Rabert D. Reasenberg

Viking relativity experiment: Verification of signal retardation by solar gravity

Analysis of 14 months of data obtained from radio ranging to the Viking spacecraft verified, to an estimated accuracy of 0.1%, the prediction of the general theory of relativity that the round-trip times of light signals traveling between the earth and Mars are increased by the direct effect of solar gravity. The corresponding value for the metric parameter gamma is 1.000 plus or minus 0.002, where the quoted uncertainty, twice the formal standard deviation, allows for possible systematic errors.

Viking Lander Location and Spin Axis of Mars: Determination from Radio Tracking Data

Radio tracking data from the Viking lander have been used to determine the lander position and the orientation of the spin axis of Mars. The areocentric coordinates of the lander are 22.27�N, 48.00�W, and 3389.5 kilometers from the center of mass; the spin axis orientation, referred to Earths mean equator and equinox of 1950.0, is 317.35� right ascension and 52.71� declination.

Mars Dynamics, Atmospheric and Surface Properties: Determination from Viking Tracking Data

Approximately 3 months of radio tracking data from the Viking landers have been analyzed to determine the lander locations, the orientation of the spin axis of Mars, and a first estimate from Viking data of the planets spin rate. Preliminary results have also been obtained for atmospheric parameters and radii at occultation points and for properties of the surface in the vicinity of lander 1.

New results from the viking relativity experiment

Abstract The predicted general relativistic effect of solar gravity on the round-trip times of electromagnetic signals traveling between Earth and Mars has been verified by means of radio ranging to the Viking spacecraft. The ranging measurements were found to be consistent with the predicted increases of up to 200 μsec in the travel times of the signals to within the estimated uncertainty of 0.2%.