally intense and time consuming when applied to the large data sets typical in thermography. Additionally, PCA can experience problems when very large defects are present (defects that dominate the field-of-view), since the calculation of the eigenvectors is now governed by the presence of the defect, not the good material. To increase the processing speed and to minimize the negative effects of large defects, an alternative method of PCA is being pursued when a fixed set of eigenvectors is used to process the thermal data from the RCC materials. These eigen vectors can be generated either from an analytic model of the thermal response of the material under examination, or from a large cross section of experimental data. This paper will provide the details of the analytic model; an overview of the PCA process; as well as a quantitative signal-to-noise comparison of the results of performing both embodiments of PCA on thermographic data from various RCC specimens. Details of a system that has been developed to allow insitu inspection of a majority of shuttle RCC components will be presented along with the acceptance test results for this system. Additionally, the results of applying this technology to the Space Shuttle Discovery after its return from flight will be presented.

Cramer, K. Elliott; Winfree, William P.

2006-01-01

392

Can we predict temperature-dependent chemical toxicity to marine organisms and set appropriate water quality guidelines for protecting marine ecosystems under different thermal scenarios?  

PubMed

Temperature changes due to climate change and seasonal fluctuation can have profound implications on chemical toxicity to marine organisms. Through a comprehensive meta-analysis by comparing median lethal or effect concentration data of six chemicals for various saltwater species obtained at different temperatures, we reveal that the chemical toxicity generally follows two different models: (1) it increases with increasing temperature and (2) it is the lowest at an optimal temperature and increases with increasing or decreasing temperature from the optimal temperature. Such observations are further supported by temperature-dependent hazardous concentration 10% (HC10) values derived from species sensitivity distributions which are constructed using the acute toxicity data generated at different temperatures. Considering these two models and natural variations of seawater temperature, we can scientifically assess whether applying an assessment factor (e.g. 10) to modify water quality guidelines of the chemicals can adequately protect marine ecosystems in tropics, subtropics and temperate regions, respectively. PMID:25176278

Zhou, Guang-Jie; Wang, Zhen; Lau, Edward Tak Chuen; Xu, Xiang-Rong; Leung, Kenneth Mei Yee

2014-10-15

393

Fire Protection Materials  

NASA Technical Reports Server (NTRS)

Avco has drawn upon its heat shield experience to develop a number of widely-accepted commercial fire protection materials. Originating from NASA's space shuttle thermal protection system, one such material is Chartek 59 fireproofing, an intumescent epoxy coating specifically designed for outdoor use by industrial facilities dealing with highly flammable products such as oil refineries and chemical plants. The coating is applied usually by spray gun to exterior structural steel conduits, pipes and valves, offshore platforms and liquefied petroleum gas tanks. Fireproofing provides two types of protection: ablation or dissipation of heat by burn-off and "intumescence" or swelling; the coating swells to about five times its original size, forming a protective blanket of char which retards transfer of heat to the metal structure preventing loss of structural strength and possible collapse which would compound the fire fighting problem.

1980-01-01

394

Protection by Thermal and Chemical Activation with Cerium Salts of the Alloy AA2017 in Aqueous Solutions of NaCl  

NASA Astrophysics Data System (ADS)

A wide variety of anticorrosive treatments for aluminum alloys that can be employed as "green" alternatives to those based on Cr(VI) are currently under development. This article reports a study of the morphological and anticorrosive characteristics of surface layers formed on the Al-Cu alloy AA2017 by immersion treatment in baths of cerium salt, accelerated by increased temperature and the employment of hydrogen peroxide. Scanning electron microscopy (SEM)/X-ray energy dispersive spectroscopy (XEDS) studies of the samples treated have demonstrated the existence of a heterogeneous layer formed by a film of aluminum oxide/hydroxide on the matrix, and a series of dispersed islands of cerium over the cathodic intermetallics. The protective efficacy has been evaluated using electrochemical techniques, linear polarizations (LP) and electrochemical impedance spectroscopy (EIS), and salt spray tests. The results obtained indicate that the layer provided good resistance to corrosion in media with chlorides, and the method gives a considerable reduction of the time required for the immersion treatments.

Bethencourt, Manuel; Botana, Francisco Javier; Cano, María José; González-Rovira, Leandro; Marcos, Mariano; Sánchez-Amaya, José María

2012-01-01

395

Replacing Effective Spectral Radiance by Temperature in Occupational Exposure Limits to Protect Against Retinal Thermal Injury from Light and Near IR Radiation.  

