The Lunar Meteoroid Impact Observer (LUMIO) is a mission designed to observe, quantify, and characterize the impacts of meteoroids on the lunar far side and, therefore, complement in both space and time the observations currently taken from Earth. While Earth-based lunar observations are restricted by weather, geometric and illumination conditions, a Moon-based observation campaign can improve the detection rate of impact flashes and the general quality and reliability of the final scientific product. The mission has successfully completed the Phase A design, after successfully passing Phase 0 and an independent study in the ESA Concurrent Design Facility that has fully confirmed its feasibility. The LUMIO spacecraft is a 12U XL CubeSat with a mass of around 28 kg, released into Lunar orbit by a carrier spacecraft and capable of autonomously transferring from this initial parking orbit to its final destination, a halo orbit about the Earth–Moon L2 point from which permanent fulldisk observation of the Lunar far side can be performed. The mission objectives will be achieved thanks to the LUMIO-Cam, a custom-designed optical instrument capable of detecting light flashes in the visible spectrum, and an innovative on-board data processing system, capable of drastically reducing the amount of information that needs to be transmitted back to Earth. The camera is capable of generating 5TBd−1 of data, out of which only approximately 1MBd−1 will need to be transmitted to Earth, since impact identification will be performed autonomously onboard and only relevant information will be actually transmitted. This paper will present the current status of the mission, summarising the main results of the Phase A design and the way forward to the following steps in mission implementation (Phases B-C). The paper will include a summary of the spacecraft system design and mission analysis. Particular focus will be given to the mission operations aspects. @en

The Lunar Meteoroid Impact Observer (LUMIO) is a mission designed to observe, quantify, and characterize the meteoroid impacts by detecting their flashes on the lunar far side. Earth-based lunar observations are restricted by weather, geometric and illumination conditions, while a lunar orbiter can improve the detection rate of lunar meteoroid impact flashes, as it would allow for longer monitoring periods. This paper will focus on the communications and radio navigation system of the mission, designed for the ESA roadmap for lunar exploration. LUMIO has been designed to operate autonomously after deployment from a lunar mother spacecraft in a low inclination lunar orbit and to reach without human intervention his final destination orbit close to the Earth-Moon L2 point, where science can be carried out. Being the destination orbit always in view from Earth (despite a distance of 460000 - 480000 km), Direct-to-Earth communication was added to the mission as a mean to reduce risk and allow independent verification of several of the innovative technologies that would be demonstrated, first of all autonomous navigation. A detailed link budget analysis will be presented for all mission phases for both the link with the mother spacecraft in low lunar orbit and the link with Earth. Beside defining the achievable data transfer, we will focus also on evaluating the available ground stations to better evaluate mission cost with respect to science return. Radio-navigation performances will also be evaluated to estimate the position and relative velocity accuracy, given also the limited performances available for the on-board navigation transponder. This will help also better defining the on-board autonomous navigation system, constraining the total error budget. Further strategies, such as beacon tones, will be evaluated to lower the overall operational cost by employing continuous monitoring with a low performances ground station and, only when needed, perform high speed downlink using a deep-space class ground station. This strategy is considered of extreme importance, especially for small missions, to allow opportunistic operations on high gain antennas, given their very busy schedule. Keywords: LUMIO, CubeSat, Lunar, Radio, link @en

