In Solar Thermal Propulsion, a high-temperature Receiver-Absorber Cavity (RAC) converts concentrated sunlight into heat, which is then transferred to a propellant and expanded through a nozzle to generate thrust. Conventional RACs are often limited by material coupling issues, such as thermal expansion mismatches, material degradation , and restricted geometric freedom, leading to inefficiencies or failure under the demanding operating temperatures involved. This work presents a comprehensive approach to the design and manufacturing of a Solar Thermal Thruster (STT) core that integrates the RAC Thermal Energy Storage (TES) capability and the Heat Exchanger (HEX) into a single component, enabled by advancements in Additive Manufacturing (AM) for high-temperature applications. ... Read more

ars was long thought to be in a quiescent state with minimal geodynamic processes taking place at present. However, NASA's InSight mission shed light on the planet's present-day tectonic activity, part of which is likely related to mantle plumes and associated magmatic that, in the recent past, might have contributed to building up the Martian atmosphere through mantle outgassing. We propose a dedicated gravimetric satellite mission for Mars: the Mars Quantum gravity sensing of Interior Structure and atmosphere mission (MaQuIS) to understand these intricate dynamic processes and use gravity observations to constrain the interior structure and geologic evolution of the red planet. The mission will enable us to decipher Mars' ongoing geodynamic activity, the structure of its lithosphere, as well as to probe for subsurface water reservoirs and to characterise the temporal dynamics of the atmosphere. MaQuIS follows a well-crafted mission scenario, inherited from the successful Gravity Recovery and Climate Experiment (GRACE) and Gravity Recovery and Interior Laboratory (GRAIL) missions deployed around Earth and the Moon, respectively. Compared to its predecessors, MaQuIS will include state-of-the-art quantum sensing technologies to improve the detection of fine variations in Mars' gravitational field and maximize the mission's scientific return. MaQuIS will contribute to the following main science objectives:

1. Uncover the evolution of Mars by studying interior dynamics, detailed structure and composition of the planet's lithosphere and deep mantle.

2. Capture Mars' climate history by monitoring the density of the planet's upper atmosphere and uncover the monthly, seasonal, and long-term changes.

3. Explore potential scenarios for the fate and sequestration pathways of Mars' surface liquid water.

These primary mission goals will have profound and long-lasting impacts on the study of Mars, shedding new light on Mars' geologic evolution and ongoing interior and atmosphere activity.

Activities are ongoing to increase the TRL-level of the instrument technology. Both improved systems for the main instruments are being developed. LRI link acquisition is being developed to improve the initialisation phases. Also, other laser frequencies are being looked at to be able to share laser sources for the LRI and CAI accelerometers. Improvements of the internal layout of the CAI instrumentation help in detecting bottlenecks in the new technology. Mission design studies are improving the understanding of the impact of certain orbit choices to the precission and coverage of the observations. Finally we will also present some preliminary CFD studies performed on the whole mission design, highlighting that the mission is technological feasible and will provide excellent data to improve our understanding of Mars. ... Read more

The renewed interest in lunar exploration and the development of future lunar communication and navigation services highlight the need for a precise, stable, and interoperable geodetic and timing infrastructure on the Moon. NovaMoon, proposed as a scientific and navigation payload for ESA’s Argonaut lander, is designed as a lunar-based local differential, geodetic, and timing station supporting both the operational needs of the Moon’s south polar region and a broad range of scientific investigations. The payload integrates a lunar laser retroreflector, a Very Long Baseline Interferometry transmitter, a receiver for lunar navigation signals compatible with LunaNet standards, high-stability atomic clocks, and direct-to-Earth radio links, making it the first lunar station to co-locate multiple ranging, tracking, and timing techniques.

NovaMoon will enable sub-metre- to decimetre-level positioning in the south polar region, provide local differential corrections for lunar navigation users, and ensure an accurate and stable realisation of position and time for the lander. Through preliminary simulation studies, we show that the resulting multi-technique dataset significantly improves the lunar reference frame, the determination of lunar orientation and ephemerides, and the estimation of interior parameters such as tidal response, core properties, and dissipation.

