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March 1985 - December 2015
March 1985 - January 2016
Publications
Publications (176)
In this paper we introduce a new index for evaluating the likelihood of accidental collisions leading to the complete destruction of intact objects in a volume of space in low Earth orbit (LEO). The proposed index is therefore not intended to assess the criticality of individual objects or missions, but rather to estimate the global impact of space...
Over the last 11 years (2010–2020), more than 600 intact objects larger than 1 m2 have re-entered without control into the Earth's atmosphere. The total returned mass was approximately 1100 t, roughly corresponding to the re-entry of nearly 100 t per year, mostly concentrated (79%) in rocket bodies. Objects with a mass greater than 500 kg re-entere...
The substantial space traffic changes occurred since the 2010s are having measurable repercussions even at the altitudes used for human spaceflight. These changes were mainly driven by the deployment of thousands of small satellites and cubesats below 600 km.
After having evaluated how the situation evolved, from 2008 to 2021, at the altitudes of t...
A new satellite-based experiment in the field of gravitation, SaToR-G, is presented. It aims to compare the predictions of different theories of gravitation in the limit of weak-field and slow-motion. The ultimate goal of SaToR-G is searching for possible “new physics” beyond General Relativity, which represent the state-of-the-art of our current k...
The evolution of cataloged orbital debris in low Earth orbit (LEO) over the last quarter of century was analyzed in detail, to gather insights on the development of space activities, on the effectiveness of the debris mitigation measures recommended in the meantime, and on the environmental impact of fragmentations, in particular collisions, both i...
A new experiment in the field of gravitation, SaToR-G, is presented. The experiment aims to compare the predictions of different theories of gravitation in the limit of weak field and slow motion. The ultimate goal of the experiment is to look for possible "new physics" beyond the current standard model of gravitation based on the predictions of ge...
This paper describes a process for identifying the intact objects in orbit that (a) pose the greatest debris-generating potential risk to operational satellites or (b) would reduce the risk the most if they were removed or prevented from colliding with each other (i.e., remediated). To accomplish this, a number of diverse, international space organ...
During Solar Cycle 24, the passive spherical satellites LARES and Ajisai, placed in nearly circular orbits with mean geodetic altitudes between 1450 and 1500 km, were used as powerful tools to probe the neutral atmosphere density and the performances of six thermospheric models in orbital regimes for which the role of dominant atomic species is con...
A new measurement of the gravitomagnetic field of the Earth is presented. The measurement has been obtained through the careful evaluation of the Lense-Thirring (LT) precession on the combined orbits of three passive geodetic satellites, LAGEOS, LAGEOS II, and LARES, tracked by the Satellite Laser Ranging (SLR) technique. This general relativity pr...
The uncontrolled re-entry of spacecraft and upper stages is quite common, occurring nearly every week. Among them, intact objects having a mass greater than five metric tons re-enter, on average, 1–2 times per year. Therefore, the re-entry of the first Chinese Space Station, Tiangong-1, was far from unusual, but attracted anyway a great worldwide a...
A specific criticality index, the collision rate percentage increase, was introduced in 2017 to assess the environmental impact of large satellite constellations in low Earth orbit (LEO). That index was estimated in this paper for various constellation arrangements, ranging in altitude from 800 km to 1400 km. The results obtained clearly show that...
Launched in September 2011, the first Chinese space station Tiangong-1 was originally planned to be deorbited with a controlled re-entry at the end of its operational life. However, due to a fatal on-board failure that occurred in March 2016, it was irremediably doomed to an uncontrolled decay. The latter was regularly monitored at ISTI-CNR, which...
We present a new measurement of the Lense-Thirring effect on the orbits of the geodetic satellites LAGEOS, LAGEOS II and LARES. This secular precession is a general relativity effect produced by the gravitomagnetic field of the Earth generated by its rotation. The effect is a manifestation of spacetime curvature generated by mass-currents, a peculi...
