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Silverberg, E. C.

Publications and source records attributed to Silverberg, E. C..

34 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Analysis of the first laser echoes obtained on the reflector of Luna 21

The international program of lunar telemetry, which has been in operation for three and one-half years, is intended to supply basic information for study of the lunar motion and the internal physics of the moon and the earth, particularly with reference to movement of the pole and displacements of plates. Laser echoes were obtained on Jan. 23, 1973 from the French reflector placed on the moon by Luna 21. Two series of firings, made with a 3-J laser radiated by the 2.7-m telescope of the McDonald Observatory (Texas) made it possible to identify significant echoes of an intensity comparable to those obtained with the reflector set down by Apollo 15. The path time measurements are compatible with normal coordinates.

Abalakin, V. K.↗
NASA NTRS1972

The angular diameter of X Cancri.

Analysis of an occultation reappearance of the semiregular variable X Cancri observed with the 107-inch telescope of McDonald Observatory on 9 November 1971 by the laser group using slightly modified laser equipment. The problem of the effective temperature of this carbon star is discussed, and estimates near 2500 K are derived both from the occultation data and from an integration based on the multicolor photometry reported by Mendoza (1967). This figure is 300-400 K higher than Mendoza's calibration, and it is clear that unsolved problems remain in many areas connected with these stars.

Bartholdi, P.↗
NASA NTRS1972

Report on the lunar ranging at McDonald Observatory

The laser ranging operation successfully measured more than 150 lunar ranges during the three lunations ending on 13 May 1972. The accuracy of the measurements averaged about plus or minus 15 cm.

Silverberg, 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

Increasing the time resolution of a multichannel scaler.

Description of an economical buffer unit which will extend the time resolution of a multichannel scaler to better than 100 nsec. The buffered multiscaler produces a system which has negligible dead time between the bins even at the highest resolutions. It is suitable for use in any digital signaling averaging application which meets certain conditions.

Silverberg, E. C.↗
NASA NTRS1972

Laser ranging retroreflector

The lunar laser ranging retroreflector (LRRR) experiments to define the motion of the moon in its orbit are described, and the properties of the LRRR arrays and ground-station operation are discussed. It is concluded that primary benchmarks on the lunar surface are provided by the Apollo 11 and 14 arrays, and the placement of the Apollo 15 reflector.

Faller, J. E.↗
NASA NTRS1972

A description of the lunar ranging station at McDonald Observatory.

The equipment of this station which has been in operation since the deployment of the first corner reflector by the Apollo 11 astronauts. The McDonald 2.7-m telescope is used for both transmission and reception of pulsed ruby laser light during three 45-minute daily laser runs about three weeks in a month. The present laser pulse width, timing system, calibration procedures, and signal levels are designed to achieve ranging with an accuracy to 1 nanosecond. The data rates obtained since September, 1970, are consistent with the scientific commitments of the lunar ranging program. Most of the over 200 acquisitions obtained have an accuracy to better than plus or minus 30 cm. Details of the telescope matching optics, guiding and timing equipment, and calibration procedures are discussed. Representative lunar range data are included.

Silverberg, E. C.↗
NASA NTRS1972

Geodesy results obtainable with lunar retroreflectors.

Retroreflector packages have been carried to the moon by the Apollo 11, Apollo 14, and Apollo 15 missions, as well as by Luna 17. Laser ranging from the earth onto these packages should eventually yield information on polar motions and crustal movements accurate to a few centimeters, and on UT1 to 100 microsec. Present (1971) error of the range measurements is 30 cm, but accuracy to 3 cm should be obtainable with improvements in methods and equipment.

Faller, J. E.↗
NASA NTRS1971

The lunar laser ranging experiment

With data from two or more well-located observing stations, the lunar range can be corrected accurately for the effects of polar motion and fluctuations in the earth's rotation rate. Very accurate corrections can be made for the earth tides at each station. It appears that the use of lasers giving roughly 0.1-msec pulse lengths is highly desirable. With them, single-shot ranging accuracies of about 3 cm are expected. The actual lunar range results will be analyzed by fitting a numerical integration for the lunar motion to the data. A mathematical model for lunar range is given. Tests of the theory of gravitation are considered.

Bender, P. L.↗
NASA NTRS1971

Laser ranging retroreflector

Laser ranging retroreflector deployed on lunar surface to study lunar librations for defining precisely lunar orbits and studying earth planetary structure - Apollo 14 flight

Alley, C. O.↗