A self-propelling, octopus-inspired rocket can zoom through water using energy more efficiently than fish that accelerate rapidly to escape.

Credit: Gabriel D. Weymouth and Vignesh Subramaniam

Gabriel Weymouth of the University of Southampton, UK, and his colleagues were inspired by the escape manoeuvres of the octopus, which fills its body with water and then quickly expels it to dart away. On the basis of this principle, the authors built their rocket using a flexible hull, which they inflated with water (pictured). They then measured the rocket's speed as it shot the fluid out through its base. As the rocket contracted, it achieved more than 2.6 times the thrust of a rigid rocket doing the same manoeuvre.

The researchers calculate that making the robot bigger would improve its accelerating performance, and suggest that their technology could be used in underwater vehicles.

Bioinspir. Biomim. http://dx.doi.org/10.1088/1748-3190/10/1/016016 (2015)