# Giovanni MengaliUniversità di Pisa | UNIPI · Department of Civil and Industrial Engineering

Giovanni Mengali

Professor

## About

200

Publications

29,355

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3,047

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Introduction

**Skills and Expertise**

Additional affiliations

June 1992 - present

## Publications

Publications (200)

A challenging problem from a technological viewpoint is to send a spacecraft at a distance of about 600 au from the Sun, comparable with that of the Sun’s gravitational focus (that is, the general relativistic focusing of light rays, whose minimum solar distance is obtained when the light rays are assumed to graze the Sun’s surface), and reach it i...

The recent successes of demonstration missions based on solar sail technology have paved the way for designing new mission scenarios with propellantless propulsion systems. In this context, the Italian Space Agency has been supporting a preliminary study of Helianthus, an innovative concept of deep-space mission, which is designed to use a solar sa...

This study made use of a shape-based method to analyze the orbital dynamics of a spacecraft subject to a continuous propulsive acceleration acting along the circumferential direction. Under the assumption of a logarithmic spiral trajectory, an exact solution to the equations of motion exists, which allows the spacecraft state variables and flight t...

The aim of this paper is to analyze the performance of a solar sail-based spacecraft in a heliocentric V∞ leveraging maneuver. Assuming a circular restricted three-body framework, and using an optical force model for the description of the propulsive acceleration vector, this work quantifies the solar sail performance with an optimal approach, that...

The Electric Solar Wind Sail (E-sail) is an innovative propellantless propulsion system conceived by Pekka Janhunen in 2004 for use in interplanetary space. An E-sail consists of a network of electrically charged tethers maintained at a high voltage level by an electron emitter. The electrostatic field surrounding the E-sail extracts momentum from...

The aim of this Correspondence is to analyze the performance of a solar sail-based spacecraft in a two-impulse orbit transfer between circular and coplanar heliocentric orbits of assigned radii. In particular, assuming a transfer trajectory with a sweep angle and a flight time equal to those of a classical Hohmann orbit, the sail propulsive acceler...

This Short Communication analyzes the motion of a spacecraft whose primary propulsion system generates an inward, radial propulsive acceleration of constant magnitude. Starting from the classical literature results regarding the more common outward radial-thrust case, the proposed mathematical model uses a set of modified non-singular orbital eleme...

The aim of this article is to analyze the two-dimensional heliocentric trajectory of a solar sail with constant attitude in presence of reflective film optical degradation. The proposed procedure starts from the results obtained for a non-degrading flat sail and, taking into account the film optical degradation, obtains an analytical (although appr...

The propellantless working principle of a solar sail requires the total flight time to be minimized when looking for the optimal trajectory to reach a given target state. In this work the solar sail steering law is found by applying a Q-law algorithm, which aims at driving the spacecraft toward the final (target) orbit by decreasing the distance be...

The aim of this paper is to investigate the heliocentric motion of a passively actuated solar balloon placed at a distance of about one astronomical unit from the Sun. The analysis exploits a recent thrust model, according to which a solar balloon undergoes a passive control of its lightness number (that is, the ratio of the generated thrust to the...

Propellantless propulsion systems allow innovative mission scenarios to be envisaged, including the generation and the stabilization of artificial equilibrium points in the circular restricted three-body problem. This paper discusses the generation of collinear, L1-type, artificial equilibrium points in the Sun-[Earth+Moon] system, using a (photoni...

The aim of this paper is to analyze optimal trajectories of a solar sail-based spacecraft in missions towards the outer Solar System region. The paper proposes a simplified approach able to estimate the minimum flight time required to reach a given (sufficiently high) heliocentric distance. In particular, the effect of a set of solar photonic assis...

A heliogyro is a rotating solar sail with the reflecting surface divided into a number of long and slender blades, which are stiffened by a spin-induced centrifugal force. Each blade can rotate around its own longitudinal axis so as to change the pitch angle and allow the thrust vector to be effectively controlled. The aim of this paper is to analy...