Recent results of the LARASE research program in terms of model improvements and relativistic measurements are presented. In particular, the results regarding the development of new models for the non-gravitational perturbations that affect the orbit of the LAGEOS and LARES satellites are described and discussed. These are subtle and complex effect...
More than 24,400 catalogued orbiting objects have re-entered so far into the Earth's atmosphere since the beginning of the space age. The associated returning mass, close to 30,000 metric tons, was mainly concentrated in intact objects, i.e. payloads and spent upper stages, accounting for nearly 29% of the re-entered objects. During the 10 years fr...
The uncontrolled re-entry of spacecraft and upper stages is quite common, occurring nearly every week. Among them, intact objects having a mass greater than five metric tons re-enter, on average, 1-2 times per year. Therefore, the re-entry of the first Chinese Space Station, Tiangong-1, was far from unusual, but attracted anyway a great worldwide a...
Recent results of the LARASE research program in terms of models improvements and relativistic measurements are presented. In particular, the results regarding the development of new models for the non-gravitational perturbations that affect the orbit of the LAGEOS and LARES satellites are described and discussed. These are subtle and complex effec...
Approximately 95% of the mass in Earth orbit is currently concentrated in about 6700 intact objects, of which nearly 80% are abandoned and more than 90% cannot be maneuvered. The intact objects abandoned in low Earth orbit (LEO) above 650 km, i.e. with an average residual lifetime of more than 25 years, represent the main potential mass reservoir f...
After a brief review of the risk represented by the uncontrolled re-entry of sizable spacecraft and upper stages, a statistical analysis of 316 predictions issued during the first 20 IADC test campaigns was presented, in order to characterize the errors affecting the estimate of the residual lifetime in the couple of weeks preceding the re-entry. O...
Currently, nearly 70% of the re-entries of intact orbital objects are uncontrolled, corresponding to about 50% of the returning mass, i.e. approximately 100 metric tons per year. In 2015, 79% of the mass was concentrated in 40 upper stages and the remaining 21% mostly in about ten large spacecraft. The average mass of the sizable objects was around...
Looking at the situation in low Earth orbit (LEO), i.e. below 2000 km, on September 9, 2017, there were 21 Italian satellites, one spent upper stage, crossing most of the region, and one debris related to the OptSat 3000 classified mission, probably a mission related object (MRO). They represented just 0.18% of the objects cataloged in LEO by the U...
The laser-ranged satellite LARES is expected to provide new refined measurements of relativistic physics, as well as significant contributions to space geodesy and geophysics. The very low area-to-mass ratio of this passive and extremely dense satellite was chosen to reduce as much as possible the disturbing effects of non-gravitational perturbatio...
Several analytical expressions, based on reasonable simplifying assumptions, were developed for the assessment of the environment criticality of large constellations and huge numbers of small satellites in low Earth orbit. They can provide preliminary quantitative answers to difficult questions, with no need of complex models and computations. More...
The LARASE research program is funded by the
Italian National Institute for Nuclear Physics and it is a collaboration
between different institutions. LARASE aims to provide
very precise and accurate measurements of the General Relativity
effects that perturb, from the Newtonian point of view, the
trajectory of a satellite orbiting the Earth. The im...
After two decades of slightly declining growth rate, the population of cataloged objects around the Earth increased by more than 56% in just a couple of years, from January 2007 to February 2009, due to two collisions in space involving the catastrophic destruction of three intact satellites (Fengyun 1 C, Cosmos 2251 and Iridium 33) in high inclina...
Uncontrolled reentries of sizable space objects are becoming of growing concern due to the increase of space activities around the Earth and population on the ground. After providing an updated review of various aspects of the problem, this paper presents the exemplar case of Progress-M 27M, whose control was lost immediately after launch, on April...
