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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1970

Passive gravity gradient libration dampers

Book on passive gravity gradient libration dampers covering design, flight experience, evaluation criteria, performance monitoring, failure prevention, etc

Herzl, G. G.↗
NASA NTRS1971

Experiment S029: Earth-Moon libration regions photography

Eleven photographs were taken of the L sub 4 earth-moon libration region during the Gemini 12 mission. The objective was to investigate the possible existence of clouds or particles of dust orbiting the earth in the L sub 4 region by the use of photographic techniques. No identifiable data were found in the first sequence of five photographs. Star field images could be recognized in two photographs of the second sequence of pictures. A light flare, of unknown source but possibly caused by light refraction from the window of the spacecraft, was recorded in both pictures. A reconstructed star field region (as photographed) is shown Isodensitraces of the two recognizable star fields were made; however, no conclusive results were obtained.

Morris, E. C.↗
NASA NTRS1972

Measurement of physical librations using laser retroreflectors.

Discussion of the applicability to lunar physics of the libration measurements obtained from the Apollo lunar laser ranging experiment, and assessment of the data obtained with respect to their adequacy for providing the desired information. A review of measurement principles and lunar properties is followed by an evaluation of the status of data collection.

Mulholland, J. D.↗
NASA NTRS1972

Quasi-periodic orbits about the translunar libration point.

Analytical solutions for quasi-periodic orbits about the translunar libration point are obtained by using the method of Lindstedt-Poincare and computerized algebraic manipulations. The solutions include the effects of nonlinearities, lunar orbital eccentricity, and the sun's gravitational field. For a small-amplitude orbit, the orbital path as viewed from the earth traces out a Lissajous figure. This is due to a small difference in the fundamental frequencies of the in-plane and out-of-plane oscillations. However, when the amplitude of the in-plane oscillation is greater than 32,379 km, there is a corresponding value of the out-of-plane amplitude that will produce a path where the fundamental frequencies are equal. This synchronized trajectory describes a 'halo orbit' of the moon.

Farquhar, R. W.↗