Results for “certification testing” — Page 13

NASA NTRS1983

Development of the Space Shuttle main engine

The history of the development, certification, and launch operations of the Space Shuttle Main Engine is described. Development problems and their solutions are discussed. Ground testing at both rated and full power levels involving four engines and eight certification test cycles totalling more than 40,000 seconds of hot-fire testing, which qualified both Columbia's and Challenger's engines for flight, are discussed. Ground checkout and flight performance of Columbia's and Challenger's engines are revealed. Future plans for the Space Shuttle Main Engine are outlined including flight certification testing to verify a life of 40 flights and 20,000 seconds operation before overhaul.

Klatt, F. P.↗

NASA NTRSDate not supplied

Ground Test Technology Demonstration for Nuclear Thermal Propulsion Engines

Nuclear Thermal Propulsion (NTP) engines have been deemed a key technology to enable human missions to Mars due to their high efficiency, also known as specific impulse (Isp). Ground testing the NTP engine is critical in maturing the technology and increasing the design’s Technology Readiness Level (TRL), thus mitigating risk from NTP engine performance/operations. NTP engine development began with open-air ground testing through the Rover/NERVA program back in the 1960s when regulatory requirements were not as stringent as they are today. Due to the formation of regulatory bodies, increase in oversight and environmental requirements, the exhaust gas released from NTP engines must be captured or processed to gain approval in the case that the exhaust gas contains fission products from the nuclear fuel elements within the reactor. Ground test campaigns following Rover/NERVA focused on the certification of a full scale NTP engine, which led to exhaust processing systems such as the Rocket Exhaust Capture System (RECS) and Real Time (RT) exhaust processing. These systems were deemed favorable for regulatory compliance but have a high initial investment cost. Reassurance on the feasibility of ground testing and the NTP engine technology likely need to be achieved before NASA invests in these systems. Recently the objectives for NTP engine ground testing have shifted from certification testing of a full scale engine to demonstration testing of a subscale engine. The shift to demonstration testing allows for a shorter testing duration and a lower operational thrust (for demo testing purposes only) to demonstrate the NTP engine (5k-12.5k lbf). Due to these factors, the infrastructure, consumables, total footprint, and exhaust system complexity are able to be drastically reduced, thus reducing cost significantly. The High-pressure Exhaust Capture System (HECS) concept was designed for a NTP engine ground test demonstration. The HECS concept greatly reduces cost compared to previous concepts and suggests favorable regulatory acceptance due to its ability to capture all of the exhaust gas from the NTP engine.

Nuclear Thermal Propulsion↗

NASA NTRSDate not supplied

Nuclear Thermal Propulsion Engine Technology Demonstration Testing

Nuclear Thermal Propulsion (NTP) engines have been deemed a key technology to enable human missions to Mars due to their high efficiency, also known as specific impulse (Isp). Ground testing the NTP engine is critical in maturing the technology and increasing the design’s Technology Readiness Level (TRL), thus mitigating risk from NTP engine performance/operations. NTP engine development began with open-air ground testing through the Rover/NERVA program back in the 1960s when regulatory requirements were not as stringent as they are today. Due to the formation of regulatory bodies, increase in oversight and environmental requirements, the exhaust gas released from NTP engines must be captured or processed to gain approval in the case that the exhaust gas contains fission products from the nuclear fuel elements within the reactor. Ground test campaigns following Rover/NERVA focused on the certification of a full scale NTP engine, which led to exhaust processing systems such as the Rocket Exhaust Capture System (RECS) and Real Time (RT) exhaust processing. These systems were deemed favorable for regulatory compliance but have a high initial investment cost. Reassurance on the feasibility of ground testing and the NTP engine technology likely need to be achieved before NASA invests in these systems. Recently the objectives for NTP engine ground testing have shifted from certification testing of a full scale engine to demonstration testing of a subscale engine. The shift to demonstration testing allows for a shorter testing duration and a lower operational thrust (for demo testing purposes only) to demonstrate the NTP engine (5k-12.5k lbf). Due to these factors, the infrastructure, consumables, total footprint, and exhaust system complexity are able to be drastically reduced, thus reducing cost significantly. The High-pressure Exhaust Capture System (HECS) concept was designed for a NTP engine ground test demonstration. The HECS concept greatly reduces cost compared to previous concepts and suggests favorable regulatory acceptance due to its ability to capture all of the exhaust gas from the NTP engine.

