Designing an offset cable net in parabolic reflectors introduces several complexities compared to prime focus configurations. This study aims to develop a versatile cable net generation algorithm capable of adapting to the reflector’s dimensions and the curvature of the paraboloid surface. In this regard, we propose a methodology that leverages specific paraboloid surface curves known as quasi-geodesic curves. Similar to geodesic curves on a sphere, quasi-geodesic curves visually resemble proper geodesic shapes but may follow distinct mathematical principles. We introduce two types of quasi-geodesic curves: primary curves that intersect the center point of the cable net and secondary curves that pass through any two points on the net. We present various solutions accommodating different cable net layouts and introduce a quality index based on an equilateral triangle cable net. Finally, we compare the quasi-geodesic-type cable net with the isogrid-type cable net to highlight tension distribution and surface accuracy improvements.

Two basic Large Reflector technologies, to meet different mission requirements, are under development in Thales Alenia Space Italy.The Large Deployable Reflector (LDR) technology adopts mesh reflecting surface and can afford very large offset optics (up to 18 m) up to Ku band. The LDR is a patented design which should allow for the development of European Radiometric and Earth Observation missions. A 6 meters LDR demonstrator, fully representative of the design but with dummy mesh, has been manufactured and tested to demonstrate the whole deployment kinematic, deployment accuracy and surface repeatability. These activities were initially carried out within the ESA `Innovative, Scalable, Large Deployable Antenna Reflector' 108005/13/NL/CP contract and continued with internal R&D funding. RF mesh design will be addressed in the study follow on.The Large Unfurlable Reflector Assembly (LURA) technology is focused on large onset optics (5 to 7 m) based on solid unfurlable petals for wide band application from C up to Ka band. The LURA shall serve as a key component for Earth Observation missions. The axially symmetric configuration is suitable to be accommodated directly on the earth facing panel thus allowing to use small platforms and small launchers. The wide band operating frequency (C to Ka) is permitted because of the high surface accuracy, good reflectivity and high thermal stability. A 5 meter LURA demonstrator, fully representative of the real design, has been manufactured to demonstrate kinematics, deployment accuracy and repeatability. The whole reflector assembly is being qualified within a large space contract.

Deployable mesh reflector antennas are widely used for space applications and the form-finding analysis plays an important role to reach the high surface accuracy. In this paper, an optimized algorithm extends the traditional force density method for the form-finding analysis of an asymmetric offset antenna. The optimization problem is solved by minimizing the RMS error with respect to the ideal paraboloid. First, the algorithm is implemented considering rigid ring truss support. Then, the effect of the elastic deformation of truss support is taken into account. The minimum distance between each free node of the front net and the ideal surface is used for the calculation of the RMS error. Finally, a numerical example is carried out to demonstrate the validity of the proposed method.

The paper provides an overview of the most significant space antenna products and technologies for Observation, Exploration and Navigation (OEN) developed by ThalesAleniaSpace-Italia (TAS-I) over more than 30 years. These antennas provided a determinant contribution to the scientific community in understanding earth environment and solar planets. An outline of today key developments is also presented.

In view of next solar system exploration missions, such as Bepicolombo, Exomars and Juice, this paper overviews the present TAS-I antenna developments focusing on High Gain Antennas (HGA's) for earth-to-planet communications and onboard altimeter/sounder antenna technologies in their specific harsh environment.

Scope of this work is to highlight the heritage dev eloped by ThalesAleniaSpace-Italia (TASI) in HF deployable dipoles for Radar Sounders applications. The RF experience acquired by TAS-I in the frame of the SHARAD P/L (SHAllow RADar PayLoad) provided by the Italian Space Agency (ASI) as a facility instrument for the 2005 NASA mission to Mars called MRO (Mars Reconnaissance Orbiter) was complemented within the ESA study named HILDRA (Highly Integrated Low power ice penetrating Deployable Radar Antenna), by exploiting the technology relevant to the deployable dipole. This ESA study entails the design and the development and verification of a technology demonstrator for a highly integrated low power ice penetrating Radar Antenna, targeting the next European and US deep space missions within Horizon 2020 program. The paper summarises the technological development activity experienced by TAS-I including trade-off and design capabilities both at system and at unit level for electrical and technology aspects, includ ing the test campaign carried out over the demonstrator. Main objective of the Demonstration Model (DM) was to exhibit by test the deployment performance of the selected technology, as the deployment of the long dipole was recognised a critical issue for the feasibility of the JUICE (JUpiter ICy Moon Explorer) mission.

In this paper, a novel mathematical model for a traveling wave ultrasonic motor, developed by Alenia Spazio, now Alcatel Alenia Space Italia S.p.A. (Roma, Italy), within an Italian Space Agency (ASI) program, is described. The dynamic equations for the stator and the rotors of the ultrasonic motor are assembled into a differential system, whose equations are coupled by terms which represent interface generalized forces. Neglecting transient conditions, the complete mathematic model of the system is solved and an iterative process is developed, in order to obtain the motor’s running curves for different operation parameters, geometric dimensions and physical features of the system. The algorithm is implemented in Matlab\({^{\circledR}}\) environment and a graphical user interface is constructed for user-friendly managing. The model, also validated by means of experimental tests, can be used for parametric analyses with respect to different parameters, in order to optimize motor’s configuration. It represents a simple but powerful aid to determine final motor design that can satisfy specifications or to predict motor’s behavior under different working conditions.

In this paper, a novel method of numerical computation of the natural frequencies, depending on the most important running parameters for an ultrasonic motor, is described. The analyzed configuration by the Space Division of Alenia Spazio, Rome, within an Italian Space Agency (ASI) development program, is the flexural traveling wave one. The dynamic equations for the stator and the rotors of the ultrasonic motor are assumed into a differential system, whose equations are coupled by terms that represent interface generalized forces. In order to calculate natural frequencies of the motor-coupled terms of the equations are worked out with respect to the variables of the degrees of freedom. Hence, the mass, damping, and stiffness matrix for the whole system are obtained, then resonance frequencies, depending on the most important running parameters such as axial preload of the motor, are calculated. The results are compared with numerical ones, obtained by a finite element modeling (FEM) model, showing a good agreement.

In this paper a dynamic simulation of a new model for a Travelling Wave Ultrasonic Motor for antennas' reflectors positioning, developed by Alenia Spazio S.p.A. (Roma, Italy) within an Italian Space Agency (ASI) development Program, is described. The dynamic equations for the stator and the rotors of the ultrasonic motor are assumed into a differential system, whose equations are coupled by terms which represent interface generalized forces. Neglecting transient conditions, the complete mathematic model of the system is solved and an iterative process is developed, in order to obtain the motor's running curves for different operation parameters, geometric dimensions and physical features of the system. The algorithm is implemented in Matlab environment and a Graphical User Interface is constructed for user-friendly managing. This model represents a simple and powerful aid to determine final motor design that can satisfy specifications or to predict motor's behaviour under different working conditions, as orbital ones.