Hendrik Kolvenbach

Last Name

Kolvenbach

First Name

Hendrik

ORCID

0000-0003-1229-7537

Organisational unit

09570 - Hutter, Marco / Hutter, Marco

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Publications 1 - 10 of 33

Lunarleaper - Unlocking a Subsurface World
Mittelholz, Anna; Stähler, Simon Christian; Kolvenbach, Hendrik; et al. (2024)
EGUsphere
We present LunarLeaper, a robotic explorer concept in response to the ESA 2023 Small Missions call. Pits, volcanic collapse features with near-vertical walls, have been identified across the lunar and Martian surface. These pits are high priority exploration destinations because some, referred to as skylights, might provide access to subsurface lava tube systems. Lava tubes are of particular interest for future human exploration as they offer protection from harmful radiation, micrometeorites and provide temperate and more stable thermal environments compared to the lunar surface. We propose to use a small legged robot (ETH SpaceHopper, <10 kg), to access and investigate the pit edge, using its ability to access complex and steep terrain more safely than a wheeled rover. LunarLeaper will land in Marius Hills within a few 100 m of the pit and traverse across the lateral extent of the hypothesized subsurface lava tube. On its traverse it will take measurements with a ground penetrating radar and a gravimeter, measurements that will allow us to survey the subsurface structure and detect and map lava tube geometry if present. The robot will approach the pit edges and acquire high resolution images of the pit walls containing uniquely exposed layers of the geophysically mapped lava flows and regolith layers. These images will allow not only scientific advances of lunar volcanism and regolith formation, but also enable assessment of the stability of the pit structure and its use as a possible lunar base. The mission is expected to last 1 lunar day. The robot could be delivered to the surface by a small lander, as they are currently developed and planned by various national and commercial agencies and hop off the landing platform without the need for a robotic arm. It is highly flexible in accommodation and can thus make full use of the new international lunar ecosystem.
LunarLeaper—A mission concept to explore the lunar subsurface with a small-scale legged robot
Kolvenbach, Hendrik; Mittelholz, Anna; Stähler, Simon Christian; et al. (2026)
Acta Astronautica
We present the LunarLeaper mission concept, which aims to robotically investigate volcanic pits on the lunar surface. Volcanic pits, or skylights, are collapse features that may provide access to subsurface lava tubes, which could serve as shelters for future human explorers and offer insight into the volcanic history of the Moon by exposing ancient lava flows. The existence and extent of large caves are still debated today and require in situ analysis. The Marius Hills site in particular offers a potential entry point to a cave system in a volcanic region on the lunar nearside. Our mission aims to deploy a payload-equipped 15 kg-class legged robot that can approach a pit, such as the Marius Hills pit, while taking measurements during the traverse. During the mission, measurements from a ground-penetrating radar (GPR) and a gravimeter will allow us to survey the subsurface and map any underlying lava tube, if present. The mission will investigate key questions regarding lunar volcanism, such as the existence and geometry of subsurface caves and the magnitude and timing of lava flows, while assessing the site's suitability for future human utilization and habitation. Furthermore, the mission will demonstrate key enabling technologies such as legged robots, serving as building blocks for the next generation of planetary missions.
Quadrupedal Robots for Planetary Exploration
Kolvenbach, Hendrik (2021)
Dr. Hendrik Kolvenbach presents the research results performed at the Robotic Systems Lab of ETH Zurich on dynamically walking quadrupedal robots for planetary exploration. He focuses on the locomotion aspects and experimental validation.
LunarLeaper: From Simulation to Hardware for Lunar Legged Locomotion
Church, Joseph; Fuhrer, Adrian; Fischer, Oliver; et al. (2025)
IAC 2025 Congress Proceedings
Following a successful Mission Concept Review in April 2025, the LunarLeaper team is advancing the design of a ~15 kg legged robot for investigation of a lunar volcanic pit. The review established Level 0/1 requirements and a concept of operations, while highlighting key challenges in locomotion maturity (TRL 4), power and thermal margins, and dust mitigation. To address these challenges, we are conducting interconnected studies that include morphology analyses, learning-based locomotion control, actuator and thermal modeling, and simulations of regolith interaction. Together, these activities form a framework that links morphology, actuation, control, and environment to mission level feasibility. By exposing key sensitivities of a legged robot, they enable better-informed Level 2/3 requirements, provide the foundation for the upcoming System Requirements Review (SRR), and establish a path toward hardware designs in Phase B.
Dataset and Analysis of River Waste Pollution in the Limmat River, CH, during a One-day City Festival (Zurich Street Parade, 2023)
Esquivel Estay, Fidel; Kolvenbach, Hendrik; Strübin, Dario; et al. (2024)
This paper introduces a dataset of instance seg- mentation of waste items collected from the Limmat River in Zurich, Switzerland, after the annual festival “Street Parade” held on August 12th, 2023. We have collected the objects during and after the event took place. The objective of the data collection is to gain a better understanding of waste items commonly found in rivers and to provide an open-source dataset for technology developers fighting ocean-bound plastic pollution. Volunteers and scientists from the Autonomous River Cleanup (ARC) team, a project at the Robotic Systems Lab at ETH Zurich, collected the data. The dataset contains 585 annotations of waste objects across 8 classes. Plastic bottles form the predominant part of the dataset by far, matching 436 items to this class. We attribute this number to the high consumption rate of beverages in plastic bottles during this hot summer day and the buoyant properties of plastic.
Concept Study of a Small-Scale Dynamic Legged Robot for Lunar Exploration
Trentini, Marco; Arm, Philip; Valsecchi, Giorgio; et al. (2023)
IAC 2023 Conference Proceedings
