This science case is focused on the detection and mapping of sinkhole-like depressions on Mars and the Moon through Deep Learning Object Detection and Instance Segmentation.

The term sinkhole refers to different morphologies that have a in common the processes of depleting materials of different type into an area within the morphology itself (Waltham, 2005). On Earth the formation of sinkholes is related to a cluster of processes, and could occur in various type of grounds, furthermore presence of water has a key-role. On other terrestrial planets, although the mechanisms for the origin of these landforms are similar, if not the same, with the main difference that as far as we know there is no liquid water that can be involved in the formation of these landforms, and therefore the mechanisms and processes are still debated. Several authors suggested the hypothesis of formation from lava tube collapses (Greeley, 1971; Cruikshank and , 1972; Carr et al., 1977), others imply different volcanic and tectonic processes involved (Wyrick et al., 2004). In karst environment, sinkholes are called “doline” and are more related to processes connected to dissolution of carbonates and evaporites, while in volcanic environments they are called “pit craters” and are more related to process connected to lava tube stability.

Doline, pit craters, pit chains and lava tubes are well-known morphologies on Earth (Lauterbach et al., 2019; Díaz Michelena et al., 2020), Mars (Carr, 1973; Cushing et al., 2007; Cushing, 2012a; Cushing et al., 2015), Moon (Chappaz et al., 2017), Venus (Ernst et al., 2015), Mercury (Gillis-Davis et al., 2009), and Ganymede and Saturnian satellites (Barlow et al., 2017). Studies suggested the presence of sinkholes both in karst (Baioni and Tramontana, 2015, 2016) and volcanic terrains of Mars (Sauro et al., 2020a), in particular thanks to HiRISE and CTX cameras on board MRO more than 1000 potential cave entrances have been identified on Mars (Cushing, 2012a), while on Moon thanks to SELENE and LRO cameras more than 300 (Wagner and Robinson, 2014).

In the framework of geological exploration of terrestrial planets like Earth, those landforms - being a potential direct access to subsurface - are one of the most promising environments where to focus the research of valuable data of different kind, from planet's geological stratigraphy (Lauterbach et al., 2019; Sauro et al., 2020a) to valuable ore deposits (Blamont, 2014). They could also provide access to cave entrances where it is possible to gather even more data since caves are a natural shelter from cosmic radiation, and thus potentially provide a feasible environment for searching of life traces (Léveillé and Datta, 2010; Cushing, 2012a), for the development of future human outposts (Cushing, 2012a; Blamont, 2014; Carrer et al., 2018), and for the planning of future missions (Hare et al., 2018).