The Earth-Moon system is constantly bombarded by meteoroids of different size and impact speed. Observation of the impacts on the Moon can enable thorough characterization of the Lunar meteoroid flux, which is similar to that of the Earth. While Earth-based Lunar observations are restricted by weather, geometric and illumination conditions, a Lunar-based observation campaign can improve the detection rate and, when observing the Lunar far side, complement in both space and time the observations taken from Earth. The Lunar Meteoroid Impact Observer (LUMIO), one of the two winning concepts of the ESA SysNova Lunar CubeSats for Exploration challenge, is a mission designed to observe, quantify, and characterize the micro-meteoroid impacts on the Lunar far side. It is based on a 12U CubeSat that carries the LUMIO-Cam, a custom-designed optical instrument capable of detecting light flashes in the visible spectrum. The spacecraft is placed on a halo orbit about the Earth–Moon L2 point, where permanent full-disk observation of the Lunar far side can be performed with excellent quality, given the absence of Earth background noise. After passing Phase 0 and an independent feasibility study in the ESA Concurrent Design Facility, the mission has successfully completed its Phase A in March 2021. Although the Phase 0 design of the LUMIO spacecraft was assessed as feasible by the ESA CDF study, a number of critical issues were identified, which have been tackled by the Phase A design. The paper presents the outcome of this Phase A design effort for the LUMIO spacecraft. Particularly relevant changes or updates in the spacecraft design include: a consolidated design of the LUMIO-Cam, with longer baffle for straylight protection; a set of ADCS sensors and actuators with increased redundancy; a combination of Direct-to-Earth communication and inter-satellite link with a mothership in Lunar orbit; use of Earth ranging to complement and validate the current innovative autonomous navigation strategy based on optical observations of the Moon by means of the LUMIO-Cam; re-assessment of the COTS components selection for the power and propulsion systems. @en

The Lunar Meteoroid Impact Observer (LUMIO) is one of the four projects selected within ESA’s SysNova competition to develop a small satellite or scientific and technology demonstration purposes to be deployed by a mothership around the Moon. Themission utilizes a 12U form-factor CubeSat which carries the LUMIO-Cam, an optical instrument capable of detecting light flashes in the visible spectrum to continuously monitor and process the meteoroids impacts. In this chapter, we will describe the mission concept and focus on the performance of a novel navigation concept using Moon images taken as byproduct of the LUMIOCam operations. This new approach will considerably limit the operations burden on ground, aiming at autonomous orbit-attitude navigation and control. Furthermore, an efficient and autonomous strategy for collection, processing, categorization, and storage of payload data is also described to cope with the limited contact time and downlink bandwidth. Since all communications have to go via a lunar orbiter, all commands and telemetry/data will have to be forwarded to/from the mothership. This will prevent quasi-real-time operations and will be the first time for CubeSats as they have never flown without a direct link to Earth. This chapter was derived from a paper the authors delivered at the SpaceOps 2018 conference.@en

Stand-alone CubeSat missions to Mars that escape Earth and experience a deep-space cruise require robust primary propulsion systems for orbit manoeuvring and precise trajectory control. Combined chemical{electric propulsion systems enable a hybrid high-thrust{ low-thrust transfer from a high energy Earth orbit to Mars. High-thrust chemical propulsion is used for Earth escape and the low-thrust electric propulsion is used in deep-space cruise, ballisitic capture, and final circularization to an operational orbit about Mars. This work focuses on the performance and design characterization of an iodine-propelled electric propulsion system, concomitant with low-thrust trajectory optimization of the heliocentric transfer and ballistic capture at Mars for a 16U stand-alone CubeSat. A performance model of an inductively coupled miniature ion thruster is implemented to calculate thrust, speci_c impulse, and e_ciencies. A power-constrained low-thrust optimal control problem utilizing the thruster performance is solved to calculate the trajectory, ight time, _V , and the propellant consumption for time-optimal and fuel-optimal strategies. @en

The Lunar Meteoroid Impact Observer (LUMIO) is a mission designed to observe, quantify, and characterize the meteoroid impacts by detecting their flashes on the lunar farside. Earth-based lunar observations are restricted by weather, geometric, and illumination conditions, while a lunar orbiter can improve the detection rate of lunar meteoroid impact flashes, as it would allow for longer monitoring periods. This paper presents the scientific mission of LUMIO, designed for the ESA SysNova LUCE competition, that resulted as the ex-aequo winner in the competition. LUMIO, a 12U CubeSat weighting approximately 20 kg, is expected to be deployed into a quasi-polar selenocentric orbit by a mother spacecraft, which also acts as communication relay. From a lunar high-inclination orbit, LUMIO will autonomously determine its trajectory to reach the Moon–Earth L2 point and perform the cruise phase. From the operative orbit, LUMIO will observe the lunar farside. When the lunar disk illumination is less than 50%, LUMIO autonomously performs the scientific task without direct coordination from Earth. Fully autonomous operations will include science, communication, and navigation. A similar concept can be re-used for a wide variety of future missions. The scientific mission will also be possible thanks to an innovative on-board data processing system, capable of drastically reducing the information to transmit to Earth. The camera, designed to capture the flashes and measure their intensity is, in fact, capable of generating 2.6 TB/day while only approximately 1 MB/day will need to be transmitted to Earth. Impact identification will be autonomous and only relevant information will be transmitted. A study at the ESA/ESTEC concurrent design facility has shown evidence of feasibility and that a CubeSat orbiting along an Earth–Moon L2 quasi-halo orbit is expected to bring a relevant contribution to lunar science and innovation to space exploration.@en

