Mohawk Valley Astronomical Society

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The Fiery Truth

by Perry Pezzolanella

Venus is one of the most neglected planets for planetary missions even though it is right next door, but it is finally back in the exploration spotlight after decades of neglect by NASA. The hostile environment does not make it an attractive place to explore with surface temperatures near 900ºF, an atmospheric pressure over 90 times Earth’s, and a corrosive carbon dioxide atmosphere laced with sulfuric acid. Sending a spacecraft to float among the acidic clouds or explore a surface hot enough to melt lead does not seem attractive or worth the investment.

VERITAS (Venus Emissivity, Radio Science, INSAR, Topography, and Spectroscopy) is a NASA Jet Propulsion Laboratory (JPL) mission approved on June 2, 2021, to map the surface of Venus in high resolution. It will orbit Venus and gather data to reveal how the evolutionary paths of Venus and Earth diverged, and how Venus lost its potential to be a habitable world. There will be many firsts for VERITAS: Creating the first global high-resolution topographic and radar images of Venus, the first maps of regions where geological processes are actively deforming the surface of Venus, the first global map of surface rock composition, and refine the estimate of the core size and composition.

VERITAS, which means “truth” in Latin, is tentatively scheduled to launch no sooner than 2031 and would begin orbiting Venus during 2032 pending funding. How did Venus become a sulfurous inferno while Earth became lush with life? Venus is the most Earth-like in size, overall composition, and energy from the Sun on the inner edge of the “Goldilocks Zone,” or habitable zone, the distance from the Sun where temperatures are just right for water to remain liquid. One theory is that Venus may have been habitable long before life began on Earth. Now Venus is a hellishly hot world with a thick, acidic, toxic atmosphere, crushing air pressure, and surface temperatures hot enough to melt lead, tin, and zinc. Venus might not have had an ocean, magnetic field, or plate tectonics that enabled Earth to support life.

VERITAS has three main scientific goals: 1). Determine what processes shape rocky planet evolution. 2). What geological processes are currently active on Venus? 3). Is there evidence of past or present water on Venus? The VERITAS mission team will answer these questions: What is the composition and origin of the different terrains on Venus, such as its mountains, volcanoes, valleys, highlands, domes, ridges, and impact craters? What is the planet’s geological history? What is volcanic activity like on Venus? Is it constant or intermittent? What are the major tectonic processes that shape Venus? What is the size and state of the core? How thick is the mantle? Is the surface being changed by active volcanoes? Are the plateaus on Venus, known as tesserae, or tiled terrain, like Earth’s continents? Is water from the interior being released as a gas from volcanoes?

VERITAS will use two powerful instruments to obtain the truth from Venus. The Venus Emissivity Mapper (VEM) will peer through 5 infrared windows in Venus’ thick atmosphere to “see” the differential flow of heat from the various kinds of surface rocks to identify them. The Venus Interferometric Synthetic Aperture Radar (VISAR) is designed to generate global data sets for topography with an accuracy of 15-feet and SAR imaging with sufficient resolution to detect active surface deformation. This high-resolution imaging data will allow scientists to locate active volcanic eruptions, to understand the age and composition of surface features, and better understand the overall geology. VERITAS will map Venus’ gravitation field, measure the size of the core, and determine the topography beneath the surface. This wealth of new data may help answer the question of whether Venus was once a habitable world that went bad or if it has been hostile all along.

Veritaserum is a powerful truth serum in the Wizarding World of Harry Potter. Professor Snape threatened to slip a few drops of it into Harry Potter’s pumpkin juice to make him come forward with the truth he thought Harry was hiding from him. VERITAS will slip into orbit around Venus with the hopes of uncovering the hidden truth about its past and present, and ultimately give a better idea of its evolution and future.