Roving with the Stars

Space exploration offers numerous benefits that extend far beyond the realms of curiosity and adventure. One of the most significant advantages lies in the potential discovery and extraction of valuable raw materials. Many celestial bodies, such as the Moon, asteroids, and even Mars, are believed to contain abundant resources like precious metals and rare minerals. By mining these resources, space exploration can alleviate resource scarcity on Earth and provide a sustainable supply for future industries. Not only will this reduce our dependence on terrestrial resources, but it could also stimulate economic growth and open up new avenues for commercial ventures.

Robots play a pivotal role in space exploration, particularly in situations where human presence is either too risky or impractical. Robotic missions enable us to gather essential data and perform complex tasks in environments that are hostile to humans, such as the harsh vacuum of space or the extreme temperatures and radiation of distant planets. Robots can be designed to withstand these conditions and execute precise maneuvers with high accuracy and efficiency. They can collect samples, conduct experiments, analyze data, and even repair or maintain equipment with minimal human intervention.

Every kilogram of payload carried into space comes at a significant cost, making it crucial to minimize the size and weight of onboard robots. This has generally led engineers to target the development of single, multipurpose robots that can carry out all of the mission objectives. But that strategy does come at a cost — while it cuts down on launch expenses, it limits the utility and effectiveness of the robot once it arrives at its destination, and therefore the overall value of the mission.

Researchers at ETH Zurich have taken a contrarian approach in designing a fleet of space exploration robots, each with different capabilities. At present, they have outfitted three ANYmal quadrupedal robots with the equipment they need to carry out a number of tasks important in planetary exploration. Conventional thinking might lead one to believe that this is unnecessary overhead, but this approach does offer many benefits.

Since there is not a single robot that needs to be a jack of all trades, each robot can be designed such that it is ideally suited for a small set of tasks, rather than being just good enough for a lot of tasks. These robots can also work in parallel, doing more work in less time. Moreover, sending multiple robots provides redundancy, such that if only some of them fail, most or all of the mission objectives can still be carried out — with a single robot there is a single point of failure.

The team equipped two of the robots as specialists. One is outfitted with laser scanners and multiple cameras to map terrain and classify geological features. The other is equipped with a Raman spectrometer and a microscopy camera such that it can precisely identify rocks. The third robot is more of a generalist. It can both map terrain and identify rocks, but with less precision, giving it the ability to fill in for either of the specialists in a pinch, or seek out interesting features for the better equipped robots to follow up on later.

The legged design may also give the team’s fleet an advantage in many situations over traditional wheeled rovers, especially where granular slopes, loose soil, or unstructured terrain are present. This was confirmed in the Beyond Gravity ExoMars rover test bed in a quarry in Switzerland, where the ANYmal robots showed themselves to be very adept at getting around in tough conditions.

At present the robots are manually operated via a control center, but the team has plans to build in autonomy in the future such that they can carry out tasks in remote areas of the solar system where communications delays prevent efficient manual control. They are also exploring the idea of adding more types of robots to the fleet, including those with the ability to fly to collect more types of data.