The Earth–Moon system is constantly being bombarded by a significant number of meteoroids with different sizes and velocities. Observation of the lunar surface impacts will enable characterization of the lunar meteoroid flux, which is similar to that of the Earth, and provide more detailed information on meteoroid size, velocity, temporal and spatial distribution. The Lunar Meteoroid Impacts Observer (LUMIO) is a CubeSat mission at Earth–Moon L2 to observe, quantify, and characterise these meteoroid impacts by detecting their flashes on the lunar farside. LUMIO is one of the two winners of ESA’s LUCE (Lunar CubeSat for Exploration) SysNova competition, and as such is being considered by ESA for implementation in the near future. This paper will present the design of the LUMIO spacecraft that will host the payload to capture the meteoroid flashes. Key system specifications, trade-offs and consequent design iterations are presented. The final design yields a feasible spacecraft budget and a configuration that enables the LUMIO mission to be realized by 2023. The spacecraft is a 12U form-factor CubeSat, with a mass of less than 22 kg. A zero-redundancy and COTS based approach has been adopted for the spacecraft design. A strong emphasis has been placed on realizing high onboard autonomy. A novel and autonomous navigation strategy that uses optical observations of the Earth and the Moon is proposed for navigation around the Moon and beyond. The payload and navigation are the key drivers of the pointing requirements. Pointing requirements are achieved through reaction wheels, IMUs, star trackers, and fine sun sensors. A hybrid micro-propulsion system is included for orbital control, de-tumbling, and reaction wheel desaturation. Steady solar power availability is ensured with a one-axis solar array drive assembly in combination with an innovative attitude algorithm. Communication with Earth is through the Lunar Orbiter with a low-bandwidth UHF link, which places high constraints on the data throughput. An onboard payload data processor has been designed that compresses the science data to a fraction of the raw data with no loss of information. The paper will conclude with the key findings of a concurrent design review of the LUMIO spacecraft design that was performed at ESA/ESTEC’s Concurrent Design Facility (CDF). The major design changes are outlined along with a summary and discussion of the iterated design.

Testing micro-propulsion systems is often a hard and challenging phase in the characterisation process of similar technologies, which are very sensitive to environmental noise and errors due to the human operator. At the Department of Space Engineering of the Delft University of Technology, a thrust bench of the hanging pendulum type is used to assess the performance of the in-house developed micro-resistojets. In order to reduce the influence of external factors and limit the influence of the operator during the testing phase, a calibration process that uses an electromagnetic actuator to find the relation between the pendulum displacement measured by a capacitive sensor and a known exciting force has been developed. The found relations is then used to reconstruct the variation of the thrust over time. However, the numerous wires connected to hardware on the pendulum represents a disturbing effect and seems to affect the results of the measured thrust. This work presents an upgrade version of the pendulum which aims to reduce the unwanted and unpredictable disturbing effects of the wirings through a wireless Bluetooth connection system. Besides that, a new analysis model has been developed to assess the performance of the micro-thrusters, which can be used as a comparison to the calibration method mentioned above. A series of tests has been completed to validate the model. The configuration of the pendulum used in the testing phase has been optimised with respect to the position of the counter mass and displacement sensor position on the thrust stand. The results show an unexpected apparent shift of the pendulum centre of mass. This causes the model to have a higher level of inaccuracy. Further analyses are need in order to understand the causes of this phenomenon. However, it has been possible to located the apparent shift within a specific range. The model has shown promising results, but more tests are needed in order to precisely determine its inaccuracy, mainly due to this unexpected behaviour of the shift of centre of mass.