Mars has been the subject of speculation regarding the presence of liquid water for well over a century (Lowell, 1895;Lowell & Lockyer, 1906), and this hypothesis persisted until the Mariner missions visited the planet for the first time in the 1960s and found the planet to be dry, rocky, and mostly covered with impact-induced craters (McCauley et al., 1972). Numerous outflow channels were observed, but with higher resolution and better coverage from the Viking missions, they turned out to be ancient and dry (Baker, 1982). As a result of these robotic investigations, discussions of current liquid water on Mars moved into the subsurface, where temperature and pressure regimes could plausibly lead to melting of ice (Clifford, 1993), potentially at the poles (Clifford, 1987). It was primarily for this reason that the Mars Advanced Radar for Subsurface and Ionosphere Sounding instrument (MARSIS) was sent to Mars, as specifically noted in a paper describing the instrument: "The primary scientific objective of the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS), which will be on board Mars Express mission scheduled for launch in 2003, is to map the distribution and depth of the liquid water/ice interface in the upper kilometres of the crust of Mars." (Picardi et al., 2004).In 2018, after more than a decade of acquiring observations and examining subsurface reflections (or the lack thereof), a candidate liquid detection was found beneath a portion of the south polar layered deposits (SPLD, Orosei et al., 2018). Orosei et al. (2018) reported anomalously bright MARSIS radar reflections near a region around 81°S, 193°E (Figure 1), in which the subsurface reflection was brighter than the surface

This list includes many of the hundreds of current students and scientists who have made significant contributions to Mars Polar Science in the past decade. Every name listed represents a person who asked to join the white paper or agreed to be listed and provided some comments.