NovaMoon will also provide the first long-duration physical realisation of a lunar time reference, enabling precise timing for lunar navigation users and contributing to the establishment of a future lunar timescale.

Beyond its primary goals, NovaMoon supports improved cartography, more accurate geolocation of surface features, and higher-resolution topography in the south polar region, contributing to safer and more precise landing and surface operations. Its multi-technique measurements also open new opportunities for fundamental physics, including enhanced tests of the Equivalence Principle, improved constraints on relativistic gravity, and increased sensitivity to deviations from classical gravitational models or potential variations in fundamental constants. ... Read more

CubeSats, particularly those developed by student teams, often face extremely short development cycles, leading to limited attention to detailed thermal analysis. Accurate thermal modelling is important to ensure the reliable operation of on-board systems. However, professional thermal modelling tools such as ESATAN are complex, and correlation-based validation methods are time-consuming and resource-intensive. Consequently, small satellite teams frequently rely on simplified models with large error margins in temperature predictions.
This paper presents the design of experiments to determine thermo-optical properties for materials commonly used in student CubeSat construction. Additionally, a database is presented that highlights the thermal conductivity, solar absorptivity, heat capacity and infra-red emissivity, obtained from the experiments, for printed circuit boards (PCBs), solar cells and solar panels. Finally, a sensitivity analysis is performed to indicate the effect of the uncertainties in property values on the average battery temperature as it is a thermally critical component.
The design of experiments can be used by student teams to perform their own experiments and the properties obtained in this work can be used for their initial thermal design. This will allow student teams to make better estimates for the thermal budget of their CubeSat missions. ... Read more

As interest in lunar exploration grows, efficient and cost-effective navigation methods are becoming increasingly important. Traditionally, ground-based radiometric tracking has been the primary approach for spacecraft navigation, particularly for missions beyond Earth. In contrast, Satellite-to-Satellite Tracking (SST) enables onboard Orbit Determination (OD) without continuous ground support. This study focuses on optimizing SST periods for a cislunar satellite formation to improve autonomous navigation performance. The timing of tracking windows is critical, as selecting the most informative observation periods can significantly enhance OD accuracy and reduce station-keeping costs. Systematic measurement biases present additional challenges, making careful scheduling essential to mitigate their effects. To address this, we employ Particle Swarm Optimization (PSO) to determine effective tracking schedules while accounting for bias constraints. The results show that this approach yields near-optimal schedules that outperform uniform, evenly spaced observation strategies with respect to the objective function, defined as a weighted combination of OD error and station-keeping costs, even under non-optimal parameter settings. The optimized schedules are irregularly distributed over the mission timeline, reflecting adaptation to time-varying geometries and uncertainties. This approach improves autonomous navigation accuracy, reduces station-keeping costs, and supports the cost-effective design of cislunar satellite formations, thereby improving the feasibility of satellite operations beyond Earth. ... Read more

High-precision inter-satellite ranging is critical for formation flying, autonomous navigation, and scientific measurements in small-satellite missions. Laser communication terminals (LCTs) offer an opportunity to perform both data transfer and ranging, but their dual-use imposes stringent requirements on onboard clocks and timing electronics. This paper investigates the impact of clock-induced timing errors on two-way LCT-based ranging between CubeSats operating around the near-Earth asteroid 99942 Apophis. A methodology is developed to unify clock noise specifications provided in datasheets, generating realistic timing errors across microsecond-to-hour integration periods. Using high-fidelity orbital simulations, two orbital configurations—coplanar and non-coplanar—are analyzed to evaluate how relative satellite geometry influences the propagation of clock errors into range measurements, orbit determination, and the estimation of Apophis’ gravitational parameter. Results demonstrate that inter-satellite links (ISLs) can reduce orbit determination errors along directions weakly constrained by Earth-based Doppler—from 1–3 m to 0.1–0.3 m in coplanar formations, and even further in non-coplanar formations—corresponding to improvements of one to two orders of magnitude. Subsystem-level noise, such as detector jitter and time tagging, can still limit achievable precision, even with high-performance clocks. The methodology provides a framework applicable to a broad range of small-satellite missions, guiding the selection of clocks, formation geometry, and system design to optimize both navigation performance and science return. ... Read more

