If ever a planet was suited for radar remote sensing observations, it would be Venus. Shrouded in an optically thick atmosphere, and with conditions at the surface inhospitable to in situ investigations, radar observations of Venus are integral to unraveling Venus’ secrets. Earth- and orbital-based radar observations of Venus began in the 1960s, giving a first glimpse of how extremely divergent Venus was from the Earth. From its inexplicably low and retrograde rotation rate, to temperature and pressure conditions at the surface hotter than the surface of Mercury and equivalent to being 1 km deep in the ocean, Venus was full of surprises. How Venus and Earth could have formed so differently is perhaps one of the most fundamental questions associated with understanding habitability of rocky planets. Deep understanding of planetary habitability requires identifying key factors that govern the surface environment over time. Plate tectonics on Earth is vital to its habitability, linking the atmosphere, surface and interior through its influence on the geology, continents, volcanism and volatile cycles. Venus lacks Earth-like plate tectonics but shows hints of subduction a possible precursor to plate tectonics and Venus today offers the opportunity to observe the processes that form subduction, absent plate tectonics. Similarly, the nature of volcanism on Venus, whether it is episodic or in steady state like Earth, and its role in the planet’s evolution, is still poorly understood. Two new missions to Venus, VERITAS by NASA and EnVision by ESA would bring modern radar interferometric and polarimetric measurements to Venus in the 2030s to answer these fundamental questions. VERITAS, planned for launch in 2027, carries a two-aperture X-band synthetic aperture radar interferometer to acquire global imagery and topography of the surface. EnVision, planned for launch in 2031, carries among its instrument suite a dual polarization S-band synthetic aperture radar that will acquire targeted SAR imagery of the surface, as well as nearly global altimetry and microwave surface emissivity when operating in its altimeter and radiometer modes.
This talk will describe how past radar observations of Venus have informed our understanding of the planet and how these planned new radar observations will extend our knowledge of Venus and rocky planet evolution in general.
Scott Hensley received his BS degrees in Mathematics and Physics from the University of California at Irvine and the Ph.D. in Mathematics from Stony Brook University where he specialized in the study of differential geometry. In 1991, Dr. Hensley joined the staff of the Jet Propulsion Laboratory where he is currently a Senior Research Scientist studying advanced radar techniques for geophysical applications. He has worked on the Magellan and Cassini radars, was the Chief Scientist of GeoSAR, an airborne X and P-band single pass interferometric radar, led the Shuttle Radar Topography Mission Interferometric Processor Development Team, and was Principal Investigator and is currently the Project Scientist for the NASA UAVSAR L-band airborne radar. He is the Project Scientist for the recently selected NASA VERITAS and ESA EnVision missions to Venus. He is an IEEE Fellow and recipient of numerous NASA individual and group achievement awards.