PubMed

Exposure to visible light and near infrared (NIR) radiation in the wavelength region of 380 to 1400 nm may cause thermal retinal injury. In this analysis, the effective spectral radiance of a hot source is replaced by its temperature in the exposure limit values in the region of 380-1400 nm. This article describes the development and implementation of a computer code to predict those temperatures, corresponding to the exposure limits proposed by the American Conference of Governmental Industrial Hygienists (ACGIH®). Viewing duration and apparent diameter of the source were inputs for the computer code. At the first stage, an infinite series was created for calculation of spectral radiance by integration with Planck(')s law. At the second stage for calculation of effective spectral radiance, the initial terms of this infinite series were selected and integration was performed by multiplying these terms by a weighting factor R(?) in the wavelength region 380-1400 nm. At the third stage, using a computer code, the source temperature that can emit the same effective spectral radiance was found. As a result, based only on measuring the source temperature and accounting for the exposure time and the apparent diameter of the source, it is possible to decide whether the exposure to visible and NIR in any 8-hr workday is permissible. The substitution of source temperature for effective spectral radiance provides a convenient way to evaluate exposure to visible light and NIR. PMID:25175283

Madjidi, Faramarz; Behroozy, Ali

2014-10-01

396

Sun protection  

MedlinePLUS

... age spots, are caused by exposure to the sun. The two types of sun rays that can injure the skin are ultraviolet ... changes is to protect your skin from the sun. This includes using sunscreen and other protective measures. ...

397

Protective Measurements  

E-print Network

A review of protective measurements. Protective measurement is a method for measuring an expectation value of an observable on a single quantum system. The quantum state of the system can be protected by a potential, when the state is a nondegenerate energy eigenstate with a known gap to neighboring states, or via Zeno effect by frequent projection measurements.

L. Vaidman

2008-01-17

398

Thermal Spray Coatings for Coastal Infrastructure  

SciTech Connect

Several protection strategies for coastal infrastructure using thermal-spray technology are presented from research at the Albany Research Center. Thermal-sprayed zinc coatings for anodes in impressed current cathodic protection systems are used to extend the service lives of reinforced concrete bridges along the Oregon coast. Thermal-sprayed Ti is examined as an alternative to the consumable zinc anode. Sealed thermal-sprayed Al is examined as an alternative coating to zinc dust filled polyurethane paint for steel structures.

Holcomb, G.R.; Covino, BernardS. Jr.; Cramer, S.D.; Bullard, S.J.

1997-11-01

399

Insider protection  

SciTech Connect

The government community is broadly addressing the insider threat. The first section of this paper defines protection approaches and the latter sections present various applicable technology developments. The bulk of the paper discusses technology developments applied to (1) personnel and material tracking and inventory, (2) classified document protection, and (3) protecting security systems. The personnel and material tracking system uses a PC based-host to (1) collect information from proximity tags and material movement sensors, (2) apply rules to this input to assure that the ongoing activity meets the site selectable rules and, (3) forward the results to either an automated inventory system or an alarm system. The document protection system uses a PC network to efficiently and securely control classified material which is stored on write-once-read-mostly optical media. The protection of sensor to multiplexer communications in a security system is emphasized in the discussion of protecting security systems.

Waddoups, I.G.

1993-07-01

400

Protective coating for ceramic materials  

NASA Technical Reports Server (NTRS)

A protective coating for ceramic materials such as those made of silicon carbide, aluminum oxide, zirconium oxide, aluminoborosilicate and silicon dioxide, and a thermal control structure comprising a ceramic material having coated thereon the protective coating. The protective coating contains, in admixture, silicon dioxide powder, colloidal silicon dioxide, water, and one or more emittance agents selected from silicon tetraboride, silicon hexaboride, silicon carbide, molybdenum disilicide, tungsten disilicide and zirconium diboride. In another aspect, the protective coating is coated on a flexible ceramic fabric which is the outer cover of a composite insulation. In yet another aspect, a metallic foil is bonded to the outer surface of a ceramic fabric outer cover of a composite insulation via the protective coating. A primary application of this invention is as a protective coating for ceramic materials used in a heat shield for space vehicles subjected to very high aero-convective heating environments.

