UNFOLD THE FUTURE

A girl uses an empty ball-point pen to score a large dodecagonal sheet of paper marked with precise lines, that run from a central hexagon to the corners. More lines connecting points of the primary lines run parallel to each other and to alternating edges. Together, the lines form a neat geometric pattern. After the girl meticulously scores all the lines, she begins to fold along the creases. The primary lines fold 180 degrees and the girl gathers them together to form a spiral wrap. She pulls and pushes back the wrap in a motion that resembles a blooming flower to switch between a large outspread flat sheet and a small three-dimensional tube-like structure.

This is the basic design of the Starshade, developed at NASA’s Jet Propulsion Laboratory, a baseball-diamond-sized spacecraft that can ‘unfurl’ to block light from a star. The sunflower-shaped shield flying tens of thousands of kilometres in front of a space telescope would hide the distant star from view, enabling the telescope to capture images of faint exoplanets surrounding the star. The design allows the large Starshade to be packed down to a compact size that can be launched to space.

Rocket science? No, the Starshade’s mechanism called the ‘iris-folding pattern’ took inspiration from origami, the centuries-old Japanese art of folding paper. An origami pattern called a ‘flasher’ involves collapsing a large sheet of paper into a tightly packed cylinder. “Once I realized this is how you fold spacecraft structures, I became interested in origami,” said Manan Arya, a NASA technologist who worked on the Starshade, in a statement from NASA.

Tiny Robot Heroes

Origami can be used to make large structures smaller but can it be applied to objects that are already small? Yes, origami principles can be used to create self-folding designs in any size. “The fundamental laws of folding apply at any scale,” said celebrity origami artist and physicist Robert Lang, as reported in Popular Science.

For instance, scientists at Massachusetts Institute of Technology and the Technical University of Munich have developed an “untethered miniature origami robot that self-folds, walks, swims, and degrades”. The machine, made of PVC and tiny magnets, weighs less than half a gram and is less than two centimetres long. It can even be dissolved in acetone.

Origami-inspired miniature robots are very popular with independent groups of researchers from around the world working on different prototypes. Scientists at Harvard have built a working ‘Transformer’ robot that can be flattened to take on multiple forms.  

What purpose would such robots serve? “In the future, we imagine robots like this could become mini surgeons, squished into a pill that you swallow,” said MIT-based Daniela Rus in an interview with NewScientist. Rus’ team designed Primer, a tiny transforming robot that can change its exoskeleton ‘outfits’ to switch between activities like walking, rolling, sailing and gliding.

After years of research on origami robots, Rus’ team along with scientists from the University of Sheffield and the Tokyo Institute of Technology have demonstrated a tiny ingestible origami robot that can be used for minor surgeries in the stomach. The untethered robot can unfold itself from a swallowed capsule and can crawl across the stomach wall to remove a swallowed button battery or patch a wound, with the help of steering using external magnetic fields.

How to Save a Life

Origami-inspired science is definitely ‘cool’ and will likely have an important role to play in the science of the future. But how useful is such science practically?

Origami has found its way to the design of air bags in cars, the safety mechanism that protects car passengers from injuries during an accident. Designing an air bag is not easy since it has to inflate within seconds and maintain its tautness without being too rigid. Celebrity origrammer Robert Lang has helped a German company develop software that model the inflation of the air bags on the same origami principles that enable folding three-dimensional polyhedrons from flat sheets. The software simulation has been used to improve the company’s airbags.

Researchers at the Brigham Young University have designed a lightweight bulletproof shield based on a ‘Yoshimura origami crease pattern’. The shield, that can be folded into a compact form when not in use and can be reassembled within seconds, can be useful in protecting law enforcement or even military personnel from gunfire. It is also much lighter and easier to deploy than the steel-based shields that are commonly used, at present.

Since it makes possible the creation of light-weight yet strong collapsible structures, origami-based designs have a great potential for application in disaster relief operations. For instance, a team from the Graduate School of Engineering in Hiroshima University has developed a temporary and portable bridge design called the Mobile Bridge Version 4.0 using an accordion-like scissoring design that minimises warping. The 70-feet long bridge, that does not need existing foundations, can be ‘unfurled’ and fully deployed in less than an hour, making it ideal for reaching disaster-hit places that are cut off due to broken bridges.

Self-assembling robots of varying sizes may be useful for search-and-rescue operations in conflict or disaster situations. Origami-reinforced materials may also be employed to construct rigid temporary shelters that are easier to transport and erect than canvas tents.

The usefulness of origami-inspired miniature robots for diagnosis of defects, drug delivery and surgeries in the human body is evident. But origami has another more direct application to human medicine, as well and this is in the form of stents. Oxford University researchers including Zhong You developed a heart stent that works using the concept of a ‘waterbomb base’, the same design that is used in origami boxes. The stent can be contracted to be small enough to fit through a catheter and can be inflated to open up arteries once it reaches its position.

According to a Japanese superstition, a person who folds a 1000 origami cranes may be granted a wish, perhaps to save a life. In any case, origami-inspired science is already saving lives.