Lunar Reflectance Research Articles

Low Insertion-Loss, Capacitively Scanned Goniometer for Faraday Rotation Measurements in the vhf Range

The theory and design of a low insertion-loss electrical device to simulate a rotating dipole for Faraday rotation measurements in the frequency range 20–60 Mc is discussed. Experiment involving satellite emissions and lunar reflections are described.

A Note on the Theory of Moon Echoes

A simple statistical model of the large-scale irregularities of the moon's surface is described, which gives agreement with the main features of lunar radio reflections.

Irregular lunar reflection polarization changes noted in the presence of aurora

Bistatic lunar reflection of 99.4-Mc signals was used to determine the total integrated ionospheric electron density. On November 13, 1960, fast, irregular changes in the received signal polarization occurred during the time that a visible aurora was observed along one leg of the bistatic path- After sunrise on the same day slow, regular Faraday polarization rotation was observed. It is suggested that the ordinary and extraordinary ray components that travel along slightly different paths may have encountered small, high-velocity ionospheric irregularities, thus producing unusual signal phase changes. (auth)

Early Results of the 1961 JPL Venus Radar Experiment.

view Abstract Citations (10) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Early Results of the 1961 JPL Venus Radar Experiment. Muhleman, Duane O. Abstract A strong radar contact with Venus was made during the 1961 Venus conjunction utilizing the Goldstone, California, radar facilities of the Jet Propulsion Laboratory. Observations were made nearly daily from March to through May to. A t2.5-cm CW signal was transmitted with an 85-ft parabolic antenna, and the returned signal was received with a second 85-ft antenna. The transmitted frequency stability was held to within 1 cps for the signal-delay time. This reference signal was used to synchronously detect the returned signal and to determine the Doppler shift with an accuracy of 1 cps which corresponds to 0.07 m/sec. The transmitter was also keyed off and on for purposes of making unambiguous range measurements (time-of-flight measurements). Preliminary results of an astronomical unit determination yield a value approximately 60 000 km larger than the value determined by Kabe (1960). The accuracy of the data suggests the possible improvement of the Venus ephemeris. Analysis of the returned signal indicates a reflectivity relative to a perfectly conducting sphere of about 10% at this wavelength as compared with the lunar reflectivity of about 2 %. Doppler spreading of the returned signal due to the rotation of Venus strongly indicates synchronous rotation of the planet. The spectrum of the Doppler-spread signal is very similar in shape to the spectrum computed from a lunar-reflected signal at the same wavelength indicating similar backscattering characteristics. The analysis of the change in spectral width as a function of time for purposes of determining the Venus rotation axis orientation has not been completed as yet. Publication: The Astronomical Journal Pub Date: September 1961 DOI: 10.1086/108422 Bibcode: 1961AJ.....66..292M full text sources ADS |

A study of UHF space communications through an aurora using the moon as a reflector

A lunar reflection experiment has been performed with a transmitting site in the auroral zone and two receiving sites at mid-latitudes. With this arrangement a study has been made both of the reflection characteristics of the moon and of the characteristics of UHF signals from space propagated through auroral-type disturbances. It was found that auroral ionization in the propagation path increased the signal fading rate and produced rapid fluctuations in the Faraday rotation but did not absorb an appreciable amount of UHF energy.