Nuclear Thermal Propulsion↗

NASA NTRS1986

Automation of electromagnetic compatability (EMC) test facilities

Efforts to automate electromagnetic compatibility (EMC) test facilities at Marshall Space Flight Center are discussed. The present facility is used to accomplish a battery of nine standard tests (with limited variations) deigned to certify EMC of Shuttle payload equipment. Prior to this project, some EMC tests were partially automated, but others were performed manually. Software was developed to integrate all testing by means of a desk-top computer-controller. Near real-time data reduction and onboard graphics capabilities permit immediate assessment of test results. Provisions for disk storage of test data permit computer production of the test engineer's certification report. Software flexibility permits variation in the tests procedure, the ability to examine more closely those frequency bands which indicate compatibility problems, and the capability to incorporate additional test procedures.

Harrison, C. A.↗

NASA NTRS1991

Status of turbulence Prediction System's AWAS 3

The status of the Airborne Warning and Avoidance System 3 (AWAS 3) is reported in viewgraph form. Information is given on flight tests and FAA certification. Included is a description of the flight test of a passive infrared system that achieved the first ever advanced warning of an in-flight windshear encounter. The infrared system recorded the detection of the windshear with a 35 second advance warning. The data recorded in-flight by the infrared system was later compared to and found to agree with the data recorded by the Terminal Doppler Weather Radar (TDWR) and the in-situ air data.

Adamson, Pat↗

NASA NTRS2010

Replacement/Refurbishment of JSC/NASA POD Specimens

The NASA Special NDE certification process requires demonstration of NDE capability by test per NASA-STD-5009. This test is performed with fatigue cracked specimens containing very small cracks. The certification test results are usually based on binomial statistics and must meet a 90/95 Probability of Detection (POD). The assumption is that fatigue cracks are tightly closed, difficult to detect, and inspectors and processes passing such a test are well qualified for inspecting NASA fracture critical hardware. The JSC NDE laboratory has what may be the largest inventory that exists of such fatigue cracked NDE demonstration specimens. These specimens were produced by the hundreds in the late 1980s and early 1990s. None have been produced since that time and the condition and usability of the specimens are questionable.

Castner, Willard L.↗

NASA NTRS1994

Certify for success: A methodology for human-centered certification of advanced aviation systems

This position paper uses the methodology in Design for Success as a basis for a human factors certification program. The Design for Success (DFS) methodology espouses a multi-step process to designing and developing systems in a human-centered fashion. These steps are as follows: (1) naturalizing - understand stakeholders and their concerns; (2) marketing - understand market-oriented alternatives to meeting stakeholder concerns; (3) engineering - detailed design and development of the system considering tradeoffs between technology, cost, schedule, certification requirements, etc.; (4) system evaluation - determining if the system meets its goal(s); and (5) sales and service - delivering and maintaining the system. Because the main topic of this paper is certification, we will focus our attention on step 4, System Evaluation, since it is the natural precursor to certification. Evaluation involves testing the system and its parts for their correct behaviors. Certification focuses not only on ensuring that the system exhibits the correct behaviors, but ONLY the correct behaviors.

Small, Ronald L.↗

NASA NTRS2017

Space Launch System, Core Stage, Structural Test Design and Implementation

As part of the National Aeronautics and Space Administration's (NASA) Space Launch System (SLS) Program, engineers at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama are working to design, develop and implement the SLS Core Stage structural testing. The SLS will have the capability to return humans to the Moon and beyond and its first launch is scheduled for December of 2017. The SLS Core Stage consist of five major elements; Forward Skirt, Liquid Oxygen (LOX) tank, Intertank (IT), Liquid Hydrogen (LH2) tank and the Engine Section (ES). Structural Test Articles (STA) for each of these elements are being designed and produced by Boeing at Michoud Assembly Facility located in New Orleans, La. The structural test for the Core Stage STAs (LH2, LOX, IT and ES) are to be conducted by the MSFC Test Laboratory. Additionally, the MSFC Test Laboratory manages the Structural Test Equipment (STE) design and development to support the STAs. It was decided early (April 2012) in the project life that the LH2 and LOX tank STAs would require new test stands and the Engine Section and Intertank would be tested in existing facilities. This decision impacted schedules immediately because the new facilities would require Construction of Facilities (C of F) funds that require congressional approval and long lead times. The Engine Section and Intertank structural test are to be conducted in existing facilities which will limit lead times required to support the first launch of SLS. With a SLS launch date of December, 2017 Boeing had a need date for testing to be complete by September of 2017 to support flight certification requirements. The test facilities were required to be ready by October of 2016 to support test article delivery. The race was on to get the stands ready before Test Article delivery and meet the test complete date of September 2017. This paper documents the past and current design and development phases and the supporting processes, tools, and methodology for supporting the SLS Core Stage STA test stands and related STE. The paper will address key requirements, system development activities and project challenges. Additionally, the interrelationships as well as interdependencies within the SLS project will be discussed.

