Promises and Challenges of Robotic Quadrupeds for Space Exploration

Kurzfassung

After numerous successful space missions with wheeled rovers such as Curiosity or Perseverance to explore open areas and collect samples, space agencies and private ventures around the world are shifting their focus to also explore more challenging environments. These include lunar lava tubes and Martian caves, which hold great promises to scientific discoveries. In these scenarios, the accessibility for large and wheeled robots would be limited, such that (small) legged robots capable of climbing, jumping, and dynamically adapting their gaits to different environments become necessary. However, despite the recent advances and increased commercial availability of quadrupedal robots, the exact requirements that a quadruped has to fulfill in a space setting remains an open topic. To address this question, this paper reviews current solutions and capabilities of robotic quadrupeds to assess the specific benefits that this technology offers as part of a robotic team for operations on celestial surfaces such as the Moon and Mars. Additionally, the main open challenges are identified to adapt the state-of-the-art technology in terrestrial systems for in-space deployment and operations. For this analysis, we leverage findings from the ISS technology demonstration mission, Surface Avatar. In two space-to-ground experiment sessions, three astronauts in orbit teleoperated a small quadrupedal robot to survey its environment and retrieve small objects. These insights were extended in a follow-up mission in July 2025, in which multiple quadrupeds were included operated by the astronauts for different tasks. Additionally, this new session included a cave exploration scenario. The experiment findings and astronaut feedback were evaluated under consideration of preparatory work carried out for planned quadruped space missions such as ESA's LEAP project and NASA's NeBula-SPOT. By examining and analyzing the experimental results and astronaut feedback from our Surface Avatar mission with the current state of technology, this paper derives specific requirements to employ quadrupedal robots in space, either in a remote control setting or for autonomous tasks. Based on the identified requirements, we will propose design recommendations for both control strategies of robotic quadrupeds to be included for different tasks in human-robot teams for future space exploration.