The laser-ranged satellite LARES is expected to provide new refined measurements of relativistic physics, as well as significant contributions to space geodesy and geophysics. The very low area-to-mass ratio of this passive and dense satellite was chosen to reduce as much as possible the disturbing effects of non-gravitational perturbations. Howeve...
In recent years, the development of active removal missions, to face th growing risk of catastrophic collisions and new debris generation due to the high density of orbital debris in LEO, is widely discussed in the international space community. Besides legal and political issues, active removal solutions are strongly hampered by the high costs inv...
Uncontrolled reentries of sizable space objects are becoming of growing concern due to the increase of space activities around the Earth and population on the ground. After providing an updated review of various aspects of the problem, this paper presents the exemplar case of Progress-M 27M, whose control was lost immediately after launch, on April...
A new ranking index was developed and applied to a wide set of rocket body families, characterized by stage dry masses greater than 500 kg and by the presence of at least 5 stages abandoned in LEO. The upper stages selected accounted for more than 80% of the unclassified rocket bodies in LEO and nearly 95% of the associated dry mass. The detailed r...
This paper addresses the problem of ranking the upper stages in orbit in order to evaluate their potential detrimental effects on the debris environment over the long-term, and the relative advantage of having them actively de-orbited. To do so, a new ranking scheme is introduced, applicable to any object in low Earth orbit (LEO) and able to priori...
Since the launch of Sputnik-I in 1957, the amount of space debris in Earth׳s orbit has increased continuously. Historically, besides abandoned intact objects (spacecraft and orbital stages), the primary sources of space debris in Earth׳s orbit were (i) accidental and intentional break-ups which produced long-lasting debris and (ii) debris released...
In this work, the Laser Ranged Satellites Experiment (LARASE) is presented. This is a research program that aims to perform new refined tests and measurements of gravitation in the field of the Earth in the weak field and slow motion (WFSM) limit of general relativity (GR). For this objective we use the free available data relative to geodetic pass...
LARASE represents a new experiment whose main goal is to provide accurate measurements for the gravitational interaction in the weak field and slow motion limit by means of the laser tracking of satellites orbiting around the Earth. Among the various ingredients needed, two of them play a very significant role: i) the quality of the tracking observ...
As of mid-2014, nearly 50 years since the launch of the first satellite, Italy had placed in low Earth orbit 29 objects: 27 payloads, 1 rocket body and 1 mission related object. 19 were yet in space: the IRIS rocket body and 18 payloads, 4 of which, belonging to the COSMO-SkyMed constellation, still operational and maneuverable. 16 objects had been...
The present distribution of intact objects is a good proxy to quantify the catastrophic collision risk and consequences in the coming decades. The results of a large number of long term simulations of the LEO environment perturbed by the collisional fragmentation of massive objects are used to identify the main driving parameters of the long term c...
In order to meet the specific requirements of civil protection authorities, since 2003 a set of tailored products has been developed and applied in Italy to define, a few days ahead of re-entry and in wide areas of interest, risk zones and corresponding alert time windows in the event of an uncontrolled satellite decay leading to undue debris impac...
By mid-2013, four accidental hypervelocity collisions among cataloged objects have been recorded in low Earth orbit. Three were debris–intact impacts, generating very few cataloged fragments (less than 10, in total), while one involved the collision between two intact spacecraft, one of which maneuverable, with the consequent production of more tha...
The management of the Global Navigation Satellite Systems (GNSS) and of the Medium Earth Orbit (MEO) region
as a whole is a subject that cannot be deferred, due to the growing exploitation and launch rate in that orbital regime. The advent of the European Galileo and
the Chinese Beidou constellations significantly added complexity to the system and...
During the last 40 years, the mass of orbiting objects increased at the rate of about 145 metric tons annually, leading to a total of approximately 7000 metric tons. Most of the cross-sectional area and mass (97% in low Earth orbit, LEO) is concentrated in about 4500 intact objects, i.e. abandoned spacecraft and rocket bodies, plus a further 1000 o...
