If humans are ever to set foot on Mars and live to tell the tale, they will need water (among other essentials, of course). But almost all of the H2O on the Red Planet’s surface is frozen, and most of that ice is in the polar regions that are too cold and dark for astronauts to land there.
In more temperate regions, NASA has detected water ice buried under the dusty surface of Mars. Extracting, melting and purifying this H2O to make it drinkable will likely require specialized tools. The space agency therefore invited teams of university-level engineering students to design and build prototypes that could achieve this goal.
A team of Northeast undergraduate engineering students built a robot to meet this challenge. Their device, called PARSEC (Percussive And Rotary Surveying & Extracting Carousel), won the RISE award for Innovation at this year’s Research, Innovation, Scholarship and Entrepreneurship Fair.
“It was an amazing project that just keeps on giving,” says Sam Hibbard, a third-year mechanical engineering student and project team leader since 2019. “When we were announced as one of the RISE Awards, it was a huge moment.”
Previously, the team had taken PARSEC to compete against other university teams in a NASA challenge under the Revolutionary Aerospace Systems Concepts–Academic Linkages program (NAUGHTY) program. In the timed challenge, the robot had to extract water from the ice beneath a Mars-like regolith – the layer of dirt, dust, sand, stones and other rocky material that makes up the planet’s land surface.
NASA chooses to solve some tough problems by “bringing together a team of undergraduates, a team of makers,” says Taskin Padir, director of the Institute for Experiential Robotics and associate professor of electrical and computer engineering at Northeastern, and academic advisor for the project. “Undergraduate students really think outside the box. Not all solutions will be part of the final solution that will be deployed. However, nuggets from each project” could be included.
PARSEC operates in stages mounted on a turntable. First, the robot drills a hole through the rock layer and into the ice. After learning from previous teams in the North East to meet the challenge, the engineering students are building their system to both spin as it drills into the material and use a percussive, hammering motion.
“We previously created a robot that only does the percussion movement. As soon as it hit this material called aircrete [concrete with air bubbles in it]it couldn’t break through the surface and we couldn’t collect water in this competition,” says Ethan Holand, third-year mechanical engineering student and mechanical lead for the project.
The two different motions can handle a wide variety of material types, says Holand. For harder materials like stone and concrete, the percussion motion can grind it into pieces. The spinning motion works to dig out those smaller bits, as well as softer, looser materials like soil and sand.
Once the robot has made a hole in the ice, the melting tool can be inserted. This tool is basically a very hot probe. The team designed it to be able to twist and turn in the ice to create a kind of bowl filled with freshly melted water.
Attached to the heating probe is a tube that can suck out liquid that collects at the bottom of the ice cream bowl. The water is pumped through a multi-stage filtration system. It first flows through a custom-built mesh system to filter out sediment from the water – and the team found that a lot of sediment can be transported through the water, Hibbard says. This actually caused some hangs during the NASA competition, but the team has some ideas on how to avoid this in future iterations of the robot.
Once the sediments are removed from the water, they pass through a reverse osmosis system to purify them and make them drinkable.
Jarrod Homer, systems manager and third-year electrical engineering student tasted when the team was building the robot, having used topsoil as regolith on the ice. It meets tap water needs, he says, adding that it tastes like “infused mineral water”.
The system does not only deal with water. While PARSEC drills through dirt and rocks, it is also designed to detect the types of materials it encounters. To do this, the software team designed the system to use machine learning to classify materials by hardness to identify the difference between, for example, sand and rock. The algorithm is fed information from sensors on the drill and microphones mounted on the system.
This approach worked well when the team tested it before the competition, says Jack Wilkins, head of the project’s digital core and a third-year computer science and physics student. But machine learning is only as good as the data available for training, and NASA’s competition hardware was different enough from the hardware the team used in testing that the system didn’t perform as well. .
That could be a problem if the robot goes to the Red Planet, Wilkins says, “because you have no idea what the Martian surface looks like.” The team therefore proposed that the next iteration of the robot use an approach that groups materials by similarity rather than labeling them outright.
This robot was not only built on the Northeastern campus in Boston. Students worked from their bedrooms and garages at home when classes were remote, their dorms and apartments when in-person learning returned, and hotel rooms during competition to put the finishing touches on the robot.
“This team has worked through the blues of the COVID era,” says Padir. “They really worked hard to solve not only the technical challenges of building the system, but also the logistical challenges. [of the pandemic].”
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