G. B. Valsecchi
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View article: Coordinated Planetary Defence in action: orbit determination and impact monitoring of asteroid 2024 YR4
Coordinated Planetary Defence in action: orbit determination and impact monitoring of asteroid 2024 YR4 Open
Asteroid 2024 YR4 was discovered on 27 December 2024 by the ATLAS survey, and within days, preliminary orbit determinations revealed a non-negligible probability of Earth impact in December 2032. Less than a month after discovery, the impa…
View article: NEOROCKS project: surface properties of small near-Earth asteroids
NEOROCKS project: surface properties of small near-Earth asteroids Open
We present new results of the observing program which is a part of the NEOROCKS project aimed to improve knowledge on physical properties of near-Earth Objects (NEOs) for planetary defense. Photometric observations were performed using the…
View article: On the predictability horizon in Impact Monitoring of Near Earth Objects
On the predictability horizon in Impact Monitoring of Near Earth Objects Open
The Impact Monitoring (IM) of Near Earth Objects (NEOs) is a fundamental part of the planetary defense strategy. Current NEO IM systems (Aegis, NEODyS and Sentry) scan the Confidence Region (CR) of each observed object looking for Virtual …
View article: Direct-retrograde orbit flips at planetary close encounters
Direct-retrograde orbit flips at planetary close encounters Open
Aims . We want to find the conditions under which planetary close encounters transform the orbits of small Solar System bodies from direct to retrograde, and vice versa. Methods . We derive analytical constraints on the orbital elements of…
View article: A dynamical definition of the sphere of influence of the Earth
A dynamical definition of the sphere of influence of the Earth Open
The concept of sphere of influence of a planet is useful in both the context of impact monitoring of asteroids with the Earth and of the design of interplanetary trajectories for spacecrafts. After reviewing the classical results, we propo…
View article: A dynamical analysis of the Taurid Complex: evidence for past orbital convergences
A dynamical analysis of the Taurid Complex: evidence for past orbital convergences Open
The goal of this work is to determine if the dynamics of individual Taurid Complex (TC) objects are consistent with the formation of the complex via fragmentation of a larger body, or if the current orbital affinities between the TC member…
View article: Luminous efficiency of meteors derived from ablation model after assessment of its range of validity
Luminous efficiency of meteors derived from ablation model after assessment of its range of validity Open
Context. The luminous efficiency, τ , can be used to compute the pre-atmospheric masses of meteoroids from corresponding recorded meteor brightnesses. The derivation of the luminous efficiency is non-trivial and is subject to biases and mo…
View article: FRIPON: a worldwide network to track incoming meteoroids
FRIPON: a worldwide network to track incoming meteoroids Open
Context: Until recently, camera networks designed for monitoring fireballs worldwide were not fully automated, implying that in case of a meteorite fall, the recovery campaign was rarely immediate. This was an important limiting factor as …
View article: Cavezzo, the first Italian meteorite recovered by the PRISMA fireball network. Orbit, trajectory, and strewn-field
Cavezzo, the first Italian meteorite recovered by the PRISMA fireball network. Orbit, trajectory, and strewn-field Open
Two meteorite pieces have been recovered in Italy, near the town of Cavezzo (Modena), on 2020 January 4th. The associated fireball was observed on the evening of New Year’s Day 2020 by eight all-sky cameras of the PRISMA fireball network, …
View article: A report on the New Year's meteorite found near Cavezzo, Italy
A report on the New Year's meteorite found near Cavezzo, Italy Open
In this talk we report about the recent finding of two meteorite samples in Italy, near Cavezzo (Modena). The meteorite-dropping fireball was observed on the evening of New Year's Day 2020 by eight all-sky cameras of the PRISMA network, pa…
View article: A Case Study of the May 30th, 2017 Italian Fireball
A Case Study of the May 30th, 2017 Italian Fireball Open
On May 30th, 2017 at about 21h 09m 17s UTC a green bright fireball crossed the sky of north-eastern Italy. The fireball path was observed from some all-sky cameras starting from a mean altitude of $81.1 \pm 0.2$ km (Lat. $44.369^{\circ} \p…
View article: A vertical facility based on raster scan configuration for the x-ray scientific calibrations of the ATHENA optics
