The increasing urgency of climate change mitigation necessitates innovative solutions beyond terrestrial efforts. Space-based solar geoengineering – particularly a Planetary Sunshade System (PSS) positioned near the photo-gravitational equilibrium point L<inf>1</inf>^∗, which lies closer to the Sun than the classical L<inf>1</inf> due to the effect of solar radiation pressure – has been proposed as a potential method to reduce incoming solar radiation and stabilize global temperatures. This paper presents the preliminary design of a precursor mission aimed at demonstrating key technologies essential for the deployment of a full-scale PSS. The proposed mission features a 12U CubeSat equipped with a 400 [m²] solar sail, which will be used for propulsion, attitude control, and station-keeping at L<inf>1</inf>^∗. The mission objectives focus on validating the long-term performance of optical shielding materials, demonstrating solar sailing as a sustainable propulsion method, and assessing the feasibility of autonomous orbit and attitude control systems. The technical and economic feasibility of the precursor mission, with an estimated budget of 10M USD is examined. By addressing key uncertainties in spacecraft formation flying, material degradation, and long-term solar sailing operations, this mission represents a crucial step toward the realization of a scalable PSS for climate intervention.

The objective of this paper is to present a roadmap for the technology development toward a Planetary Sunshade System, a space-based solar geoengineering project aimed at reversible solar radiation modification to mitigate global warming. Earth's climate change is mostly due to the increasing concentration of greenhouse gases in the atmosphere, which leads to a general rise of the temperatures. A space-based geoengineering infrastructure has been previously proposed to reduce the oncoming solar irradiance, by placing a 'solar light umbrella', called Planetary Sunshade System, between the Sun and the Earth. To address the full development of a Planetary Sunshade System, a technology roadmap is needed which considers a step-by-step high-level plan of technology development, mission planning, launch preparation, international cooperation, highlighting the multi-phase development strategy from initial design to final deployment. First, the roadmap phases for production and deployment are outlined in chronological order. The analysis of technology development begins with the current technology readiness level, encompassing system design and factors such as mass, dimensions, area, and the total number of solar-sail satellites. Logistic aspects, including in-space assembly of the fully deployed system, are also examined. Finally, launch preparation is discussed encompassing heavy launcher design, facilities, production and launch sites. The proposed roadmap not only provides a starting point for the design and development of the Planetary Sunshade System but also a critical tool for evaluating the feasibility of direct climate action from space. Through this paper, we aim to establish the groundwork for a future Planetary Sunshade endeavour, and to contribute to the broader discussion on space-based climate action.

This paper presents a method to characterize six anisotropic thermal moduli for lattice structures, enabling the estimation of full anisotropic thermal elastic moduli. The study focuses on a group of distorted Kelvin cells, generated by twisting the four-node faces, to explore the relationship between distortion, anisotropic thermal expansions, and dynamic responses. Through parametric studies, the anisotropic thermal moduli are characterized as functions of the twisting angles, revealing that thermal moduli related to compression decrease with increasing twisting angles, while those related to shearing, which do not exist in isotropic materials, are identified. Dynamic responses reveal complex modal shapes and coupling between longitudinal and transverse directions, enhancing vibration mitigation. The proposed lattices and methods offer a promising structure for assembling and designing dual-functional metamaterials, featuring customizable thermal elastic moduli, ease of space assembly, lightweight structure, and effective vibration mitigation capabilities.

This paper presents a novel 3D lattice metastructure featuring customizable elastic moduli in all three dimensions, achieved through distorted Kelvin cells. These structures are fabricated using thermoplastic polyurethane (TPU) materials through selective laser sintering (SLS) additive manufacturing techniques. Static compression tests reveal significant recoverable deformations and near-zero Poisson effects. Numerical simulations indicate that distorted Kelvin cells (DKCs) exhibit lower transmission in the longitudinal direction compared to standard Kelvin cells within the frequency range of interest. Additionally, DKCs demonstrate increased coupling between longitudinal and transverse directions at resonant frequencies. Parametric studies explore various lattice sizes, face configurations (closed or open), twisting angles, and matrix materials. Optimization studies, focusing on different twisting angles on each pair's faces, aim to minimize the response under 400 Hz, showcasing the potential for tuning these structures for specific applications.

The objective of this paper is to present the design of a precursor mission for the Planetary Sunshade System, positioned near the photo-gravitational equilibrium point L1*, located between the Sun and the Earth-Moon system's center of mass. This study pioneers the integrated system engineering design and mission scenario definition. Earth's climate change, driven predominantly by the escalation of greenhouse gases in the atmosphere, poses an unprecedented threat to global stability and sustainability, manifesting through increased global temperatures. In response, a space-based geoengineering infrastructure has been previously proposed as a mitigation measure. It would enable to reduce the oncoming solar irradiance, by placing a 'solar-light umbrella', called Planetary Sunshade, strategically positioned between the Sun and the Earth. The proposed Planetary Sunshade precursor mission aims at pushing forward through in-space testing some of the critical enabling technologies for such a space-based climate change mitigation solution. First, the precursor Planetary Sunshade System and mission requirements are discussed, for the first time to the best knowledge of the authors. Emphasis is put on the astrodynamics of the mission, analyzing the orbital regimes suitable for maximizing efficacy and stability. Then, the system design is introduced, based on small satellite components, focusing on critical aspects of subsystems such as solar sail, attitude and orbit control system, deployable structures and mechanisms, thermal system, and telemetry. Particular attention will be paid to the choice of solar sail materials, emphasizing their optical properties. This precursor mission is meant to serve not only as a proof of concept but also as a critical technology testbed. By studying the feasibility of such a mission, we contribute to a broader discussion on possible space-based interventions for climate change mitigation. Our work aligns with several UN Sustainable Development Goals, notably SDG 13 (Climate Action), by exploring innovative solutions to mitigate climate change, and SDG 9 (Industry, Innovation, and Infrastructure), by pushing the boundaries of current space technology.

