When Perseverance arrives on Mars early next year, it will be the first landfall for a rover carrying 3D-printed metal parts and a small victory for proponents of the technique in the high-cost, high-risk world of the U.S. aerospace program.

NASA's Jet Propulsion Laboratory, nestled in the foothills of La Cañada Flintridge, has seen a slow cultural shift over the last decade toward the adoption of 3D printing techniques, more formally known as "additive manufacturing," in spacecraft design. The technology uses lasers to melt metal powder that is layered to precise computer modeling, until that metal takes the shape of whatever engineers need.

For years, 3D printing has been relegated to the realm of nerdy hobbyists, but its adoption by startups and big business has helped push NASA leaders toward accepting more innovation despite the risks. These days, 3D printing has been used on airplane engines, houses, hearing aids, chocolates, Tesla car components and even a pair of Adidas shoes.

"I have seen a 3D printed burrito, and it didn't look as delicious as Chipotle," said Scott Roberts, a JPL materials technologist, with a laugh.