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A 54 km diameter Noachian-aged crater in the southern highlands of Mars contains unusually well preserved inverted fluvial channel networks and lacustrine deposits, all of which formed completely inside the crater. This “closed-source drainage basin” (CSDB) crater is distinct from previously documented fluvially breached or groundwater-fed crater basin lakes on Mars. We compare our observations to previously established models of crater degradation, fluvial incision, and topographic inversion on Mars to assess the most likely origins of the water that formed the fluvial and lacustrine features. We favor top-down melting of a cold-based glacier as the source of water in the CSDB crater, which would represent the first examples of proglacial fluvial channels and lakes found on Noachian Mars.

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Described here is a concept for a variable-altitude aerobot mission to Venus developed as part of the 2020 NASA Planetary Science Summer School in collaboration with NASA Jet Propulsion Laboratory. The Venus Air and Land Expedition: a Novel Trailblazer for in situ Exploration (VALENTInE) is a long-duration New Frontiers–class mission to Venus in alignment with the goals recommended by the 2013 Planetary Science Decadal Survey. VALENTInE would have five science objectives: (1) determine the driving force of atmospheric superrotation, (2) determine the source of D/H and noble gas inventory, (3) determine the properties that govern how light is reflected within the lower cloud later, (4) determine whether the tesserae are felsic, and (5) determine whether there is evidence of a recent dynamo preserved in the rock record. The proposed mission concept has a total duration of 15 Earth days and would float at an altitude of 55 km, along with five dips to a lower altitude of 45 km to study Venus’s lower atmosphere. The instrument payload allows for measurements of the atmosphere, surface, and interior of Venus and includes six instruments: an atmospheric weather suite, a mass spectrometer, a multispectral imager, a near-infrared spectrometer, light detection and ranging, and a magnetometer. Principle challenges included a limitation caused by battery lifetime and low technology readiness levels for aerobots that can survive the harsh conditions of Venus’s atmosphere. This preliminary mission was designed to fit within an assumed New Frontiers 5 (based on inflated New Frontiers 4) cost cap.