The GEOSA T spacecraft was launched into a retrograde orbit from the Western Test Range in March 1985. The first 18 months were dedicated to completing the high-resolution mapping of the marine geoid undertaken by the Seasat mission in 1978 and interrupted by its early demise. In September 1986, the spacecraft was maneuvered into an orbit more suited for oceanography. That phase of the mission ...

Introduction: Crater distribution on Venus indicates that the surface has undergone global-scale resurfacing in a short period of time [1]. Determining the timing of events has been difficult due to the near-random crater pattern. Some progress has been made in the relative dating of various types of features [2,3,4]. In addition, current deformation of Venus' surface has been described as a sw...

This article summarises some considerations surrounding a geoid-model-based vertical datum that have to be thought through before its implementation and adoption. Our examples are based on many Australian and some South-East Asian experiences, but these probably also apply elsewhere. Thekey considerations comprisedataquality andavailability, politics, anddifficulties thatusersmayencounterwhen a...

Many features of the oceanic plates cannot be explained by conductive cooling with age. A number of these anomalies require additional convective thermal sources at depths below the plate: mid-plate swells, the evolution of fracture zones, the mean depth and heat flow relationships with age and the observation of small scale (150-250 km) geoid and topography anomalies in the Central Pacific and...