  The interest in exploring planetary bodies for scientific investigation and
in-situ resource utilization is ever-rising. Yet, many sites of interest are
inaccessible to state-of-the-art planetary exploration robots because of the
robots' inability to traverse steep slopes, unstructured terrain, and loose
soil. Additionally, current single-robot approaches only allow a limited
exploration speed and a single set of skills. Here, we present a team of legged
robots with complementary skills for exploration missions in challenging
planetary analog environments. We equipped the robots with an efficient
locomotion controller, a mapping pipeline for online and post-mission
visualization, instance segmentation to highlight scientific targets, and
scientific instruments for remote and in-situ investigation. Furthermore, we
integrated a robotic arm on one of the robots to enable high-precision
measurements. Legged robots can swiftly navigate representative terrains, such
as granular slopes beyond 25 degrees, loose soil, and unstructured terrain,
highlighting their advantages compared to wheeled rover systems. We
successfully verified the approach in analog deployments at the BeyondGravity
ExoMars rover testbed, in a quarry in Switzerland, and at the Space Resources
Challenge in Luxembourg. Our results show that a team of legged robots with
advanced locomotion, perception, and measurement skills, as well as task-level
autonomy, can conduct successful, effective missions in a short time. Our
approach enables the scientific exploration of planetary target sites that are
currently out of human and robotic reach.
