Our next speaker is going to share with us his research that is currently underway in the International Space Station. Yes, it's space. Please welcome Teg Agnostic, a PhD student from the Department of Chemical and Biomolecular Engineering at the College of Engineering. His top title is Designing Lunar Construction Materials, Experiments on the International Space Station. Please welcome Ted to the stage. All right. Yeah, thank you for the introduction. Thank you all for being here. So one of NASA's major goals in the next decade as part of their project Artemis is to create a lunar base camp. This is going to enable long-term scientific research and provide a habitat for astronauts to stay on the moon while they perform that research. So if you look at these renderings of this future base camp from NASA, you can see that there's a lot of infrastructure involved. We have roads, landing pads, storage facilities, and habitats for the astronauts to actually stay in, right? But the moon is a harsh environment, right? There's massive temperature swings from day to night, total lack of any atmosphere. So there's very little protection from micrometeorites and radiation. And there's also lower gravity, right? And all of these pieces of infrastructure will require construction materials. And due to this harsh environment, sorry, I'm not sure the clicker's not there. All right, so stick with me. So we go back to these construction materials, right? They have three main requirements, right? They have to be sourced from the lunar surface. We can't bring material with us from Earth to design these structures. They have to have targeted strength for specific applications, right? If we have a road versus a landing pad, there's different strength requirements. And they also have to be durable to withstand this harsh lunar environment that I described. So on the topic of construction materials, if you've ever been to Lowe's or Home Depot, picked up a bag of cement, you know that traditional cement, which makes concrete when mixed with aggregate, is just made from cement powder and water. And that cement powder is made from limestone primarily, but also some clay minerals and gypsum. So in the Wagner Research Group here at the University of Delaware, we study geopolymer construction materials. And these are formed from abundant clay materials and a chemical activator. So on the left-hand side of the screen, I'm showing some geopolymers that we've made over the past few years. And the key objective of these is to use local clay minerals, which are abundant and available all around us. All right, so we've made slabs, cubes, cylinders, whatever you can think of. And we can make these from different clay materials. On the top right, I'm showing this high-purity metakalan clay, which is industrially available. But on the bottom right, we've taken some extremely local clays. We've gone to White Clay Creek State Park with a permit and collected some clays and turned these into different geopolymers. And what I want to emphasize is that these are typically used for traditional construction applications, right? They're used around the globe in different capacities, but the locality of the input to the material is what's important here. And this also provides us one potential solution to this lunar construction problem. So if we look at the moon, right, you see different colored craters and things like that. This is all the lunar regolith. This is the dirt that covers the surface of the moon. And this has a very specific clay-like chemistry, which would allow it to be transformed into a geopolymer binder. But unfortunately, we don't have access to large amounts of lunar soil, right? So companies here on Earth make these lunar regolith simulants, and these are materials that are meant to mimic different regions of the composition on the lunar surface, right? So we purchase these materials, we transform them into geopolymers, and because the composition varies with location, right, you can see, for example, the lunar highlands near the South Pole, which is the proposed landing site of these Artemis missions, has a very light color. So we use our lunar highland simulant. And in the top, you can see around the equatorial region, we have this blackpoint mare soil simulant. So we buy these. We turn them into geopolymers. And the overall goal now is to evaluate the durability of these materials in the real location. We'd love to go to the moon. Unfortunately, we can't go to the moon. But we can do the next best thing and take advantage of NASA's Materials International Space Station experiment, or the MISI set of experiments. And we're in the 20th iteration of these experiments where you can send a sample to NASA. They will bring it to the International Space Station in this panel array. So looking at the left-hand side of the screen, you can see this panel with one sample that's floating off, but the rest are stuck, and they're exposed for a period of time anywhere from six months to around three years. And if you look at the right, this is where that panel actually sits on the exterior of the International Space Station. So we applied for this program. We were accepted. and last year we made our samples and sent them to NASA. So on the left is just a closer image of what these panels look like and on the right are our actual samples in NASA's array. So we have four different geopolymer compositions and four replicates of each composition. So 16 total samples. So last November, these were sent to NASA and then they were shipped to the International Space Station on a SpaceX rocket. And what I'm showing on the right-hand side of the screen is actually that capsule docking into the International Space Station which carried our samples. So they're there. They're going to be there for six months, and we're going to get them back later this summer. But what can we actually learn from this experience? What can we take away that will help us design these materials in the future? So these are the three-month images. Over time, we get back images of the samples. We get back temperature data over time and also some estimate of how much radiation is hitting the samples. So this is great. This is excellent. We have two samples, our two lunar samples, that have no cracks, no warping, no visual damage. However, we also sent up what we thought would be our control, right? I mentioned that high-strength metakalan clay earlier on, which we think this is the best thing. This makes the strongest geopolymer here on Earth, but it's obviously failed significantly. And so now we have three successful compositions, one slight failure, but now we can learn from this once we get these samples back and understand why did this one fail, why do others succeed. We can do chemical and mechanical testing here at UD to determine that, and hopefully this will provide us some idea for the future to design these construction materials for high efficacy and high strength. So thank you very much for your time and happy to take any questions you might have. Yeah, back there. So for cement and a lot of building materials here on Earth, water and drying and air are factors in composing them. So you've got the raw materials on the moon, so how would they then be converted into a polymer that can be used for building? Sure. So the one downside, which you're totally right about, is water is required for these construction materials. The difference between the geopolymers and the cements is that these are water neutral overall, where cement, that water is consumed in the reaction that forms the strong material. In geopolymers, it's both consumed in one reaction and produced in another. So they're totally water neutral. So they would need to be produced inside of some contained environment. But then afterwards, we can recover that water. And then they're totally stable if they're the right composition afterwards. But you're right. The reaction is affected by humidity, by temperature, and by the time