Kourtides, Demetrius A. (inventor); Churchward, Rex A. (inventor); Lowe, David M. (inventor)

1994-01-01

401

Alkali metal protective garment and composite material  

DOEpatents

A protective garment and composite material providing satisfactory heat resistance and physical protection for articles and personnel exposed to hot molten alkali metals, such as sodium. Physical protection is provided by a continuous layer of nickel foil. Heat resistance is provided by an underlying backing layer of thermal insulation. Overlying outer layers of fireproof woven ceramic fibers are used to protect the foil during storage and handling.

Ballif, III, John L. (Salt Lake City, UT); Yuan, Wei W. (Seattle, WA)

1980-01-01

402

Cathodic protection  

Microsoft Academic Search

Cathodic protection is the electrical solution to the corrosion problem. In this article, the history of cathodic protection (CP) is traced, and the design fundamentals are developed, including the three components of a corrosion system, the three elements of an electric circuit, and the three configurations causing potential difference. CP is the process of forcing a metal to be more

MARCUS O. DURHAM; ROBERT A. DURHAM

2005-01-01

403

Thermal Reactor Safety  

SciTech Connect

Information is presented concerning fire risk and protection; transient thermal-hydraulic analysis and experiments; class 9 accidents and containment; diagnostics and in-service inspection; risk and cost comparison of alternative electric energy sources; fuel behavior and experiments on core cooling in LOCAs; reactor event reporting analysis; equipment qualification; post facts analysis of the TMI-2 accident; and computational methods.

Not Available

1980-06-01

404

Laser optics protective device  

NASA Astrophysics Data System (ADS)

A broadband thermal optical limiter disposed between a laser oscillator and a laser amplifier system for protecting optical components in the laser oscillator from damage due to amplified optical feedback from the laser amplifier system at all near ultraviolet, visible, and near infrared wavelengths is disclosed. The thermal optical limiter comprises: a first lens for focusing the amplified optical feedback to a focal point on an optical axis; a flowing dye cell disposed near the focal point and being responsive to the focused amplified optical feedback for thermally defocusing and aberrating the focused amplified optical feedback into a plurality of rings about the optical axis; a second lens for passing only a small portion of the defocused amplified optical feedback; and a blocking aperture disposed around the second lens for blocking substantially all of the thermally defocused amplified optical feedback from the flowing dye cell and passing therethrough into the second lens only a small portion of the thermally defocused amplified optical feedback from the flowing dye cell.

Huston, Alan L.; Justus, Brian L.; Merrit, Charles D.; Campillo, Anthony J.

1994-11-01

405

NASA Now: Materials Science: Thermal Protection Systems  

NASA Video Gallery

Metallurgical and materials engineers use science, technology and mathematics to study different types of materials. They analyze the materials to determine what they are made of and evaluate their...

406

Thermal Protection Systems Materials and Manufacturing  

E-print Network

Avionics, Navigation, and Instrumentation Software Structural Design Robotics and Automation Systems of the Main Propulsion System-- the Space Shuttle Main Engine and the Solid Rocket Boosters (SRBs)-- powering leap from previous rocket engines. The main engines were the most reliable and extensively tested

407

Multilayer insulation thermal protection systems technology  

NASA Technical Reports Server (NTRS)

A summary is presented of the work performed by Marshall Space Flight Center (MSFC) and industry toward the development of flight-type multilayer insulation(MLI) systems. The MSFC MLI program is divided into three large categories: (1) the generation and compilation of MLI composite test data; (2) the analysis, design, and testing of heat flow through MLI applied to ducting, seams, electrical feedthroughs, structural supports, and the tank sidewall; and (3) the development, modification, and utilization of new testing procedures, tanks, and the test facilities. Numerous data have been generated, analyzed, and documented on different MLI composites.

Hyde, E. H.

1971-01-01

408

Thermal protection systems for space transportation vehicles  

NASA Technical Reports Server (NTRS)

The topics addressed are history of reusable external insulation (RSI), and examples of shuttle RSI development challenges, which includes: (1) manufacturing of raw materials, such as fibers, coating components; (2) design of tile planform size, strain isolation, and gap heating; (3) insulation, such as bonding, bond verification, tolerances, and quality control; and (4) operation, such as durability, and water proofing.

Goldstein, Howard E.

1993-01-01

409

Thermal protection system repair kit program  

NASA Technical Reports Server (NTRS)

The feasibility and conceptual design aspects of repair materials and procedures for in orbit repair of the space shuttle orbiter TPS tiles are investigated. Material studies to investigate cure in place materials are described including catalyst and cure studies, ablation tests and evaluations, and support mixing and applicator design. The feasibility of the repair procedures, the storage of the TPS, dispensing, and cure problems are addressed.