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This paper presents an experimental activity aimed at assessing performance of techniques for inertia and attitude parameters estimation of an uncooperative but known space target. The adopted experimental set-up includes a scaled-down 3D printed satellite mock-up, a spherical air bearing and a low-cost solid-state LIDAR. The experimental facility also comprises a motion capture system to obtain a benchmark of the pose (position and attitude) parameters and an ad-hoc designed passive balancing system to keep the centre of mass as close as possible to the centre of rotation. The LIDAR-based 3D point clouds, collected while the target rotates on the spherical air-bearing to reproduce the rotational dynamics of an almost-free rigid body, are processed to obtain pose and angular velocity estimate. Those data are used to determine the inertia properties of the target by solving a linear system based on the integral form of Euler equations. Performance and robustness of the algorithm for attitude and inertia properties estimation are assessed considering both the inertia benchmark provided by a high-fidelity CAD model of the target and the pose solution obtained from the motion tracking system and its extrinsic calibration with respect to the LIDAR.

This paper presents an innovative multi-sensor relative navigation module conceived to enable close-proximity operations for on-orbit servicing of small satellites. The module is composed of a Near-Infrared Laser Range Finder, acting both as range measurer and illuminator, and a monocular camera able to detect a set of reflecting fiducial markers installed on the target for pose estimation. Sensor fusion is performed in several points of the proposed processing pipeline, first following a cross-cueing logic in which the range aids the pose determination process, and later through the integration of both measurements into a Multiplicative Extended Kalman Filter for relative state estimation. The entire relative navigation architecture is first tested by numerically reproducing a close-range rendezvous trajectory of a chaser spacecraft moving toward the target, and using the open-source software Blender for synthetic image generation. Simulations are aimed at determining nominal relative state estimation accuracy (also considering variable sensors' acquisition rates) as well as performance under non-nominal conditions (e.g., due to a temporary loss of measurements). Focusing on the image processing and pose estimation pipeline, an in-depth analysis of the computational efficiency is then carried out by running the proposed algorithms on an embedded processing unit (i.e., the Raspberry Pi 4 Model B) using both synthetic data and real images collected within a dedicated experimental testbed. Numerical and experimental results demonstrate capability to attain pose and relative state estimates in line with accuracy requirements to ensure autonomous and safe close-proximity operations, e.g., up to sub-cm and sub-degree error levels in relative position and attitude respectively. In addition, the algorithm's computational runtime has shown to be compatible with real-time implementation at an acquisition frequency of 2 Hz.

Given the increase of mental health problems in youth, focusing on the promotion of psychological well-being is essential. Among the variables recognized as linked to children’s psychological well-being, trait emotional intelligence, emotional self-efficacy and coping seem to be crucial, whereas the role played by intelligence is still controversial. In the present study, we explored the combined effects of these variables, aimed at disentangling their unique contribution to psychological well-being of 74 children (41 males, mean age: 9.03 years). We administered verbal and reasoning tests as intelligence measures and self-report questionnaires to assess trait emotional intelligence, regulatory emotional self-efficacy, coping styles, psychological well-being. Correlations revealed two independent clusters of variables: a first cluster including intelligence indexes and a second cluster including psychological well-being, trait emotional intelligence, regulatory emotional self-efficacy and adaptive coping styles. Hierarchical regression analyses showed that only trait emotional intelligence and positive restructuring coping style significantly contributed to psychological well-being. This study highlights that, unlike general intelligence, trait emotional intelligence was associated to psychological well-being, whereas coping styles play a negligible role in explaining this relationship. These findings are valuable in identifying the most relevant factors for children’s adjustment and in enhancing emotion-related aspects in interventions for psychological well-being promotion.

Body image is a multifaceted construct that includes attitudinal and perceptual components, but its attention has mainly been focused on the facet of body dissatisfaction. The present longitudinal study extended the validation of a multifacet attitudinal questionnaire, the Body Uneasiness Test (BUT), against perceptions of body shape and weight. A convenient sample of adolescents took part in a 2-year unbalanced panel study (5 waves). The participants completed the BUT questionnaire and selected their perceived actual, ideal, and reflected body figures along the Contour Drawing Rating Scale; ideal/actual and ideal/normative body mass index discrepancies were also included. After replicating the expected five-factor structure of the BUT items, results from confirmatory factor analysis revealed that the five BUT scales loaded on an attitudinal dimension, whereas the perceived body figures and the discrepancy indices were on a perceptive domain. Such a two-domain structure of body image measures showed gender and seasonal (1-year) measurement invariance, whereas longitudinal 6-month and 18-month invariance partially failed. Overall, the present findings support the validity of the Body Uneasiness Test in adolescence, further demonstrating a preliminary multidimensional structure of body image onto which attitudinal and perceptual body image-related measures were projected.

