A PROTOTYPE FLUX-PLATE HEAT-FLOW SENSOR FOR VENUS SURFACE HEAT-FLOW

Venus is the most Earth-like planet in the Solar System in terms of size, and the densities of the two planets are almost identical when self-compression of the two planets is taken into account [1]. Venus is the closest planet to Earth, and the sim-plest interpretation of their similar densities is that their bulk compositions are almost identical. Models of the thermal evolution of Venus predict interior tem-peratures very similar to those indicated for the regions of Earth subject to solid-state convection [2, 3], but even global analyses of the coarse Pioneer Venus ele-vation data suggest Venus does not lose heat by the same primary heat loss mechanism as Earth, i.e., sea-floor spreading [4]. The comparative paucity of im-pact craters on Venus has been interpreted as evidence for relatively recent resurfacing of the planet associ-ated with widespread volcanic and tectonic activity [5]. The difference in the gross tectonic styles of Ve-nus and Earth, and the origins of some of the enig-matic volcano-tectonic features on Venus, such as the coronae, appear to be intrinsically related to Venus heat loss mechanism(s) [6, 7]. An important parameter in understanding Venus geological evolution, there-fore, is its present surface heat flow.