1,721,157 research outputs found
SIRDARIA: A low-cost autonomous deorbiting system for microsatellites
No full textIn the last decades the increasing in space activities produced a growth of the space debris. They are mostly concentrated in Low Earth Orbit, (LEO) and Geostationary Earth Orbit, (GEO), since these are the most used region in space activities. The Inter-Agency Space Debris Coordination Committee (IADC) released guidelines which could provide a reduction of debris number uncontrolled growth. The main guideline for LEO satellite suggests reducing mechanical lifetime to 25 years.
This paper deals with the design of an autonomous system for deorbiting microsatellites in low earth orbit based on the increasing of ballistic coefficient to reduce satellite life time. A prototype, feasible for small low-cost microsatellites, has been manufactured and is depicted in the paper. This prototype has been subdued to DNEPR launch campaign qualification tests and will be boarded on UNISAT-4, the fourth satellite of the UNISAT program which was established in late nineties from professors, researchers and students of the Group of Astrodynamics of University of Rome (GAUSS) at Scuola di Ingegneria Aerospaziale with the aim to design, realize and operate in orbit small educational satellites. In the framework of this program three satellites have already been launched (UNISAT on September 2000, UNISAT-2 on December 2002 and UNISAT-3 on June 2004 which is still operative) and a fourth satellite, UNISAT-4, to be launched on July 2006. The deorbiting device proposed fulfils with UNISAT programs didactical purposes because a complete space culture cannot ignore the education to the space environment respect
A deorbiting system for microsatellites
No full textThe paper deals with the design, the realization and test campaign of an autonomous system for deorbiting microsatellites in low earth orbit (SIRDARIA, Spacecraft Integrated Re-entry Device, Aero-Resistant, Increasing Area). The system based on the increasing of ballistic coefficient reduces satellite life time overcoming complexity related to using propulsion system or electrodynamic tether. Main components of the proposed system are the sail, the booms, thermal cut for deployment command and power generation and management unit. The whole system is contained, in bowed configuration, inside a box with dimensions of 3x10x10 cm. The sail, deployed exploiting booms, is large about 0.5 m2.
A prototype has been realized and boarded on UNISAT-4. This is the fourth satellite manufactured in the framework of UNISAT program which was established in early nineties by professors, researchers and students at Scuola di Ingegneria Aerospaziale of University of Rome with the aim to design, realize and operate in orbit small educational satellites. The deorbiting system realization fits well with UNISAT program educational goals since a complete space culture and didactical aims cannot ignore the education to comply with a sustainable space environment
The UNISAT program for space education, Keynote Paper
No full textUNISAT is a program established at Universita
di Roma "La Sapienza", Scuola di Ingegneria
Aerospaziale, in which members of the Academic
staff, PhD candidates, graduated and undergraduate
students work together to design and manufacture
an e4ucational microsatellite. The whole proj ect has
been thought as a unique occasion for lecturers to
show an actual space system being designed and
integrated in the academic environment and for
students to develop real world proj ects, "playing and
learning" on specific subsystems of the
microsatellite. Furthermore a cooperation has been
started with a tearn of Italian Universities to
exchange information and experience about
microsatellite technology. Contacts have been
established also with Research Centers and Private
Companies involved in space activity.
The first satellite built in the framework of the
UNISAT program was successfully launched on
September 26, 2000. The second one, UNISAT-2, is
scheduled for launch within 2002. Near future
activity includes developing and launching of a
cluster of four "one liter" nanosatellites.
A general overview of the UNISAT spacecrafi
bus and technological experiments is given and the
experience gained described, focussing on the
educational aspects and achievements of' the
program
University Nanosatellites Flying In Formation: An Innovative Tool To Improve Cooperation Among Italian Universities
No full text
Nessuna salvezza per Jean Valjean: la giustizia secondo l’ispettore Javert. Recensione a L. Manconi – F. Graziani, Per il tuo bene ti mozzerò la testa. Contro il giustizialismo morale (Einaudi Stile libero, 2020)
No full textRecensione a L. Manconi – F. Graziani, Per il tuo bene ti mozzerò la testa.
Contro il giustizialismo moral
The unisat program: Lessons learned and achieved results
No full textThe Group of Astrodynamics of University of Roma "La Sapienza" (GAUSS) established the UNISAT program at the Scuola di Ingegneria Aerospaziale of the University of Roma "La Sapienza". It is an educational project for designing, manufacturing and operating in orbit small microsatellites. The main goal of the UNISAT program is the education, with the aim of the participation of the students in all the phases of a real space program, from the initial mission concept to the operations in orbit. There is a strict time constraint on the mission development, which must fit in the two years didactical plan of the students. In the framework of this project four microsatellite have already been launched from Baikonour cosmodrome using the DNEPR launch vehicle, and UNISAT-4 is scheduled to be launched on May 2006. The program has now achieved an experience of several years, in which the methods of hands-on education have been employed, along with traditional class teaching, to improve the students skills. Many program organization issues have been faced in these years, to improve and verify the didactical effectiveness of the teaching method followed. The paper describes briefly the program, focussing on the didactical aspects and describing the direct experience of some students, involved in the design of the satellite subsystems. Other goal of the UNISAT program is testing in orbit and space qualifying the terrestrial off the shelf commercial and industrial components and technologies, yielding a direct technological interest for the industries and contributing to keep low the program cost and affordable for the University research budget. The main microsatellite subsystems are described in this paper, showing the students contribution to the program and their involvement in the decision process of the design, manufacturing and testing. The design process includes the realization of a virtual "digital mock-up" of the satellite, in which all the parts are simulated to verify dimensions, fitting conflicts, and weight distributions. The electronic boards have been completely designed by the students. A significant effort has been devoted to the ground station automation, including remote operation by accredited users. In particular high school students are involved in an education program for space culture diffusion among young people
Optical features and space debris observation capabilities of the first dedicated italian observatory
No full textIn October 2006, the Italian Space Agency, in the framework of a contract which involves many italians groups working on space debris, gave to GAUSS the task to manufacture a small, easy to transport, observatory completely dedicated to space debris monitoring.
The observatory will host three telescopes, with different diameters, focal lengths and optical configuration, all of them can be equipped with two CCDs and moved by robotic mounts.
A deep analysis of optical properties of the complete system has been carried out in order to evaluate instruments features, constraints and capabilities.
Particularly difficult is the a priori assessment and evaluation of the performances of optical system for LEO or GEO objects tracking and orbit determination
The paper presents the expected orbit determination results keeping into account different orbital regimes, different orbital determination strategies and instruments configurations, sketching numerical simulation results
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