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At least 1,243 records · Page 69
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Results of acoustic tests of a Prop-Fan model

Results of acoustic tests in a low speed open jet anechoic wind tunnel are presented for a counter rotation Prop-Fan model. The model tested had 5 front and 5 rear rotor blades with swept planform. Noise spectra are presented showing the influence of operating and configuration variables such as: (1) power absorption, (2) tip speed, (3) rotor-rotor spacing, (4) power split between the front and rear blade rows, (5) variation of the RPM ratio between front and rear blade rows, (6) tractor versus pusher (pylon effects), and (7) angle of attack. In addition to model scale results, calculated levels derived from test are presented showing the influence of the above variables on Effective Perceived Noise Level of a 13.1 ft diameter Prop-Fan at a flyover distance of 1500 ft. It was found that the strongest effects are caused by tip speed and power absorption. A significant finding was that there is an optimum operating tip speed for minimum noise for a given power absorption. Effects of other parametric variations are generally small but measurable. In order to minimize noise to meet airplane certification limits, operation at moderate tip speeds and power absorption is shown to be desirable. Accuracy of predicted Effective Perceived Noise Level is shown to be good with the best accuracy in the 590 to 670 ft/sec tip speed range.

Metzger, F.B.↗
NASA NTRS1987

A monograph of the National Space Transportation System Office (NSTSO) integration activities conducted at the NASA Lyndon B. Johnson Space Center for the EASE/ACCESS payload flown on STS 61-B

The integration process of activities conducted at the NASA Lyndon B. Johnson Space Center (JSC) for the Experimental Assembly of Structures in Extravehicular activity (EASE)/Assembly Concept for Construction of Erectable Space Structures (ACCESS) payload is provided as a subset to the standard payload integration process used by the NASA Space Transportation System (STS) to fly payloads on the Space Shuttle. The EASE/ACCESS payload integration activities are chronologically reviewed beginning with the initiation of the flight manifesting and integration process. The development and documentation of the EASE/ACCESS integration requirements are also discussed along with the implementation of the mission integration activities and the engineering assessments supporting the flight integration process. In addition, the STS management support organizations, the payload safety process leading to the STS 61-B flight certification, and the overall EASE/ACCESS integration schedule are presented.

Chassay, Charles↗
NASA NTRS1987

Experiments in fault tolerant software reliability

The reliability of voting was evaluated in a fault-tolerant software system for small output spaces. The effectiveness of the back-to-back testing process was investigated. Version 3.0 of the RSDIMU-ATS, a semi-automated test bed for certification testing of RSDIMU software, was prepared and distributed. Software reliability estimation methods based on non-random sampling are being studied. The investigation of existing fault-tolerance models was continued and formulation of new models was initiated.

Mcallister, David F.↗
NASA NTRS1988

Recent Langley helicopter acoustics contributions

The helicopter acoustics program at NASA Langley has included technology for elements of noise control ranging from sources of noise to receivers of noise. The scope of Langley contributions for about the last decade is discussed. Specifically, the resolution of two certification noise quantification issues by subjective acoustics research, the development status of the helicopter system noise prediction program ROTONET are reviewed and the highlights from research on blade rotational, broadband, and blade vortex interaction noise sources are presented. Finally, research contributions on helicopter cabin (or interior) noise control are presented. A bibliography of publications from the Langley helicopter acoustics program for the past 10 years is included.

Morgan, Homer G.↗
NASA NTRS1988

Airborne Wind Shear Detection and Warning Systems: First Combined Manufacturers' and Technologists' Conference

The purpose of the meeting was to transfer significant, ongoing results gained during the first year of the joint NASA/FAA Airborne Wind Shear Program to the technical industry and to pose problems of current concern to the combined group. It also provided a forum for manufacturers to review forward-looking technology concepts and for technologists to gain an understanding of FAA certification requirements and the problems encountered by the manufacturers during the development of airborne equipment.

Spady, Amos A., Jr.↗
NASA NTRS1988

Airworthiness considerations

Guidance is provided for the airworthiness approval of both annunciation only and annunciation with guidance airborne windshear warning systems. Characteristics of a comprehensive certification plan, the criticality of certain system failure cases for windshear warning with and without escape guidance, software based systems, and probability analysis are among the topics covered.