that the material has to cure as well. Just out of curiosity, how available is the lunar soil to your research? I think 2 kilograms, around $100. But they have a wide variety of simulants. We chose these for the reason I outlined. But it's becoming more available. And they're typically used for remote vehicles, right? So NASA has a huge pit with that BP-1 lunar regula simulant in it. And they'll host competitions for different robotics applications to go and manipulate that soil and create different structures out of it. Hi, I'm Carlos. I'm an oceanographer, so I don't know anything about this. Do you have any idea what the main source of failure for this kind of materials will be on the moon? So considering these materials in general, it's defects in the cast cube or slab or whatever it may be. So that only gets worse as you incorporate more large aggregate. Like I talked about cement, but in concrete, there's everything from sand up to small pebbles in it. So the more failure modes you introduce is by introducing more defects into the material. Thank you. Very interesting talk. You mentioned that these materials respond to humidity. Will you have to keep these in a vacuum-controlled environment while you do all of your testing here at UD? Sure. So when we're actually making the samples, we don't have to worry about vacuum. But the reason why I think that the one sample did fail is due to the combined vacuum and temperature. So the French used these materials to sequester their nuclear waste, And so they've bombarded these with radiation, you know, everything that you can think of, right? And they've held up without a problem. They haven't had any damage. But what we've seen, similar samples fail. It's when we take them from high temperature to low temperature and simultaneously out of a vacuum chamber. So I think that would be the failure mode in this case. But here on Earth, where they're primarily used for typical construction, more humidity is generally not a problem. But dryness is an issue. Thank you. Yeah, please. yeah thanks for your presentation I'm interested a little bit in the the actual samples themselves and how you design the construction of that so you showed one that was kind of floating away and and I'm interested in kind of what the the mounting material is and can that have I guess the real question can that have any effect on the materials like interface kinds of differentials and heat and other kinds of things from the actual mounting of the material? Sure. So when we send these samples to NASA, they go through what's called bakeout testing. So they're put in total vacuum, right, to evaporate off any material that's able to evaporate. Then they take them to the highest temperature they think they'll experience, and then the lowest temperature they think they'll experience prior to integrating them into these, if I can go back, into this array that you're seeing there. So that's their way of sort of foolproofing the process. We've managed to get around that. But what you're seeing there is the cubes are two inches by two inches and then there's a bit of an overhang right on that on that panel in front so they're trapped in physically and then the back there's some sort of adhesive that they're taped on within the back so that's why our samples that have cracked those with the light colored metakalan ones that's why they haven't floated away so far but I hope that hope that answer your question thank you thank you for your presentation so you've got these successful samples what happens next what are your next steps sure so we should get them back sometime between July and August side side note so you all may have heard about the astronauts that were postponed and stuck up in the International Space Station this was supposed to go up August of last year but they needed things like food and water and not cement samples so we were delayed till till November but once we get these back we will do sort in rank we'll do non-destructive testing first so I might have actually one or two backup slides yeah so on the left we can use some of the material the resources here at UD to look at the internal structure of the samples before they're destroyed before we destroy them we can look at their we can kind of scan through the depth and see if there's any differences for example at the surface versus in the bulk of the material and then on the right hand side you're seeing compression compressive strength testing so we have three sets of these 16 samples. One that we made initially and tested right away, so we have kind of compressive strength measurements for those already, one that went to space that's up there now, and then a third is kind of a control group that we've made at the same time and retained here at UD in like a black box in Colburn basement. And so whenever we get these samples back we'll test those two samples in tandem to have an equal comparison for something that has been exposed up in space and then kept here without any exposure. So we'll get strength measurements structural measurements and then there are techniques we can use to understand if the chemistry the material has changed too so I was gonna ask something similar and that you answered a little bit of it but has are you comparing this with other experiments done by possibly other people how like have there been things like this in the past or you mentioned This was like the sixth iteration of this experiment. So are there other people working on this similar project? Yeah, there are a lot of people that are interested in lunar geopolymers and geopolymers in general. It's a huge field, and it continues to grow. This is the first time that these samples have been put on the space station or in space that we know of, or at least it's been published, that we have access to. But people do a lot of testing that's similar in terms of putting them under vacuum or exposing them to temperature swings or temperature, you know, cycles over time. So we can compare to that literature, but this is kind of the first time they're being put into that total experience of being in the low-Earth orbit kind of condition. Impressive achievement, then. Well, thank you. UD is funding it, so it's... That's great. It's good. Thanks. What do you see the value of NASA kind of outsourcing the research to you guys in university other than they don't have the talent that we have? It's nice to say that that's the reason. But we kind of have a competing technology, if you will. So in addition to this, which does require water, which is a bit of an issue, The other competing technology that NASA is investigating is called laser sintering. So essentially they take a high-powered laser and just melt the soil and turn it into this glassy material. So you kind of think of like a Zamboni on ice. You could think of something that would suck up the lunar dirt in front of this machine and out the back set down layers of solidified soil. So they're working on geopolymers in some capacity. They're also pushing this laser sintering approach. But we applied kind of independently of NASA's existing programs. So you mentioned the word technology, and I'm from the UD Tech Transfer Office. And so have you worked with the Tech Transfer Office on any of these innovative either compositions or technology that you have or ideas, even though, you know, you're working on a project with NASA here? Thank you for the question. We have not yet. this is all pretty open source stuff right in terms of we're not developing the regolith simulants and the chemistry is all pretty pretty well defined but the the complexity comes in the the space of compositions right you can you can make anything under the Sun in terms of mixing different additives together and different amounts of the different components of the sample so it definitely could be a conversation to have but we haven't yet
2025 Spark Symposium EGNACZYK
From Kyle Chappell April 18, 2025
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