Ice worlds are at the forefront of astrobiological interest because of the evidence of subsurface oceans. Enceladus in particular is unique among the icy moons because there are known vent systems that are likely connected to a subsurface ocean, through which the ocean water is ejected to space. An existing study has shown that sending small robots into the vents and directly sampling the ocean water is likely possible. To enable such a mission, NASA’s Jet Propulsion Laboratory is developing a snake-like robot called Exobiology Extant Life Surveyor (EELS) that can navigate Enceladus’ extreme surface and descend an erupting vent to capture unaltered liquid samples and potentially reach the ocean. However, navigating to and through Enceladus’ environment is challenging: Because of the limitations of existing orbital reconnaissance, there is substantial uncertainty with respect to its geometry and the physical properties of the surface/vents; communication is limited, which requires highly autonomous robots to execute the mission with limited human supervision. Here, we provide an overview of the EELS project and its development effort to create a risk-aware autonomous robot to navigate these extreme ice terrains/environments. We describe the robot’s architecture and the technical challenges to navigate and sense the icy environment safely and effectively. We focus on the challenges related to surface mobility, task and motion planning under uncertainty, and risk quantification. We provide initial results on mobility and risk-aware task and motion planning from field tests and simulated scenarios.

This work considers global path planning enabled by generative adversarial networks (GANs) on a 2D grid world. These networks can learn statistical relationships between obstacles, goals, states, and paths. Given a previously unseen combination of obstacles, goals, and an initial state, they can be asked to guess what a new path would look like. We performed experiments on a 64 × 64 pixel grid that generated a training set by using randomly positioned obstacles and goals. The heuristic search algorithm A* was used to create training paths due to its significant presence in the literature and ease of implementation. We experimented with architectural elements and hyperparameters, converging to a pix2pix-based architecture in which the generator was trained to generate plausible paths given obstacles and two points. A discriminator tried to determine whether these maps were real or fake. Additionally, we defined a qualitative path-generation “success rate” metric derived from the Fréchet inception distance (FID) and optimized our architecture’s parameters, ultimately reaching a 74% success rate on the validation set. Furthermore, we discuss the applicability of this approach to safety-critical settings, concluding that this architecture’s performance and reliability are insufficient to offset the downsides of a black-box approach to path generation.

Relative visual navigation based on CNN in a proximity operation space mission A. D’Ortona, G. Daddi [button link="https://www.mrforum.com/wp-content/upload