Uncertainty in atmospheric density models and drag coefficient modelling contributes to orbit prediction errors for satellites in Low Earth Orbit (LEO).
It is of interest to better characterise the Gas-Surface Interactions (GSI) to improve drag coefficient modelling, which is, however, hindered by a lack of dedicated in-orbit experiments. We propose a new experiment to estimate the energy accommodation coefficient of the Diffuse Reflection with Incomplete Accommodation (DRIA) GSI model. The experiment consists of two small satellites with Global Navigation Satellite Systems (GNSS) receivers and attitude determination systems to derive atmospheric density observations from the positioning data. The experiment has two key features. The first is the satellites' close along-track formation flying, such that they should observe the same atmospheric density with a slight delay due to their along-track separation. Second, the satellites have controllable panels to modify their drag coefficients' response to GSI substantially. Hence, the satellites' atmospheric density observations will agree only when the DRIA model's energy accommodation coefficient is selected correctly. We demonstrate by simulation that the energy accommodation coefficient can be estimated at least once daily with a precision of 5-10% for satellites with decimeter-accuracy GNSS positioning. Given that GNSS receivers and attitude determination systems are common for small satellites currently in LEO, we conclude that there are plenty of opportunities to utilise existing data for the proposed experiment. Valuable byproducts would be atmospheric density observations that are relatively free of systematic errors. ... Read more

Delfi-PQ is a pioneering 3P PocketQube developed at Delft University of Technology, measuring 50x50x178 mm and weighing 545 g. Launched on January 13th 2022, it remained operational until its deorbit in January 2024, demonstrating nearly two years of sustained in-orbit functionality. Its architecture features a standardized core that supports reusable hardware and software across multiple subsystems, while an innovative structural design maximizes the limited internal volume. This paper presents results in orbit, the lesson learnt and a detailed hardware development cost analysis of a 3P PocketQube. Cost containment was a central mission objective. Using commercial off-the-shelf components, modular subsystem design, and iterative manufacturing, the Delfi-PQ team maintained tight budget control. Multiple hardware revisions allowed lessons learnt at each stage to be quickly integrated back into the design cycle. A detailed cost breakdown shows that a standardized core can substantially reduce non-recurring engineering expenses, making advanced pico-satellite development feasible within academic constraints. During its mission, Delfi-PQ encountered substantial thermal swings (up to 75◦C), yet consistently maintained full functionality. Although some limitations in battery protection arose from specific design choices, the paper documents which components performed reliably in space and how others deteriorated over time, offering critical guidance for future teams. In addition, the inclusion of a laser reflector payload designed to enhance tracking accuracy| and the structural innovations required to optimize space usage are discussed. A global network of amateur radio operators, together with the ground station in Delft, regularly received telemetry throughout the mission. This support was vital for tracking spacecraft health, investigating anomalies, and refining subsystem performance: the extended reliability of Delfi-PQ underscores the value of cost-conscious engineering, modular architectures, and strategic community partnerships to extend the service life of the mission. In summary, Delfi-PQ demonstrates that a lean yet robust satellite design based on modular principles, iterative development, and close collaboration| can reliably operate over extended mission durations. By presenting a full cost breakdown and comprehensive mission results, this paper offers practical insights for institutions aiming to deploy similarly innovative, affordable PocketQubes for advanced research and education. ... Read more

