Orbital transfers between libration point orbits have played a crucial role in meeting diverse mission constraints around a libration point. Existing analytical theories for such transfers, built on the linearization of the circular restricted three-body problem, have shown promising results in developing transfer strategies. However, given the large excursions of actual mission trajectories, the influence of the neglected high-order dynamics is expected to have a nontrivial effect on these transfers. This study proposes a numerical method that iteratively refines the solutions for impulsive transfers obtained from linear theory, based on the semi-analytical Lindstedt–Poincaré expansion. This method not only provides a means for refinement but also enables systematic validations of linear transfer theories within a broader dynamical framework while retaining orbital parameters. The proposed method is applied to in-plane single-impulse transfers between two Lissajous orbits around a collinear libration point in the Sun-Earth+Moon and Earth-Moon systems. The results show that while the linear solutions remain relatively accurate near optimalities, they are significantly disturbed at the two extremities of the Lissajous orbits by the high-order dynamics. The deviation from the linear solutions exhibits a clear dependency on parameters such as the in-plane phase, transfer orbit families, and the libration point, leading to either improvements and deteriorations in the transfer cost. These results provide insights into the validity of existing linear theories and show how the nonlinearity can be leveraged to improve maneuver strategies.

Climate change mitigation may require transformative strategies beyond emission reduction. This paper introduces a technology roadmap for developing a Planetary Sunshade System: a space-based solar geoengineering concept designed for reversible Solar Radiation Management. The proposed roadmap is a structured, multi-phase plan from early technology demonstrations to full deployment at the Sun–Earth/Moon Center of Mass photo-gravitational Lagrange point. The roadmap addresses critical aspects such as solar-sail design, in-space assembly, swarm logistics, and launch infrastructure, while outlining milestones for initial operations by 2040 and full capability by 2080. By integrating technological, logistical, and programmatic considerations, this roadmap serves as a framework for assessing feasibility and guiding international collaboration on space-based climate interventions.

The VITA (Visualising In-space Tx-Tl Astropharmaceuticals) mission is a teleoperated Astropharmaceutical cube-payload that is aiming to launch a biological experiment to the ICE Cubes Facility (ICF) on board the International Space Station (ISS). Project VITA aims to enable on-site, on-demand production of therapeutics for long-duration human spaceflight, addressing the critical need for transportable medicines as outlined by the International Space Exploration Coordination Group (ISECG) Global Exploration Roadmap (GER). The main scientific goal is to demonstrate efficient and effective cell-free synthesis in a compact and flexible platform. Considering the possible increase in future human spaceflight missions to the Moon and Mars, the success of VITA will be a turning point to further satisfy the demand for medical drugs during long duration missions.Following weeks of preservation, the experiment intends to demonstrate the ability to rehydrate the freeze-dried cellulose stacks, kickstarting the synthesis of fluorescent proteins, and perform real-time, in situ detection through fluorescence spectroscopy and imaging.The aim of this paper is to present the system architecture required for teleoperated Astropharmaceutical experiment cubes and CubeSats, covering merits and drawbacks. Considering the potential large variation of temperature in a spaceflight mission, and the critical temperature dependency to maintain protein stability, this paper also presents studies carried out and outcomes for active and autonomous thermal management systems. A key innovation of the mission is the implementation of a miniaturised, dual-mode thermal control system using Peltier modules and a predictive two-way control algorithm, enabling precise and autonomous temperature regulation within strict power constraints. Since this will be just a first step for in space pharmaceutical production, it will open a new broad subject and the final part will focus on future work areas to improve the project for possible Astropharmaceutical production platforms beyond Low Earth Orbit (LEO). Knowing that one of the biggest challenges for human spaceflight is related to human health and reflecting the limited access to Earth, the medical challenges must be overcome, and in-situ therapeutic production shall be proved. Hence, the initial success of the VITA mission will be a pioneering step to enable deep space human missions.

In planetary satellite systems, identifying low-energy, stable orbits that reduce interplanetary mission costs are critical for exploring minor celestial bodies in a variety of highly complex gravitational environments. To identify suitable trajectories in planetary systems with multiple moons, prominent ring systems and varying levels of planetary oblateness, the application of the Circular Restricted Three-Body Problem (CR3BP) framework is proposed. Classical celestial mechanics demonstrates that CR3BP may generate an infinite number of periodic orbits. Nonetheless, the original framework represents an idealized scenario that does not consider the dynamic influences of perturbations, such as those that stem from planetary rings and the oblateness of celestial bodies, leading to incomplete assessments of orbital stability. The proposed CR3BP-based framework involves the implementation of a perturbed propagator that can automate the generation of large periodic orbit databases via pseudo arc-length continuation (PAL). In this context, the Saturn–Titan system is employed as a relevant case study to demonstrate the capability of this framework to simulate complex gravitational dynamics. Furthermore, the behavior of Distant Retrograde Orbits (DROs), Southern and Northern Halo orbits around one of the collinear equilibrium points in this planetary system is also analyzed to demonstrate the applicability of this model to multi-body environments. Results indicate that despite the introduction of these perturbations, the model is capable of capturing low-energy trajectories that may offer significant potential for designing sustainable, more cost-efficient deep-space missions in the Saturn-Titan system. The proposed approach is applicable to any planetary system with similar characteristics, thereby providing a foundation that may be extrapolated to higher fidelity models for the design of future interplanetary space missions.