This paper investigates approximate solutions to the two-dimensional equations of motion of a generalized sail-based spacecraft. A generalized sail is a propellantless propulsion system that produces a continuous thrust the magnitude of which varies with the heliocentric distance as 1/rη, where η is a positive real number that characterizes the pro...

We address the heliocentric in-orbit repositioning problem of an E-sail-based spacecraft that covers a circular parking orbit of given radius, with the assumption that the propulsive acceleration is directed along the Sun-spacecraft line. According to the recent literature, the analysis exploits the possibility of reducing the mathematical problem...

In this study, new analytical solutions to the equations of motion of a propelled spacecraft are investigated using a shape-based approach. There is an assumption that the spacecraft travels a two-dimensional spiral trajectory in which the orbital radius is proportional to an assigned power of the spacecraft angular coordinate. The exact solution t...

The analysis of the optimal control law that steers a solar sail-based spacecraft from a given initial condition toward a final target state is typically carried out using either indirect or direct approaches. Both these methods are usually time-consuming and require good initial guesses of costates or state vector. This paper presents a procedure...

A solar sail generates thrust without consuming any propellant, so it constitutes a promising option for mission scenarios requiring a continuous propulsive acceleration, such as the maintenance of a (collinear) L1-type artificial equilibrium point in the Sun-[Earth+Moon] circular restricted three-body problem. The usefulness of a spacecraft placed...

The aim of this paper is to evaluate the effect of a maximum admissible value of the sail cone angle on the transfer performance of a solar sail-based spacecraft in an interplanetary mission scenario. The proposed approach models the possible constraint on the maximum Sun angle of the solar panels, when thin film solar cells are attached to the fla...

The optimization of a solar sail-based orbital transfer amounts to searching for the control law that minimizes the flight time. In this context, the optimal trajectory is usually determined assuming constant solar properties. However, the total solar irradiance undergoes both long-term (solar cycles) and short-term variations, and recent analyses...

The propulsive characteristics of an Electric Solar Wind Sail are usually evaluated using a simplified model in which all the sail tethers are coplanar and form a sort of rigid disk. However, the three-dimensional arrangement of the tethers is fundamental information in the study of the spacecraft performance, and must be accounted for in refined m...

This article discusses the maintenance of an L
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-type artificial equilibrium point in the Sun-[Earth+Moon] circular restricted three-body problem by means of an electric solar wind sail. The reference configuration instability is compensated for wi...

The heliocentric orbital dynamics of a spacecraft propelled by a solar sail is affected by some uncertainty sources, including possible inaccuracies in the measurement of the sail film optical properties. Moreover, the solar radiation pressure, which is responsible for the solar sail propulsive acceleration generation, is not time-constant and is s...

The aim of this work is to investigate heliocentric phasing maneuvers performed by a spacecraft propelled by an Electric Solar Wind Sail, that is, an innovative propellantless propulsion system that consists of a spinning grid of charged tethers that uses solar wind momentum to produce thrust. It is assumed that the Electric Solar Wind Sail may be...

This paper deals with the problem of determining an analytical control law capable of maintaining highly elliptical heliosynchronous polar orbits around Venus. The problem is addressed using the Smart Dust concept, a propellantless propulsion system that extracts momentum from the solar radiation pressure using a reflective coating. The modulation...

This paper analyzes reachable domains of spacecraft using a single impulsive maneuver. In particular, compact expressions are obtained of the envelopes of spacecraft trajectories in closed form, in both cases of either radial or tangential impulse. Suitable bounds are enforced on the magnitude of the velocity variation to obtain an elliptic transfe...

This paper discusses the linearized relative motion and control of Electric Solar Wind Sails (E-sails) operating in formation flight around a heliocentric displaced orbit. An E-sail is constituted by thin and centrifugally stretched tethers, and generates a propulsion by momentum interaction with the charged particles from the solar wind. Feasible...

