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Student team designs tool to pick up lunar samples

10/7/2020

Debra Levey Larson

Every year, NASA’s Micro-g Next program poses challenges to undergraduate students. They must design, build, and test a tool that addresses an authentic, current space exploration challenge. This year’s challenges focused on aspects of the Artemis program to land American astronauts on the Moon by 2024.

AE students designed LETo, or Lunar Exploration Tool, in response to the NASA Micro-g NExt challenge.
AE students designed LETo, or Lunar Exploration Tool, in response to the NASA Micro-g NExt challenge.
A team of Illinois Space Society students from the University of Illinois at Urbana-Champaign chose to design a tool that would be dust tolerant as it collects loose samples on the Moon. They named the device LETo, which stands for Lunar Exploration Tool but as a nice twist is also the name in Greek mythology for the mother of Artemis, the goddess of the Moon.

“The competitive portion of the challenge actually takes place at the beginning of the process,” said the team’s faculty adviser Michael Lembeck. “They write a proposal in response to a challenge posed by Micro-g NExT. If your proposal is accepted, the ‘prize’ is getting your device demonstrated by divers at the NASA Neutral Buoyancy Laboratory in Houston where astronauts train for spacewalks.”

The team members and their roles were as follows: David Gable, project manager and team lead; David Robbins, design lead; Audrey Godsell, safety and testing lead; and Anshuk Chigullapalli, manufacturing lead. Additional team members included Calvin Berg, Dean Darhussein, Alan Hong, Eric Monson, and Matt Taylor.

Gable commented on the deep impact the pandemic had on the project.

“A very significant impact of the pandemic was on our manufacturing schedule,” he said. “Although we had more time to prepare for our test week, much more care had to be taken to maintain communication with the machine shops which did the majority of the work. In the meantime, I ended up manufacturing a few components in my garage just in case we would not have access to the shops. Thankfully, we were able to have a completed tool ready just in time to be shipped to Houston.”

Gable said meeting online also posed challenges.

“In-person meetings make bouncing ideas off one another much easier and strengthens our friendships. So not being able to meet in person definitely added strain to the team. The meetings had been a constant for all of us until March. Ultimately, though, the team was able to adapt quickly to the new structure and we continued to hold online meetings to prepare our final report.”

Gable was on the team last year that developed a tool to detect sharp edges and eliminate the risk to astronauts at the International Space Station.

“This year was very different because of the new challenges that working on the moon’s surface introduces,” he said. “The harsh regolith was constantly a talking point for the team. In the end, we focused on a simple yet robust design that would be able to thrive in an environment which discourages more complex designs.”

LETo final design
LETo final design
LETo’s shaft is 32 inches long, weighs 2.71 pounds and is designed so that it can be used with either hand. The tool has a chamber with inner and outer walls that revolve like the walls of the entrance to a dark room. A handle at the top of the tool actuates the inner shell to make an opening for a three- to five-inch sample to enter, then the chamber rotates shut while the sample is transferred to storage. It also features a locking mechanism at the top to keep the shells from unexpectedly rotating. The bottom plate has small holes to allow dust and smaller debris to be sifted out.

The final prototype was made of primarily stainless steel and aluminum 6061. Portions of the tool were made from composite materials with the sole purpose of protecting the operators from what could be sharp edges or pinch points around the part of the handle that rotates.

A week prior to the underwater testing, Godsell presented a test readiness review. Her thorough oral presentation included how to assemble the tool, schematics showing how each part contributed to its structure, and all the steps they took along the way to address the requirements and challenges of the project.

“In addition to other modifications, we made the inner and outer shafts thinner to reduce weight, and we made the stationary handle thicker to be more ergonomic with the test suits. We tried various bottom plate designs and ultimately streamlined our design by having only one circular bottom plate with a grate to sift out regolith. We found that this change to a single bottom plate made it a lot more dust tolerant and made sample collection less complicated,” she said.

Although, the team couldn’t travel to Houston to be there in person due to the Covid-19 pandemic, NASA arranged a live, interactive online demonstration. A diver in the pool in Houston followed instructions from the team, asked them questions, provided instant feedback on how the device functioned, and gave suggestions for how it might be improved.

Divers at NASA's NBL in Houston demonstrate LETo.
Divers at NASA's NBL in Houston demonstrate LETo.
“The diver said that although he’d never seen it before, he was able to figure how LETo operates just by looking at it,” Gable said. “Using the tool also got easier over time as the diver became more familiar with it. The diver suggested slight modifications to the tool, particularly lengthening the tool, changing the size of the main handle, and adding a positive-force locking mechanism. Interestingly, going into our test week we actually had a design that included a spring to hold the lock. Because we didn’t have enough time to fully test, it was omitted. Overall, the diver thought the tool worked incredibly well and that only slight modifications would need to be made to further improve the effectiveness of LETo.

“All in all, leading this team has been a massive privilege for me and I know the entire team is looking forward to the prospect of getting to improve the tool further,” Gable said.

The Illinois Space Society is a technical, professional, and educational outreach student organization at the U of I in the Department of Aerospace Engineering. The society consists of 150 active members.

This work was supported by The Department of Aerospace Engineering; the Laboratory for Advanced Space Systems at Illinois; the machine shop at the School of Chemical Life Sciences at Illinois for manufacturing the majority of LETo; and the Department of Mechanical Sciences and Engineering machine shop for their support in manufacturing components of LETo's scooper. The MechSE machine shop also provided advice on welding and waterjetting components of the tool.