Fabien Royer

This study presents a novel programmable structure that can be shaped directly on-orbit through elastic buckling in a new hybrid In-Space Servicing, Assembly, and Manufacturing process. This process takes inspiration from recently proposed in-space deformation processing and enables the shaping of ultrathin composite deployable booms to create large space structures. The design concept uses bistable unit cells as building blocks for a cellular deployable metastructure that can transition between multiple stable configurations through the trigger of snap-through instabilities in a sequence of cells. Conditions leading to multistability in individual cells and the full metastructure were investigated, highlighting the influence of stiffness, geometry, and target cell location on achievable deformed configurations. Another aspect of this study is the exploration of the scalability and programmability of this cellular architecture, which enables a single structure to adaptively meet a wide range of mission requirements, ranging from large deployable reflectors to reconfigurable antennas and structural booms for space infrastructure. By applying various actuation strategies, the shape of the structure can be precisely reconfigured to achieve a wide range of geometries, such as curved circular beams of varying radii or S-shaped profiles. This study offers a proof of concept for the design and assembly of complex, large ultralightweight space structures with minimal power consumption.

CRISPI (Compositional Regolith and Icy Surface analysis via Particle Impact) is a proposed ridealong in-situ mass spectrometer (MS) smallsat mission to provide synergistic astrobiology science at Ariel to the Uranus Orbiter and Probe (UOP) mission. By utilizing a high-resolution impact ionization MS based on the Europa Clipper’s Surface Dust Analyzer on a deployable smallsat platform, CRISPSI will provide in-situ mass data of the surface of Ariel, a moon of Uranus and one of the highest-priority astrobiology targets in the outer solar system. Ariel is specifically called out in the Origins, Worlds, and Life (OWL) Decadal Survey as a high-priority target because it is potentially a liquid-water-bearing icy ocean world that is known to have ammonia, an organic volatile species that indicates recent surface processing (possibly from cryovolcanism or other subsurface sources) and may act as an anti-freeze for water. However, the baseline UOP mission has few flybys of Ariel with limited compositional data provided only by optical spectrometers. CRISPI addresses this gap by enabling the direct and unambiguous detection of organics and salts present in and the quantification of ice-to-rock and salt-to-water ratios of >1000 surface dust grains mapped to visible features on Ariel’s surface. In principle, CRISPI may also be used to study Miranda (another high priority astrobiology target) and the Uranus ring systems, which are poorly understood and are also specifically called out in the OWL Decadal Survey. Here we present results from the Cornell SmallSat Mission Design School (SMDS) that developed the CRISPI mission concept. We propose CRISPI to work in synergy with the UOP’s magnetometer, imagers, and optical spectrometers to extend its science reach, break ambiguities in optical spectrometer data, and provide unique and critical in-situ mass spectral data to assess Ariel’s habitability and search for organic signs of past or extant life.

Ultra-lightweight space apertures require structural concepts that exceed deployable packaging limits. A recently proposed elastic snap-through shaping approach uses bistable composite unit cells to form programmable, coilable feedstock, avoiding the mass and power limitations of conventional in-space manufacturing and assembly. This paper develops a comprehensive multidisciplinary design optimization framework for these programmable cellular architectures. A single bistable unit cell, acting as a surrogate for the metastructure, is analyzed using nonlinear finite element simulations to characterize its mechanical response and actuation capabilities. A Gaussian Process Regression surrogate model is constructed to enable rapid evaluation of the high-dimensional design space. Particle Swarm Optimization is then employed for both single-objective maximization, and multi-objective trade-off analysis using an epsilon-constraint Pareto-front method. The optimized designs reveal distinct families that balance stability, actuation energy, and manufacturability. Sensitivity studies further identify the geometric parameters that exert the strongest influence on system performance. The proposed methodology provides a mission-relevant optimization framework for shaping large, deployable, and reconfigurable space structures.

This work introduces a new approach for shaping ultra-lightweight space structures by combining programmable elastic instabilities with the principles of in-space assembly and manufacturing. We present a deployable cellular meta-structure composed of bistable thin-shell composite cells whose snap-through response enables low-power morphing into target geometries. Building on earlier studies of cell-level and network-level multistability, this paper extends the investigation to the global bending stiffness of snap-through-shaped booms, a key property governing structural performance after deployment. Through finite element simulations, we characterize how boundary conditions, cell placement, target-cell density, and row activation influence the post-morphing stiffness of long booms. The results show that the stiffness of these structures can be tuned in a smooth and predictable fashion without compromising bistability or structural integrity. The study further verifies that these trends remain consistent even in larger multi-row networks. These findings establish a detailed mechanical understanding of snap-through-shaped cellular booms and demonstrate their reliability as programmable building blocks for large space structures.

