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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Interferometric studies of interstellar calcium lines.

Review of interferometric, photoelectric scans of the interstellar calcium K-lines in the spectra of 65 stars. The scans were obtained with a PEPSIOS spectrometer having a passband with a full half-intensity width of 1.0 km/sec or 0.013 A. The fivefold improvement in resolution over that used by Adams reveals numerous line components which correspond very well to those of the interstellar sodium lines, apart from frequent differences in relative intensities.

Marschall, L. A.↗
NASA NTRS1973

Interferometric rotation sensor

An interferometric rotation sensor and control system is provided which includes a compound prism interferometer and an associated direction control system. Light entering the interferometer is split into two paths with the light in the respective paths being reflected an unequal number of times, and then being recombined at an exit aperture in phase differing relationships. Incoming light is deviated from the optical axis of the device by an angle, alpha. The angle causes a similar displacement of the two component images at the exit aperture which results in a fringe pattern. Fringe numbers are directly related to angle alpha. Various control systems of the interferometer are given.

Walsh, T. M.↗
NASA NTRS1972

Interferometric observations of an artificial satellite.

Very-long-baseline interferometric observations of radio signals from the TACSAT synchronous satellite, even though extending over only 7 hours, have enabled an excellent orbit to be deduced. Precision in differential delay and delay-rate measurements reached 0.15 nanosecond and 0.05 picosecond per second, respectively. The results from this initial three-station experiment demonstrate the feasibility of using the method for accurate satellite tracking and for geodesy.

Preston, R. A.↗
NASA NTRS1973

Interferometric studies of interstellar CH/+/ molecules.

The work reported consists of interferometric, photoelectric scans in the region of the line at 4232 A in the spectra of 28 stars. An instrumental passband of about 0.014 A was selected for the observations. In comparison with the capabilities of the older methods utilized in particular by Adams, the present method yields a fivefold improvement in spectral resolution, as well as the higher accuracy inherent in photoelectric detection. As a result, the detailed line profiles of individual line components can be recorded rather than only the composite equivalent widths.

Hobbs, L. M.↗
NASA NTRS1973

Investigation of laser holographic interferometric techniques for structure inspection

The application of laser holographic interferometric techniques for nondestructive inspection of material structures commonly used in aerospace works is investigated. Two types of structures, composite plate and solid fuel rocket engine motor casing, were examined. In conducting the experiments, both CW HeNe gas lasers and Q-switched ruby lasers were used as light sources for holographic recording setups. Different stressing schemes were investigated as to their effectiveness in generating maximum deformation at regions of structural weakness such as flaws and disbonds. Experimental results on stressing schemes such as thermal stressing, pressurized stressing, transducer excitation, and mechanical impact are presented and evaluated.

Chu, W. P.↗
NASA NTRS1974

Interferometric scans of interstellar K I lines

Results of interferometric scans of the interstellar 7669 wavelength line of neutral potassium are reported toward 26 stars at 1.2 km/sec resolution. The advantages of the K I line, as compared with other optical interstellar lines, are discussed. Recent progress in photoanalytical techniques are shown to make possible the effective realization in practice of the inherent advantages of the K I line.

Hobbs, L. M.↗