Science

How origami machines might unlock secrets of Mars and the universe

New thinking

More than a mere pastime, the tools of origami are leaping off the page and into the realms of engineering and manufacturing. 

If some NASA researchers have their way, Mars exploration technology of the future may rely on an art form from the past.

NASA’s Jet Propulsion Laboratory (JPL) has developed a Pop-Up Flat Folding Explorer Robot (PUFFER) prototype that could change how we explore Mars. The rugged yet portable machine takes its inspiration from the art of origami, which, despite Americans' association with grade-school arts and crafts, is proving to be a cutting-edge design philosophy. Recent developments in the field have led to an explosion of uses ranging from solar panels to bulletproof barriers.

What sets PUFFER apart from other rovers is that it folds flat, making its mini-profile even slimmer. Mission planners find this feature attractive, because it means they can pack many robots into one spacecraft. After popping up and assuming their full 3-D form on Mars, such robots could accompany a main explorer, scouting out fascinating but perilous targets such as caves, craters, lava tubes, and overhanging rocks.

“We’ve seen a lot of interesting terrain features we have yet to explore,” says project manager Jaakko Karras. “But they tend to be places you don’t want to send your one multi-billion dollar rover,” he tells The Christian Science Monitor in a phone interview.

Rover design balances the need to cram the vehicle into a small rocket with the desire for high clearance, using big-wheeled machines that won’t get “hung up on every pebble,” Mr. Karras explains. “The expanding chassis sort of gives you the best of both worlds.”

In addition to serving as “mobility supplements,” PUFFERs’ literal flexibility pays off in a number of areas. They can squeeze into small spaces, survive rough falls, climb steep slopes, and easily flip themselves over to expose solar panels for charging. In fact, they’re so rugged Karras suspects that, before they’re ready for Mars, PUFFERs may find use as cheap, remote, long-term sensors of seasonal ice changes in the Arctic.

And PUFFER isn’t the first time engineers have turned to the Japanese art of paper-folding to solve aerospace problems. In 2013, then-JPL researcher Brian Trease partnered with renowned origami pioneer Robert Lang to design a novel scheme for packaging space solar cells.

Rather than using the square creases seen in the International Space Station’s panels, they based their device on a circular pattern that easily folds to pack around a spacecraft, before fanning out for deployment in space. Their solution allowed them to fold an 82-foot wide cell into a 9-foot wide package.

“Origami naturally lent itself as a solution because if you want to fold anything, that comes from origami,” explains Dr. Trease, who has fond memories of his time studying abroad in Japan and origami’s power to bridge the language barrier with his host family.

More than just origami-inspired, the solar panel’s design relied directly on a classic technique called the flasher pattern. “We started applying some basic patterns that were originally from children's origami books. We took those and used engineering to make them useful for thick structures,” Trease says.

Origami's practical applications extend far beyond aerospace. Mechanical engineers from Brigham Young University harnessed the curvature of what’s known as the Yoshimura folding pattern to manufacture a stable, quick set-up bulletproof shield that shelters up to three police officers, yet weighs just half as much as similar barriers.

In a phone interview with The Christian Science Monitor, Dr. Lang cites this shield as an example of an especially unique application, because unlike other armor designs, its single-sheet manufacturing means it has no weak joints between neighboring plates.

Just sixty years after Akira Yoshizawa formalized the arrow-and-crease-based visual language that spread origami around the world, what was born an art is coming of age as a science.

And in this case, the partnership has proved fruitful for the art, as well. “You can find a lot of examples where engineering and science try to take inspiration from art or nature, but usually that’s a one way transaction,” Trease says. “With this particular marriage,... [Robert Lang] came up with these general [mathematical] tools that the origami community took back, and used to advance their own art. It was a great acceleration, an explosion by origami artists to create the most amazing, intricate patterns,” he explains.

The frenzy of activity has advanced the field of math, as well. When asked what insights he’s gained from origami, Lang mentions a proof he worked on showing that one can fold a shape in such a way that its perimeter grows. Formally known as the napkin folding problem, it’s a result many find surprising, but Lang credits his origami experience for providing the intuition necessary for one of his solutions.

But despite its numerous engineering successes, origami sometimes suffers from its image as a juvenile pastime, according to Trease. “The biggest obstacle is going forward and saying ‘I want to use origami to do something,’ and getting serious bias for that. Everyone remembers doing origami when they were a kid and it’s kind of a child’s toy thing,” he explains.

It’s a perception that couldn’t be farther from the truth, as the field grows to include ever-more abstract branches of mathematics. “Geometry is definitely part of the mix,” says Lang. “For a lot of designs, nothing more than simple, plain geometry is needed,” but when designing large deployable space structures, for example, engineers also rely on linear algebra, and differential geometry, among other fields of computational geometry.

Fortunately for origamist researchers, funding organizations seem to be getting the message. The National Science Foundation has distributed millions of dollars in grants to origami-inspired design, and the PUFFER program received support from JPL’s Game Changing Development Program, a NASA funding source that purposely tries to foster what Karras calls “out-there ideas.”

While Lang’s algorithms are powerful enough to take in a stick-figure sketch of an insect and spit out a fold pattern for a terrifyingly realistic paper model, the field of origami manufacturing is still in its infancy. Both Lang and Trease point out the need for better mathematical models that can incorporate thickness (since you can’t make a bulletproof barrier out of thin paper), and bending (good for paper beetles but bad for ceramic or glass solar panels).

These open problems represent hurdles that stand in the way of translating the wealth of knowledge origamists have gathered over the last century about design into practical manufacturing processes that work in materials besides paper, such as the Smart Composite Microstructures architecture, which Karras and his team implemented in PUFFER.

As engineers overcome these obstacles, Trease suggests origami-based design may even emerge alongside 3-D printing as a tool for quickly and cheaply creating structures with volume. After all, we already have a heritage of 2-D printing techniques that stretches back centuries, he points out.

“So origami presents this potential platform where we do all these interesting things leveraging all this great 2-D technology, and then in this last step in the end you pop or transform it into its 3-D form,” Trease explains.

Lang too predicts a bright future for the origami-based design and its applications. Especially in the realm of space, he says, origami is playing a direct role in “increasing our store of knowledge about the universe and our place in it.”