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NASA NTRS1973

Lunar Surface Gravimeter Experiment

The lunar surface gravimeter which was emplaced on the moon by the Apollo 17 flight is described and a schematic diagram of the sensor is provided. The objective of the lunar surface gravimeter is to use the moon as an instrumented antenna to detect gravitational waves. Another objective is to measure tidal deformation of the moon. Samples of signals received during lunar sunrise activity and during quiet periods are presented in graph form based on power spectrum analysis

Giganti, J. J.↗

NASA NTRS1973

Gravitation

This textbook on gravitation physics (Einstein's general relativity or geometrodynamics) is designed for a rigorous full-year course at the graduate level. The material is presented in two parallel tracks in an attempt to divide key physical ideas from more complex enrichment material to be selected at the discretion of the reader or teacher. The full book is intended to provide competence relative to the laws of physics in flat space-time, Einstein's geometric framework for physics, applications with pulsars and neutron stars, cosmology, the Schwarzschild geometry and gravitational collapse, gravitational waves, experimental tests of Einstein's theory, and mathematical concepts of differential geometry.

Misner, C. W.↗

NASA NTRS1974

Gravitational Stokes parameters

The electromagnetic and gravitational Stokes parameters are defined in the general theory of relativity. The general-relativistic equation of radiative transfer for polarized radiation is then derived in terms of the Stokes parameters for both high-frequency electromagnetic and gravitational waves. The concept of Stokes parameters is generalized for the most general class of metric theories of gravity, where six (instead of two) independent states of polarization are present.

Anile, A. M.↗

NASA NTRS1975

Extragalactic cosmic rays

A survey of the components of the extragalactic universe is presented. Attention is given to galaxies, quasi-stellar objects, highly evolved or collapsed configurations, faint low mass stars, diffuse matter, the electromagnetic fields, neutrino flux, gravitational waves, and cosmic rays. Radio sources are discussed along with the requirements for an extragalactic theory of cosmic rays.

Burbidge, G. R.↗

NASA NTRS1977

Feasibility analysis of gravitational experiments in space

Experiments on gravitation and general relativity suggested by different workers in the past ten or more years are reviewed, their feasibility examined, and the advantages of performing them in space were studied. The experiments include: (1) the gyro relativity experiment; (2) experiments to test the equivalence of gravitational and inertial mass; (3) an experiment to look for nongeodesic motion of spinning bodies in orbit around the earth; (4) experiments to look for changes of the gravitational constant G with time; (5) a variety of suggestions; laboratory tests of experimental gravity; and (6) gravitational wave experiments.

Everitt, C. W. F.↗

NASA NTRS1978

Quantum nondemolition measurements of harmonic oscillators

Measuring systems to determine the real component of the complex amplitude of a harmonic oscillator are described. This amplitude is constant in the absence of driving forces, and the uncertainty principle accounts for the fact that only the real component can be measured precisely and continuously ('quantum nondemolition measurement'). Application of the measuring systems to the detection of gravitational waves is considered.

Thorne, K. S.↗

NASA NTRS1978

Parametric modeling of low-frequency water-vapor-induced tropospheric path length fluctuations

Detailed wet tropospheric fluctuation information is presented in support of proposals to search for gravitational waves in ultra-precise Doppler data. The similarities between the solar wind and tropospheric effects on apparent signal path length are used to hypothesize a parametric model for low-frequency wet tropospheric path length fluctuation. Experimental observations of wet tropospheric signal delay fluctuations are interpreted as confirmation of this parametric form. The model is used to suggest the appropriate conditions for collection of experimental tropospheric fluctuation data.

Berman, A. L.↗

NASA NTRS1979

The challenge of detecting gravitational radiation is creating a new chapter in quantum electronics: Quantum nondemolition measurements

Future gravitational wave antennas will be approximately 100 kilogram cylinders, whose end-to-end vibrations must be measured so accurately (10 to the -19th power centimeters) that they behave quantum mechanically. Moreover, the vibration amplitude must be measured over and over again without perturbing it (quantum nondemolition measurement). This contrasts with quantum chemistry, quantum optics, or atomic, nuclear, and elementary particle physics where measurements are usually made on an ensemble of identical objects, and care is not given to whether any single object is perturbed or destroyed by the measurement. Electronic techniques required for quantum nondemolition measurements are described as well as the theory underlying them.

Braginsky, V. B.↗

NASA NTRS1979

On the structure of the upper atmosphere of Mars according to data from experiments on the Viking space vehicles

Altitude profiles of the concentrations of the atmospheric components measured by the on board mass spectrometers during the descent of Viking lander are discussed by assuming that temperature has a smoother profile, and the eddy mixing coefficients are smaller at altitudes of 120 to 170 km than those formally determined. The influence of acoustic gravitational waves and errors in measurements and calculations are discussed in relation to the convolutions in the altitude profiles of the concentrations of the atmospheric components and the temperature of the atmosphere.

Izakov, M. N.↗

NASA NTRS1980

Quantum nondemolition measurements

The article describes new electronic techniques required for quantum nondemolition measurements and the theory underlying them. Consideration is given to resonant-bar gravitational-wave antennas. Position measurements are discussed along with energy measurements and back-action-evading measurements. Thermal noise in oscillators and amplifiers is outlined. Prospects for stroboscopic measurements are emphasized.

