Contribution of the spatial part of the metric tensor to the observed frequency shift in the maser clock experiment
Formula for frequency shift of maser clock in orbit to identical maser on earth
Eby, P.↗
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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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Probing the solar plasma with Mariner radio metric data, preliminary results
Radio technique for probing solar plasma during superior conjunction of Mariner 6 and 7 spacecraft
Callahan, P. S.↗
Databook for human factors engineers. Volume 2 - Common formulas, metrics, definitions
Human factors engineering manual including mathematical formulas, nomographs, conversion tables, units of measurement, and nomenclatures
Kubokawa, C.↗
Study of the determination of the coefficients beta and gamma of the generalized metric of Robertson and of the dynamical oblateness of the sun
Motion of a space probe about a spherical center of attraction is considered, applying the general theory of relativity. Motion of a probe under the influence of the sun's oblateness is also discussed. Estimates of beta, gamma, and J20 using solar probe motion are presented. It is concluded that such measurements are possible if the unknown long-period perturbing acceleration is of the order of 10 to the -11th or -12th power m/sec. sq.
Marchal, C.↗
Metric analysis of minitrack optical and interferometer data
The network analysis program (NAP-2), which has the capability of simultaneously solving for orbits and tracking station error model terms, was, after several modifications, used in the calibration of minitrack stations using minitrack satellite measurements (self-calibration). Several support programs were written to aid in this task. A simultaneous four-arc solution was obtained. A comparison with optically determined arcs for the same time spans showed rms position differences of 67m, 86m, 124m and 168m for the 4 arcs considered. An apparatus incorporating a diffraction grating was designed and successfully used to measure the drift rate of the Fort Myers MOTS camera drive.
Brown, D. C.↗
A new two-metric theory of gravity with prior geometry
A theory is presented of gravity which has the same post-Newtonian (PN) as that of general relativity. The field equations, and a calculation of the PN limit of the theory are discussed along with the equations of stellar structure for static spherically symmetric stars. A special exterior spherically symmetric solution, time dependent solutions, conservations, and gravitational waves are analyzed.
Lightman, A. P.↗
Solar energetic particles and wide-band continuum storms from metric to hectometric frequencies.
Explore the source record for details and available documents.
Sakurai, K.↗
Image quality against metric capability of an aerial camera
Glass plate targets containing multiple contrast three bar patterns and a military standard resolution target were photographed through a light-source collimator-camera system. The glass plate targets and images were then scanned. Through a computer plotting program selected portions of the scanned items were presented. The plots were then measured and analyzed to obtain information of image quality parameters and effects. The measurement errors are discussed together with aspects of resolution determination.
Ghosh, S. K.↗
Corruption of radio metric Doppler due to solar plasma dynamics: S/X dual-frequency Doppler calibration for these effects
Doppler data from Mariner 6, 7, 9, and 10 and Pioneer 10 and 11 were discussed and the rms noise level for various sun-earth-probe angles were shown. The noise levels of both S- and X-band Doppler data for sun-earth-probe angles smaller than 20 deg were observed to be orders of magnitude greater than nominal. Such solar plasma-related Doppler degradation reduced the Mariner 10-Mercury 11 encounter navigation accuracy by nearly a factor of 10. Furthermore, this degradation was shown to be indirectly related to plasma dynamics and not a direct measure of the dynamics.
Winn, F. B.↗
US metric study mission to the United Kingdom and the Federal Republic of Germany: Report of the NASA representative (Full Report)
For abstract, see preceding accession.
Vlannes, P. N.↗
A solar plasma stream measured by DRVID and dual-frequency range and Doppler radio metric data
S- and X-band DRVID, S- and X-band dual-frequency range (SX(p)), and Doppler (SX(p)) measured a 15-fold increase in the line-of-sight electron content of the solar plasma above the normal plasma background. A general increase in the plasma electron content continued for nearly 50 hours: it started about 12:00 (GMT) on 12 March 1976 and continued to grow until 17:00 (GMT) on 14 March. For the next 55 hours, between 17:00 (GMT) on 14 March to 00:54 (GMT) on 17 March, the plasma level diminished as the background level was approached. Not only were the temporal changes and absolute level of the plasma content measured but the measurements were also used to ascertain the mean-plasma-concentration location: it was estimated to be 4.1 light minutes from earth.