The paper focuses on space system design aspects related to an end-to-end demonstration mission, aiming at showing the feasibility of a Formation Flying Synthetic Aperture Radar (FF-SAR) with microsatellite class platforms (~100 kg). Trajectory design approaches that can fulfil payload requirements are addressed to enable selected FF-SAR applications. The exploitation of these applications relies on suitable combinations of FF-SAR techniques like Signal-to-Noise Ratio (SNR) enhancement, High-Resolution Wide Swath (HRWS) SAR imaging, and Coherence Resolution Enhancement (CRE). In this framework, a cluster of 3 micro-satellites, working in X-band, flying in a Low Earth Orbit (LEO) close-formation, has been designed as a candidate end-to-end system demonstration mission. One satellite embarks a Transmitting-Receiving (Tx/Rx) radar, i.e. it is a monostatic SAR. The other two satellites are Receiving-only platforms. Critical design aspects related to spacecraft subsystems and formation-flying analysis are addressed to confirm the technical feasibility of the spaceborne distributed system implementing the FF-SAR principle.

Future Active Debris Removal missions will require an autonomous spacecraft (chaser) to safely monitor at close distance, and then approach and dispose an inactive artificial space object (target). Since these targets are uncooperative, meaning that they cannot provide any hint or help to the chaser navigation system, such operations require the target-chaser relative state and the target inertia parameters to be accurately estimated relying only on measurements from active or passive Electro-Optical sensors. In this framework, this paper proposes an original multi-step architecture for the estimation of the relative motion and inertia parameters of an uncooperative target during a close-range monitoring trajectory. In the first phase, LIDAR-based pose measurements and a smoothing approach are used to retrieve accurate, linearly independent estimates of the target angular velocity. These estimates are then used to compute the target's moments of inertia ratios solving a linear system based on the conservation equation for the angular momentum. Once the inertia parameters are accurately estimated, the LIDAR-based pose measurements are used to feed an Unscented Kalman Filter to determine the full relative state according to a loosely coupled configuration. The architecture foresees autonomous failure detection strategies to avoid divergence in the relative state estimation error caused by unavoidable, unfavorable target observation conditions occurring during the monitoring trajectory. Performance assessment is carried out through numerical simulations realistically reproducing close-range relative motion dynamics and LIDAR sensor operation, and considering targets characterized by highly variable size, shape, and orbital dynamics as test cases.

The purpose of the present study was to examine the efficacy of a short training programme (eight 1-hour sessions) aimed to promote Emotional Intelligence (EI) abilities in primary school on a set of outcomes related to affect, coping and psychological well-being. Sixty-eight preadolescents (10.68±.58 years) were randomly assigned to either the experimental condition (EI training) or the active control condition (pro-environmental training). ANOVAs and Bayesian analyses were performed on pre/post-training measures of ability and trait EI, positive/negative affect, regulatory emotional self-efficacy, coping styles, and psychological well-being. Results showed that only in the EI training condition emotional abilities significantly improved, whereas negative affect and the preference for distraction coping significantly diminished. Although the effects of the present EI training did not extend to the other measures, the findings suggest its effectiveness in improving preadolescents’ EI basic skills and some important adjustment variables. This study confirms the efficacy of short school-based programmes in enhancing EI abilities and highlights the importance of further investigating the training features required to extend its benefits also to psychological well-being. Implications for research and educational practices are discussed.

Habituation to novel stimuli has been associated with behavioural differences among individuals in numerous animal species. Because the habituation mechanisms depend on previous experiences with a stimulus, one would expect individuals to develop their habituation capacity based on the life experiences that also shape their behavioural traits. And indeed, in adult lizards, exploratory behaviour and body size correlates with habituation. However, here we show that the same factors correlate with habituation of domestic chicks reared under controlled laboratory conditions and tested in the first 3 days after hatching. This result indicates that the covariation between habituation, exploration, and body size does not necessarily depend on experience. Rather, it represents an innate association between exploratory behaviour and risk assessment, which may provide an immediate survival advantage to new-borns of this precocial avian species.

