# An Optimised Spider-Inspired Soft Actuator for Extraterrestrial Exploration

## TL;DR

This paper introduces a spider-inspired soft robot optimized for extraterrestrial exploration, capable of efficient jumping and stowage.

## Contribution

A novel soft actuator inspired by spider physiology with a non-backdriveable clutch for energy-efficient position holding in space.

## Key findings

- The robot achieves a power-to-weight ratio of 249 W/kg and can jump 1.86 times its body length.
- The collapsible design allows efficient stowage and self-deployment for space missions.
- Optimization across materials and pressures improved actuation efficiency and controllability.

## Abstract

Extraterrestrial exploration presents unique challenges for robotic systems, as traditional rigid rovers face limitations in stowage volume, traction on unpredictable terrain, and susceptibility to damage. Soft robotics offers promising solutions through bio-inspired designs that can mimic natural locomotion mechanisms. Here, we present an optimised, spider-inspired soft jumping robot for extraterrestrial exploration that addresses key challenges in soft robotics: actuation efficiency, controllability, and deployment. Drawing inspiration from spider physiology—particularly their hydraulic extension mechanism—we develop a lightweight limb capable of multi-modal behaviour with significantly reduced energy requirements. Our 3D-printed soft actuator leverages pressure-driven collapse for efficient retraction and pressure-enhanced rapid extension, achieving a power-to-weight ratio of 249 W/kg. The integration of a non-backdriveable clutch mechanism enables the system to hold positions with zero energy expenditure—a critical feature for space applications. Experimental characterisation and a subsequent optimisation methodology across various materials, dimensions, and pressures reveal that the robot can achieve jumping heights of up to 1.86 times its body length. The collapsible nature of the soft limb enables efficient stowage during spacecraft transit, while the integrated pumping system facilitates self-deployment upon arrival. This work demonstrates how biologically inspired design principles can be effectively applied to develop versatile robotic systems optimised for the unique constraints of extraterrestrial exploration.