Transmissive solar sail designs have been proposed with performance and utility benefits over traditional solar sails, particularly in low Earth orbit. The functional element of these new sails is their refractive or diffractive surface pattern. This paper explores the design of refractive sail patterns using numerical optimisation, and explores the validity of using model-free reinforcement learning algorithms for this purpose. In particular, the performances of triangular prism and semi-cylindrical lightfoil patterns from prior literature are iteratively improved. To do this, a ray tracing optical simulation was developed that models the solar radiation pressure and torque per unit area of illuminated, refractive patterns in a vacuum. Meanwhile, a numerical optimiser was developed to iteratively improve upon simulated patterns according to user-defined fitness functions. Depending on their purpose, patterns were optimised for either tangential-to-sail solar radiation pressure or self-stabilising corrective torque at a Sun-pointing attitude, or range of attitudes. The optimiser was shown to be capable of substantially improving the performance of optical elements, particularly through the harnessing of total internal reflection. In one case, the numerical optimiser was shown to improve the maximum tangential radiation pressure of an analytically optimised polystyrene prism pattern by 58%. In another case, the optimiser improved the peak corrective torque of a pattern of polyethylene terephthalate lightfoils by 74%.

This paper investigates the design of optimal low-thrust transfers between relative planar and spatial quasi-satellite orbits (QSOs) in the Earth–Moon system under the Circular Restricted Three-Body Problem (CR3BP). A key contribution is the adaptation of a trajectory optimization framework, previously applied to halo orbit transfers, to accommodate the unique challenges of QSO families, especially the transition between planar and spatial configurations. The method employs a refined beam search strategy to construct diverse initial guess chains, which are then optimized via a successive convexification algorithm tailored for the spatial dynamics of QSOs. Additionally, a linear–quadratic regulator (LQR)-based control scheme is implemented to ensure long-term station-keeping of the final 3D-QSO. Simulation results demonstrate the feasibility of connecting planar and spatial QSOs with minimum-fuel trajectories while maintaining bounded terminal deviations, offering new tools for future Earth–Moon logistics and navigation infrastructure. Key findings include the successful design of low-thrust transfer trajectories between planar QSOs and 1:5 3D-QSOs, with a minimum total ΔV of 195.576 m/s over a time of flight (ToF) of 261 days, and a minimum ToF of 41 days with a total ΔV of 270.507 m/s. Additionally, the application of LQR control demonstrated the ability to maintain 1:5 3D-QSO families around the Moon with less than 12 mm/s ΔV over two months. This research provides valuable insights into the optimization of low-thrust transfer trajectories and the application of advanced control techniques for space missions, particularly those targeting lunar and planetary satellite exploration.

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 & lowast;1, which lies closer to the Sun than the classical L1 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 & lowast;1. 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.

As global temperatures continue to rise despite international mitigation efforts, geoengineering has emerged as a potential avenue for climate intervention. One of the most promising and ambitious concepts is the Planetary sunshade—a large-scale structure located at Lagrange Point L1, designed to reduce solar irradiance by physically blocking or redirecting incoming photons. This paper presents a structural design solution for this ambitious system, focusing on deployable mechanisms, frame architecture, and sail configurations that enable rapid mass production and deployment of solar sails components. The design process follows the European Cooperation for Space Standardization (ECSS) methodology through its early-phase stages, utilizing weighted decision matrices for concept selection and material evaluation. Finite element analysis (FEA) was used to validate structural integrity under Atlas V launch and operational conditions. The final design features a 1297 m2 sail composed of four triangular segments, deployed via booms and stowed using a vertical folding pattern around a central spool. The booms incorporate arch-shaped cross-sections to enhance stiffness. This configuration achieves a radius expansion ratio of 25 and a sail efficiency factor of 0.5, ensuring survivability under Atlas V launch loads.