Spacecrafts continuously need for low cost and weight sensor easy to integrate in a plug-in approach and capable to improve platforms versatility while reducing integration time and complexity. This is particularly true for the new generation of small and micro satellites to be launched in constellation and formation. Controlling small satellites cooperation and protecting the space assets from debris are two important issues of current and future missions. The cost reduction and safety of space missions is a key issue for further expand European leadership in the Earth Observation and Communication sectors. The POLIFEMO (Panoramic Multifunctional Sensor for Small/Micro Satellite) is a unique solution for an integrated sensor capable to replace by one single unit the functions of Sun sensor, Earth sensor and Star tracker and, additionally, providing external situational awareness. POLIFEMO is based on an innovative lens with a very wide angle (with a hyper-hemispheric field of view) able to look at a field of view of 360 in azimuth (panoramic omnidirectional lens) and 270 in elevation (hyper-hemispheric capabilities), designed and patented by the Italian National Institute for Astrophysics (INAF). POLIFEMO, with that extremely high field of view and unique imaging detection capability, results in a small, low weight, low cost and reliable (no moving part, potentially failure point) space sensor. It is unique in the market of space sensors and suitable for many spaces and non-space missions (e.g., communication, weather, imaging, surveillance, deep space but also UAV/HAP). Progetti Speciali Italiani s.r.l., a SME active in developing microsatellite and space applications, has set up, during the phase 1 project, a very experienced team of engineering and commercial specialists for carrying on the proposed project. University of Napoli (Parthenope) is expert on developing satellites star trackers solutions. This paper reports a summary extracted from a more detailed BP (Doc: ECSME-PSI-POLIFEMO-BP-2016) which has been prepared within the EU-H2020 contract framework. The full BP is available on request.

This paper describes the design, characterization and preliminary testing of a relative navigation module based on electro-optical sensors and tailored for close-proximity operations with respect to passively cooperative targets of the CubeSat class. The proposed unit relies on a laser range finder with a relatively large beam divergence and a visual camera. The laser range finder operates in the near-infrared band and is exploited to both provide direct range measurements and actively illuminate the scene. The visual sensor and its optics are coherently chosen and allow obtaining full pose (i.e., relative position and attitude) measurements by processing the acquired target’s images. The pose estimation procedure is based on the detection and identification of a set of fiducial markers installed on the target surface and highly reflective in the near-infrared band. Experimental tests are carried out at components level to both characterise the laser range finder and preliminarily assess the performance of the proposed pose determination approach. The results show that the proposed approach is robust to a large number of outliers, produced by highly reflective insulation layers typically covering satellite surfaces. Also, in all the considered test cases pose estimates with pixel-level reprojection errors, corresponding to sub-millimetre accuracy, are obtained.

This paper presents the design of the receiving antenna of an upcoming formation-flying synthetic aperture radar (FF-SAR) based on the CubeSat standard and on a preexisting spaceborne SAR of opportunity. The receiving antenna operates at X-band and is compliant with the imaging modes of the FF-SAR, namely a stripmap mode for signal-To-noise ratio improvement (IM1) and a High-Resolution Wide-Swath mode for the monitoring of large areas (IM2). A large reflector has been designed to meet the high-gain requirement in IM1, while the wide coverage needed in IM2 is ensured by a reconfigurable patch array feed. Full-wave analysis shows that the designed receiving antenna achieves 37.42 dBi gain in IM1 and 12.1 degree half-power beamwidth in IM2.

Performing orbital insertion around Mars using aerocapture instead of a propulsive orbit insertion maneuver allows the saving of resources and/or the increase of the payload mass fraction. Aerocapture has never been employed to date because of the high uncertainties in the parameters from which it depends, mainly related to atmospheric density modeling and navigation errors. The purpose of this work is to investigate the feasibility of aerocapture at Mars with an innovative deployable drag device, whose aperture can be modulated in flight, and to assess the effects of the main uncertainties on the success of the maneuver. This paper starts with the presentation of a parametric bidimensional analysis of the effectiveness of aerocapture, for which a wide range of uncertainty levels in the atmospheric density and the ballistic coefficient are considered. Then, an application to a real mission scenario is carried out, including the error of the targeting maneuver performed at the limit of the sphere of influence of the planet. The analyses show the strong influence of the uncertainties in the atmospheric density and the ballistic coefficient, which significantly narrow the solution space and limit its continuity. However, viable solutions for aerocapture can still be identified, even in the worst conditions. This work has been supported by Khalifa University of Science and Technology’s internal grants FSU-2018-07 and CIRA-2018-85. J. Peláez and E. Fantino acknowledge also the support provided by the project entitled “Dynamical Analysis of Complex Interplanetary Missions,” with reference ESP2017-87271-P sponsored by Spanish Agencia Estatal de Investigación (AEI) of Ministerio de Economía, Industria y Competitividad (MINECO) and by European Fund of Regional Development (FEDER). The work was also supported by the internal grants of the Department of Engineering of the University of Naples.