Winn, F. B.↗
General relativity and satellite orbits - The motion of a test particle in the Schwarzschild metric
The motion of a satellite of negligible mass about a massive spherically symmetric object in a space of Schwarzschild geometry is calculated by using ordinary Newtonian methods for an inverse-square gravitational field acted upon by an inverse-cube disturbing function. The disturbing function is expressed in terms of the Keplerian elements of the orbit and substituted in the Lagrange planetary equations. The equations can be integrated to calculate the displacement in position of the satellite due to the relativistic potential. For example, the Beacon Explorer C satellite is found to be displaced by about 17.4 cm after one revolution. For Mercury the advance of the perihelion is about 85 km after one orbit, and the maximum periodic displacement is about 13 km.
Rubincam, D. P.↗
Radio metric direction finding - A new approach to deep space navigation
The paper explores an alternate technique for the determination of the angular position and velocity of deep-space probes, wherein the two-way range and Doppler measurements are abandoned for large portions of the mission in favor of differential one-way measurements. The spacecraft employs a wideband beacon rather than a coherent transponder, and differential measurements of one-way range and perhaps range rate are made between the spacecraft and each of three tracking stations. Advantages include the following: (1) Range measurements do not require the long horizon-to-horizon Doppler passes, so that the tracking stations can be released to support other functions of the deep space network. (2) Improved accuracy in the angular coordinates of the spacecraft can be obtained. (3) The need for an uplink is eliminated. A system implementation of the concept is developed that appears economically feasible and achieves a 0.05 microrad baseline accuracy
Melbourne, W. G.↗
Time-of-day Corrections to Aircraft Noise Metrics
The historical and background aspects of time-of-day corrections as well as the evidence supporting these corrections are discussed. Health, welfare, and economic impacts, needs a criteria, and government policy and regulation, are also reported.
Clevenson, S.↗
Historical development of noise exposure metrics
Some of the historical events that led to the introduction of night penalties are reported with emphasis on what happens with different kinds of day/night operations when night pentalties are employed. These effects are considered in terms of the difference between a nighttime weighting cumulative measure of noise exposure verses simply not using any night weighting at all, in decibles.
Galloway, W. J.↗
Evaluation of a pilot workload metric for simulated VTOL landing tasks
A methodological approach to measuring workload was investigated for evaluation of new concepts in VTOL aircraft displays. Multivariate discriminant functions were formed from conventional flight performance and/or visual response variables to maximize detection of experimental differences. The flight performance variable discriminant showed maximum differentiation between crosswind conditions. The visual response measure discriminant maximized differences between fixed vs. motion base conditions and experimental displays. Physiological variables were used to attempt to predict the discriminant function values for each subject/condition/trial. The weights of the physiological variables in these equations showed agreement with previous studies. High muscle tension, light but irregular breathing patterns, and higher heart rate with low amplitude all produced higher scores on this scale and thus, represented higher workload levels.
North, R. A.↗
Tracking and Data Relay Satellite System (TDRSS) navigation with DSN radio metric data
The use of DSN radiometric data for enhancing the orbit determination capability for TDRS is examined. Results of a formal covariance analysis are presented which establish the nominal TDRS navigation performance and assess the performance improvement based on augmenting the nominal TDRS data strategy with radiometric data from DSN sites.
Ellis, J.↗
On the use of the OCM's quadratic objective function as a pilot rating metric
A correlation between the magnitude of the quadratic objective function from an optimal control pilot model and the subjective rating of the vehicle and task provides a valuable tool for handling qualities research and flight control synthesis. An analysis of simulation results for fourteen aircraft configurations flight tested earlier was conducted. A fixed set of pilot model parameters, are found for all cases in modeling the simulated regulation task. The agreement obtained between performance statistics is shown and a strong correlation was obtained between the cost function and rating.
Schmidt, D. K.↗