A SAR Interferometer Experiment to Explore the Surface of Venus

Abstract:
A deep understanding of solar system evolution is limited by a great unanswered question: How Earthlike is Venus? We know that these “twin” planets formed with similar bulk composition and size. Yet Venus followed a divergent evolutionary path, losing its surface water and becoming hotter than Mercury. How did this happen? The answer has profound implications for how terrestrial planets become habitable and the potential for life in the universe. To provide an answer to these questions a proposal has been submitted to NASA in the frame of the Discovery Program, for a mission called VERITAS (Venus Emissivity, Radio science, InSAR, Topography and Spectroscopy). The VERITAS payload is formed by a Venus Interferometric Synthetic Aperture Radar (VISAR), a Venus Emissivity Mapper and a Gravity Science Investigation. Interferometric Synthetic aperture radars are well-established tools for generating topographic maps of the Earth (see among the others [1]-[2]). Two spaceborne radar interferometric mapping missions, the Shuttle Radar Topography Mission (see for example [3]) and the Tandem-X Mission (see for example [4]) have generated unprecedented measurements of the Earth’s topography and informed many area of scientific investigation. Having such a comparable data set is needed to resolve the geologic evolution of the surface of Venus. Owning to the optically opaque cloud cover of Venus, radar interferometry is ideally suited to making these measurements. In this paper we provide a look at some of the system engineering and performance considerations for this instrument.