POPSCI.COM•FALL 2019 89line. The “ink” the contraption lays down, layer by layer as it follows instructions
from a computer, is a mixture of recyclable plastic grown by bacteria and fine basalt
fibers that could theoretically be gleaned from Martian rock. “Just getting the
material to ooze out was a happy day,” Malott says.--
Habitat construction got off to a rough start the first day of the May 2019 competitions.
The teams worked in an enormous exhibition hall owned by heavy-equipment manu-
facturer Caterpillar, which typically uses the space to demonstrate earth-movers and
other big machines. The arena briefly lost power, causing hiccups in the teams’ printer
programs, and wonky extrusions required occasional troubleshooting. Judges dis-
creetly warned NASA’s Monsi Roman, who oversaw each of the phases leading up to
the final event, to prepare for disappointment. But within a day, both teams found their
momentum, and the mesmerizing whir of the printers drew company employees and
field-tripping students to watch the structures rise in fits and starts.
The Penn State crew used an industrial robotic arm rigged with an extruder, but
scuttled its plan to build with something it calls MarsCrete because the material,
designed for the frigid environment of Mars, set too quickly at room temperature. The
team switched to concrete made with conventional cement, but the mixture would jam
the apparatus if the machine stopped or paused too long. “Printing with concrete is very,
very difficult,” says planetary geologist Jennifer Edmunson, who was among the judges.
Still, the team finished its tallest structure 11 minutes early. Cheers erupted as the ma-
chine sealed a habitat some in the crowd had taken to calling Dairy Queen because its
twin 13-foot peaks resembled great swirls of soft-serve ice cream.
Marsha’s texture looked like an old sweater, each lump and seam and loose strand in-
dicating a pause or deviation in the layering process. Montes did his best to minimize
deformities by running the robot more slowly, but lost that luxury as time passed. With
seconds left and the uppermost section drooping, Montes gave the order to release the
skylight. The walls held for a moment, then the rim sagged inward, and the window fell
to the floor with a thud. Montes descended the ladder to hesitant applause. “If you want
drama, there’s drama,” he said to the NASA film crew.
Some wondered if the tumble doomed AI SpaceFactory’s chance of winning, even
though the team had earned high scores in several categories and intervened in its auto-
mated print less often than the Penn State crew. After letting the habitats cure overnight,
the judges spent a few hours beating them mercilessly to ensure they were airtight, check
their impact resistance, and assess their strength. Dairy Queen proved remarkably ro-
bust during a simulated meteorite strike, enduring a barrage of increasingly heavy balls
until the last one, a 26-pounder, removed a small chunk of the roof. More impressive, the
structure resisted the crushing vertical assault of a 96-ton excavator—at least for a cou-
ple of minutes, before collapsing with the percussive crack of a bowler throwing a strike.
Strictly speaking, Marsha was incomplete because it lacked a roof. It clearly wasn’t
airtight: The habitat emitted great plumes of colorful smoke when a contest official
tossed a test flare into it. The judges saw no point to dropping fake meteorites on it
either. The model, however, surrendered just a few small pieces to the excavator,
which placed its bucket on Marsha’s rim and pushed down with enough force to raise
the front of the rumbling machine’s treads off the ground.
After spending a few hours reviewing notes and tallying points, the judges named
AI SpaceFactory the winner. Montes, grinning with teammates as they held an
oversize check for $500,000, seemed almost as pleased as NASA’s Roman, who
considered the build a great success. Despite their scars, the habitats provided per-
haps the most tangible evidence yet of what homes on another world could look like.
“They’re not perfect,” she said, “but they’re beautiful.”You see those concerns reflected in
Marsha. Montes favored a tower because
it maximizes usable space. The shape also
easily divides into floors, and building up in-
stead of out lends itself to 3D printing. He
thinks the skylight, curved walls, and a Swiss-
cheese-like interior shell will add variety and
idiosyncrasy to daily life on a distant world.
Creating the model of Marsha’s outer
shell required first spending many months
developing the 3D printer and the goop it
spits out. Montes’ team built an enormous
machine that features an off-the-shelf
nozzle—called an extruder—modified
with grippers and various sensors. They
mounted all that hardware to a robotic arm
similar to those you’d see welding bodies or
painting cars on an automobile assemblyscientist at the Technical University of Berlin, thinks an ancient method of making ceramics just might workto convince the engineering types I work with here to do some stupid vases as a big project,” he says.MAKING IT ON MARSCO
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