DANIELA HERNANDEZ
In late August, scientists, engineers and a small army of
robots left Norway on a research ship headed toward the North Pole. The plan
was to explore, from top to bottom, a section of the Arctic Ocean near
Greenland. With help from the machines, oceanographers hoped to gain insights
about the ocean’s chemistry and ecology, including the types of creatures that
inhabit these pitch-dark, near-freezing waters, the communities they build, and
the energy sources they consume at depths that can exceed 3 miles. Scientists
had surveyed some of these areas before, but new technologies promised more
precise measurements and a clearer picture of how the icy ocean was changing.
The polar mission was the capstone of a five-year
collaboration between 16 German organizations. Dubbed the Robex Alliance (short
for Robotic Exploration of Extreme Environments), the project is one of several
world-wide academic and commercial initiatives with the same end: to develop
technologies—sensors, batteries, chips, robot bodies, software—that could
fast-track exploration of places that are too dangerous or hostile for humans
to explore on their own. The advances have applications in search-and-rescue,
the oil and gas industries, law enforcement, and others. They could also usher
in a golden era for deep exploration of Earth’s oceans, only 5% of which have
been surveyed by humans.
In the long term, this testing, prototyping and exploration
will serve a second purpose: to create the robots that will search for life on
the moons of other planets.
A large part of August’s polar mission was locating and
retrieving Tramper, a 1,400-pound tank-like rover that had spent more than a
year autonomously inching along the frozen terrain about a mile and a half
below the surface. While ice made the water impassable for ships, Tramper
roamed the sea floor, measuring oxygen content and collecting data. According
to Frank Wenzhöfer, a microbiologist at the Alfred Wegener Institute Helmholtz
Center for Polar and Marine Research and the vessel’s crew leader, the year
Tramper spent underwater is the longest time a robot had been left to its own
devices in the Arctic with no human contact.
Engineers also tested a prototype of a yellow space
shuttle-looking glider designed to measure temperature, salt content and oxygen
concentration closer to the surface to complement TRAMPER’s data. A
torpedo-shaped autonomous underwater vehicle studied the biology at the
interface between water and free-floating ice sheets called floes, an area
researchers think is sensitive to changing conditions. To avoid collisions with
fast-moving ice when the robot surfaced, a drone atop a floe beamed the
engineers on the boat GPS coordinates they could use to change where the
machine emerged from the water.
Planetary scientists and astrobiologists once believed life
could exist only in the so-called Goldilocks zone, defined by the distance that
separates the sun from Earth’s orbit, where the temperature allows for liquid
water and a breathable atmosphere. But over the past few decades, scientists
have discovered that some of the solar system’s far-flung planets, including
Jupiter and Saturn, have moons with liquid oceans. NASA posits that these moons
are our best shots at finding extraterrestrial life.
Data from Galileo, a spacecraft that flew by Jupiter’s
Europa in the late 1990s, suggested that the moon might have a subsurface ocean
with plumes of gases bursting through fissures in its icy crust. In 2005, the
Cassini-Huygens probe took images of similar structures on Enceladus, a tiny
moon orbiting Saturn. Sensors suggest that Enceladus has an active ocean
sandwiched between a layer of ice dozens of miles thick and a rocky bottom.
Earth ocean’’s own rocky bottom, scientists believe, could have provided the
essential building blocks of life—some of which, including hydrogen, nitrogen
and salt, were detected by Cassini’s instruments in the plumes of Enceladus.
On Sept. 15 of this year, Cassini—low on fuel after 20 years
of exploring—intentionally flew
into Saturn’s atmosphere and burned up to avoid crashing into
Enceladus and possibly contaminating environments that could already harbor or
one day bear life.
A flyby mission to Europa is scheduled to launch in the
2020s, and scientists are awaiting funding decisions for proposed missions to
Enceladus. But before space programs can embark on multimillion-dollar
expeditions to the outer solar system, scientists need robots that can handle
on-the-ground exploration of extremely hostile environments where surface
temperatures can plummet to nearly minus 400 degrees Fahrenheit.
This is where Earth’s most remote and inhospitable regions
come in handy. The ice-covered oceans of the Arctic and the Antarctic resemble
those discovered on Enceladus and Europa, and Mount Etna in Sicily has a craggy
terrain and hazy atmosphere similar to that of Titan, Saturn’s largest moon.
Collaborations like the Robex Alliance, which includes space engineers, enable
planetary scientists to test-drive robot prototypes in places similar to the
extraterrestrial terrains they hope to explore.
In July, a Robex team tested a Mars rover-like machine that
positioned seismic sensors on the surface of Mount Etna to study its quakes.