This paper presents a thin-shell, bending-stiff, and deployable structure inspired by the origami flasher pattern to develop large-aperture space systems. A novel composite boom cross-section was created as the main load-bearing member and composite tape springs are implemented as transverse battens. A finite element model is developed to perform vibration simulations on idealized and modified models in the deployed configuration to investigate and optimize the stiffness of the architecture. A custom out-of-autoclave and multi-stage manufacturing process is used to produce a large-scale quarter flasher model prototype.

This study investigates the influence of imperfections on the buckling response of an open-section thin-shell structure. Using finite-element simulations, we examine how localized geometric imperfections modify the stability characteristics of an initially perfect shell. The imperfection takes the shape of a single dimple, which has been shown to be the most detrimental imperfection type. A probing methodology is employed to quantify this influence by evaluating the buckling energy barrier, defined as the minimum energy required to trigger a local instability. The findings reveal that the natural buckle width acts as a critical threshold that dictates whether imperfections stabilize or destabilize the structure. When the width of an outward imperfection exceeds this threshold, the dimple effectively alters the buckling behavior, preventing the formation of post-buckling equilibria and thus suppressing the potential for early buckling. This demonstrates that beyond modulating the buckling energy barrier, positive dimples can also serve as a mechanism for increasing the minimum buckling load and thereby act as a stabilizing feature. Conversely, when the imperfection is narrower than the natural buckle width, inward dimples unexpectedly raise the minimum buckling load, stabilizing the shell rather than destabilizing it. However, once the imperfection becomes wider than the natural buckle, this stabilizing effect reverses, and the associated energy barrier decreases, making the structure more prone to premature buckling. Probing across the full shell length further shows that positive imperfections localize the disturbance-sensitive region, making buckle formation spatially deterministic, whereas negative dimples broaden this region and yield a more spatially unpredictable instability response.

Synchrokinesis is a novel paradigm for simple, reversible, automation first assemblies. It consists of simultaneous displacing all the parts of an ensemble, each equipped with a directional connector, such as to eventually make them self-interlock, eliminating the need for fasteners. The resulting constructions are very robust to shocks and come in a variety of shapes and sizes - e.g. from simple cubic volumes to arbitrarily large arrays of tiles. This paper introduces five conceptual synchrokinetic assemblers designed for modular construction in microgravity environments, extending the principles of the translational assembly presented in.1 The purpose is to investigate the challenges and the potentials of the various assembly processes, which all have in common that they are based on Euclidean motions.

Thin-shell structures, integral to ultra-lightweight deployable systems, face challenges due to their extreme sensitivity to imperfections, which can significantly influence their buckling stability. We employ a perturbation approach to quantify the effects of local geometric imperfections on the buckling energy barrier. A probing methodology is used to map stability landscapes, quantify energy barriers, and explore the buckling behavior of both perfect and imperfect geometries. Through finite element simulations, this study demonstrates how localized imperfections can either enhance or erode the buckling energy barrier depending on their location, amplitude, and width. Negative dimples significantly lower the resistance to buckling, which often results in an early spontaneous collapse, whereas positive dimples mainly enhance stability up to a specific threshold, after which structural integrity is threatened. Furthermore, we demonstrate that the influence of the width of the imperfection follows three distinct regimes and that there exists a critical threshold beyond which the minimum load required to initiate buckling under disturbances increases. The findings provide effective strategies to utilize imperfections for modulating the buckling energy barrier, thus enhancing the performance of thin shells.

We present a novel programmable structure which can be shaped directly on-orbit through elastic buckling in a new hybrid in-space assembly and manufacturing (ISAM) process. This process takes inspiration from recently proposed in-space deformation processing and enables the shaping of ultra-thin composite deployable booms to create large space structures. The design concept uses bistable unit cells as building blocks for a cellular deployable meta-structure that can transition between multiple stable configurations through the trigger of snap-through instabilities in a sequence of cells. This study investigates the conditions for which the individual cells and the full meta-structure become bistable, highlighting the influence of stiffness, geometry, and target cell location on achievable deformed configurations. This work offers a proof of concept for designing and assembling complex, large ultra-lightweight space structures with minimal power consumption.

