Air travel is a disaster for the environment. Currently, the aviation industry accounts for over 2% of global carbon dioxide emissions. A single flight between New York and California produces around 20% of the emissions that a car would in the course of a year. And as rates of air travel increase by around 6% each year, it’s difficult for the small gains in efficiency that airplane designers have made over the years to offset demand.
Nevertheless, there’s room for improvement. Commercial airlines have, since 2011, been experimenting with using biofuels, which reduce emissions. In recent years, the industry has shifted away from using metal and steel in the main body and wings of airplanes, and toward lighter materials, like carbon fiber composites. Carbon fiber is often hailed as a sustainability hero: Its strength and low weight means it performs efficiently and requires less fuel to power. But it’s energy-intensive to produce, and very difficult to recycle.
So in the quest to find a more sustainable, equally lightweight material to work into commercial airplane construction, the aerospace corporation Airbus landed on a surprising solution: synthetic spider silk.
Airbus has set up a partnership with AMSilk, a German manufacturer that claims to be the first industrial supplier of synthetic silk biopolymers. AMSilk’s Biosteel is produced in a lab and designed to mimic the flexibility and uncanny strength of spider silk. The closed-loop, bacterial fermentation process for making Biosteel does not require either fossil fuels or high temperatures, making it both energy-efficient and sustainable. With Airbus, AMSilk will be working closely to develop a prototype composite material–made of Biosteel fiber and resin–which they hope to debut in 2019, says AMSilk CEO Jens Klein.
Biosteel has generated buzz over the past couple years, since it debuted in a biodegradable Adidas shoe. Athletic-wear companies have been flocking to the material because of its lightweight and durable properties. AMSilk also has a partnership with a health company, which is using its biofabricated silk to develop a safer coating for medical implants–because the material is derived from a natural protein, human bodies accept it more readily than they do synthetic polymers.
But it’s quite a leap to go from these fashion and medical applications to airplanes. The timeline for seeing Biosteel in actual flying airplanes is still unclear, since it’s contingent on the prototyping process, but Airbus is eager to prove that the aviation industry can integrate more sustainable materials into construction.
“Airbus was looking for a material with properties that are not currently available for the industry,” Klein says. Carbon fiber, while lightweight, tends to be brittle and inflexible. “There’s a need for aircraft and other flying objects to be both flexible and strong at the same time,” he adds, which is something that existing materials do not deliver well, but Biosteel could. The spider-silk-like fiber is also more malleable and able to be woven seamlessly into unconventional shapes (like shoes), which could help facilitate innovation in the way airplanes are constructed.
For AMSilk, too, the partnership represents a significant expansion of its business. “Work in composite materials is really something new for us,” Klein says. “We know how to develop fibers, and now we’re gaining the know-how for composite materials.” It also demonstrates how an innovative material can scale: While biodegradable shoes represent an important, if small, shift in fashion and apparel, working a sustainably produced, innovative material into the aviation industry could help accelerate progress in a large sector that, quite notoriously, has a long way to go to meet environmental standards.