Shaughnessy, Ray↗

DOE OSTI2024

Nuclear Requalification of the ATR Core

The Advanced Test Reactor (ATR) creates a unique, high neutron flux materials testing environment that subsequently causes neutron embrittlement damage to its beryllium reflector. The reflector is eventually required to be replaced during a reactor Outage. Concurrently, a piece-for-piece core replacement is conducted to maintain reactor functionality called a core internals changeout (CIC). Once changeout is complete, ATR Reactor Engineering utilizes previous CIC data, notably 1977-1994 CIC data, to conduct predictive criticality analysis on the new, unirradiated core. However, CIC data has been inconsistently reported over the years making it difficult, and in some cases impossible, to utilize. These inconsistencies arise in various forms of not using correct units, inconsistent diagram usage, and not portraying the same kind of data similarly across the reports. To work around this inconsistency issue, Reactor Engineering is implementing the use of several new neutronic modeling codes that utilize modern computation speeds and methods to model the new core in different criticality environments. Further validation is then conducted by nuclear testing and bringing the reactor critical and conducting various irradiation tests. Upon completion and certification that the reactor passed all testing requirements, ATR can once again re-start normal operations.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2021

Cybersecurity Certification Recommendations for Interconnected Grid Edge Devices and Inverter Based Resources

Escalating deployment of PV and grid-edge devices on the distribution grid has increased the sustainability and efficiency of the electric grid. However, the increasing number of distributed energy resources (DERs) deployed creates a heightened cyber-physical interdependency on the distribution grid and thus creates more vectors for cyber-attacks to exploit through information and communication technology (ICT) systems and networks. For example, control signal packets can be modified, intercepted, or corrupted due to vulnerabilities in communication protocols used by microgrid controllers and grid edge devices for power control. Therefore, to mitigate and prevent cyber-attacks on grid edge devices and the inverter-based resources connected to the distribution grid, the U.S. Department of Solar Energy Technologies Office (SETO) awarded funding to the National Renewable Energy Laboratory and Sandia National Laboratory (SNL) to research, develop, and harmonize cybersecurity standards for Photovoltaic (PV) systems and for other kinds of DERs. To help develop a standard for DER cybersecurity, NREL established certification recommendations and test cases, in consensus with the solar industry and UL, for ensuring intrinsic design security for DERs. These recommendations were developed to bolster the cybersecure functionalities such as TLS, MAC, CRL, session resumption/renegotiation, and password, system, and service security management within the DER devices. The proposed test cases verify authentication, authorization, confidentiality, and data integrity for data and communications of DERs that use Transmission Control Protocol/Internet Protocol (TCP/IP). They were also developed to protect DER communications from eavesdropping, replay, man-in-the-middle, denial of service (DoS), spoofing through security certificates, least-privilege violation, and brute-force credentials. This report, which has been validated and reviewed by UL, expands upon those test cases to provide DER cybersecurity certification recommendations which increase DER resiliency and help to mitigate cyber-attacks. UL's collaboration with NREL and approval of this document will accelerate the adoption of a UL standard for DER cybersecurity.