Contrails, or condensation trails, left by aircraft, significantly contribute to global warming by trapping heat in the Earth’s atmosphere. Despite their critical role in climate dynamics, the environmental impact of contrails remains underexplored. This research addresses this gap by focusing on the use of CubeSats for real-time contrail monitoring, specifically over major air routes such as the Europe–North Atlantic Corridor. The study proposes a 3 × 3 CubeSat constellation in highly eccentric orbits, designed to maximize coverage and data acquisition efficiency. Simulation results indicate that this configuration can provide nearly continuous monitoring with optimized satellite handovers, reducing blackout periods and ensuring robust multi-satellite visibility. A machine learning-based system integrating space-based humidity and temperature data to predict contrail formation and inform flight path adjustments is proposed, thereby mitigating environmental impact. The findings emphasize the potential of CubeSat constellations to revolutionize atmospheric monitoring practices, offering a cost-effective solution that aligns with global sustainability efforts, particularly the United Nations Sustainable Development Goal 13 (Climate Action). This research represents a significant step forward in understanding aviation’s non-CO2 climate impact and demonstrates the feasibility of real-time contrail mitigation through satellite technology.

The JamSail mission is an educational CubeSat aiming to design, develop, and demonstrate two new technologies on a small satellite, tentatively scheduled for launch no earlier than 2026. When launched, JamSail will demonstrate the functionality of two new payloads in low Earth orbit. First, a flexible, low-cost GNSS interference detection payload capable of characterising and geolocating the sources of radio interference regarding the E1/L1 and E5a/L5 bands will be demonstrated on a global scale. The data produced by this payload can be used to target anti-interference actions in specific regions and aid in the design of future GNSS receivers to better mitigate specific types of interference. If successful, the flexibility of the payload will allow it to be remotely reconfigured in orbit to investigate additional uses of the technology, including a potential demonstration of GNSS reflectometry aboard a CubeSat. Second, a compact refractive solar sail will be deployed that is capable of adjusting the orbit of JamSail in the absence of an on-board propellant. This sail will be used to gradually raise the semi-major axis of JamSail over the span of the mission before being used to perform rapid passive deorbit near the end-of-life juncture. Additionally, self-stabilising optical elements within the sail will be used to demonstrate a novel method of performing attitude control. JamSail is currently in the testing phase, and the payloads will continue to be refined until the end of 2024. This paper discusses the key objectives of the JamSail mission, the design of the payloads, the expected outcomes of the mission, and future opportunities regarding the technologies as a whole.

Quasi-satellite orbits (QSO) are stable retrograde parking orbits around Phobos that are currently being considered for JAXA's upcoming robotic sample return mission Maritan Moons Exploration (MMX). During the proximity operations of MMX, the spacecraft inserted in a high altitude QSO will gradually descend to lower altitude QSOs with suitable transfer and station-keeping techniques between different relative QSOs. Preliminary analysis of two-impulsive planar transfers between relative retrograde orbits utilizing the bifurcated QSOs families is studied to estimate the Delta V costs and time of flights of the transfers. In this paper, differently from previous works, we utilize the initial guesses found through the preliminary results that provide two-impulsive transfer Delta V execution points and optimize the transfers between relative QSOs around Phobos. Primer vector theory is applied to investigate the primer vector of the MMX transfer trajectories to evaluate whether intermediate maneuver or initial/final coasting times along the trajectories can minimize the total Delta V cost between the transfers. Based on the primer vector analysis of the impulse transfer trajectories, it is found that departing and arriving at the same periphobian sides with an additional mid-course impulse results in the optimal impulse solution.

Refractive and diffractive solar sails have been cited to yield benefits in both performance and utility over reflective sails, but their range of viable flight regimes and future applications have not been fully explored. In this paper, a flight model is developed to test and compare these transmissive sail designs under realistic conditions. Raw performance is translated into tangible flight characteristics within a range of flight regimes, such as rate change of orbital energy and minimum operational altitude, and used to make comparison with reflective sails and contemporary thrusters. Additionally, the sensitivity of these flight characteristics to certain orbital parameters is explored when operating under either a locally optimal or simplified Sun-pointing steering law. The developed flight model focuses on solar radiation pressure, atmospheric drag and the effects of eclipse and orbital precession; locally optimal steering laws are numerically generated for every flight regime using a ray tracing-derived performance sensitivity profile. Relative to an idealised reflective sail, the sensitivity of transmissive sail performance is found to be lower for altitude, but higher for orbital inclination. High performance transmissive sail designs are found to outperform idealised reflective ones in every flight regime nonetheless. Meanwhile, only certain lower performance designs demonstrate this trait; others retain advantage only within high inclination, low altitude orbits. 36m2 transmissive sails performing an orbit-raising manoeuvre from low Earth orbit are shown to generate transit times comparable to mid-range electric thrusters. In light of these findings, potential applications for transmissive sails are discussed, as well as several practical considerations and potential limitations.