Research Highlights

Current manufacturing techniques for thermoset-matrix fiber-reinforced composites rely primarily on bulk polymerization of the resin. In addition to the substantial capital investments required for autoclaves, ovens, or heated molds, the long and complex heat and pressure cycles involved in the thermal curing process make manufacturing time-consuming and energy-intensive.

Frontal Polymerization (FP), which involves a self-propagating polymerization wave that converts monomer into polymer, has been demonstrated as an alternative approach that eliminates the need for autoclaves and makes the process substantially faster and more energy-efficient by orders of magnitude. While FP has been observed in a variety of thermoset polymers, particular emphasis is placed on the manufacturing of composites made of carbon fibers embedded in a dicyclopentadiene (DCPD) resin. The UIUC team is currently applying FP-based manufacturing to space structures.

Reference: Robertson, I. D., Yourdkhani, M., Centellas, P. J., Aw, J. E., Ivanoff, D. G., Goli, E., Lloyd, E. M., Dean, L. M., Sottos, N. R., Geubelle, P. H., Moore, J. S., and White, S. R. (2018) “Rapid energy-efficient manufacturing of polymers and composites via frontal polymerization.” Nature, 557, 223-227. https://doi.org/10.1038/s41586-018-0054-x

Our team is working on a project to test a material-curing technology that could enable on-orbit manufacturing and construction of large, high-precision space structures. Next-generation space telescopes, space-based solar power plants, and radio-frequency antennas will require ultra-large and ultra-stiff trusses, exceeding 300 meters in diameter, and/or structures with extremely high dimensional precision. Realizing such structures will unlock unprecedented growth in the space economy.

Mission Illinois is an interdisciplinary project funded by the Defense Advanced Research Projects Agency (DARPA) that integrates scientific research in mechanical design for on-orbit manufacturing equipment, as well as material science and engineering. The team is designing, fabricating, and testing a payload for an on-orbit composite manufacturing experiment. This payload is a fabrication system carefully engineered to operate while attached to the external truss of the International Space Station (ISS). Its design incorporates a suite of motors and linkage mechanisms for manufacturing processes, a heater for curing polymer composite material, and the necessary electronics and software to ensure reliable operation in compliance with space design standards.

Flexible space structures capable of folding, deploying, and morphing represent critical enabling technologies for advanced space systems. Understanding their complex structural behavior and response to extreme space environments provides fundamental knowledge essential for the development of next-generation space structure concepts. Integrating advanced ultralight, ultrathin, space-survivable soft electronics with flexible structures offers a new approach to achieve multifunctionality. Our center is investigating the design, manufacturing, and underlying mechanics of these multifunctional flexible space structures to advance this emerging technological frontier.

1. Guanghui Li, Yao Yao, Nikhil Ashok, and Xin Ning. "Ultra-Flexible Visible-Blind Optoelectronics for Wired and Wireless UV Sensing in Harsh Environments," Advanced Materials Technologies, 2021.

͏2. Yao Yao, Juan M. Fernandez, Sven G. Bilén, Xin Ning. "Multifunctional Bistable Ultrathin Composite Booms with Flexible Electronics," Extreme Mechanics Letters, 2024.

͏3. Yao Yao, Guanghui Li, Xin Ning. "Origami Electronic Membranes as Highly Shape-Morphable Mechanical and Environmental Sensing Systems," Extreme Mechanics Letters, 2024.

4. Zarader, Chloé, and Xin Ning. “Structural Effects of Ply-level Imperfections and Extreme Temperatures on Bistable Ultra-Thin Composite Booms.” Extreme Mechanics Letters (2025): 102305.

Morphogenic composites that use frontal polymerization (FP) to rapidly cure flat, fiber-reinforced laminates into predetermined 3D shapes without external molds or temporary pre-forming. By initiating a self-propagating cure front, the process embeds controlled residual strains that drive predictable out-of-plane morphing, delivering complex curvature with low energy input and short cycle times, which is a compelling route for in-space manufacturing and deployable structures where tooling, power, and volume are constrained.

"Morphogenic composites: Frontal polymerization induced autonomously shaped composites" I.C. Wu, S. Vayas. P. H. Geubelle P, J.W. Baur, Composites Part A: Applied Science and Manufacturing.  (2025), 193:108827. https://doi.org/10.1016/j.compositesa.2025.108827

Deployment of in-space manufacturing technologies requires careful consideration of environmental conditions in Low Earth Orbit (LEO), including vacuum ultraviolet (VUV) radiation, temperature fluctuations, and gravity that are not typically of concern during ground-based manufacturing. We develop multiphysics and multiscale finite element and AI-based models to predict and guide rapid manufacturing processes using frontal polymerization. At the core of this multiphysics framework is a thermo-chemical reaction–diffusion model that describes the evolution of temperature and degree-of-cure fields.

To simulate the propagation of a polymerization front in composite laminates and woven composites, we have also developed a mesoscale reaction–diffusion model that captures the heterogeneity of the temperature field during manufacturing. Furthermore, we are advancing predictive multiphysics and multiscale simulations spanning length scales from nanometers to millimeters to simulate and predict the lifetimes of materials exposed to atomic oxygen (AO) in LEO.

