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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 901 records · Page 50
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Experimental and calculated LET distributions in the Cosmos-2044 biosatellite orbit

During the flight of the Cosmos-2044 biosatellite, joint U.S.S.R.-U.S.A. investigations of different characteristics of cosmic radiation (CR) in the near-Earth environment were carried out. The U.S. dielectric track detectors CR-39 and Soviet BYa- and BR-type nuclear photo-emulsions were used as detectors. The present work shows some results of experimental measurements of linear energy transfer (LET) spectra of CR particles obtained with the use of these detectors, which were placed both inside and outside the satellite. The LET spectra measurement with plastic detectors is composed of two parts: the measurement of galactic cosmic rays (GCR) particles, and of short-range particles. The contributions of these components to the total LET distribution at various thicknesses of the shielding were analyzed and the results of these studies are presented. Calculated LET spectra in the Cosmos-2044 orbit were compared with experimental data. On the basis of experimental and calculated values of the LET spectra, absorbed and equivalent CR doses were calculated. In the shielding range of 1-1.5 g cm-2, outside the spacecraft, the photo-emulsions yielded 10.3 mrad d-1 and 27.5 mrem d-1 (LET > or = 2 MeV cm-1) while the CR-39 yielded averages of 1.43 mrad d-1 and 13.4 mrem d-1 (LET > or = 40 MeV cm-1). Inside the spacecraft (> or = 10 g cm-2) the photo-emulsions yielded 8.9 mrad d-1 and 14.5 mrem d-1.

NASA Program Radiation Health↗
NASA NTRS1996

In-flight radiation measurements on STS-60

A joint investigation between the United States and Russia to study the radiation environment inside the Space Shuttle flight STS-60 was carried out as part of the Shuttle-Mir Science Program (Phase 1). This is the first direct comparison of a number of different dosimetric measurement techniques between the two countries. STS-60 was launched on 3 February 1994 in a nearly circular 57 degrees x 353 km orbit with five U.S. astronauts and one Russian cosmonaut for 8.3 days. A variety of instruments provided crew radiation exposure, absorbed doses at fixed locations, neutron fluence and dose equivalent, linear energy transfer (LET) spectra of trapped and galactic cosmic radiation, and energy spectra and angular distribution of trapped protons. In general, there is good agreement between the U.S. and Russian measurements. The AP8 Min trapped proton model predicts an average of 1.8 times the measured absorbed dose. The average quality factor determined from measured lineal energy, y, spectra using a tissue equivalent proportional counter (TEPC), is in good agreement with that derived from the high temperature peak in the 6LiF thermoluminescent detectors (TLDs). The radiation exposure in the mid-deck locker from neutrons below 1 MeV was 2.53 +/- 1.33 microSv/day. The absorbed dose rates measured using a tissue equivalent proportional counter, were 171.1 +/- 0.4 and 127.4 +/- 0.4 microGy/day for trapped particles and galactic cosmic rays, respectively. The combined dose rate of 298.5 +/- 0.82 microGy/day is about a factor of 1.4 higher than that measured using TLDs. The westward longitude drift of the South Atlantic Anomaly (SAA) is estimated to be 0.22 +/- 0.02 degrees/y. We evaluated the effects of spacecraft attitudes on TEPC dose rates due to the highly anisotropic low-earth orbit proton environment. Changes in spacecraft attitude resulted in dose-rate variations by factors of up to 2 at the location of the TEPC.

NASA Discipline Radiation Health↗
NASA NTRS1975

Influence of head orientation on visually induced pitch and roll sensation

Observers viewing rotating scenes in their periphery frequently experience self-motion in the opposite direction. A full field flight simulator projection system was used to investigate the sensations resulting from pitch, roll, and yaw stimuli at various head orientations. Steady yaw rate (circularvection) and development of a constant roll tilt angle, for the head erect and constant velocity yaw and roll stimuli, confirmed previous reports. Pitch stimuli also were found to produce a sensation of tilting to a steady pitch angle, which was much stronger for pitch forward than backward. Pitch and roll effects were strongly dependent on head position, increasing for the head rolled 90 deg to the side or inverted, and decreasing for the head pitched 25 deg forward. These results support a hypothesis that visually induced tilt is limited by conflict with otolith information.

Young, L. R.↗
NASA NTRS1977

Effect of forward motion on engine noise

Methods used to determine a procedure for correcting static engine data for the effects of forward motion are described. Data were analyzed from airplane flyover and static-engine tests with a JT8D-109 low-bypass-ratio turbofan engine installed on a DC-9-30, with a CF6-6D high-bypass-ratio turbofan engine installed on a DC-10-10, and with a JT9D-59A high-bypass-ratio turbofan engine installed on a DC-10-40. The observed differences between the static and the flyover data bases are discussed in terms of noise generation, convective amplification, atmospheric propagation, and engine installation. The results indicate that each noise source must be adjusted separately for forward-motion and installation effects and then projected to flight conditions as a function of source-path angle, directivity angle, and acoustic range relative to the microphones on the ground.