The drag coefficient C_D of a satellite is an important input for predicting satellite orbits in low Earth orbit, but determining C_D is difficult due to limited knowledge of Gas-Surface Interactions (GSI), leading to orbit prediction errors and increased collision risk. We propose an experiment that leverages the concept of differential drag to gain more insight into GSI, as differential drag causes a varying frontal area and C_D while other conditions stay the same, allowing us to estimate GSI parameters using orbit determination. Both analytical and numerical methods to obtain C_D and their sensitivity to GSI parameters are discussed, and these methods are then used to determine the optimal maneuvers for the experiment. As a case study, simulations are shown of a planned experiment using the BRIK-II satellite of the Royal Netherlands Air Force. It is expected that this method can be used to obtain more knowledge on GSI modelling, as well as give satellite operators a method to estimate C_D of a satellite with less bias than conventional methods. ... Read more

With the rapid growth of operational satellites and debris in congested areas, such as Low Earth Orbit, moving in the traffic is becoming key also due to new regulations potentially coming into play. This paper presents a selection of current guidelines that can play a major role in small satellite mission design and presents the Delfi-Twin mission, conceived to demonstrate Space Traffic Management capabilities. The mission s made by two small satellites which will operate as a formation using differential drag as control strategy. On-board orbit determination will be employed to speed-up the availability of high-accuracy ephemeris and improve their dissemination to other operators. Miniaturized commercial receivers have been evaluated in an emulated orbital scenario to assess the performances of future on-board orbit determination system, providing some insights on existing problems related to commercial receivers not designed for operating in space. ... Read more

The Da Vinci Satellite is a 2U CubeSatellite that is being developed with the goal to inspire and enthuse the youth to learn more about technology and space travel. The team at Delft University of Technology consists of over 80 Bachelor and Master students from disciplines such as Aerospace Engineering, Computer Science, Electrical Engineering and Applied Physics. There are also multiple Precision Engineers part of the team, that have joined from the Leiden Instrumenten Maker School (LIS) in the Netherlands. Through working on the satellite and educational modules, the multidisciplinary team focuses on demystifying space and making it a fun and engaging subject for children in primary schools and high schools. That is why the satellite harbours two novel custom-made payloads on board; the Dice Payload and the BitFlip Payload.

The Dice Payload consists of a small chamber with five small aluminium dice of different colours, which will be used by primary school children. In collaboration with the LIS, a special mechanism has been designed to ‘roll the dice’ in microgravity and clamp them such that a picture of the numbers can be taken with the Earth as a backdrop. After the design, manufacturing, and assembly of the parts, the payload underwent a series of tests. These tests have included multiple 0g flight tests and a vibration test. Through the extensive testing, there have been iterative design changes to improve the payload’s overall performance and design.

The second payload of the Da Vinci Satellite is the BitFlip Payload. This novel payload recently has been tested in a proton accelerator facility at the Paul Scherrer Institute. This subsystem is a stack of PCB’s with SRAM that has been designed for high school students. High school students can send a picture of themselves to the satellite where the data will be stored on the SRAMs. Because of the radiation environment in LEO and the susceptibility of the memory, bitflips will occur. These changes in the information from a 1 to a 0 (or the other way around), will result in the information of the picture being changed. When the picture has been compressed using a compression algorithm such as GIF, JPEG, or PNG interesting effects can occur. Once the student will receive the altered picture, they will be able to compare it with the original and learn about space, radiation, compression algorithms, and electronics. ... Read more

The Delft University of Technology has been working on Delfi–PQ, a 3P PocketQube developed by Aerospace Engineering students during their education. The satellite, while being only 50x50x178 mm and having a mass of 545 g, shares the same problems and requirements as larger satellites. Delfi–PQ was launched on January 13th, 2022, and stayed operational till it decayed on January 9th, 2024. This paper presents the design concept, development, and cost of Delfi–PQ to help other teams in their development. This paper will provide a detailed overview of the hardware cost of Delfi–PQ. This cost breakdown will be from multiple angles; system costs, components, structural pieces, and the cost of a specific function in a subsystem. Such a detailed breakdown can be used for future satellite cost modeling and create a foundation for other institutions for their satellite projects. ... Read more