This paper presents a strategy to adaptively select the field of view and the resolution of a scanning LIDAR in the frame of close-proximity operations with non-cooperative space targets. Specifically, the idea is to relate the selection of these operational parameters to the estimated target-chaser relative distance as well as to the size occupied by the target in the sensor field of view, with the goal to improve the performance of the relative navigation system. The proposed method is supported by a chaser attitude control strategy which allows keeping the sensor boresight axis always pointed towards the center of mass of the target. The performance achieved by the adoption of this strategy is evaluated by simulating two types of close-range trajectories in a numerical simulation environment which reproduces both the operation of a scanning LIDAR and the relative motion between two spacecraft.

This paper lies in the framework of mission scenarios, such as Active Debris Removal and On-Orbit Servicing, which require an active spacecraft (chaser) to orbit in close-proximity with respect to a space target. Specifically, these activities involve relative orbital maneuvers, such as monitoring, rendezvous and docking, in which the target-chaser distance ranges from a few tens of meters (depending on the target size) up to contact (in the case of docking). A critical challenge related to the realization of these maneuvers is the need to minimize the risk of collision, considering that the target is a non-cooperative object which may be characterized by uncontrolled rotational dynamics. This goal can be achieved by designing relative trajectories which satisfy specific constraints in terms of safety and stability, on one side, as well as by exploiting relative navigation technologies and algorithms which provide highly accurate estimates of the target-chaser relative motion parameters thus allowing to relax the control requirements. Both these aspects are addressed by this paper with focus on Geostationary Earth Orbits since they represent a particularly crowded orbital region in which the possibility to remove large debris and to extend the operative life of spacecraft, such as telecommunication ones, may have a significant scientific and economic benefit. Hence, an original method is presented to design safety ellipses for target monitoring around GEO targets, which, simultaneously, can provide optimal relative observation geometry for relative navigation (pose determination) using Electro-Optical sensors. The design approach is formulated in mean orbit parameters and it is based on a relative motion model relevant to two-satellite formations which includes the non-Keplerian perturbations due to secular Earth oblateness, as well as the possibility of considering targets moving along a small-eccentricity orbit. An example of trajectory design is shown considering a GEO target as test case. Given this trajectory, pose determination performance is also evaluated within a numerical simulation environment capable of realistically reproducing target-chaser relative dynamics, the operation of a scanning LIDAR selected on board the chaser as relative navigation sensor, and pose estimation algorithms based on the processing of 3D point clouds.

The interest of the space community toward missions like On-Orbit Servicing of functional satellite to extend their operative life, or Active Debris Removal to reduce the risk of collision among artificial objects in the most crowded orbital belts, is significantly increasing for both economical and safety aspects. These activities present significant technical challenges and, thus, can be enabled only by increasing the level of autonomy and robustness of space systems in terms of guidance, navigation and control functionalities. Clearly this goal requires the design and development of ad-hoc technologies and algorithms. In this framework, this paper presents an original architecture for relative navigation based on a single passive camera able to fully reconstruct the relative state between a chaser spacecraft and a non-cooperative, known target. The proposed architecture is loosely coupled, meaning that pose determination and full relative state estimation are entrusted to separate, but rigidly interconnected processing blocks. Innovative aspects are relevant to both the pose determination algorithms and the filtering scheme. Preliminary performance assessment is carried out by means of numerical simulations considering multiple realistic target/chaser relative dynamics and target geometries. Results allow demonstrating robustness against measurement error sources caused possibly by image processing as well as fast rotational dynamics.

