If you want to see science fiction at work, visit a modern machine shop, where 3-D printers create materials in just about any shape you can imagine. NASA is exploring the technique—known as additive manufacturing when used by specialized engineers—to build rocket engines as well as potential outposts on the Moon and Mars. Nearer in the future is a different milestone: NASA’s Perseverance rover, which lands on the Red Planet on Feb. 18, 2021, carries 11 metal parts made with 3-D printing.
Instead of forging, molding, or cutting materials, 3-D printing relies on lasers to melt powder in successive layers to give shape to something. Doing so allows engineers to play with unique designs and traits, such as making hardware lighter, stronger, or responsive to heat or cold.
“It’s like working with papier-mâché,” said Andre Pate, the group lead for additive manufacturing at NASA’s Jet Propulsion Laboratory in Southern California. “You build each feature layer by layer, and soon you have a detailed part.”
Curiosity, Perseverance’s predecessor, was the first mission to take 3-D printing to the Red Planet. It landed in 2012 with a 3-D-printed ceramic part inside the rover’s ovenlike Sample Analysis at Mars (SAM) instrument. NASA has since continued to test 3-D printing for use in spacecraft to make sure the reliability of the parts is well understood.
As “secondary structures,” Perseverance’s printed parts wouldn’t jeopardize the mission if they didn’t work as planned, but as Pate said, “Flying these parts to Mars is a huge milestone that opens the door a little more for additive manufacturing in the space industry.”
A Shell for PIXL
Of the 11 printed parts going to Mars, five are in Perseverance’s PIXL instrument. Short for the Planetary Instrument for X-ray Lithochemistry, the lunchbox-size device will help the rover seek out signs of fossilized microbial life by shooting X-ray beams at rock surfaces to analyze them.
PIXL shares space with other tools in the 88-pound (40-kilogram) rotating turret at the end of the rover’s 7-foot-long (2-meter-long) robotic arm. To make the instrument as light as possible, the JPL team designed PIXL’s two-piece titanium shell, a mounting frame, and two support struts that secure the shell to the end of the arm to be hollow and extremely thin. In fact, the parts, which were 3-D printed by a vendor called Carpenter Additive, have three or four times less mass than if they’d been produced conventionally.
“In a very