This novel underwater robot can explore extraterrestrial oceans

RoboSalps can function on their own and in 'colonies'

With their semi-transparent barrel-shaped bodies, salps resemble jellyfish, but they belong to the family of Tunicata and have a complex life cycle and change between solitary and "aggregate" generations by forming colonies.

"RoboSalp is the first modular salp-inspired robot. Each module is made of a very lightweight soft tubular structure and a drone propeller which enables them to swim. These simple modules can be combined into 'colonies' that are much more robust and have the potential to carry out complex tasks," researcher Valentina Lo Gatto of Bristol's Department of Aerospace Engineering, who is leading the study, said in a statement.

"Because of their low weight and their robustness, they are ideal for extra-terrestrial underwater exploration missions, for example, in the subsurface ocean on the Jupiter moon Europa," she said.

It is to be noted that each module of RoboSalps can also swim on its own, thanks to a small motor with rotor blades in the soft tubular structure.

And when multiple units are joined together, they form a "redundant" system and can still function despite failure. The whole colony can move even if one module breaks.

A novel concept for a wide range of applications

Such a colony of soft robots is a novel concept and has a wide range of interesting applications. Their energy-efficient feature makes them ideal for autonomous missions.

"These include the exploration of remote submarine environments, sewage tunnels, and industrial cooling systems. Due to the low weight and softness of the RoboSalp modules, they are also ideal for extra-terrestrial missions. They can easily be stored in a reduced volume, ideal for reducing global space mission payloads," said Dr. Helmut Hauser of Bristol's Department of Engineering Maths.

It also provides safer interaction with delicate ecosystems, both on earth and extra-terrestrial, thereby reducing the risk of environmental damage. Interestingly, RoboSalps can also split into multiple segments, each exploring in a different direction and later reassembled in a new configuration for a different objective.

The team is also developing control approaches that can "exploit the compliance of the modules to achieve energy-efficient movements close to those observed in biological salps."