Blankenship, G. L.↗
NASA NTRS1981

Assessment of inflow control structure effectiveness and design system development

Inflow control structures used during static testing of fans are shown to minimize inflow distortions and thus stimulate the inflight flow field and noise generating mechanisms. Acoustic tests are conducted on a Pratt and Whitney aircraft JT9D engine with and without an inflow control structure. Raw data are corrected to 77 deg, and time is averaged over 0.5 second intervals. Use of an inflow control structure is found to significantly reduce blade passage frequency tone, while having little effect on twice blade passage frequency tones, and significantly improves agreement between static data projected to flight and flight data for the blade passage frequency fan tone. A design system is also presented, which prescribes structure shape, size and construction.

Peracchio, A. A.↗
NASA NTRS1981

Preprototype Vapor Compression Distillation Subsystem development

Vapor Compression Distillation (VCD) has evolved as the most promising approach to reclaim potable water from wastewater for future long-term manned space missions. Life Systems, Inc. (LSI), working with NASA, has developed a preprototype Vapor Compression Distillation Subsystem (VCDS) which processes wastewater at 1.4 kg/h. The preprototype unit weighs 143 kg, occupies a volume of 0.47 cu m, and will reclaim 96 percent of the available wastewater. This unit has been tested by LSI and is scheduled for further testing at NASA-JSC. This paper presents the preprototype VCDS design, configuration, performance data, test results and flight system projections.

Thompson, C. D.↗
NASA NTRS1984

Measurement and prediction of Energy Efficient Engine noise

The NASA/GE Energy Efficient Engine (E3) static noise levels were measured in an acoustic arena on the Integrated Core and Low Spool Test System. These measured levels were scaled to the appropriate size to power four study aircraft and were projected to flight for evaluation of noise levels relative to FAR36, Stage III limits. As a result of these evaluations, it is predicted that the NASA/GE E3 engine with a wide spacing cut-on blade/vane ratio fan and a forced mixer nozzle can meet FAR36 Stage III limits with sufficient design margin.

Lavin, S. P.↗
NASA NTRS1987

Product assurance policies and procedures for flight dynamics software development

The product assurance policies and procedures necessary to support flight dynamics software development projects for Goddard Space Flight Center are presented. The quality assurance and configuration management methods and tools for each phase of the software development life cycles are described, from requirements analysis through acceptance testing; maintenance and operation are not addressed.

Perry, Sandra↗
NASA NTRS1985

Space missions for automation and robotics technologies (SMART) program

The motivations, features and expected benefits and applications of the NASA SMART program are summarized. SMART is intended to push the state of the art in automation and robotics, a goal that Public Law 98-371 mandated be an inherent part of the Space Station program. The effort would first require tests of sensors, manipulators, computers and other subsystems as seeds for the evolution of flight-qualified subsystems. Consideration is currently being given to robotics systems as add-ons to the RMS, MMU and OMV and a self-contained automation and robotics module which would be tended by astronaut visits. Probable experimentation and development paths that would be pursued with the equipment are discussed, along with the management structure and procedures for the program. The first hardware flight is projected for 1989.

Ciffone, D. L.↗
NASA NTRS1988

Configuration management issues and objectives for a real-time research flight test support facility

An account is given of configuration management activities for the Western Aeronautical Test Range (WATR) at NASA-Ames, whose primary function is the conduct of aeronautical research flight testing through real-time processing and display, tracking, and communications systems. The processing of WATR configuration change requests for specific research flight test projects must be conducted in such a way as to refrain from compromising the reliability of WATR support to all project users. Configuration management's scope ranges from mission planning to operations monitoring and performance trend analysis.

Yergensen, Stephen↗
NASA NTRS1988

Recent laboratory results of the KITE attitude dynamics simulator

It has previously been shown that, for all but the most simple tethered satellite missions, conventional means of performing attitude control are insufficient. A particularly effective method of implementing attitude control for tethered satellites is to use the tether tension force to generate control torques by moving the tether attach point relative to the satellite center of mass. It has been proposed to demonstrate this attitude control technique in a Space Shuttle flight test project known as the Kinetic Isolation Tether Experiment (KITE). This paper describes a scaled, one dimensional laboratory simulation of the KITE mission. The simulator has been built to verify theoretical predictions of attitude control ability and to investigate the technological requirements in order to implement this concept. The laboratory apparatus is described in detail and preliminary experimental results are presented and discussed. The results to date have shown a fine pointing accuracy of 5 arc-seconds RMS and a closed-loop bandwidth of 0.08 Hz.

Kline-Schoder, Robert↗