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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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Highly efficient laser sources are required for deep space optical telecommunication. This paper investigates the efficiency components for pulsed diode pumped solid state laser transmittersand determines the overall wall-plug efficiency applicable to a spaceborne system.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
A self-pulsing oscillator transmits a pulsed signal. The time between pulses and the frequency are controlled by two networks. Variations in the component values in each of the two networks, due to environmental changes, appear as changes in frequency and time between pulses in the transmitted signal. Such a sensor is used to measure physical magnitudes.
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For two-way radio communication where safety gear is required, a lightweight helmet with few protrusions has been designed. The electronics components and power supply are mounted between the inner and outer shells, and resilient padding is used for the lining.
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Television system - evaluation of transmitting and receiving equipment
Linear frequency modulation of locked oscillator design specifications
Application of the exposure value system requires that the system be extended to high brightness level and expanded to include filter factors. A minimum of four photographic factors are involved in the evaluation of an exposure which, when determined from tables of 1-stop interval, could introduce noticeable error.
Energy transmitting characteristics and wall local energy absorption distribution of curved specular reflecting duct irradiated by collimated beam
The transmission characteristics of synthesized optical single-pass and double-pass birefringent networks is obtained by measuring network transmission as a function of network temperature. This technique is most useful for testing those birefringent networks whose bandwidths and periods are very small.
Crash locater is automatically ejected from aircraft at time of crash and begins transmitting at emergency radio frequencies monitored by all airports and airport control towers. Advantages are smaller size, simpler design and installation, extended transmitting range and life, greater deployment reliability and increased crash resistance.
Development of apparatus for amplitude modulation of diode laser by periodic discharge of direct current power supply
Two endurance tests of a 5-cm mercury bombardment thruster are reported. Both tests used a translational screen-grid system with the beam vectored 10 degrees. The first test lasted 141 hours and the second test operated for 2026 hours. In each test two fused silica samples (solar cell covers), 2.0 cm by 2.1 cm, were placed in shielded holders to detect materials sputtered from the thruster. Spectral optical properties between 0.398 and 2.16 microns were measured on each sample, both before and after the endurance tests. The deposition on each sample was spectrographically analyzed to determine the type of materials sputtered from the thruster. It was found that sputtering from the neutralizer is highly dependent on its position with respect to the beam edge. The sputtering from the accelerator grid of the translational screen-grid system of the 2026 hour test was sufficient to form an opaque film on the sample located in the direction opposite to the vectored beam.
The results achieved toward developing a baseline communications channel model for studying low bit rate telemetry transmissions from Venus Planetary Explorer spacecraft are presented. The overall communications systems model, discrete channel model, input signal generation, and signal acquisition model are discussed. Discrete Fourier transform considerations, sampling routines, and flow charts are included.
The level of irradiation-induced optical absorption and the resulting heat deposition in the transparent fused-silica wall of a nuclear light bulb engine during normal operation are investigated by means of a series of related experiments using available radiation sources, each of which simulates some aspect of the radiation flux or dose of the engine. A comparison of the results obtained in electron and reactor experiments indicates that the generation of optical absorption is due to ionizing effects and that neutron-caused displacement effects do not contribute significantly to optical absorption. The implications of these and other results obtained are discussed.