Stoer, Ray↗
NASA NTRS1988

Specification for IBM/IBM compatible 3480 tape cartridge

This document establishes the same kinds of standards and controls that are currently in use for the procurement on new analog and digital magnetic tapes. The Magnetic Tape Certification Facility (MTCF) currently maintains a Quality Products List (QPL) for all new analog and digital magnetic tapes purchased by NASA-GSFC. Extensive tests are conducted in the MTCF on an annual basis to determine the manufacturer's tape types to be added to or deleted from the current QPL. The MTCF currently maintains two specifications for magnetic tapes: NASA TM-79724 is used for the QPL and acceptance testing of new analog tapes; and NASA TM-80599 is used for the QPL and acceptance testing of new digital tapes. This specification will be used for the QPL and acceptance testing of new 3480 cartridges. The magnetic tapes used by GSFC, LaRC, ARC/Dryden, WFF, and the Network Tracking Stations are covered by the NASA-GSFC specifications. The 3480 cartridge was introduced approximately 3.5 years ago and is becoming an increasingly attractive alternative to digital magnetic tapes. Many users have already converted to the 3480 system and have more tape drives on order.

Perry, Jimmy L.↗
NASA NTRS1988

Langley Research Center Metrology Program status for fiscal year 1987

The status of the Langley Research Center's metrology program for fiscal year 1987 is presented. The NASA Metrology Information System, which was operational for the entire year, provided the majority of performance data describing work analysis, turnaround time, out-of-tolerance instrument data, and other instrument service data. Calibration system development, equipment replacing and updating, status of last year's planned objectives, and Reference Standard certification requirements are described. The status of the LaRC voltage and resistance measurement assurance program and the agency-wide resistance program are reviewed. Progress on fiscal year 1987 objectives is discussed and fiscal year 1988 objectives are stated.

Kern, Frederick A.↗
NASA NTRS1987

Status review of atmosphere turbulence and aircraft response

A brief review is made of the understanding of aircraft encounter of atmospheric turbulence, both from the point of view of describing or modeling the turbulence and with respect to the ability to calculate resulting airplane loads. Some of the more recent studies of gust measurements and of reducing airline gust response data are discussed. Special attention is given to gust analysis requirements as involved in airplane certification and whether there is a need for additional or different requirements. A review is made of a recent study in which amazingly simple and universal gust response equations were discovered; the possible impact of these new findings on future work is indicated.

Houbolt, J. C.↗
NASA NTRS1987

U.S. Space Shuttle Solid Rocket Booster - Return to flight

The Space Shuttle Solid Rocket Booster (SRB) redesign program instituted in the wake of the Challenger accident encompassed a design requirements review, a failure modes effect analysis/critical items list determination, a hazards analysis, an operational maintenance and requirements specification study, the definition of operational maintenance instructions and launch commit criteria, and design certification and flight readiness reviews. Attention is presently given to the SRB's thrust vector control, separation, and recovery functions, as well as its electrical and instrumentation systems and its case assembly and hardware interfaces.

Coates, K. D.↗
NASA NTRS1988

Launch team training system

A new approach to the training, certification, recertification, and proficiency maintenance of the Shuttle launch team is proposed. Previous training approaches are first reviewed. Short term program goals include expanding current training methods, improving the existing simulation capability, and scheduling training exercises with the same priority as hardware tests. Long-term goals include developing user requirements which would take advantage of state-of-the-art tools and techniques. Training requirements for the different groups of people to be trained are identified, and future goals are outlined.

Webb, J. T.↗
NASA NTRS1988

Identification of large structures on orbit - A survey

This paper seeks to provide a brief overview of the somewhat unfamiliar concept underlying system identification especially as it applies to large flexible space structures. Having elaborated on the concept, the authors provide a detailed description of the identification process including model development, its experimental validation and final certification. This discussion is followed by a classification of the different identification methods and a brief evaluation of the potential of existing methodology to address special circumstances of large flexible space structures. The paper concludes by making a few recommendations that are deemed necessary to meet the enormous challenges posed by the deployment or erection of large space structures.

Denman, Eugene E.↗
NASA NTRS1988

Specification for wide channel bandwidth one-inch video tape

Standards and controls are established for the procurement of wide channel bandwidth one inch video magnetic recording tapes for Very Long Base Interferometer (VLBI) system applications. The Magnetic Tape Certification Facility (MTCF) currently maintains three specifications for the Quality Products List (QPL) and acceptance testing of magnetic tapes. NASA-TM-79724 is used for the QPL and acceptance testing of new analog tapes; NASA-TM-80599 is used for QPL and acceptance testing of new digital tapes; and NASA-TM-100702 is used for the QPL and acceptance testing of new IBM/IBM compatible 3480 magnetic tape cartridges. This specification will be used for the QPL and acceptance testing of new wide channel bandwidth one inch video magnetic recording tapes. The one inch video tapes used by the Jet Propulsion Lab., the Deep Space Network and the Haystack Observatory will be covered by this specification. These NASA stations will use the video tapes for their VLBI system applications. The VLBI system is used for the tracking of quasars and the support of interplanetary exploration.

