For hobbyists and makers, 3D printing expands creative possibilities; for specialized engineers, it’s also key to next-generation spacecraft design.
If you want to see science fiction at work, visit a modern
machine shop, where 3D 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 3D printing.
Instead of forging, molding, or cutting materials, 3D
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.”
Perseverance’s predecessor, was the first mission to take 3D printing to the
Red Planet. It landed in 2012 with a 3D-printed ceramic part inside the rover’s
ovenlike Sample Analysis at Mars (SAM) instrument. NASA has since continued to test 3D
printing for use in spacecraft to make sure the reliability of the parts is
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
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
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 3D printed by a vendor
called Carpenter Additive, have three
or four times less mass than if they’d been produced conventionally.
“In a very real sense, 3D printing made this instrument
possible,” said Michael
Schein, PIXL’s lead mechanical engineer at JPL. “These techniques
allowed us to achieve a low mass and high-precision pointing that could not be
made with conventional fabrication.”
MOXIE Turns Up the
Perseverance’s six other 3D-printed parts can be found in an
instrument called the Mars Oxygen
In-Situ Resource Utilization Experiment, or MOXIE. This
device will test technology that, in the future, could produce industrial
quantities of oxygen to create rocket propellant on Mars, helping astronauts
launch back to Earth.
To create oxygen, MOXIE heats Martian air up to nearly
1,500 degrees Fahrenheit (800 degrees Celsius). Within the device are six heat
exchangers – palm-size nickel-alloy plates that protect key parts of the instrument
from the effects of high temperatures.
While a conventionally machined heat exchanger would need to
be made out of two parts and welded together, MOXIE’s were each 3D-printed as a
single piece at nearby Caltech, which manages JPL for NASA.
“These kinds of nickel parts are called superalloys
because they maintain their strength even at very high temperatures,” said
Samad Firdosy, a material engineer at JPL who helped develop the heat
exchangers. “Superalloys are typically found in jet engines or
power-generating turbines. They’re really good at resisting corrosion, even
while really hot.”
Although the new manufacturing process offers convenience, each
layer of alloy that the printer lays down can form pores or cracks that can
weaken the material. To avoid this, the plates were treated in a hot isostatic
press – a gas crusher – that heats material to over 1,832 degrees Fahrenheit
(1,000 degrees Celsius) and adds intense pressure evenly around the part. Then,
engineers used microscopes and lots of mechanical testing to check the
microstructure of the exchangers and ensure they were suitable for spaceflight.
“I really love microstructures,” Firdosy said.
“For me to see that kind of detail as material is printed, and how it
evolves to make this functional part that’s flying to Mars – that’s very
More About the Mission
A key objective of Perseverance’s mission on Mars is astrobiology, including the search
for signs of ancient microbial life. The rover will characterize the planet’s
geology and past climate, pave the way for human exploration of the Red Planet,
and be the first mission to collect and cache Martian rock and regolith (broken
rock and dust).
Subsequent missions, currently under consideration by NASA
in cooperation with ESA (the European Space Agency), would send spacecraft to
Mars to collect these cached samples from the surface and return them to Earth
for in-depth analysis.
The Mars 2020 mission is part of a larger program that
includes missions to the Moon as a way to prepare for human exploration of the
Red Planet. Charged with returning astronauts to the Moon by 2024, NASA will
establish a sustained human presence on and around the Moon by 2028 through
NASA’s Artemis lunar
JPL, which is managed for NASA by Caltech in Pasadena,
Southern California, built and manages operations of the Perseverance and
For more about Perseverance:
News Media Contact
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Source: Jet Propulsion Laboratory