The Lunar Meteoroid Impact Observer (LUMIO), one of the two winning concepts of the SysNova Lunar CubeSats for Exploration call by ESA, is a mission designed to observe, quantify, and characterize the meteoroid impacts on the Lunar far side by detecting the flashes generated by the impact. While Earth-based Lunar observations are restricted by weather, geometric and illumination conditions, a Lunar-based observation campaign can improve the detection rate and, when observing the Lunar far side, complement in both space and time the observations taken from Earth. The mission, which has successfully completed its Phase A in March 2021, is based on a 12U CubeSat that carries the LUMIO-Cam, a custom-designed optical instrument capable of detecting light flashes in the visible spectrum. The spacecraft is placed on a halo orbit about the Earth–Moon L2 point, where permanent full-disk observation of the Lunar far side can be performed with excellent quality, given the absence of background noise due to the Earth. The propulsion system is one of the most crucial design choices for the LUMIO spacecraft. It accomplishes various functions: orbital transfer from the initial Lunar orbit to the final halo orbit around L2, station keeping, reaction wheel desaturation, end of life disposal manoeuvres. The total required Delta-V budget for orbital transfer and station keeping is 201.8 m/s, plus an additional total impulse for reaction control tasks ranging from 110 Ns to 170 Ns, depending on the type of reaction control system that is selected. This paper presents a detailed summary of the phase A selection and design of the LUMIO propulsion system, based on the full list of requirements generated by the mission analysis. The main challenges of this process and the way they have been tackled are presented and discussed, including: use of two separate systems as opposed to an integrate one for main propulsion and reaction control tasks; availability of sufficiently reliable European propulsion options, to reduce the general mission costs; feasibility of replacing a chemical/cold gas system with electric propulsion; possible need for custom changes to the design of the selected COTS option (e.g. due to tank sizing). @en

The Earth-Moon system is constantly bombarded by meteoroids of different size and impact speed. Observation of the impacts on the Moon can enable thorough characterization of the Lunar meteoroid flux, which is similar to that of the Earth. While Earth-based Lunar observations are restricted by weather, geometric and illumination conditions, a Lunar-based observation campaign can improve the detection rate and, when observing the Lunar far side, complement in both space and time the observations taken from Earth. The Lunar Meteoroid Impact Observer (LUMIO), one of the two winning concepts of the ESA SysNova Lunar CubeSats for Exploration challenge, is a mission designed to observe, quantify, and characterize the micro-meteoroid impacts on the Lunar far side. It is based on a 12U CubeSat that carries the LUMIO-Cam, a custom-designed optical instrument capable of detecting light flashes in the visible spectrum. The spacecraft is placed on a halo orbit about the Earth–Moon L2 point, where permanent full-disk observation of the Lunar far side can be performed with excellent quality, given the absence of Earth background noise. After passing Phase 0 and an independent feasibility study in the ESA Concurrent Design Facility, the mission has successfully completed its Phase A in March 2021. Although the Phase 0 design of the LUMIO spacecraft was assessed as feasible by the ESA CDF study, a number of critical issues were identified, which have been tackled by the Phase A design. The paper presents the outcome of this Phase A design effort for the LUMIO spacecraft. Particularly relevant changes or updates in the spacecraft design include: a consolidated design of the LUMIO-Cam, with longer baffle for straylight protection; a set of ADCS sensors and actuators with increased redundancy; a combination of Direct-to-Earth communication and inter-satellite link with a mothership in Lunar orbit; use of Earth ranging to complement and validate the current innovative autonomous navigation strategy based on optical observations of the Moon by means of the LUMIO-Cam; re-assessment of the COTS components selection for the power and propulsion systems. @en

