To be safely and reliably deployed in outer space, underwater and in other extreme environments, robots need to be able to withstand harsh conditions without breaking. In addition, they should be able to promptly and rapidly adapt to dynamic changes in their surroundings.
While in recent years, robotics engineers have developed a wide range of highly flexible and adaptable systems, most of these systems do not work well at extremely low or high temperatures and at low pressure. One solution that has proved promising for improving the resilience of robots in extreme environments entails the use of dielectric elastomer actuators (DEAs).
DEAs are devices made from stretchy insulating materials called elastomers. When a voltage is applied to them, these materials can store electrical energy, converting into movement.
Researchers at the University of Connecticut recently developed a silicon-based DEA that could be more resistant in harsh environments, such as those found in space and in the upper layer of the atmosphere (i.e., stratosphere). Their actuator, introduced in a paper posted to the arXiv preprint server, is based on a silicon elastomer that was chemically processed to improve its resilience in harsh conditions.
“Machines designed for operation in space, as well as other extreme environments, need to be both resilient and adaptable when mission parameters change,” wrote Codrin Tugui, Tirth Thakar and their colleagues in their paper. “Soft robots offer advantages in adaptability, but most lack resilience to the pressure and temperature extremes found as close as the stratosphere. Dielectric elastomer actuators overcome some of those limitations when built as solid state compliant capacitors capable of converting electrical energy into mechanical work, but the elastomer resilience limits the device’s operating window.”
A more resistant silicon elastomer
In their paper, Tugui, Thakar and their colleagues introduced a new crosslinking mechanism, a chemical process that strengthens and stabilizes materials by joining their underlying molecular chains. To promote this mechanism, they used a combination of ultraviolet (UV) light and a platinum-based catalyst.
“We present a crosslinking mechanism for silicone elastomers under ultraviolet light using trimethyl(methylcyclopentadienyl)platinum(IV) as a catalyst to react hydrosilane to vinyl groups,” wrote the researchers. “The formation of carbon-carbon bonds enables fast processing under UV light and exceptional electro-mechanical performance in dielectric elastomer actuators.”
The team used their proposed approach to create a new silicon-based elastomer and then tested its resilience in extreme environments. Specifically, they tested it at temperatures ranging from -40°C to 120°C and at extremely low (i.e., near-vacuum) pressure, comparing it with widely used elastomers based on acrylic and silicon.
Their elastomer was found to be significantly more resilient to harsh environments than the materials it was compared with. In addition, the team used the material they created to build autonomous soft robotic grippers, which they used to carry balloon payloads.
Balloon payloads are packages suspended under high-altitude balloons. These balloons are commonly used to carry electronics, sensors and other equipment at high altitudes (between 19,000 and 36,000 meters above the ground), allowing scientists to capture data in the stratosphere.
“Fully autonomous systems controlling grippers made with the novel silicone were integrated into payloads for high altitude balloon testing,” wrote the authors. “Two stratospheric balloon missions were carried out and demonstrated DEAs as a viable soft robotic technology under space-like conditions (as high as 23.6 km elevation, at
Opening new avenues for space robotics
The new crosslinking mechanism proposed by Tugui, Thakar and their colleagues was found to result in a stronger elastomer that worked well at extreme temperatures and low temperatures, without degrading. Their initial tests demonstrate the potential of actuators strengthened using their approach for aerospace applications, showing that they function reliably at high altitudes.
In the future, the team’s proposed method could be used to enhance the resilience of other elastomers and create a broader range of actuators that can be deployed in the stratosphere or in space. Meanwhile, the researchers are planning to improve their approach to overcome other limitations of existing silicon-based elastomers.
“The combinations of chemical building blocks and catalyst can be further expanded to address other challenges for silicones, including adhesion and additive manufacturing,” wrote the authors.
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Publication details
Codrin Tugui et al, A Soft Robotic Demonstration in the Stratosphere, arXiv (2026). DOI: 10.48550/arxiv.2603.04352
Journal information:
arXiv
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