Sea urchin inspired device may help explore Mars

Scientists have 3D printed a claw-like device, inspired by the sea urchin's intricate mouth and teeth, that may be used to sample sediments on planets such as Mars.
The urchin's mouthpiece is composed of an intricate framework of muscles and five curved teeth with triangle-shaped tips that can scrape, cut, chew and bore holes into the toughest rocks.
The teeth are arranged in a dome-like formation that opens outwards and closes inwards in a smooth motion, similar to a claw in an arcade prize-grabbing machine.
The urchin's extraordinary ability to rip through rock could translate to a good sediment sampler for space vehicles like the Mars rovers, which currently use shovels to collect ground samples, said Michael Frank, a PhD candidate at the University of California, San Diego (UC San Diego).

"Our goal was a bioinspired device that's more precise and efficient at grabbing ground samples from different areas, and won't disturb the surrounding area like a shovel would," Frank said.
One finding was the importance of a T-shaped structure running down the middle of each of the urchin's teeth, called the keel.

Simulations show that teeth with keels experienced 16 per cent less stress than teeth without keels when subjected to a 4.5 kg load. Researchers also noted that adding the keel increases the mass of the tooth by only 4 per cent.
Bio-inspiration for the study came from pink sea urchins (Strongylocentrotus fragilis), which live off the West Coast of North America, at depths ranging from 100 to 1000 metres in the Pacific Ocean.

The urchins were collected for research by the Scripps Institution of Oceanography at UC San Diego.
Researchers extracted the urchins' mouthpieces, scanned them with microCT, essentially a 3D microscopy technique, and analysed the structures. This allowed engineers to build a highly accurate model of the mouthpiece's geometry.
They also used finite element analysis to investigate the teeth structure, a method that allowed them to determine the importance of the keel to the teeth's performance.
They used the microCT data to make prototypes of the claw-like device using 3D printers.
The device was then attached to a remote-controlled small rover. The researchers first tested the claw on beach sand, where it performed well.

They then used the claw on sand that simulates Martian soil in density and humidity (or lack thereof). The device was able to scoop up sand efficiently.
Researchers envision a fleet of mini rovers equipped with the claw that could be deployed to collect samples and bring them back to a main rover.
The research was published in the Journal of Visualised Experiments.