POPSCI.COM•FALL 2019 87architects, engineers, and scientists are exploring how
early residents might use recycled waste and the planet’s
loose rock and dust, called regolith, to craft tools, erect
homes, pave launchpads and roads, and more.
Rovers and probes have revealed enough about Mar-
tian geology for us to start figuring out how that might
work. The surface contains an abundance of iron, mag-
nesium, aluminum, and other useful metals found here at
home. Scientists also believe the crust consists largely of
volcanic basalt much like the dried lava fields of Hawaii.
Here on Earth, researchers often employ crushed
basalt as an analog for Martian
regolith. They can heat and com-
press the sandy material, a process
called sintering, to create paving
tiles. NASA and aerospace agency
Pacific International Space Center
for Exploration Systems did exactly
that in 2015, then had a robotic rover
called Helelani use the pavers to build a launchpad
66 feet in diameter. Compacted regolith might even hold
together without heat, according to a team led by Yu Qiao
of the University of California at San Diego. Their 2017
study posits that iron oxide, which gives Mars its rusty
tint, could serve as a binding agent.
Still, if you’re creating anything more complex thanblocks, regolith can be a hassle. It lacks the plasticity that makes clay
easy to manipulate. Working independently, Makaya’s team at the
European Space Agency and researchers at Northwestern University
printed tools and small objects, including gears and blocks. But their
method requires mixing regolith with solvents and a sticky binder—all
of which would have to be carried from Earth or made on Mars.
David Karl, a materials scientist and doctoral student at the Tech-
nical University of Berlin, thinks there’s an easier way. He works in
a research laboratory that creates advanced ceramics for electron-
ics, biomedical implants, and other applications. His background in
art makes him prone to saying things like, “Cement looks beyond
incredible under a microscope.” A few years ago, he and his aca-
demic adviser, Aleksander Gurlo (who also leads the lab), pondered
how astronauts might use regolith without having to add anything
hauled through space. It occurred to them that everyone trying to
solve that riddle had overlooked an ancient solution: mixing the
material with water, which humans around the world have done to
make earthenware ceramics for at least 30,000 years.
They turned to a relatively simple method of pottery-making
called slip casting. It calls for pouring a soupy mixture of clay and
water, called slip, into a plaster mold and allowing it to set. Then you
dump out the excess material and remove the object for firing in a
kiln. Instead of using clay, Karl and Gurlo tried it with a simulatedPress Here
NASA sub-
jects the
Marsha model
to a crush-
ing test to
assess its
durability.
MAKING IT ON MARS