24 POWER TRANSMISSION AND DISTRIBUTION↗

NASA NTRS1991

Preparation of the Ice Certification of the Dornier 328 Regional Airliner By Numerical Simulation and By Ground Test

The Dornier 328, a new regional airliner, is to be qualified to FAR25/JAR25 requirements for operation into known icing conditions. All lifting surfaces are pneumatically deiced. Impingement limits were determined using a validated computational fluid dynamic (CFD) code. Wind tunnel tests with a model of the whole aircraft and the isolated empennage equipped with artificial ice shapes showed a degradation of handling characteristics due to ice accretion. Extensive two and three dimensional CFD calculations evaluated ice accretion at the deflection elevator horn. Icing tunnel tests were performed with a model of the horizontal tail with icing similitude fulfilled. The Dornier Do328 powerplant air induction system has successfully completed a program of icing tests in support of aircraft certification for operation into known icing conditions. Potential flight icing conditions were extensively analyzed using a CFD potential flow code and 3-D particle tracking routine to identify critical flight icing conditions. The tunnel test program verified the analytically predicted critical ice accretion surfaces of the air induction system, the adequacy of the ice protection provisions and demonstrated compliance with the applicable (JAR25) regulatory material.

D Welte↗

NASA NTRSDate not supplied

Aircraft Certification by Analysis (CbA): 20-year Vision for Virtual Flight Testing

Explore the source record for details and available documents.

Certification by analysis↗

NASA NTRS2009

Bayes Analysis and Reliability Implications of Stress-Rupture Testing a Kevlar/Epoxy COPV Using Temperature and Pressure Acceleration

Composite Overwrapped Pressure Vessels (COPVs) that have survived a long service time under pressure generally must be recertified before service is extended. Flight certification is dependent on the reliability analysis to quantify the risk of stress rupture failure in existing flight vessels. Full certification of this reliability model would require a statistically significant number of lifetime tests to be performed and is impractical given the cost and limited flight hardware for certification testing purposes. One approach to confirm the reliability model is to perform a stress rupture test on a flight COPV. Currently, testing of such a Kevlar49 (Dupont)/epoxy COPV is nearing completion. The present paper focuses on a Bayesian statistical approach to analyze the possible failure time results of this test and to assess the implications in choosing between possible model parameter values that in the past have had significant uncertainty. The key uncertain parameters in this case are the actual fiber stress ratio at operating pressure, and the Weibull shape parameter for lifetime; the former has been uncertain due to ambiguities in interpreting the original and a duplicate burst test. The latter has been uncertain due to major differences between COPVs in the database and the actual COPVs in service. Any information obtained that clarifies and eliminates uncertainty in these parameters will have a major effect on the predicted reliability of the service COPVs going forward. The key result is that the longer the vessel survives, the more likely the more optimistic stress ratio model is correct. At the time of writing, the resulting effect on predicted future reliability is dramatic, increasing it by about one "nine," that is, reducing the predicted probability of failure by an order of magnitude. However, testing one vessel does not change the uncertainty on the Weibull shape parameter for lifetime since testing several vessels would be necessary.

Phoenix, S. Leigh↗

NASA NTRSDate not supplied

Development, Build and Certification of the Alternate Fecal Canister (AFC) Hardware for the NASA Exploration Toilet

On longer range exploration missions, the mass and volume of critical hardware and consumables that will be needed to support crew will pose a big stowage challenge. This includes the hardware needed for the collection and storage of human metabolic waste. The amount of stowage needed for this hardware both before (empty) and after (full) use will be a significant burden on the overall spacecraft habitable volume, layout, and design. To help with this challenge, the National Aeronautics and Space Administration (NASA) has developed a collapsible canister for the collection and containment of fecal deposits. The Alternate Fecal Canister (AFC) is an alternative to the exploration toilet hard-sided fecal canister. The AFC is collapsible in its empty state which is a volume benefit to smaller vehicles on longer missions. In addition, the use of lighter-weight materials provides a reduction in mass of the overall container. This paper will provide a summary of the AFC design including final flight design and build, acceptance and qualification testing completed, final certification and delivery and forward plans for a technology demonstration with the exploration toilet on the International Space Station (ISS). In addition, a summary of issues and final resolution encountered during flight build and testing will also be provided. As part of the acceptance and certification process for AFC, the hardware was also put into several rounds of odor testing with the support of the White Sands Test Facility (WSTF). The details, planning and anomalies identified during odor testing will also be summarized in this paper. Finally, a brief overview of potential future design upgrades including changes to address any crew feedback from the ISS demonstration will be discussed.

