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NASA likes SDSU’s lunar water delivery idea

What sounds like science fiction today may be reality tomorrow.

The premise certainly applies to an award-winning idea submitted by a team of South Dakota State University engineering students in a contest organized by NASA. Student and professional engineers were asked to provide the conceptual design of how frozen water could be extracted from a lunar crater.

SDSU’s creative idea involves filling a canister with melted ice water and then using a railgun to launch them 2 miles into a net.

Todd Letcher
Associate professor Todd Letcher

SDSU’s Space Trajectory team was one of 10 runners-up in the Break the Ice Lunar Challenge and took home a $25,000 prize that the team plans to spend on materials as it enters the second phase of the NASA contest—actually building some of the project, according to Todd Letcher, an associate professor in the mechanical engineering department at SDSU.

Redwire Space of Jacksonville, Florida, won the $125,000 top prize. Colorado School of Mines ($75,000) and Austere Engineering, Littleton, Colorado, ($50,000) were second and third, respectively.

Thirty-one teams, including academia, industry and independent inventors from 17 U.S. states, Canada, Australia and Sri Lanka, submitted eligible proposals that were evaluated by a team of NASA-convened experts that scored each team based on its solution's potential performance in extreme conditions.


Team of eight has plans for Phase 2

“I am proud of our team and the work we submitted. I am excited to move into Phase 2 of the competition,” team member Evan Steers said.

Steers, a senior from Miller, is one of eight team members. Others are Austin Lohsandt, a senior form Madison; Brock Heppner, a junior from Crookston, Minnesota; Andrew Zimmerman, a senior from Urbandale, Iowa; Ben Brainard, a junior from Prior Lake, Minnesota; John Christianson, a sophomore from Jefferson City, Missouri; Ben Diersen, a junior from Brookings; and Vishnu Pfeiffer, a junior from Aberdeen.

NASA announced the Phase 1 results Aug. 21 but has yet to announce the time frame for Phase 2, Letcher said.

Right now, he and the students are just excited about the Phase   1 results.

“One of the reasons I'm so proud of our team is because this is not a competition specifically for university teams. This is a competition for professional engineering teams/firms from all over the world. What's really impressive is that across our entire team, besides me, we have one person with an engineering degree (a May graduate) and the rest haven't even made it to their senior-level courses yet,” Letcher said.


Entry tweaked right up to deadline

NASA announced the competition in November 2020.

“I thought about it during Christmas break and decided to do it. Then I found some people that were excited by the challenge,” Letcher said.

“Throughout the spring semester, we worked hard together holding weekly full team meetings and many work sessions in between meetings. After the semester ended, everyone scattered to their summer internships and we continued working over Zoom and Slack conversations almost every evening until the deadline in the middle of June.

“Many of us worked together online until 4 a.m. on a Saturday to make sure we had the best submission possible by the 6 a.m. deadline,” Letcher said.

The proposal involves three phases—an excavator to mine the soil, which includes frozen water; a rover to deliver soil to a dehydrator, which is a NASA-designed machine that separates water and ice and melts the ice; and the water delivery system. 


Aerial delivery easier on moon

“We decided to launch water capsules on a railgun that get caught in a net at the base camp 2 miles away. Empty water canisters are sent back using a different railgun and caught in a different net. On the moon, there is no wind and no friction, so the canisters should land in the exact same spot every time,” Letcher said.

Landing on the launching scheme was a product of numerous meetings.

“We spent from January until spring break talking about different strategies to accomplish all this. It felt like the least risky way to produce a lot of water because of the rocky lunar landscape. Also, launching of water canisters seemed like an interesting idea no one else would think of,” Letcher said.


Adjustments made for cold temps

Diersen spearheaded water delivery.

He said the most challenging part was “finding materials that could withstand the extreme temperatures (-200 degrees). I researched through Briggs Library scholarly journals. Google didn’t lead to good sources in cryogenics,” he said.

“I came up with using a fair amount of aluminum alloys for structural features and Kevlar and specialized fibers for the netting. Common materials would become brittle like chalk. I was looking at the material used for soccer nets. They would not hold up at all,” Diersen explained.

With this unique delivery system, team members were confident they had an entry that could bring home prize money.

Steers said, “When we submitted the proposal, I was confident that our team would at least place as a runner-up. Once I heard that 31 teams had applied, I was more concerned about our final placement, but my initial confidence proved to be well-placed.”


Earlier lessons prove useful in competition

It should be noted that while the SDSU team is relatively young, they’re not inexperienced.

During the 2020-21 school year, Steers worked on the SDSU autonomous human-carrying drone that was funded by a NASA grant obtained by Letcher and his colleague Marco Ciarcia. Steers said, “I was familiar with some of the design processes that go into designing complex aerospace machinery.”

Likewise, Diersen, president of the SDSU Robotics Club, directed an extracurricular team that competed in a different NASA competition last school year. They built small-scale robots—an excavator and a rover—that autonomously dug and delivered “lunar” soil. They were scheduled to meet at Kennedy Space Center but COVID-19 measures ended that effort.

He put those skills to work in the Break the Ice Lunar Challenge.

“It helped considerably to have done design and 3D modeling steps in robotics club. I was leaps and bounds ahead of what I would have been with just classroom experience. Also, the group organizational experience was invaluable, such as already having familiarity with file-sharing software,” Diersen said.


Calculations gauge future lunar population

Letcher said the work also required lots of math.

“We had to do energy calculations, calculations to determine amount of soil that could be excavated and how much water could be extracted,” Letcher said. They determined they could deliver 30,000 kilograms of water (9,300 gallons) from 458,000 kilograms of soil. The average American uses about 90 gallons per day for indoor home use, but much of that is from flushing the toilet.

The proposal was submitted in a 25-page report along with a two-minute introduction video and a five-minute animation of how the system works.