In recent years, the trend towards satellite miniaturization has led to a considerable rise in picosatellite missions in Low Earth Orbit (LEO). Due to their size, identifying and tracking small objects poses significant challenges. While the detectability of individual picosatellites has been proven, the potential implications of clusters flying in formation remain unexplored. Therefore, the Delft University of Technology is starting a pioneering mission involving multiple picosatellites to improve Space Situational Awareness (SSA) by demonstrating the capabilities and limits of both inspace and ground-based tracking means. This paper outlines a high-level mission analysis investigating the feasibility of this formation-flying mission: in the proposed model, the autonomy of each satellite is enhanced by integrating a Global Navigation Satellite System (GNSS) receiver, which enables independent orbital determination and facilitates the validation of satellite position data against other tracking systems. The mission concept involves deploying a cluster of two identical 3P PocketQubes, launched as a single spacecraft into a near-circular orbit. Following deployment, they will be separated using springs, considering factors such as relative velocity, direction, and angle to carefully study the release process. Additionally, their relative distance is controlled using differential drag, i.e. adjusting the satellite drag area by deploying solar panels at varying angles. Through the integrated use of STK and MATLAB, two mission control sequences are defined: the former, characterized by satellite propagation stopping conditions based solely on relative distance, and the latter, in which they are based on both relative distance and relative velocity. Their comparison reveals the latter as the most effective strategy: despite the challenge of controlling satellite distance during close passes (conjunctions), the optimal sequence prioritizes maximizing time in close proximity. This approach reduces the average relative velocity and minimizes the duration of the high drag configuration, resulting in a significant extension of the mission lifetime. The simulations, along with a power budget, support the definition of both mission and GNSS receiver payload requirements. Finally, a suitable candidate is selected from among miniaturized GNSS space receivers and tested through multiple hardware-in-the-loop simulations, using a GNSS signal simulator. These simulations aim at verifying the accuracy of receiver positioning measurements and assessing power consumption. The results of this paper represent the cornerstone of a disruptive mission, providing insights into the future development of satellite control optimization strategies to minimize collision risk. Furthermore, the remarkable payload test results, while reliable, underscore the need to improve testing systems to reduce position errors and achieve higher tracking accuracy for LEO picosatellites equipped with GNSS receivers. ... Read more

The 16U4SBSP mission concept is based on using a swarm of CubeSats to perform a scaled demonstration of Space-Based Solar Power (SBSP) from Earth orbit. In this demonstration mission, seven identical spacecraft of 16U format are used to provide wireless energy in the kW-scale using Radio-Frequency (RF) Wireless Power Transfer (WPT), and the spacecraft in the swarm are designed to be suitable to both space-to-ground or space-to-space WPT applications. The main objective of the mission is to validate the general concept of providing SBSP using a swarm of satellites instead of a monolithic configuration, as well as some of the involved miniaturized technologies, in view of full-scale missions which could serve users in remote areas with low power requirements or support emergency operations in blackout zones affected by unpredicted hazards (e.g. natural disasters). More in general, the mission would represent a low-cost precursor towards MW-GW scale SBSP to supply clean and affordable energy from space to large areas on the Earth surface. A pre-Phase A study of the mission, funded by the European Space Agency (ESA) through the Sysnova campaign “Innovative Missions Concepts enabled by Swarms of CubeSats”, has led to encouraging results on the feasibility of the mission concept.