A vertical facility based on raster scan configuration for the x-ray scientific calibrations of the ATHENA optics Open
The ATHENA X-ray observatory is a large-class ESA approved mission, with launch scheduled in 2028. The technology of Silicon Pore Optics (SPO) was selected since 2004 as the baseline for making the X-ray Mirror Assembly. Up to 700 mirror m…
View article: ATHENA Telescope: alignment and integration of SPO mirror modules
ATHENA Telescope: alignment and integration of SPO mirror modules Open
ATHENA (Advanced Telescope for High-ENergy Astrophysics) is the next high-energy astrophysical mission of the European Space Agency currently planned to be launched in the early 2030s, as part of its Cosmic Vision program, on the scientifi…
View article: Yarkovsky effect detection and updated impact hazard assessment for near-Earth asteroid (410777) 2009 FD
Yarkovsky effect detection and updated impact hazard assessment for near-Earth asteroid (410777) 2009 FD Open
Aims . Near-Earth asteroid (410777) 2009 FD is a potentially hazardous asteroid with possible (though unlikely) impacts on Earth at the end of the twenty-second century. The astrometry collected during the 2019 apparition provides informat…
View article: Exploiting dynamical perturbations for the end-of-life disposal of spacecraft in LEO
Exploiting dynamical perturbations for the end-of-life disposal of spacecraft in LEO Open
As part of the dynamical analysis carried out within the Horizon 2020\nReDSHIFT project, this work analyzes the possible strategies to guide low\naltitude satellites towards an atmospheric reentry through an impulsive\nmaneuver. We conside…
View article: Periodic Orbits Close to That of the Moon in Hill's Problem
Periodic Orbits Close to That of the Moon in Hill's Problem Open
In the framework of the restricted, circular, 3-dimensional 3-body problem Sun-Earth-Moon, Valsecchi et al. (1993) found a set of 8 periodic orbits, with duration equal to that of the Saros cycle, and differing only for the initial phases,…
View article: The eROSITA X-ray mirrors: technology and qualification aspects of the production of mandrels, shells and mirror modules
The eROSITA X-ray mirrors: technology and qualification aspects of the production of mandrels, shells and mirror modules Open
The name "eROSITA" stands for extended Roentgen Survey with an Imaging Telescope Array. The general design of the eROSITA X-ray telescope is derived from that of ABRIXAS. A bundle of 7 mirror modules with short focal lengths make up a comp…
View article: Solar radiation pressure resonances in Low Earth Orbits
Solar radiation pressure resonances in Low Earth Orbits Open
The aim of this work is to highlight the crucial role that orbital resonances\nassociated with solar radiation pressure can have in Low Earth Orbit. We review\nthe corresponding literature, and provide an analytical tool to estimate the\nm…
View article: Talc a far-infrared 20m space telescope and the ELICSIR consortium to reach TRL 3
Talc a far-infrared 20m space telescope and the ELICSIR consortium to reach TRL 3 Open
Further space exploration in the far-infrared (FIR) requires larger apertures in order to improve the spatial resolution of captured images. To this purpose, the Thinned Aperture Light Collector (TALC) concept of a deployable annular teles…
View article: Distribution of long-period comets: comparison between simulations and observations
Distribution of long-period comets: comparison between simulations and observations Open
Aims. This paper is devoted to a comparison between observations and simulations of the so-called Oort spike formed by the “new” observable long-period comets. Methods. The synthetic distributions of observable comets come from the propaga…
View article: A quantitative evaluation of the environmental impact of the mega constellations
A quantitative evaluation of the environmental impact of the mega constellations Open
The main focus of this work is to highlight the main parameters driving the future evolution of the debris environment, in presence of the planned LEO mega constellation of satellites. First, in order to identify the most important paramet…
View article: Mission analysis for two potential asteroids threat scenarios: Optimal impact strategies and technology evaluation
Mission analysis for two potential asteroids threat scenarios: Optimal impact strategies and technology evaluation Open
The Space Mission Planning Advisory Group SMPAG's mission is to prepare for an international response to a Near Earth Object impact threat through the exchange of information, development of options for collaborative research and mission o…