During the last 40 years, the mass of the artificial objects in orbit increased quite steadily at the rate of about 145 metric tons annually, leading to about 7000 metric tons. Most of the cross-sectional area and mass (97% in low Earth orbit) is concentrated in about 4500 intact abandoned objects plus a further 1000 operational spacecraft. Analyse...
Fundamental Physics, Accelerometer,
As of mid-2014, nearly 50 years since the launch of the first satellite, Italy had placed in low Earth orbit 29 objects: 27 payloads, 1 rocket body and 1 mission related object. 19 were yet in space: the IRIS rocket body and 18 payloads, 4 of which, belonging to the COSMO-SkyMed constellation, still operational and maneuverable. 16 objects had been...
During the last 40 years, the mass of the artificial objects in orbit increased quite steadily at the rate of about 145
metric tons annually, leading to about 7000 metric tons. Most of the cross-sectional area and mass (97% in low Earth
orbit) is concentrated in about 4500 intact abandoned objects plus a further 1000 operational spacecraft. Analyse...
The feasibility of a mission for the active removal of a large massive debris in Low Earth Orbit region is investigated. Critical aspects and related technologies are investigated at preliminary level. A preliminary mass budget shows that the chaser spacecraft overall mass varies in the range 1500 - 1700 kg, with Hybrid Propulsion Module of about 9...
During the last 40 years, the mass of the artificial objects in orbit increased quite steadily at the rate of about 145 metric tons annually, leading to a total tally of approximately 7000 metric tons. Now, most of the cross-sectional area and mass (97% in LEO) is concentrated in about 4600 intact objects, i.e. abandoned spacecraft and rocket bodie...
This paper deals with the feasibility study of a mission for the active removal of large abandoned objects in low Earth orbit. In particular, a mission is studied in which the removal of two Cosmos-3M second stages, that are numerous in low Earth orbit, is considered. The removal system relies on a Chaser spacecraft which performs rendezvous maneuv...
The management of the Global Navigation Satellite Systems and of the MEO region as a whole is a
subject that cannot be deferred, due to the growing exploitation and launch rate in that orbital regime.
The advent of the European Galileo and the Chinese Compass constellations significantly added complexity
to the system and call for as adequate globa...
During the last 40 years, the mass of orbiting objects increased at the rate of about 145 metric tons annually, leading to a total of approximately 7000 metric tons. Most of the cross sectional area and mass (97% in low Earth orbit, LEO) is concentrated in about 4500 intact objects, i.e. abandoned spacecraft and rocket bodies, plus a further 1000 o...
This paper deals with the feasibility study of a mission for the active removal of a large massive object, such as the second stage of the Zenit launcher or the Envisat spacecraft, abandoned in the most populated orbit region in low Earth orbit. Critical mission aspects and related technologies are investigated at a preliminary level. In particular...
In just 5 months, from September 2011 to January 2012, three campaigns of reentry predictions were carried out in support of the Italian civil protection authorities. The satellites involved were UARS, ROSAT and Fobos-Grunt, which received widespread attention for the marginal risk on the ground associated with their uncontrolled reentry. From the...
Currently, approximately 70% of the re-entries of intact orbital objects are uncontrolled, corresponding to about 50% of the returning mass, i.e. about 100 metric tons per year. On average, there is one spacecraft or rocket body uncontrolled re-entry every week, with an average mass around 2000 kg. Even though a detailed demise analysis is availabl...
Following the catastrophic collisional breakups of three intact
spacecraft (Fengyun 1C, Cosmos 2251, and Iridium 33) occurred in
low-Earth orbit, a detailed analysis was carried out, with a dedicated
software tool (SDIRAT ― Space Debris Impact Risk Assessment
Tool), in order to evaluate the additional impact flux of cataloged
objects on the satelli...
The beginning of space exploration introduced a great number of objects on several orbits around the Earth. Each mission left something such as mechanical instruments, spacecraft components and upper rocket stages, that are all part of the famous category called space junk, or space debris. Moreover, when a spacecraft or a satellite comes to the en...