Interplanetary CubeSats enable universities and smallspacecraft- consortia to pursue low-cost, high-risk and highgain Solar System Exploration missions, especially Mars; for which cost-effective, reliable, and flexible space systems need to be developed. Missions to Mars can be achieved through a) in-situ deployment by a mothership and b) highly flexible stand-alone CubeSats on deep-space cruise. The current work focuses on sizing and establishing critical design parameters for dual chemical-electric propulsion systems that shall enable a stand-alone 16U CubeSat mission on a hybrid high-thrust & low-thrust trajectory. High thrust is used to escape Earth whereas low-thrust is used in autonomous deep-space cruise, achieving ballistic capture, and emplacement on an areosynchronous orbit at Mars. Chemical propulsion characterisation is based on V requirement and a heuristic optimisation of thrust, specific impulse and burn time while balancing transfer time and propellant mass. Limitations are set to minimise destabilising momentum. Electric propulsion characterisation is based on the V, power consumption, and trajectory requirements for fueloptimal and time-optimal strategies. The sizes amount to 16% and 21% of the assumed total mass ( 30 kg) for chemical and electric systems, respectively. @en

The Lunar Meteoroid Impact Observer (LUMIO) is a CubeSat mission at the Earth-Moon Lagrangian point 2 (L2) designed to observe, quantify, and characterize the meteoroid impacts by detecting their flashes on the Lunar farside. LUMIO can be deployed as one of the payloads in the NASA Commercial Lunar Payload System or from Artemis-2 mission to a low Lunar orbit and to demonstrate autonomous navigation capabilities to reach its operational orbit around the Earth-Moon L2. From there, its scientific mission to map and investigate the spatial and temporal characteristics of meteoroids impacting the Lunar surface will start and is expected to last for one year. LUMIO is a 12U CubeSat including a dedicated camera to monitor impact flashes in the visible and near-infrared spectrum, and also allows estimating the impact of temperature and energy. Optical navigation using the payload camera will also demonstrate increased on-board autonomy and drastically reduced mission costs. Navigation validation will be carried out using standard ground-based radiometric techniques enabled by a miniaturized X-band coherent transponder on-board. LUMIO can also use an inter-satellite link for telemetry and control via a commercial Lunar data relay system, providing a redundant communication system and lowering the need for high-gain ground stations for routine operations. The satellite bus derives from a commercial version designed for Low Earth Orbit and it will feature several improvements to operate in the Lunar environment, including a more advanced thermal control and radiation shielding. Commercial Off-The-Shelf systems will require a radiation screening and this will contribute to maintain the mission budget low and aim at a launch date in 2024.@en

The LUnar Meteoroid Impacts Observer (LUMIO) is a CubeSat mission to a halo orbit at Earth–Moon L2 that shall observe, quantify, and characterize meteoroid impacts on the Lunar farside, by detecting their flashes. In this way, LUMIO is expected to significantly contribute to Lunar Situational Awareness and to the current knowledge on the evolution of meteoroids in the cislunar space. This will allow, ultimately, to achieve a better understanding of the origins of the Solar System, the composition of its planets and the possible hazards caused by impacts between the Earth and Near Earth Objects. LUMIO was one of the proposals submitted to the SysNova LUnar CubeSats for Exploration call by the European Space Agency. The mission was awarded ex-aequo winner of the challenge, and its scientific relevance and technical feasibility were confirmed by an independent study conducted by the ESA Concurrent Design Facility. The LUMIO Phase A study is currently ongoing and is scheduled for completion by the end of 2020. This paper, after providing a short overview of the scientific relevance of the mission, presents in detail the status of the current LUMIO Phase A study, including an overview of all spacecraft sub-systems and the evolution of their design from Phase 0 to Phase A. @en

The Lunar Meteoroid Impact Observer (LUMIO) is a CubeSat mission to observe, quantify, and characterize the 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 it is being considered by ESA for implementation in the near future. The mission utilizes a CubeSat that carries the LUMIO-Cam, an optical instrument capable of detecting light flashes in the visible spectrum. On-board data processing is implemented to minimize data downlink, while still retaining relevant scientific data. The mission implements a sophisticated orbit design: LUMIO is placed on a halo orbit about Earth–Moon L2 where permanent full-disk observation of the lunar farside is made. This prevents background noise due to Earthshine, and permits obtaining highquality scientific products. Innovative full-disk optical autonomous navigation is proposed, and its performances are assessed and quantified. The spacecraft is a 12U form-factor CubeSat, with 22 kg mass. Novel on-board micro-propulsion system for orbital control, de-tumbling, and reaction wheel desaturation is used. Steady solar power generation is achieved with solar array drive assembly and eclipse-free orbit. @en