Increasing the size of radio frequency (RF) reflectors in space can enhance gain and spatial resolution in applications such as space-based communication and remote sensing. The size of current passive deployable reflectors is limited by a tradeoff between diameter and surface precision, which causes RF performance to degrade as size increases. A promising approach to overcome this tradeoff is to combine in-space manufacturing, which enables large structures, with distributed embedded actuation, which enables precise control over the reflector surface. Here we demonstrate a reflector antenna system that integrates these two technologies, using a candidate in-space manufacturing process, termed “Bend-Forming,” with embedded electrostatic actuators. We design and fabricate a 1-m-diam prototype of an electrostatically actuated X-band reflector with a knitted gold-molybdenum mesh as the reflector surface, carbon-fiber-reinforced plastic booms as electrodes, and a truss support structure fabricated with Bend-Forming. We characterize the RF performance of this reflector, successfully demonstrating i) control over a wide range of focal lengths by suppressing a pull-in instability and ii) beam steering over an angular range of 4.2° via asymmetric electrostatic actuation. This work lays the foundation for future space communication and remote sensing technologies, offering a scalable solution to enhance RF performance through in-space manufacturing and precision control.

This paper studies the stability of space structures consisting of longitudinal, open-section thin-shells transversely connected by thin rods subjected to a pure bending moment. Localization of deformation, which plays a paramount role in the nonlinear post-buckling regime of these structures and is extremely sensitive to imperfections, is investigated through probing experiments. As the structures are bent, a probe locally displaces the edge of the thin shells, creating local dimple imperfections. The range of moments for which the early buckling of the structures can be triggered by this perturbation is determined, as well as the energy barrier separating the pre-buckling and post-buckling states. The stability of the local buckling mode is then illustrated by a stability landscape, and probing is extended to the entire structure to reveal alternate buckling modes disconnected from the structure's fundamental path. These results can be used to formulate efficient buckling criteria and pave the way to operating these structures close to their buckling limits, and even in their post-buckling regime, therefore significantly reducing their mass. This article is part of the theme issue 'Probing and dynamics of shock sensitive shells'.

View Video Presentation: https://doi.org/10.2514/6.2023-1302.vid We present a novel electrostatic thin-shell structure concept capable of actively controlling the shape of large area systems with minimal mass overhead and complexity. It consists of an assembly of collapsible thin-shell cells for which the cross-section follows the classical Collapsible Tubular Mast (CTM) architecture. Two conductive electrodes are added to the top and bottom flanges of the cell. An electrostatic force develops between top and bottom electrodes upon voltage application, which flattens the cross-section and causes the cell to expand longitudinally. When multiple layers of these cells are bonded to each other, the controlled differential expansion of each layer can be harnessed to cause global bending.

View Video Presentation: https://doi.org/10.2514/6.2023-0756.vid Large reflectors in space (>30 m diameter) can enable advances in communications, remote sensing, and astronomy, by enabling antennas with increased gain, resolution, and bandwidth. However, modern deployable reflectors exhibit a decrease in performance as their diameter increases, due to fabrication errors, slewing, and disturbances on orbit, such as thermal distortion, which decrease surface precision. A potential solution to achieve larger apertures with high precision is to combine in-space manufacturing (ISM) with active control. Herein we demonstrate a reflector concept which combines a candidate ISM process called Bend-Forming with electrostatic actuation to achieve closed-loop control of the reflector surface. We design and fabricate a 1-meter diameter prototype of an electrostatically actuated X-band reflector, using a knitted gold-molybdenum mesh as the reflector surface, carbon fiber-reinforced plastic booms as electrodes, and a truss support structure fabricated with Bend-Forming, a deformation process for constructing trusses from wire feedstock. To characterize the performance of this prototype, we measure its radiation patterns at X-band in an RF anechoic chamber. We successfully demonstrate 1) the stabilization of a pull-in instability with closed-loop control, and 2) beam steering of up to 4.2 degrees with asymmetric electrostatic actuation. Our reflector prototype highlights the opportunities of implementing electrostatically-actuated reflector antennas in space.