Admission of applicants to higher education in a fair, reliable, transparent, and efficient way is a real challenge, especially if there are more eligible applicants than available places and if there are applicants from many different educational systems. Previous research on best practices for admission to master’s programmes identified the key question about an applicant’s potential for success in studies, but was not able to provide an answer about how to rate the merits of the applicants. In this study, indicators for study success are analysed by comparing the study performance of 228 students in master’s programmes with their merits at the time of admission. The null hypothesis was that the applicant’s average grade at the time of admission is the only indictor for study success. After testing for potential bias using almost 20 possible other indicators, the null hypothesis had to be rejected for four indicators (in order of importance): (i) university ranking, (ii) length of bachelor’s studies within subject, (iii) English language test and (iv) subject matching between bachelor’s and master’s education. Evaluation of quality of prior education is tricky and results from this study clearly indicate that students from higher ranked universities possess better knowledge and stronger skills for our master’s programmes. Work is ongoing to improve the merit rating model by involving more master’s programmes at KTH and analysing performance data from a larger number of students.

As humans increasingly begin to expand beyond the threshold of Low Earth Orbit (LEO), moving supplies and astronaut safety within the vastness of space can become daunting. Limited by Tsiolkovsky's Rocket Equation, rockets are inefficient at moving material off planet as only a small percentile of the rocket's launch pad mass reaches orbital space. While commercial enterprises have greatly increased the rate of rocket launches, a human emergency occurring far from Earth raises the question of how to send aid. Space Elevators are an additional solution to overcoming the initial constraints posed by rockets. In a simplified manner, a Space Elevator is a permanent infrastructure for moving large elevators (climbers) along a tether that extends from the surface of the Earth into space. This research looks at the volume of space between Earth and the Moon, otherwise known as Cislunar Space, and the benefits that a Space Elevator would contribute. Specifically, a safety for astronauts beyond LEO by means of the Apex Anchor (space station located at the top of the Space Elevator) as well as mass distribution to the Moon by means of the Space Elevator. Mathematical and engineering details for the Space Elevator's construction or orbits for payloads are referenced but not calculated in this study.

The present work investigates the performance of additively-manufactured sandwich structures with the goal of reducing the effect of vibrations on a spacecraft during launch, whilst minimizing mass. Additive manufacturing allows designers to implement custom and complex geometries, such as the sheet gyroid structures, inside sandwich panels. Accordingly, this work details the development of gyroid-based sandwich structures for damping. Several test specimens are designed, additively manufactured using ABS plastic, and their damping performances are evaluated based on both simulation and experiments. Damping values are identified using frequency response transfer functions. The results show that as theory predicts, adding more mass, through the added thickness of the gyroid reduces the amplitude of vibrations. However, on a damping-per-unit-mass basis, the experimental results are inconclusive mainly due to the measurements of vibrations in the center of the sandwich panels instead of the sides where the vibrations can be maximum. Therefore, simulations better illustrate the changes of the damping behavior at different applied frequencies. Lessons and experiences are summarized for future work, particularly in exploring the effects of varying other 3D printed composite meta-lattice sandwich structures for satellites. 

In engineering education, as well as in the society at large, there is an increasing focus on sustainability and sustainable development. The CDIO Standards and the CDIO Syllabus has been substantially updated to meet and drive these changes. Progressive engineering programs have by now made substantial progress in integrating environmental aspects of sustainability and sustainable development into the curriculum. However, the integration of social aspects is generally considered to be more difficult and is therefore lagging behind. This explorative research paper provides insights in efforts to integrate elements of gender equality, diversity and equal conditions (GDE) in three courses on bachelor’s, master’s, and doctoral level. The focus is on the development and implementation of reflective assignments, where a theoretical framework is used for characterizing different levels of reflection. The work has been performed by use of an action research approach that has involved close dialogue and collaboration between researchers, pedagogic developers, teachers, students, and education leaders. The paper hereby contributes with multiple perspectives on GDE integration, and significant challenges are discussed. The paper also contributes with concrete examples of reflective assignments, learning activities, and literature that can be useful also in other contexts.

Due to their tailored thermomechanical behavior and functionality, shape memory polymer matrix composites (SMPCs) are attractive as deployable structures in aerospace applications. An analytical model based on the classical laminate theory, together with the principle of minimum potential energy is developed to capture the thermo- viscoelastic behavior of a bistable tape spring (BiTS). These tape springs are known to snap between two stable configurations by different stimulus. Here, a shape memory polymer as the matrix of a fiber-reinforced polymer BiTS is introduced to actuate the snap-back. Experimental characterization was performed to obtain the time-temperature dependent properties of a Polyurethane SMPC. The time-temperature superposition principle was employed to convert the thermal effects to a viscoelastic response. Five BiTSs were manufactured and exposed to two different thermo-viscoelastic cycles to verify the model for long-term and high-temperature behaviors. The results show that the model can estimate the coiling radius and the degree of stability of the BiTS in the coiled configuration. Analytical results, supported by experimental results, show that the temperature could initiate the snap-back in BiTS. However, time-temperature history has a significant effect on the bistability and can convert a monostable tape spring to a BiTS and vice versa.