DART, Double Asteroid Redirection Test, will be the rst mission to demonstrate and characterize the concept of a kinetic impactor for planetary defense, by impacting the smaller member of a binary asteroid system Didymos. Results of this mission will have implications for planetary defense, Near-Earth Object science, and resource utilization. This research focuses on the heliocentric transfer phase of the mission. The heliocentric trajectory is evaluated using various objective functions, including a search for the latest possible escape date, the shortest time-of-ight, and the maximum impact energy. Also included in the search is the potential to use Earth gravitational assists, which proves not to oer any useful advantages. A new way to assess the trajectory's margin for missed thrust is used, which quanties the ability of the spacecraft to recover its mission following unplanned non-thrusting events, such as safe-mode. The baseline trajectory is shown to be capable of recovering from missed thrust events lasting 14 days using only 1% of its propellant as margin. Finally, we consider contingency trajectories that attempt to impact Didymos at a subsequent perihelion.
More than any other known planet, Venus is essential to our understanding of the evolution and habitability of Earth-size planets throughout the galaxy. We address two critical questions for planetary science: 1) How, if at all, did Venus evolve through a habitable phase? 2) What circumstances affect how volatiles shape habitable worlds? Volatile elements have a strong influence on the evolutionary paths of rocky bodies and are critical to understanding solar system evolution. It is clear that Venus experienced a different volatile element history from the Earth and provides the only accessible example of one end-state of habitable Earth-size planets. Venus
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