ettore perozzi CV

In the last decades, the widespread diffusion of digital computers, the sharp increase in their performances and the significant advances in chaos theory, has allowed a deeper understanding of several fundamental problems of celestial mechanics. It is now possible to follow the orbital motion of celestial bodies for a timespan comparable with the age of our planetary system: five billion years. On this timescale the Solar System is alive with events involving the major planets as well as the small bodies traveling the interplanetary space. At the same time flight dynamics specialists have learned how to use complex orbital patterns for space missions and are able to determine the position of an artificial satellite with an unprecedented accuracy. Thus modern celstial mechanics reveals a truly interdisciplinary character, involving the scientific as well as the industrial community.

Within this framework, the CELMEC meetings have been organised with the aim of estabilishing a common ground and find connections among the various fields of study involving celestial mechanics. Born at a national level in May 1993, and regularily repeated at a 4-year interval, the CELMEC meetings have quickly become a focal point to matematicians, astronomers and engineers working in celestial mechanics all over the world. About 100 participants attended CELMEC III, which took place in Villa Mondragone (Rome, Italy) in June 2001: the proceedings have been published as a special issue of the international journal Celestial Mechanics and Dynamical Astronomy (vol. 83, 2002).
Following the success of this approach, the Italian Celestial Mechanics and Astrodinamics Society (SIMCA - Societa' Italiana di Meccanica Celeste e Astrodinamica) has been also established in January 2002.

Due to the intrinsic non-integrability of the N-Body problem, the use of step-by-step numerical integration techniques has grown together with the availability of fast and reliable computers.The Laurea Thesis deals with the extension of Discrete Mechanics (an energy and angular momentum conserving numerical method for the integration of ordinary differential equations) to the case of an object orbiting around an oblate spheroid. Limitations intrinsic to the method are found, leading to a more general study on the efficiency of the most common numerical integrators used in celestial mechanichs to solve the N-body problem. A special attention is paid to the treatment of strong gravitational interactions, such as the occurrence of close encounters of comets with the major planets, and to the propagation of truncation and round-off errors during the integration. This leads to the choice of RADAU (by E. Everhart) as the core integrator for the development of high efficieny, high accuracy software to study the orbital evolution of Minor Bodies, to look for periodic orbits in the Main Lunar Problem, as well as for near-Earth and interplanetary mission design.
A specific three and four-body perturbation model (including the J2, J4 and J6 potential terms) is also developed in order both, to study the long term stability of the two coorbital satellites of Saturn (Ephimeteus and Janus) and to test numerically the so-called co-rotational resonance theory which provides the basic dynamical description of the motion of the ring arcs of Neptune. The same model is used to investigate the stability of a peculiar extra-solar planetary system composed by two equal masses in a 1:1 resonance around a pulsar.

A numerical approach is applied to the ESA SOHO (Solar Heliospheric Observatory) transfer trajectory and to the CASSINI / Huygens probe Titan encounter trajectory. In both cases the extreme sensitivity of the orbital path to inaccuracies in the dynamical model adopted and the importance of distant perturbations are pointed out.
A general purpose software (OPA: Orbit Perturbation Analysis) performing the orbital evolution of artificial satellites, with special emphasis on those in high eccentricity and inclination orbits, is developed under Italspazio contract.
The classical Hohmann and Opik analythical methods are used to develop targeting strategies for mission analysis, such as the H-plot accessibility criterion of near-Earth asteroids (NEAs) and the dynamics of close flybys.


Atti del Primo Convegno Nazionale di Meccanica Celeste. A. Celletti & E. Perozzi (editors) 118 pp, L'Aquila, Dicembre 1993.
Second Italian Meeting on Celestial Mechanics. A. Celletti, A. Milani, E. Perozzi (editors) Planetary and Space Science, Special Issue, vol.46 n.11/12, 215 pp, Nov/Dec 1998.
CELMEC III -Third Meeting on Celestial Mechanics. A.Celletti, S. Ferraz-Mello, J. Henrard (editors), Celestial Mechanics and Dynamical Astronomy. Special Issue, vol. 83, 2002.
Meccanica Celeste: A. Celletti & E. Perozzi, CUEN, Napoli, collana Tessere n.24, 140 pp, 1996. more
Costruzione di un Algoritmo per l'Integrazione delle Equazioni del Moto della Meccanica Discreta nel Campo Gravitazionale di uno Sferoide Oblato. E. Perozzi, Laurea Thesis, Universita' di Roma "La Sapienza", Aprile 1981.
The Precession of the Argument of Pericentre  in Discrete Mechanics. E. Perozzi. IAS-Internal Report n.25, 13 pag.s, 1981.
Discrete Mechanics: Some Remarks. E. Perozzi, Celestial Mechanics n.30, 249-261, 1983.
Perturbation Computations and Numerical Modelling Experiments. A. Carusi, E. Perozzi, G.B. Valsecchi. In proc. 'International School of Physics Enrico Fermi', Rendiconti S.I.F.- XCVIII, 191-201, 1985.
On Testing N-Body Numerical Integration Techniques: Some General Remarks and an Application to the SOHO Transfer Trajectory. E. Perozzi. ESA-ESOC Mission Analysis Office WP 210, 24 pp, 1984.
One of the Problems of Long-Term Integrations of Cometary Orbits. A. Carusi, E. Perozzi, E. Pittich, G.B. Valsecchi. In proc. 'Dynamics of Comets', IAU Coll.83, A.Carusi & G.B.Valsecchi eds, 227-235, 1985.
Influence of Close Encounters on the Determination of  Cometary Orbits. A. Carusi, E. Perozzi, E. Pittich, G.B. Valsecchi In proc. 'The Few Body Problem', M.Valtonen ed, 195-199, 1988.
First Ground-based images of Neptune's Ring Arcs.  B. Sicardy, F. Roddier, C. Roddier, E. Perozzi, J.E. Graves, O. Guyon, M.J. Northcott: Nature 400, 731-733, 1999
The Glitches of the Anomalous X-ray Pulsar 1RXS J170849.0-400910. S. Dall'Osso, G.L. Israel, L. Stella, A. Possenti, E. Perozzi. arXiv: astro-ph/0307235v2, (submitted) 2003.
Dynamics of the CASSINI Titan Close Encounter. E. Perozzi. In proc. 'The Solid Bodies of the Outer Solar System', ESA SP-242, A.Coradini & M.Fulchignoni eds, 283-289, 1986.
Exploiting Earth Horseshoe Orbits for Space Missions. G.B. Valsecchi and E. Perozzi. Planetary and Space Science, vol.46 n.11/12, 1623-1626, 1998.
Basic Targeting Strategies for Rendezvous and Flyby Missions to the Near-Earth Asteroids. E. Perozzi, A. Rossi, G.B. Valsecchi. Planetary and Space Science 49, 3-22, 2001.



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