The heliocentric transfer of a solar sail-based spacecraft is usually studied from an optimal perspective, by looking for the control law that minimizes the total flight time. The optimal control problem can be solved either with an indirect approach, whose solution is difficult to obtain due to its sensitivity to an initial guess of the costates,...

An Electric Solar Wind Sail is a propellantless propulsion system that gains thrust from the interaction of solar wind particles with a grid of long and charged tethers, which are deployed by spinning the spacecraft about its symmetry axis. In an ideal arrangement, the tethers are all stretched out and the sail takes the shape of a spoked wheel. Ac...

The aim of this paper is to propose a distributed control architecture for a solar sail-based formation, flying around an L2-type artificial equilibrium point in the Sun-[Earth + Moon] circular restricted three-body problem. Two typical cases, depending on whether the formation structure is leaderless or includes a virtual leader, are investigated....

The interaction between electromagnetic waves and matter is the working principle of a photon-propelled spacecraft, which extracts momentum from the solar radiation to obtain a propulsive acceleration. An example is offered by solar sails, which use a thin membrane to reflect the impinging photons. The solar radiation momentum may actually be trans...

An Electric Solar Wind Sail (E-sail) is an innovative propellantless propulsion system that generates a propulsive acceleration by exchanging momentum with the solar wind charged particles. Optimal E-sail trajectories are usually investigated by assuming an average value of the solar wind characteristics, thus obtaining a deterministic reference tr...

In-situ measurements are necessary for a long-term analysis of the spatial structure of the geomagnetic tail. This type of mission requires the use of a propellantless propulsion system, such as a classical solar sail, to continuously rotate the design orbit apse line such that it remains parallel to the Sun-Earth direction. To reduce the mission c...

The aim of this paper is to evaluate the minimum flight time of a solar sail-based spacecraft towards Earth-synchronous (heliocentric) circular displaced orbits. These are special displaced non-Keplerian orbits characterized by a period of one year, which makes them suitable for the observation of Earth’s polar regions. The solar sail is modeled as...

The working principle of the Electric Solar Wind Sail, an innovative propellantless propulsion system proposed in 2004, is based on the electrostatic interaction between a spinning grid of tethers, kept at a high positive potential, and the incoming ions from the solar wind. Similar to the well-known solar sail concept, the E-sail could simplify th...

This paper deals with the problem of determining the requirements for the maintenance of circular, displaced, non-Keplerian orbits around the Sun by means of a magnetic sail-based spacecraft. The magnetic sail is an exotic propellantless propulsion system that gains thrust from the magnetostatic interaction between the solar wind and an artificial...

The Electric Solar Wind Sail is an innovative propulsion system that gains thrust from the interaction of the incoming ions from the solar wind with an artificial electric field produced by means of long charged tethers, which are deployed and maintained stretched by rotating the spacecraft around a spin axis. Under the combined interaction between...

The aim of this paper is to analyze a potential mission scenario that could be used to perform an in situ test of the Electric Solar Wind Sail. Such an advanced propulsive system works only outside the Earth’s magnetosphere; so, a translunar mission (where the spacecraft is supposed to be inserted as a secondary “piggyback” payload) is hypothesized...

This paper introduces a mathematical model that can be used to evaluate the total velocity variation required to accomplish a given two-dimensional orbit transfer, using up to three tangential impulsive maneuvers. The problem is addressed in an optimal framework, by looking for the transfer trajectory that minimizes the total velocity variation. In...

This paper deals with the optimization of the transfer trajectory of a solar sail-based spacecraft between circular and coplanar heliocentric orbits. The problem is addressed using both a direct and an indirect approach, while an ideal and an optical force model are used to describe the propulsive acceleration of a flat solar sail. In the direct ap...