Perry, Jimmy L.↗
NASA NTRS1988

Controls and guidance: Space

The Space Controls and Guidance Research and Technology Program is directed toward enabling the next generation of space transportation systems, large future spacecraft, and space systems such as the Space Station to have large communication antennas and high precision segmented reflector astrophysical telescopes. The new generation of transportation vehicles has demanding requirements to provide for an order of magnitude reduction in cost as well as an increase in capability. The future orbital facilities have demanding control requirements for pointing and stabilization, momentum management, build-up and growth accomodation, and disturbance management. To address these advanced requirements, the research and development program is designed to provide the generic technology base to support the implementation of advanced guidance, navigation, and control. The area of computational controls will be stressed in order to develop cost effective, high speed, high fidelity control system simulation and analysis and synthesis tools. The trust of this work will be to develop methods and software to enable analysis and real-time hardware-in-the-loop simulation of complex spacecraft for control design certification. To address future orbital facilities requirements, an advanced technology program is underway in system identification, distributed control, integrated controls/structures design methods, and advanced sensors and actuators. Because the behavior of large, light weight per unit area deployable/assembled spacecraft is greatly influenced by the ground environment, the testing and verification activity is both ground- and space-based.

Dibattista, John D.↗
NASA NTRS1988

Center for Advanced Space Propulsion (CASP)

With a mission to initiate and conduct advanced propulsion research in partnership with industry, and a goal to strengthen U.S. national capability in propulsion technology, the Center for Advanced Space Propulsion (CASP) is the only NASA Center for Commercial Development of Space (CCDS) which focuses on propulsion and associated technologies. Meetings with industrial partners and NASA Headquarters personnel provided an assessment of the constraints placed on, and opportunities afforded commercialization projects. Proprietary information, data rights, and patent rights were some of the areas where well defined information is crucial to project success and follow-on efforts. There were five initial CASP projects. At the end of the first year there are six active, two of which are approaching the ground test phase in their development. Progress in the current six projects has met all milestones and is detailed. Working closely with the industrial counterparts it was found that the endeavors in expert systems development, computational fluid dynamics, fluid management in microgravity, and electric propulsion were well received. One project with the Saturn Corporation which dealt with expert systems application in the assembly process, was placed on hold pending further direction from Saturn. The Contamination Measurment and Analysis project was not implemented since CASP was unable to identify an industrial participant. Additional propulsion and related projects were investigated during the year. A subcontract was let to a small business, MicroCraft, Inc., to study rocket engine certification standards. The study produced valuable results; however, based on a number of factors it was decided not to pursue this project further.

Source record↗
NASA NTRS1989

Qualification Motor no. 8 (QM-8), volume 1

All inspection and instrumentation data indicate that the QM-8 static test firing conducted 20 January 1989 was successful. Ambient temperature at T-0 was 28 F. With two flights successfully accomplished, this final test in the redesigned solid rocket motor (RSRM) program certified that the design meets motor performance requirements under extreme cold conditions. This test was a prerequisite to the third flight. The entire test article was cold conditioned at 20 to 25 F for approximately 31 days to assure a maximum propellant mean bulk temperature (PMBT) of 40 F, making it the lowest PMBT in the history of the program. This extreme condition also presented the opportunity to certify critical components at low temperatures. Certification of field joint and igniter heaters, adhesive bondline integrity, flex bearing performance, flight instrumentation performance, RSRM seal performance, and LSC and nozzle plug performance was accomplished. Prior to motor ignition, the field joints were maintained between 75 to 130 F, the igniter-to-case joint was maintained between 75 to 123 F, and the case-to-nozzle joint was maintained between 75 to 120 F. QM-8 was tested with induced side loads to simulate the strut loads experienced during ignition and maximum aerodynamic loading conditions. The ability of the safe and arm device to change position from safe-to-arm and arm-to-safe was certified. Ballistics performance was certified at the lower limits. Values were within specification requirements. Nozzle performance was nominal with typical erosion. The use of Fiberite carbon-cloth phenolic was certified. The water deluge system, CO2 quench, and other test equipment performed as planned during all required test operations.

Garecht, D. M.↗
NASA NTRS1989

Protoflight photovoltaic power module system-level tests in the space power facility

Work Package Four, which includes the NASA-Lewis and Rocketdyne, has selected an approach for the Space Station Freedom Photovoltaic (PV) Power Module flight certification that combines system level qualification and acceptance testing in the thermal vacuum environment: The protoflight vehicle approach. This approach maximizes ground test verification to assure system level performance and to minimize risk of on-orbit failures. The preliminary plans for system level thermal vacuum environmental testing of the protoflight PV Power Module in the NASA-Lewis Space Power Facility (SPF), are addressed. Details of the facility modifications to refurbish SPF, after 13 years of downtime, are briefly discussed. The results of an evaluation of the effectiveness of system level environmental testing in screening out incipient part and workmanship defects and unique failure modes are discussed. Preliminary test objectives, test hardware configurations, test support equipment, and operations are presented.

Rivera, Juan C.↗