Mars Atmospheric Radiation Imaging Orbiter (MARIO) is a 16U stand-alone CubeSat mission that shall escape Earth, perform autonomous deep-space cruise, achieve ballistic capture, and enter an operational orbit at Mars to perform thermal radiation imaging. This work focuses on the systems design of MARIO. The design of combined chemical-electric propulsion systems, comprising FLP-106 based green chemical monopropellant thruster and the iodine-fueled RF ion thruster, for hybrid high-thrust-low-thrust Earth-Mars transfer is presented. Reflectarrays along with high-gain antennas are utilised to establish long-distance low-bandwidth X-band communication link with the Earth. Electrical power system design is pursued to provide steady power to the system during the transfer and science operations phases. A novel autonomous navigation strategy is proposed which includes horizon-based optical navigation near target bodies and deep-space line-of-sight navigation for accurate state estimation for autonomous operations. Details regarding on-board processing, attitude determination, and thermal control are delineated. Feasible budgets for mass and communications link are obtained. The structural composition of MARIO is detailed.@en

Stand-alone interplanetary CubeSats to Mars require primary propulsion systems for orbit manoeuvring and trajectory control. The context is a 30 kg 16U Interplanetary CubeSat mission on a hybrid high-thrust & low-thrusttrajectory utilising a Dual Chemical-Electric Propulsion System to achieve Earth escape (high-thrust) and perform autonomous deep-space cruise (low-thrust) to Mars. Mission analysis is performed to estimate the required V( 445m=s) for Earth escape and Mars circularisation, and calculate the required thrusts and burn durations while minimising gravity losses, Van Allen belt crossings, and irrecoverable destabilisation. Design of an ADN-based monopropellant thruster and an Ethanol-H2O2 based bipropellant thruster are performed and the critical design details regarding propellant characteristics, system sizes, operating pressures, material selection and geometry of feed systems, thrust chambers, and nozzles are delineated. Performances analysis of the monopropellant thruster yields a maximum thrust of 3.18 N (two thrusters with 1.54 N each) and an Isp = 259.7 s with nozzle area ratio of 100.Similarly, the bipropellant thruster yields a thrust of 2.91 N and an Isp = 303.15 s. The overall mass and volume of the monopropellant system are 5.6 kg (18.7%) and 7U, respectively. The bipropellant system weighs 4.85 kg (16.17%)while occupying 6.5U space.@en

Stand-alone interplanetary CubeSats to Mars require primary propulsion systems for orbit manoeuvring and trajectory control. The context is a 30 kg 16U Interplanetary CubeSat mission on a hybrid high-thrust & low-thrusttrajectory utilising a Dual Chemical-Electric Propulsion System to achieve Earth escape (high-thrust) and perform autonomous deep-space cruise (low-thrust) to Mars. Mission analysis is performed to estimate the required V( 445m=s) for Earth escape and Mars circularisation, and calculate the required thrusts and burn durations while minimising gravity losses, Van Allen belt crossings, and irrecoverable destabilisation. Design of an ADN-based monopropellant thruster and an Ethanol-H2O2 based bipropellant thruster are performed and the critical design details regarding propellant characteristics, system sizes, operating pressures, material selection and geometry of feed systems, thrust chambers, and nozzles are delineated. Performances analysis of the monopropellant thruster yields a maximum thrust of 3.18 N (two thrusters with 1.54 N each) and an Isp = 259.7 s with nozzle area ratio of 100.Similarly, the bipropellant thruster yields a thrust of 2.91 N and an Isp = 303.15 s. The overall mass and volume of the monopropellant system are 5.6 kg (18.7%) and 7U, respectively. The bipropellant system weighs 4.85 kg (16.17%)while occupying 6.5U space.@en