Formations of small satellites are becoming more and more important to many space applications, since they offer the possibility of distributing the payload functionality among the different elements of the formation, so to improve scientific return, providing at the same time a number of advantages in terms of overall system reliability, flexibility and modularity. However, precise autonomous determination of the relative positions of the formation members is required for formation acquisition and maintenance, and scientific objective achievement. For Low-Earth-Orbit formations, this task can be performed exploiting GPS-based relative positioning techniques. The technique exploited in this paper is designed for on board usage. It processes double differenced pseudo-range and carrier phase observables on two frequencies within a hybrid filtering scheme to get satisfactory precision and high robustness. However, relative positioning by GPS is affected by the capability of correctly estimating differential ionospheric delays, and, then, by the status of ionosphere activity. Hence, the filter includes an ionospheric model capable of reproducing ionosphere horizontal gradients with a minimum number of parameters, which can be estimated on the fly. In addition, a robust tuning approach is developed in the paper to get stable filter performance over long period of times. Specifically, the proposed approach combines an empirical tuning technique with a randomized algorithm to get the best filter tuning. Filter performance and tuning approach effectiveness are successfully verified using freely available GPS flight data of Gravity Recovery and Climate Experiment mission.

Deployable aerobrakes for Earth re-entry capsules may offer many advantages in the near future, including the opportunity to recover on Earth payloads and samples from Space with reduced risks and costs with respect to conventional systems. Such capsules can be accommodated in the selected launcher in folded configuration, optimizing the available volume, and when foreseen by the mission profile the aerobrake can be deployed in order to increase the surface exposed to the hypersonic flow and therefore to reduce the ballistic parameter. The ballistic parameter reduction offers as main advantage the opportunity to perform an atmospheric re-entry with reduced aerothermal and mechanical loads. It makes also possible the use of relatively lightweight and cheap thermal protection materials. There are plenty of algorithms and control methods for classical re-entry capsules, such as the Orion and Soyuz re-entry modules. However, a lot of attention is now paid towards how to control low ballistic coefficient capsules with inflatable and mechanically deployable heat shield. The aim of this study is to prove the feasibility of an aerodynamic control system, applied to a mechanically deployable re-entry capsule, in order to increase landing precision at the targeted site. The deployable heat shield is equipped with an actuation system, consisting of eight aerodynamic surfaces, referred to as flaps. The assumed control strategy is to deflect the flaps independently, in order to trim the capsule and produce enough lift and side force to give downrange and cross range maneuverability during the re-entry phase. A control algorithm was developed, implemented and tested in a 3DOF simulation environment. Capsule performances both for uncontrolled ballistic re-entries and for controlled lift re-entries starting from a low Earth orbit have been assessed, verifying the capability of the controller in guiding the capsule toward the chosen target. Monte Carlo simulations were run assuming errors and uncertainties at the de-orbit burn, and the control system has been proved to obtain good results in reducing dispersions at the landing site.

The Impact of Event Scale-Revised (IES-R) is a widely used self-report questionnaire used to assess symptoms of posttraumatic stress disorder (PTSD). Although the IES-R has been translated and validated in multiple languages, no previous version has employed the Arabic dialect commonly spoken in Syria. The present work aimed to assess the psychometric properties of a Syrian Arabic version of the IES-R. Syrian citizens (N = 288) living in refugee camps in Turkey were administered the Syrian Arabic IES-R as part of a humanitarian aid project focused on providing psychological assistance. The data were analyzed with respect to 10 previously published factor solutions. We found that the best-fitting model was a four-factor structure that included factors involving Avoidance-Numbing, Intrusion, Hyperarousal, and Sleep Disturbance. The model showed strong measurement invariance between male and female subsamples, allowing for meaningful comparisons of the factor means. Overall, the present findings support the validity of a new version of the IES-R, which can be used by both researchers and clinicians responding to the urgent need for psychological care for Syrian refugees fleeing war-related violence.

The use of biological motion (BM) stimuli (point-light walkers PLW) may be a novel alternative to improve the clinical impact of Action Observation treatments in Parkinson's Disease, by directing the patient's attentional focus on gait kinematics. However, the recognition of biological motion in Parkinson's patients has thus far been controversial. To evaluate the clinical feasibility of using BM stimuli in Action Observation treatments, we aimed at investigating whether Parkinson's patients in the ON-state condition can identify and use gender-specific cues conveyed by the body structure and by the kinematics of gait of a PLW. 30 Parkinson's patients and 30 healthy elderly observers were tested in a gender identification task with PLW. Parkinson's patients were able to correctly identify the gender of PLW; no differences were found between the two groups of observers. While for both groups, the gender identification task was easier when it required a judgment on a healthy PLW. Lastly, we found that females were more sensitive than males in our identification task. Our study shows that Parkinson's patients in the ON-state condition are able to extract subtle structural and kinematic characteristics from biological motion stimuli, which is favorable to the use of BM in Action Observation treatments.