A Smart Dust is a propellantless femtosatellite, with a characteristic side length of a few millimeters and a high value of its area-to-mass ratio. It exploits the solar radiation pressure to create a propulsive acceleration sufficient enough to substantially affect its orbital dynamics. A number of new mission concepts may thus be envisaged, where...

The aim of this paper is to propose a shape-based method in which the concept of Bezier curve is used to efficiently design the three-dimensional interplanetary trajectory of a spacecraft whose primary propulsion system is an Electric Solar Wind Sail. The latter is a propellantless propulsion concept that consists of a spinning grid of tethers, kep...

The aim of this paper is to propose a semi-analytical method for the analysis of a two-impulse transfer between two coplanar elliptic orbits, assuming each maneuver to change the magnitude of the spacecraft velocity only, without affecting its direction. Using a recent mathematical model that describes the spacecraft dynamics in a compact analytica...

This paper investigates the optimal transfer trajectories from a circular parking orbit towards the apocenter of a rectilinear ellipse, where the spacecraft reaches a quasi-stationary condition relative to an inertial reference frame. The spacecraft is equipped with a propulsion system that provides a circumferential continuous propulsive accelerat...

The Electric Solar Wind Sail (E-sail) is a propellantless propulsion system that generates thrust by exploiting the interaction between a grid of tethers, kept at a high electric potential, and the charged particles of the solar wind. Such an advanced propulsion system allows innovative and exotic mission scenarios to be envisaged, including non-Ke...

A finite element approach is used to calculate the components of forces and moments acting on a square solar sail at a sun-sail distance equal to one astronomical unit. The model takes into account the deformation effect induced by the solar radiation pressure, where the incidence of the reflected photons changes as a function of the local orientat...

The Electric Solar Wind Sail is an innovative propulsion system concept that gains propulsive acceleration from the interaction with charged particles released by the Sun. The aim of this paper is to obtain analytical expressions for the thrust and torque vectors of a spinning sail of given shape. Under the only assumption that each tether belongs...

Propellantless continuous-thrust propulsion systems, such as electric solar wind sails, may be successfully used for new space missions, especially those requiring high-energy orbit transfers. When the mass-to-thrust ratio is sufficiently large, the spacecraft trajectory is characterized by long flight times with a number of revolutions around the...

The aim of this work is to improve an efficient methodology, recently developed to study the structural response of a classical square solar sails in free flight, under the action of the solar radiation pressure. The new approach models the effect of thermal loads acting on the sail's reflective surface. In particular, a square solar sail with a si...

This paper investigates the problem of multiple solar sail-based spacecraft formation flying in which the chief follows a heliocentric displaced orbit, whereas each deputy adjusts the sail propulsive acceleration so as to track a desired (relative) trajectory with respect to the chief. In particular, coordinated control strategies are presented for...

A Smart Dust is a femto-spacecraft with an external surface coated with electrochromic material, which exploits the solar radiation pressure to produce a propulsive acceleration. As the optical properties of the electrochromic material change upon application of a suitable electric voltage, its propulsive acceleration may be modulated, within some...

This paper presents a distributed adaptive control framework for multiple spacecraft formation flying around Lagrange point orbits, which account for unmeasurable velocities and (spacecraft) mass uncertainties. The nominal trajectory for the formation system is a halo orbit parameterized by Fourier series expansions. Such an explicit, albeit approx...

Analytic solutions to continuous thrust-propelled trajectories are available in a few cases only. An interesting case is offered by the logarithmic spiral, that is, a trajectory characterized by a constant flight path angle and a fixed thrust vector direction in an orbital reference frame. The logarithmic spiral is important from a practical point...

Plasma brake is an innovative propellantless propulsion system concept that exploits the Coulomb collisions between a charged tether and the ions in the surrounding environment (typically, the ionosphere) to generate an electrostatic force orthogonal to the tether direction. Previous studies on the plasma brake effect have emphasized the existence...