Space-cleaning robots could be developed thanks to novel device that was inspired by wilting passion fruits

Turns out, dehydrated passion fruits exhibit a type of symmetry not previously known, inspiring self-adapting robots that could one day 'grasp' space junk.
Sade Agard
The novel device exhibits a previously unknown type of symmetry
The novel device exhibits a previously unknown type of symmetry

Fan Xu 

A previously unknown type of wrinkling pattern on the surface of dehydrated passion fruits inspired the invention of a device that could be used to clean up space debris and hazardous materials, according to South Morning China Post (SMCP).

The real-life application comes after Fan Xu, Xi-Qiao Feng and colleagues at Fudan University in Shanghai reported an unknown type of chiral wrinkling pattern on the surface of dehydrated passion fruits in their study published in the journal Nature Computational Science the same day.

A box of withering produce left at the office led to the discovery of a new type of symmetry

Space-cleaning robots could be developed thanks to novel device that was inspired by wilting passion fruits
Novel device was inspired by dehydrating passion fruits

SMCP claims the new study takes inspiration from a box of fruit left at the office. The researchers began dehydrating passion fruit to investigate the patterns when Xu's Tsinghua colleague called to report that he had noticed some intriguing patterns emerging in the withering produce.

They discovered that the fruit initially folded into a buckyball form, its surface covered in hexagons and pentagons in a pattern like a football. They gradually formed a network of ridges that deepened as the fruit kept drying out.

Novel 'chirality' inspired a device that could grasp small objects

As they studied the ridges, they were inspired to mimic the patterns in the lab and put their observations to use by developing a soft silicone ball. They found that the pattern of the ridges could "grasp" small objects such as a diamond, blueberry, or heart-shaped candy, thanks to a property called "chirality."

Now, the researchers claim their novel device could motivate the design of a self-adapting robot for cleaning up tiny particles of space junk floating in orbit. "A robotic arm equipped with the sphere grasper could collect small space debris with high precision," Xu said to SMCP.

He also revealed that "on Earth, it could pick up dangerous particles such as explosives."

The space junk problem:' Over half a million marble-sized pieces of debris are stuck in the Earth's orbit'

According to NASA, about half a million marble-sized pieces of debris are stuck in the Earth's orbit. Another 100 million fragments as small as a pencil tip are revolving around the globe.

Even the smallest debris, such as paint particles from rockets, can threaten spacecraft and robotic missions when colliding at extremely high speeds (about 15,700 miles per hour) in low-orbit Earth. In fact, these paint flecks alone caused the replacement of many space shuttle windows.

Additionally, for most robotic spacecraft operating in low Earth orbit, millimeter-sized orbital debris poses the greatest threat to mission termination.

For instance, in 1996, a French satellite was hit and damaged by debris from a French rocket that had exploded a decade earlier. Additionally, the 3,500 large, trackable debris pieces (and many smaller ones) were added to Earth's orbit by China's 2007 anti-satellite test. This involved using a missile to destroy an outdated weather satellite. And these are just a few examples (of many) of human-made space debris---natural types (meteoroid) exist too.

Overall, the study not only explains and anticipates the structural changes on the surface of dehydrated passion fruits. It also helps simplify the creation of an adaptive robot for grabbing objects inspired by a natural and novel type of chiral wrinkling.

Abstract:

Many biological structures exhibit intriguing morphological patterns adapted to environmental cues, which contribute to their important biological functions and also inspire material designs. Here, we report a chiral wrinkling topography in shrinking core–shell spheres, as observed in excessively dehydrated passion fruit and experimentally demonstrated in silicon core–shells under air extraction. Upon shrinkage deformation, the surface initially buckles into a buckyball pattern (periodic hexagons and pentagons) and then transforms into a chiral mode. The neighbouring chiral cellular patterns can further interact with each other, resulting in secondary symmetry breaking and the formation of two types of topological network. We develop a core–shell model and derive a universal scaling law to understand the underlying morphoelastic mechanism and to effectively describe and predict such chiral symmetry breaking far beyond the critical instability threshold. Moreover, we show experimentally that the chiral characteristic adapted to local perturbation can be harnessed to effectively and stably grasp small-sized objects of various shapes and made of different stiff and soft materials. Our results not only reveal chiral instability topographies, providing fundamental insights into the surface morphogenesis of the deformed core–shell spheres that are ubiquitous in the real world, but also demonstrate potential applications of adaptive grasping based on delicate chiral localization.

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