During five months, from September 2011 to January 2012, three campaigns of reentry predictions were carried out for the Inter-Agency Space Debris Coordination Committee (IADC) and in support of the Italian civil protection authorities. The objects involved were three massive spacecraft, UARS (NASA), ROSAT (DLR) and Fobos-Grunt (Roscosmos), which r...
This paper deals with the feasibility study of a mission in which the debris is removed by using a hybrid propulsion module as propulsion unit. Specifically, the engine is transferred from a servicing platform to the debris target by a robotic arm so to perform a controlled disposal. Hybrid rocket technology for de-orbiting applications is consider...
The long-term evolution and environmental impact in MEO of all the abandoned spacecraft and upper stages associated with the GPS and GLONASS navigation constellations were analyzed. The orbits of the disposed objects, as of 1 May 2011, were propagated for 200 years and snapshots of their evolving distribution were obtained, together with an estimat...
The population of cataloged orbital debris increased by approximately 40% in just a couple of years, from January 2007 to February 2009. This was due to two collisions in space, which involved the catastrophic destruction of three intact satellites (Fengyun 1C, Cosmos 2251 and Iridium 33) in high inclination orbits. Both events occurred in the alti...
The solutions adopted for the disposal of the upper stages used to put in orbit the first satellites of the new European (Galileo) and Chinese (Beidou) navigation constellations were analyzed. The orbit evolution of the rocket bodies was modeled for 200 years, taking into account all relevant perturbations, and the chosen disposal options were eval...
This paper presents a case study of Micrometeoroids and Orbital Debris risk assessment for a spacecraft flying in an orbit close to that of the Italian Cosmo-Skymed constellation. The aim of the analysis was to calculate the failure flux impinging on the satellite external shell, taking into account both geometry and materials of satellite surfaces...
The long-term dynamical evolution of objects with extremely high area-to-mass ratios released in synchronous and semi-synchronous Earth orbits was simulated with a numerical propagator including all the relevant perturbations. In fact, as suggested by optical observations in the geosynchronous regime and orbital analysis of breakup fragments in low...
Conditions appropriate to gas-surface interactions on satellite surfaces in orbit have not been successfully duplicated in the laboratory. However, measurements by pressure gauges and mass spectrometers in orbit have revealed enough of the basic physical chemistry that realistic theoretical models of the gas-surface interaction can now be used to c...
Uncertainties in the neutral density estimation are the major source of aerodynamic drag errors and one of the main limiting factors in the accuracy of the orbit prediction and determination process at low altitudes. Massive efforts have been made over the years to constantly improve the existing operational density models, or to create even more p...
On 11 January 2007, the People’s Republic of China conducted a successful anti-satellite test against one of their defunct polar-orbiting weather satellites. The target satellite, called Fengyun-1C, had a mass of 880 kg and was orbiting at an altitude of about 863 km when the collision occurred. Struck by a direct-ascent interceptor at a speed of 9...
A large set of simulations, including all the relevant perturbations, was carried out to investigate the long-term dynamical evolution of fictitious high area-to-mass ratio (A/M) objects released, with a negligible velocity variation, in each of the six orbital planes used by Global Positioning System (GPS) satellites. As with similar objects disco...
In early 2008, the need arose to predict the orbital decay of the American spacecraft USA-193, whose characteristics, function and orbit were classified information. With no orbit data and independent Italian tracking capability available, we turned our attention on the orbits determined by a worldwide network of about 20 visual satellite observers...
“Galileo Galilei” (GG) is a small satellite designed to fly in low Earth orbit with the goal of testing the Equivalence Principle—which is at the basis of the General Theory of Relativity—to 1 part in 1017. If successful, it would improve current laboratory results by 4 orders of magnitude. A confirmation would strongly constrain theories; proof of...