Braginskii, V. B.↗

NASA NTRS1981

Relativistic astrophysics - The view from Texas in Baltimore /Review/

Recent observational and theoretical work presented at the Tenth Texas Symposium on Relativistic Astrophysics held in Baltimore, Maryland from December 15-19, 1980, is outlined. Areas covered include the theoretical foundations of relativistic astrophysics in general relativity, quantum gravitational theory and the association of grand unification with astronomical and cosmological issues, the cosmic microwave, X-ray, gamma-ray, UV, cosmic ray and gravitational wave backgrounds, the current expansion rate and average mass-energy density of the universe, and mechanisms of galaxy formation. Also discussed are the characteristics of active galaxies and clusters emitting in the gamma-ray and X-ray regions, and compact objects formed from supernova explosions, including pulsars, X-ray-emitting neutron stars, Sco X-1 and SS 433, gamma-ray sources, and X-ray and gamma-ray bursters.

Trimble, V. L.↗

NASA NTRS1982

Astronomy and astrophysics for the 1980's, volume 1

The programs recommended address the most significant questions that confront contemporary astronomy and fall into three general categories: prerequisites for research initiatives, including instrumentation and detectors, theory and data analysis, computational facilities, laboratory astrophysics, and technical support at ground-based observatories; programs including an Advanced X-ray Astrophysics Facility, a Very-Long Baseline Array, a Technology Telescope and a Large Deployable Reflector; and programs for study and development, including X-ray observatories in space, instruments for the detection of gravitational waves from astronomical objects, and long duration spaceflights of infrared telescopes. Estimated costs of these programs are provided.

Source record↗

NASA NTRS1982

Atomic clocks for astrophysical measurements

It is noted that recently developed atomic hydrogen masers have achieved stability well into the 10 to the -16th domain for averaging time intervals beyond 1000 sec and that further improvements are in prospect. These devices are highly adaptable for space use in very high precision measurements of angle through Very Long Baseline Interferometry (VLBI) and of range and range-rate through Doppler techniques. Space missions that will use these clocks for measuring the sun's gravity field distribution and for testing gravitation and relativity (a project that will include a search for pulsed low-frequency gravitational waves) are discussed. Estimates are made of system performance capability, and the accuracy capability of relativistic measurements is evaluated in terms of the results from the 1976 NASA/SAO spaceborne clock test of the Einstein Equivalence Principle.

Vessot, R. F. C.↗

NASA NTRS1984

X-band Uplink Technology Demonstration at DSS-13

The status of the X-band uplink development program is examined from a systems' viewpoint. The hardware, designed and built under the program, is now in place at DSS-13. System stability testing is underway. An X-band receive capability is being implemented on both the Galileo and the Venus Radar Mapper spacecraft. Experiments are planned to demonstrate the capabilities of the X-band uplink system and to permit performance of the gravitational wave experiment on the Galileo orbiter and obtain a more detailed gravity map of Venus.

Meeker, J. G.↗

NASA NTRS1984

Gravitational radiation from accreting neutron stars

Attention is given to the evolution of neutron stars whose magnetic fields are so weak that (1) the effects of the magnetosphere on the accretion disk are negligible, allowing it to extend to the surface of the star; and (2) the loss of energy and angular momentum by the pulsar mechanism is negligible compared with that provided by the accretion disk. The small nonaxisymmetric distortion of the neutron star should produce some modulation of the X-ray emission at the gravitational wave frequency, and it is hypothesized that this frequency will lie in the 200-800 Hz range. This is significantly below the rotational frequency of the neutron star.

Wagoner, R. V.↗

NASA NTRS1986

Deep space network radio science system for Voyager Uranus and Galileo missions

An overview is presented of major new requirements, challenges and conceptual designs for the DSN Radio Science System in the 1985 to 1988 period. The Voyager Uranus encounter is being supported with larger combined aperture, higher sample rate, and a centrally controlled network. The Galileo mission will be provided with a high resolution S-Band Faraday rotation detection capability and a high-stability Doppler system with X-Band uplink for gravitational wave search.

Peng, T. K.↗

NASA NTRS1985

A comparison of the bounded derivative and the normal mode initialization methods using real data

A bounded derivative initialization method (BDI) formerly used only in theoretical studies to balance gravitational wave influences is extended to a real world data set and the results are compared with those from a normal mode initialization (NMI). BDI proceeds by defining the characteristic scales of motion of interest and then constraining the time derivatives to match motions on a slow scale. A global barotropic model which considers orographic forcing is initialized by the scaled balance equations of the BDI scheme, which uses vorticity alone to achieve an initial balanced state. An external mode projector is employed to realize the NMI scheme, and five Machenhauer iterations reduce the total balance by four orders of magnitude. The initial states generated with both schemes are essentially equivalent, including the time evolution of a height field and divergence behavior being centered around regions of high orographic elevation.

Semazzi, F. H. M.↗

NASA NTRS1986

Deep space network enhancement for the Galileo mission to Jupiter

The Galileo mission to Jupiter has unique scientific objectives never attempted before by a planetary mission. These objectives have presented technical challenges to the NASA Deep Space Network. New technologies and system concepts have been developed to meet these challenges. Major implementations are underway to equip the ground stations in the Network. Significant improvement in performance is expected. The ground-based navigation is expected to achieve an angular precision of 50 nanoradians using very-long-baseline interferometry (VLBI). The frequency stability of the ground instrument will be 5 x 10 to the -15th for the detection of gravitational waves. The precision of the Faraday rotation angle measurement of the spacecraft signal will be better than 2 degrees.

Peng, T. K.↗