Using cameras and planning software, it surveyed its surroundings and then
figured out where to place the sensors by itself. Similar software and versions
of the hardware reinforced for space travel could one day be used in future
missions to the moon or other celestial bodies.
“There are these areas on Earth that are as difficult to
reach as foreign planets,” says Antje Boetius, a deep-sea and polar researcher
at Germany’s Alfred Wegener Institute, which is part of Robex. “If we use Earth
as the next best analog to a planet with a deep ocean and thick ice cover, how
would we go about using a robot to explore?”
It starts with better hardware. When Robex located Tramper,
it had been going around and around in circles in the same spot for 35 weeks,
due to a broken gear. On Earth, where scientists can eventually retrieve and fix
a stuck robot, their malfunctions are merely disappointing. In space, a
mechanical failure could spell the end of the mission. (Some scientists are
also working on robots that can heal themselves, although that ability is years
if not decades away.)
ROBEX researchers got a whiff of that doomsday scenario this
summer when they deployed another crawler dubbed VIATOR and its landing station
to the seafloor. Two previous attempts had failed. They only had two days left
in the mission—and five years of work behind them.
When VIATOR finally made it to the bottom and attempted to
leave its lander, one tread started rotating at half the speed as the other. It
veered off course and crashed. On board, scientists and engineers watched
through a camera feed from a remotely operated vehicle.
“That was a real disaster,” said Sascha Flögel, a marine
geologist and lead for VIATOR. The seven-person team coded and beamed the
machine a new program that instructed the faulty tread to move at approximately
twice the normal speed to compensate. It wasn’t perfect, but the rover’s
navigation program was able to self-correct as it made its way back to the
station using light markers on the lander as guideposts.
“The future is more autonomy,” said Dr. Flögel.
Today’s autonomous robots, such as Tramper, execute a set of
predetermined commands without human intervention. If conditions change
drastically, a robot can stall. Ideally, it would be able to adapt on the fly,
but that requires learning. For instance, the robot would have to know from
experience that a spike in oxygen is worth further exploration or that a change
in the stability of the soil could put it in danger of getting stuck. This is
impossible for most robots to do fully autonomously, in part, because the
sensors that allow them to explore their environment don’t directly feed back
into the software that controls them. They lack a basic understanding of what
they’re seeing and touching.
At NASA’s Jet Propulsion Laboratory in Pasadena, Calif.,
Steve Chien is helping to build better brains for the robots of tomorrow. He’s
part of a team designing software for robotic explorers to Europa. “The places
we really want to go the most [are] the places we know the least about,” which
makes his team’s job especially challenging because their machines have to be
ready to work in an enormous range of situations, he says.
Dr. Chien is preparing for life-hunting missions to outer
space by tapping the expertise of Chris German, an experienced
hydrothermal-vent hunter. Hydrothermal vents are underwater fountains that spew
hot water and chemicals from within the Earth’s crust through ruptures on the
ocean floor. Oceanographers posit that life on Earth may have evolved in these
active zones, but only a fraction of these structures have been explored.
Finding structures similar to Earth’s hydrothermal vents on Enceladus sparked
hope of finding life there.
Dr. Chien’s team monitored Dr. German to learn how he looks
for vents. The goal: to turn his expertise into code for underwater autonomous
vehicles.
They wanted software “that could think the way I did,” says
Dr. German, who is based at the Woods Hole Oceanographic Institution in Woods
Hole, Mass., and has collaborated with the Robex Alliance. After observing Dr.
German for several weeks during a cruise through the Arctic last fall, Dr.
Chien’s team came up with an experimental algorithm to help robots search for
vents. Changes in temperature or the chemistry of water, for instance, might
signal plumes associated with hydrothermal vents. If a robot running Dr.
Chien’s algorithm detects these changes, it will try to localize the origin of
those anomalies and search that area for a stronger signal.
They’re still fine-tuning the software with computer
simulations—a standard tool in software development for robotics—and Dr. Chien
hopes to test it in a robot in the field as early as 2018.
By necessity, space robots have long had autonomous
features. The Mars rover, for instance, was able to check its own batteries,
shut down malfunctioning instruments that suck up power, and plan routes. But
Dr. Chien’s team is working on adaptive software for a new Mars rover that will
be able to adjust its schedule of experiments based on power consumption or if
some activities finish early. “That is something that the current [Mars] rover
can’t do,” he says.
A future iteration of that program would interconnect
several rovers, drones, underwater robots and landers. These robots would be
able to communicate with one another and adjust their tasks if one fails or
detects some preliminary evidence of life.
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De THE FUTURE OF EVERYTHING, revista de THE WALL STREET
JOURNAL, Noviembre-Diciembre, 2017
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