Engineering topics
Publications and source records attributed to Laing, P. A..
Radio metric data from the Pioneer 10/11, Galileo, and Ulysses Spacecraft indicate an apparent anomalous, constant, acceleration acting on the spacecraft with a magnitude ~8.5 x 10(sup -8) cm/s(sup 2), directed towards the Sun.
Further reduction of Doppler tracking data from Mariner 9 confirms our earlier conclusion that the gravity field of Mars is considerably rougher than the fields of either the earth or the moon. The largest positive gravity anomaly uncovered is in the Tharsis region which is also topographically high and geologically unusual. The value obtained for the inverse mass of Mars is in good agreement with prior determinations from Mariner fly by trajectories. The direction found for the rotational pole of Mars is in excellent agreement with Sinclair's recent value, determined from earth-based observations of Mars' satellites. Other important physical constants that have either been refined or confirmed by the Mariner 9 data include: (1) the dynamical flattening, (2) the maximum principal moment of inertia, and (3) the period of precession of Mars' pole.
Analysis of the Mariner 9 radio-tracking data shows that the Martian gravity field is rougher than that of earth or the moon, and that the accepted direction of the Mars rotation axis is in error by about 0.5 deg. Contours of equivalent surface heights deduced from a sixth-degree solution for the Martian gravity field are presented. These contours represent the deviations from sphericity of a uniformly dense body with an external potential which is given by the first sixth-degree solution. In addition to Doppler observations, ranging or group-delay measurements have been made regularly since orbit insertion.
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Global lunar gravity field from weighted least squares analysis of Lunar Orbiters elements, deriving zonal and sectorial harmonics from libration data
Lunar gravity field global model from moon orbiters secular and long period trends, noting large anomaly on far side
Lunar Orbiter tracking data for long term selenodesy