This paper presents in detail the final outcome of the pre-Phase A design effort for the 16U4SBSP spacecraft. The trade-off studies conducted to select all sub-systems and components are presented and their final outcomes detailed and justified, together with the technical budgets and the main areas of attention for the spacecraft design. Particularly critical for the success of the mission are the choices related to: the power transmission payload (DC-RF converter, transmitting antenna and heat dissipation system); the ADCS subsystem and in particular the sensors required to provide sufficient accuracy in the knowledge of the 3-axis attitude (both absolute and relative to the other spacecraft in the swarm); the relative navigation system, based on inter-satellite link between the spacecraft in the swarm and on a beacon link to the receiving station on ground, for efficient beaming coordination; the main propulsion system for continuous formation flying control through the whole mission lifetime; the electric power system, based on orientable solar arrays by means of a SADA mechanism and a set of batteries with sufficient capacity for beaming the required amount of power while in eclipse conditions. ... Read more

Current monitoring systems to detect sporadic E use ground-based setups, ionosondes, and the network of GNSS satellites in order to assess the phenomenon of sporadic E. This paper aims to monitor sporadic E using a miniature space-based platform in an atypical way. The setup consists of multiple radio-amateur beacon systems aboard satellites, each having a specific modulation and transmission scheme. This Radio Amateur Beacon System for the Investigation of the Ionosphere (RABSII) is coupled to a GNSS receiver, revealing the location of the platform. Multiple beacon data streams are sequentially sent from a satellite platform towards the Earth. By receiving and comparing the Signal-to-Noise ratios of these streams using a dedicated ground-based radio-amateur network of receiving stations, the presence of sporadic E can be determined, and a location-based model can be built. The advantage of this miniaturized, low-power, low-cost instrument is its ability to be put on any satellite platform in the future in order to map sporadic E. ... Read more

The accurate measurement of inter-satellite distances is fundamental to the successful operation of distributed spacecraft missions, facilitating diverse applications ranging from scientific exploration to navigation and communication. This study comprehensively overviews applications requiring inter-satellite tracking by analyzing 44 multi-spacecraft missions. These missions are divided into seven categories based on their use of inter-satellite distance measurements. Each category necessitates varying levels of accuracy, prompting the utilization of distinct tracking methods. The analysis reveals that missions near Earth typically rely on Global Navigation Satellite Systems measurements, achieving millimeter-level accuracy, while lunar missions opt for radio ranging for centimeter-level accuracy. Inter-satellite Laser Ranging Interferometry emerges as the preferred method for missions demanding exceptionally high accuracy (nanometer to picometer range), such as those dedicated to gravitational wave detection and gravimetry. Notably, the analysis identifies a burgeoning trend towards the adoption of Inter-satellite Laser Transponder Ranging, capable of achieving sub-millimeter accuracy. Furthermore, this work proposes a novel concept: integrating inter-satellite ranging with Laser Communication Terminal (LCTs), either to substitute for existing tracking methods or to enhance measurement accuracy within established frameworks. However, its full potential rests upon the successful adaptation of existing LCTs for ranging functionality without compromising data rates. Future research will play a critical role in quantifying achievable ranging performance by characterizing systematic errors within LCTs. ... Read more

The 16U4SBSP mission concept is based on using a swarm of CubeSats to perform a scaled demonstration of SpaceBased Solar Power (SBSP) from Earth orbit. In this demonstration mission, seven identical spacecraft of 16U format are used to provide wireless energy in the kW-scale using Radio-Frequency (RF) Wireless Power Transfer (WPT), and the spacecraft in the swarm are designed to be suitable to both space-to-ground or space-to-space WPT applications. The main objective of the mission is to validate the general concept of providing SBSP using a swarm of satellites instead of a monolithic configuration, as well as some of the involved miniaturized technologies, in view of full-scale missions which could serve users in remote areas with low power requirements or support emergency operations in blackout zones affected by unpredicted hazards (e.g. natural disasters). More in general, the mission would represent a low-cost precursor towards MW-GW scale SBSP to supply clean and affordable energy from space to large areas on the Earth surface. A pre-Phase A study of the mission, funded by the European Space Agency (ESA) through the Sysnova campaign “Innovative Missions Concepts enabled by Swarms of CubeSats”, has led to encouraging results on the feasibility of the mission concept. This paper summarizes the main results of the 16U4SBSP pre-Phase A study, including the mission design and the possible way forward to the following steps in mission implementation (Phase A and later). A summary of the spacecraft system design and mission analysis is presented, as well as a short description of the mission CONOPS (concept of operations). Particular focus is given to the available options and objectives of the SBSP demonstration, and to the proposed solutions for RF power beaming, formation flying maintenance and end-of-life operations for compliance to the new ESA regulations on space debris mitigation. ... Read more