Space structures are exposed to a harsh environment in Low Earth Orbit (LEO), which is especially detrimental to polymeric structures due to the erosive effects of atomic oxygen (AO) acting in synergy with ultraviolet (UV) radiation. We have shown that polymer nanocomposites can significantly reduce the erosion rates of epoxy matrices by controlling the nanoparticle volume fraction and size (Figure a).

Micrometeoroids and orbital debris (MMOD) traveling at velocities of 7.5 km/s and higher can also be catastrophic or initiate conditions for accelerated AO erosion. We are investigating strategies to mitigate the catastrophic effects of MMOD on lightweight composite materials. Figure (b) shows impact craters and damage profiles created on different epoxy nanocomposites by a 0.5-mm aluminum disc traveling at 4.5 km/s.

Space structures are susceptible to damage from micrometeoroid and orbital debris (MMOD) impacts, thermal cycling, and environmental degradation in Low Earth Orbit (LEO). Such damage can compromise structural integrity, block heat transfer channels, and degrade the performance of critical subsystems.

To address this challenge, we investigate thermography-based damage detection methods that leverage passive and active heating sources. For passive detection, orbital sun heating induces surface temperature variations, which can be monitored with infrared (IR) cameras to identify damaged regions. For active detection, embedded thermoresistive heaters provide controlled heating, enabling localized identification of subsurface damage via thermal contrast.

Our work also emphasizes damage quantification through machine learning and data integration. Experimental thermography data, combined with finite element analysis (FEA) simulations, are used to train models capable of predicting damage morphology with improved accuracy. Both transmission and reflection thermography modes are employed, allowing robust detection of impact craters and internal defects in composite structures.

This integrated framework enables quantifiable and scalable monitoring of damage in composite spacecraft structures, offering a pathway toward autonomous in-orbit health monitoring systems.

We analyze the failure mechanisms of the ablative thermal protection system (TPS) of the Orion spacecraft under intense thermo-chemo-mechanical loads during reentry. Using molecular dynamics simulations, we developed a fundamental understanding of the reactions occurring during pyrolysis, which provided temperature-dependent pyrolysis rates. These results were then upscaled into a micromechanics model capable of predicting the ablation rate of the TPS as a function of its microstructure. Ultimately, this research has enabled the design and optimization of TPS microstructure and geometry for specified heat loads—a critical step toward ablation-by-design.

Harpale, A., Sawant, S., Kumar, R., Levin, D., Chew, H.B., Ablative thermal protection systems: Pyrolysis modeling by scale-bridging molecular dynamics. Carbon, 130 (2018), 315-324.

Sawant, S.S., Rao, P., Harpale, A., Chew, H.B., Levin, D.A., Multi-scale thermal response modeling of an AVCOAT-like thermal protection material. International Journal of Heat and Mass Transfer, 133 (2019), 1176-1195.

We have integrated our multiscale modeling tools with ongoing research efforts in the electric propulsion (EP) community to quantify material degradation induced by ion thrusters in space environments. Our scale-bridging molecular dynamics simulations have provided fundamental insights into why steady-state sputtering yield data of carbon are independent of initial structure and prior sputtering history. In addition, these simulations have shed new light on the low-energy sputtering of carbon materials and helped clarify the origin of the large scatter reported in previous experimental studies. We have further upscaled these atomistic results into a Monte Carlo model to elucidate surface morphology effects, enabling the identification of optimized surface structures that can be engineered to mitigate thruster erosion.

Tran, H., Chew, H.B., Surface morphology and carbon structure effects on sputtering: Bridging scales between molecular dynamics simulations and experiments. Carbon, 205 (2023), 180-193.

Tran, H., Chew, H.B., Transient to steady-state morphology evolution of carbon surfaces under ion bombardment: Monte Carlo simulations. Acta Materialia, 263 (2024), 119498.

Tailoring the fracture resistance of 3D-printed materials is a key requirement for their successful deployment in space. This necessitates the development of new tools and approaches to design microstructural heterogeneities in printed materials that can control crack paths and ultimately improve fracture toughness. One such approach we have undertaken is the use of neural networks for machine learning to predict stochastic crack growth, providing a multiplicity of possible crack paths along with a quantified likelihood for each.

Worthington, M., Chew, H.B., Crack path predictions in heterogeneous media by machine learning. Journal of the Mechanics and Physics of Solids, 172 (2023), 105188.

Material systems subjected to extreme plasma environments often undergo highly complex failure mechanisms that cannot be easily characterized through experiments alone. In such cases, scale-bridging molecular dynamics (MD) simulations provide unprecedented insights into fundamental mechanistic processes, which in turn inform predictive models at higher length scales.

One example is the development of atomistically informed models to explain and predict the patterned graphene nanostructures achievable through hydrogen plasma treatment. In particular, we identified narrow plasma ion energy regimes that enable the controlled patterning of circular or hexagonal holes in graphene, as well as selective etching of graphene edges without damaging the basal plane. Identifying such mechanisms in plasma-facing devices is key to mitigating plasma-induced material degradation in space.

Harpale, A., Chew, H.B., Hydrogen-plasma patterning of multilayer graphene: mechanisms and modeling. Carbon, 117 (2017), 82-91.

Harpale, A., Panesi, M., Chew, H.B., Plasma-graphene interaction and its effects on nanoscale patterning. Physical Review B, 93 (2016), 035416.