When it comes to the exploration of the lunar surface, many high-reward targets, such as the craters at the lunar south pole or the Aristarchus Plateau, lie in hard-to-reach areas due to steep slopes, crater rims, and unstructured terrain. Therefore, such high-risk high-reward targets are currently out of human and robotic reach. Legged robots present a promising approach to exploring hard-to-access targets on the Moon. Legged robot prototypes have shown impressive locomotion capabilities in sloped, unstructured terrain in analog environments. However, despite their success in locomotion validation tests, we currently lack a target- and mission-specific analysis and design of the locomotion pattern, the thermal requirements, and the power system. We have set our goal to develop a small-scale, legged, technology demonstration robot. In this paper, we present our conceptual work on such a robot, targeting a traverse distance of 200 m and a payload capability of 1.5 kg. Our study showcases a basic locomotion study that identifies a feasible gait and its power requirements on representative terrain. We then lay our major focus on a thermal and power model considering the environment, the robot, and task schedule with sufficient accuracy to fulfill our self-defined mission success criteria. We also investigate the influence of the system’s emissivity and absorptivity on the regulation of the robot’s temperature. The simulation results suggest feasibility for missions at latitudes of 24°S and 75°S using a small-scale dynamic legged robot. However, it becomes clear that further research is required to validate the accuracy of the model. Research in solar panel degradation due to dust perturbation in legged robots will be necessary as the solar panel degradation shows a significant impact on the mission duration. Furthermore a precise soil-robot view factor needs to be determined. The determination of a realistic multi layer insulation concept for SpaceHopper in a lunar environment will be necessary to validate the assumptions draw based on the results the simulations.
Cat-Like Jumping and Landing of Legged Robots in Low Gravity Using Deep Reinforcement Learning
Rudin, Nikita; Kolvenbach, Hendrik; Tsounis, Vassilios; et al. (2022)
IEEE Transactions on Robotics
In this article, we show that learned policies can be applied to solve legged locomotion control tasks with extensive flight phases, such as those encountered in space exploration. Using an off-the-shelf deep reinforcement learning algorithm, we train a neural network to control a jumping quadruped robot while solely using its limbs for attitude control. We present tasks of increasing complexity leading to a combination of 3-D (re)orientation and landing locomotion behaviors of a quadruped robot traversing simulated low-gravity celestial bodies. We show that our approach easily generalizes across these tasks and successfully trains policies for each case. Using sim-to-real transfer, we deploy trained policies in the real world on the SpaceBok robot placed on an experimental testbed designed for 2-D microgravity experiments. The experimental results demonstrate that repetitive controlled jumping and landing with natural agility is possible.
Comparison of Legged Single-Robot and Multi-Robot Planetary Analog Exploration Systems
Arm, Philip; Kolvenbach, Hendrik; Hutter, Marco (2023)
IAC 2023 Conference Proceedings
The development of ongoing and future planetary exploration missions calls for novel, effective robotic exploration technologies. Inspired by the recent developments in terrestrial robotic teams, we investigate the design and deployment of heterogeneous robotic teams and the accompanying operation concepts in planetary analog missions. Specifically, we describe a single-robot and a multi-robot system we developed for analog exploration missions using legged robots. We focus on the field trials using these systems at the ESA/ESRIC Space Resources Challenge. We show a performance comparison of our approaches, including payload utilization, mapping performance, redundancy, and human-robot interaction metrics. Furthermore, we present our lessons learned on developing and testing single-robot and multi-robot exploration systems. Our work shows that a heterogeneous robotic team allows higher payload utilization and a safer redundancy concept than single-robot approaches. However, a higher level of autonomy per robot is required to scale up the multi-robot approach.
Towards autonomous inspection of concrete deterioration in sewers with legged robots
Kolvenbach, Hendrik; Wisth, David; Buchanan, Russell; et al. (2020)
Journal of Field Robotics
The regular inspection of sewer systems is essential to assess the level of degradation and to plan maintenance work. Currently, human inspectors must walk through sewers and use their sense of touch to inspect the roughness of the floor and check for cracks. The sense of touch is used since the floor is often covered by (waste) water and biofilm, which renders visual inspection very challenging. In this paper, we demonstrate a robotic inspection system which evaluates concrete deterioration using tactile interaction. We deployed the quadruped robot ANYmal in the sewers of Zurich and commanded it using shared autonomy for several such missions. The inspection itself is realized via a well‐defined scratching motion using one of the limbs on the sewer floor. Inertial and force/torque sensors embedded within specially designed feet captured the resulting vibrations. A pretrained support vector machine (SVM) is evaluated to assess the state of the concrete. The results of the classification are then displayed in a three‐dimensional map recorded by the robot for easy visualization and assessment. To train the SVM we recorded 625 samples with ground truth labels provided by professional sewer inspectors. We make this data set publicly available. We achieved deterioration level estimates within three classes of more than 92% accuracy. During the four deployment missions, we covered a total distance of 300 m and acquired 130 inspection samples.
Preliminary design of actuators for walking robot on the Moon
Valsecchi, Giorgio; Liconti, Davide; Tischhauser, Fabian; et al. (2022)
Legged robots have been proposed as a possible alternative to wheeled systems for accessing so-far hard to reach locations in our solar system. However, despite promising results in this field, significant challenges have to be solved before deployment. In particular, the actuation of walking robots in space is still an open engineering question. In this work, we focus on actuation of space-legged robots and propose a preliminary actuator sizing. Torque and velocity profiles are derived from simulations, and power consumption, heat generation and emission are computed as functions of several design parameters. A simplified thermal model is used to calculate the equilibrium temperature. Finally, design specifications and considerations are drawn from the analysis.

Publications 1 - 10 of 33

Hendrik Kolvenbach

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