The need for higher data rates has transitioned the satellites towards laser communication, opening up new opportunities for inter-satellite distance measurements. The stringent requirements for space missions like gravimetry, formation flying, collision avoidance, and precise orbit determination require highly precise distance knowledge, which can be offered by lasers. The past and present missions depend on radio ranging and laser interferometers to achieve up to centimeter-order and picometer-order precision, respectively. However, these methods either require additional hardware or interfere with the communication data rates as the power available is shared between communication and ranging operations. Therefore, this research explores the potential of laser communication terminals in measuring the inter-satellite distance. Numerical simulations are performed to analyze the effect of the precision of inter-satellite distance measurements on atmospheric density estimation. The analysis shows that such range measurements can only improve atmospheric density estimates if the uncertainty in the drag coefficient can be reduced below the current range of 3-5%. ... Read more

The 16U4SBSP mission aims to demonstrate Space-Based Solar Power (SBSP) using a CubeSat (CS) swarm from Earth orbit. This mission employs seven 16U CSs to deliver 1 kW-scale wireless energy via Radio-Frequency (RF) beaming, adaptable for space-to-ground and space-to-space applications. The goal is to validate SBSP provision using a satellite swarm and to explore miniaturized technologies for future large-scale missions. A pre-Phase 0 study funded by the European Space Agency (ESA) through the Sysnova campaign has shown encouraging feasibility results. This paper presents a study on the formation flying and orbital dynamics of a CS mission, using a model that includes Earth’s gravitational perturbations, solar radiation pressure (SRP), atmospheric drag, and lunar and solar gravity. The swarm configuration consists of seven CSs, with one at the center and six in a hexagonal arrangement. The Concept of Operations (CONOPS) is divided into three phases: deployment and acquisition, maintenance, and disposal. CSs are deployed at 30-second intervals, followed by a one-day Launch and Early Orbit Phase (LEOP) for subsystem checks. A 1000-meter formation is initially established, then reduced to 100 meters for the first half of the mission and 10 meters for the second half, maintained by a bang-bang limit-cycle controller. A disposal strategy compliant with ESA’s Space Debris Mitigation Requirements is outlined. The analysis characterizes propellant consumption at various altitudes, proposes optimal initial conditions and launch dates, and performs a trade-off analysis, resulting in a detailed mission characterization and baseline definition. The work presented in the paper proves the feasibility of the 16U4SBSP mission, which would supply clean energy from space through wireless power transfer. ... Read more

In recent years, there has been a growing interest in lunar missions, particularly with the growing role of small satellites facilitated by piggyback launch opportunities. Typically, ground-based radiometric tracking is the workhorse to establish the necessary navigation solution in these missions, however, this could be expensive, while small satellites development is expected to be at low cost. To address this challenge, autonomous navigation presents a potential solution: this study explores the satellite-to-satellite tracking-based autonomous on-board orbit determination method for a satellite formation in cislunar space. Several factors affect the performance of orbit determination, and one critical aspect is the timing of tracking windows. Basically, it is crucial to determine when to collect the most useful observations to optimize the outcome of the navigation filter. In some cases, there might be operational constraints such as inter-satellite distance due to the limited onboard power for ranging. This study investigates particle swarm optimization-based satellite-to-satellite tracking window planning. The findings of this work demonstrate that particle swarm optimization offers a near-optimal solution for tracking windows, taking into account constraints arising from the spacecraft itself or from other design choices. In summary, particle swarm optimization provides near-optimal tracking windows by minimizing the overall orbit determination error. The results presented have the potential to enhance the design of satellite formations performing autonomous on-board orbit determination and contribute to cost- effective mission planning solutions. ... Read more