Fecal Canister↗

NASA NTRSDate not supplied

Development, Build and Certification of the Alternate Fecal Canister (AFC) Hardware for the NASA Exploration Toilet

On longer range exploration missions, the mass and volume of critical hardware and consumables that will be needed to support crew will pose a big stowage challenge. This includes the hardware needed for the collection and storage of human metabolic waste. The amount of stowage needed for this hardware both before (empty) and after (full) use will be a significant burden on the overall spacecraft habitable volume, layout, and design. To help with this challenge, the National Aeronautics and Space Administration (NASA) has developed a collapsible canister for the collection and containment of fecal deposits. The Alternate Fecal Canister (AFC) is an alternative to the exploration toilet hard-sided fecal canister. The AFC is collapsible in its empty state which is a volume benefit to smaller vehicles on longer missions. In addition, the use of lighter-weight materials provides a reduction in mass of the overall container. This paper will provide a summary of the AFC design including final flight design and build, acceptance and qualification testing completed, final certification and delivery and forward plans for a technology demonstration with the exploration toilet on the International Space Station (ISS). In addition, a summary of issues and final resolution encountered during flight build and testing will also be provided. As part of the acceptance and certification process for AFC, the hardware was also put into several rounds of odor testing with the support of the White Sands Test Facility (WSTF). The details, planning and anomalies identified during odor testing will also be summarized in this paper. Finally, a brief overview of potential future design upgrades including changes to address any crew feedback from the ISS demonstration will be discussed.

Fecal Canister↗

NASA NTRSDate not supplied

Development, Build and Certification of the Alternate Fecal Canister (AFC) Hardware for the NASA Exploration Toilet

On longer range exploration missions, the mass and volume of critical hardware and consumables that will be needed to support crew will pose a big stowage challenge. This includes the hardware needed for the collection and storage of human metabolic waste. The amount of stowage needed for this hardware both before (empty) and after (full) use will be a significant burden on the overall spacecraft habitable volume, layout, and design. To help with this challenge, the National Aeronautics and Space Administration (NASA) has developed a collapsible canister for the collection and containment of fecal deposits. The Alternate Fecal Canister (AFC) is an alternative to the exploration toilet hard-sided fecal canister. The AFC is collapsible in its empty state which is a volume benefit to smaller vehicles on longer missions. In addition, the use of lighter-weight materials provides a reduction in mass of the overall container. This paper will provide a summary of the AFC design including final flight design and build, acceptance and qualification testing completed, final certification and delivery and forward plans for a technology demonstration with the exploration toilet on the International Space Station (ISS). In addition, a summary of issues and final resolution encountered during flight build and testing will also be provided. As part of the acceptance and certification process for AFC, the hardware was also put into several rounds of odor testing with the support of the White Sands Test Facility (WSTF). The details, planning and anomalies identified during odor testing will also be summarized in this paper. Finally, a brief overview of potential future design upgrades including changes to address any crew feedback from the ISS demonstration will be discussed.

Fecal Canister↗

NASA NTRS1991

Applied high-speed imaging for the icing research program at NASA Lewis Research Center

The Icing Research Tunnel at NASA Lewis Research Center provides scientists a scaled, controlled environment to simulate natural icing events. The closed-loop, low speed, refrigerated wind tunnel offers the experimental capability to test for icing certification requirements, analytical model validation and calibration techniques, cloud physics instrumentation refinement, advanced ice protection systems, and rotorcraft icing methodology development. The test procedures for these objectives all require a high degree of visual documentation, both in real-time data acquisition and post-test image processing. Information is provided to scientific, technical, and industrial imaging specialists as well as to research personnel about the high-speed and conventional imaging systems will be on the recent ice protection technology program. Various imaging examples for some of the tests are presented. Additional imaging examples are available from the NASA Lewis Research Center's Photographic and Printing Branch.

Slater, Howard↗

NASA NTRS1992

Applied high-speed imaging for the icing research program at NASA Lewis Research Center

The Icing Research Tunnel at NASA Lewis Research Center provides scientists a scaled, controlled environment to simulate natural icing events. The closed-loop, low speed, refrigerated wind tunnel offers the experimental capability to test for icing certification requirements, analytical model validation and calibration techniques, cloud physics instrumentation refinement, advanced ice protection systems, and rotorcraft icing methodology development. The test procedures for these objectives all require a high degree of visual documentation, both in real-time data acquisition and post-test image processing. Information is provided to scientific, technical, and industrial imaging specialists as well as to research personnel about the high-speed and conventional imaging systems will be on the recent ice protection technology program. Various imaging examples for some of the tests are presented. Additional imaging examples are available from the NASA Lewis Research Center's Photographic and Printing Branch.

Slater, Howard↗