A group of Virginia Tech students has developed a new material comprised of simulated lunar regolith and powdered aluminum that one day could be used to construct colonies on the moon.
Initially designed to construct a dome, but capable of being molded into any shape, the bricks developed by the group won the Lunar In-Situ Lunar Resource Utilization (ISRU) award this month at the Pacific International Space Center for Exploration Systems (PISCES) competition. The award was one of two prizes given out this year by the research center dedicated to supporting life on the moon and beyond.
Winning Virginia Tech student team members were Eric Faierson, a doctoral student in materials science and engineering (MSE); Susan Holt, a doctoral student in MSE from Christiansburg, Va.; Scott Hopkins, an undergraduate from Yorktown, Va., seeking a degree in mechanical engineering (ME); Michael Hunt, an MSE masters student from Virginia Beach, Va.; Sharon Jefferies, a masters student in aerospace and ocean engineering in Newport News, Va., Michael Okyen, an undergraduate from Yorktown, Va., seeking a degree in ME ; and Brian Stewart, an MSE doctoral student from Hayes, Va.
A student team from Massachusetts Institute of Technology won the second award, in the category of systems engineering.
Design work on the lunar bricks was based on previous work by Virginia Tech team advisor Kathryn Logan, an MSE professor and the Virginia Tech Langley Professor at the National Institute of Aerospace in Hampton, Va., since August 2004. In the older research, Logan mixed powdered aluminum and ceramic materials to form armor plating for tanks as part of a U.S. Department of Defense contract. “I theorized that if I could do this kind of reaction to make armor, then I could use a similar type of reaction to make construction materials for the moon,” Logan said.
Since actual lunar regolith is highly scarce, the regolith used by the student team is derived from a volcanic ash deposit on Earth. The regolith is composed of various minerals and basaltic glass, highly similar to that found on the lunar surface, according to Faierson, who led the Virginia Tech team. During the initial experiments, the regolith and aluminum powder were mixed and placed inside a shallow aluminum foil crucible. A wire was placed inside the mixture and then resistance heated to 2,700 degrees Fahrenheit, upon which the regolith-aluminum mixture initiated in a reaction known as a Self-propagating High-temperature Synthesis (SHS) reaction, Logan said. The materials then cooled to form a solid brick. Later experiments in forming the bricks for competition were created in a ceramic crucible made from silica, which allowed formation of complex curved surfaces.
Once a successful block was created, the student team found that the resulting material had a compressive strength near that of concrete, and therefore could withstand an environment where gravity is a fraction of that on the Earth. Research has been ongoing for more than a year, from initial testing to study of the bricks against solar radiation and effectiveness as a construction material in lunar applications. The group tested various compositions of bricks to determine strength thresholds, with the largest compressive strength being 2,450 psi.
The group chose small bricks, about an eighth of a pound and smaller than a DVD case, or roughly 5 inches x 2.5 inches x 1 inch, for quality control and to conserve materials. “Theoretically the material can be made in any size and shape, however performing the reaction on a larger scale increases the potential for flaws in the propagation of the reaction, and therefore the end-product,” Faierson said. “Large scale implementation might be more appropriate in applications such as landing pads, roadways, and blast berms, where flaws are less of a concern.”
The group formed several brick shapes to demonstrate the concept of forming a voissoir dome component, but did not build the full structure. Creation of larger bricks such as cinder blocks, including those closer to net shape, are forthcoming, Logan said. Also to be studied is the harnessing of large quantities of heat derived from the SHS reaction to produce electricity, and extract volatiles for the lunar colony.
Hunt, now finishing his master’s degree, studied the chemical makeup of the bricks before they went through the fusion process as a powder and then after as it formed the hard surface, among other tasks. “It’s definitely exciting” to have worked on the lunar brick project, he said. “I never would have thought coming into graduate school that I’d be a part of something like this,” Hunt said.
Jefferies focused her work on the brick’s ability to block radiation, including the right composite of aluminum and regolith materials, and the brick’s thickness. People who would colonize the moon would be under constant exposure to radiation from the sun as well as cosmic radiation. “I researched how much regolith would be required, and how thick the it would have to be to get enough protection for the long-duration stays that we’re looking at, which is six months,” she said.
Faierson first heard of the PISCES contest in November 2007, by which time research work on the lunar brick concept was just beginning. Nine teams participated in the national competition, which required reports and supporting materials to be provided to judges in July. In August, the teams from Virginia Tech and MIT were notified of their finalist status, and brought to Hawaii in November to demonstrate their findings before the judging panel.
Among the judges were members of the Japan-United States Science, Technology & Space Applications Program, which included scientists from NASA and industry. Hawaii is home to PISCES and several space-related research projects. The landscape, which is derived from volcanism, is similar to conditions found on the moon, according to Faierson. The PISCES areas will be used to test equipment and concepts prior to actual lunar use, now in progress.
PISCES contest research topics included lunar water-ice extraction, lunar outpost design, analog outpost site development, prevention of astronaut bone degeneration, crewed lunar exploration rover, energy production, and materials production from lunar resources. Judging was based on the novelty and thoughtfulness evidenced by the teams, their commitment to PISCES goals and objectives, and their compliance with the rules of the competition
“The Virginia Tech team did a superb job of presenting their project to PISCES and NASA conference attendees,” said Beth McKnight, a spokeswoman with PISCES. There were “lots of dialogue and questions.”
The Virginia Tech team at Hampton is part of the National Institute of Aerospace, a nonprofit research and graduate education institute. Formed in 2002 to support NASA’s mission of space exploration, the Institute’s graduate program offers masters and doctorate degrees in the fields of engineering and science through Georgia Tech, Hampton University, North Carolina A&T State University, North Carolina State University, the University of Maryland, the University of Virginia and Virginia Tech.
In addition to her positions at Virginia Tech, Logan is a principal research engineer emerita in the School of Materials Science and Engineering at the Georgia Institute of Technology, a member of the Clemson University Department of Materials Science and Engineering External Advisory Board, a fellow of the American Ceramic Society and the National Institute of Ceramic Engineers, and a member of the International Academy of Ceramics.
The College of Engineering at Virginia Tech is internationally recognized for its excellence in 14 engineering disciplines and computer science. The college's 5,700 undergraduates benefit from an innovative curriculum that provides a "hands-on, minds-on" approach to engineering education, complementing classroom instruction with two unique design-and-build facilities and a strong Cooperative Education Program. With more than 50 research centers and numerous laboratories, the college offers its 1,800 graduate students opportunities in advanced fields of study such as biomedical engineering, state-of-the-art microelectronics, and nanotechnology. Virginia Tech, the most comprehensive university in Virginia, is dedicated to quality, innovation, and results to the commonwealth, the nation and the world.
For more information on Logan, click on http://www.vtnews.vt.edu/story.php?relyear=2004&itemno=313.
For more information on the Pacific International Space Center for Exploration Systems (PISCES) competition, log onto http://pisces.uhh.hawaii.edu.
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