2023, Contributo in volume, ITA
Rossi Alessandro
La protezione del nostro pianeta dagli impatti contro corpi celesti (asteroidi e comete) passa anzitutto da un'accurata attività di sorveglianza e catalogazione dei piccoli corpi del sistema solare. In caso di necessità, potrebbe essere necessario ricorrere ad una missione spaziale per la deflessione dell'oggetto in "rotta di collisione" contro la Terra. La missione DART/LICIACube ha effettuato il primo test reale di deflesisone di un asteroide.
2023, Articolo in rivista, ENG
J. D. P. Deshapriya , P. H. Hasselmann , I. Gai, M. Hirabayashi , E. Dotto, A. Rossi , A. Zinzi , V. Della Corte, I. Bertini,, S. Ieva , E. Mazzotta Epifani, M. Dall'Ora , S. Ivanovski0 , D. Perna , T. L. Farnham , M. Amoroso, J. R. Brucato , A. Capannolo, S. Caporali, M. Ceresoli, Nancy L. Chabot , A. Cheng, G. Cremonese , R. T. Daly , E. G. Fahnestock, L. Gomez Casajus, E. Gramigna, G. Impresario, R. Lasagni Manghi, M. Lavagna, J.-Y. Li, M. Lombardo, A. Lucchetti, D. Modenini, M. Pajola , E. Palmer , P. Palumbo, , S. Pirrotta, G. Poggiali, , A. S. Rivkin , P. Sanchez , G. Tancredi , P. Tortora, F. Tusberti, M. Zannoni, and G. Zanotti
We modeled the geometry and the three-dimensional orientation of the ejecta cone triggered by the impact of the DART spacecraft on the asteroid Dimorphos. We used eight LUKE images of the impact acquired by the CubeSat LICIACube that flew by the Didymos system shortly after the impact. These images, which show the ejecta cone in both face-on and side-on profiles, enabled us to reconstruct the ejecta cone in inertial space. We started our model as a simple cone with a circular base and developed it to a rotated cone with an elliptical base that best fit the data. The cone axis points to R.A., decl. (in J2000): 147, +16. . The cone is characterized by two perpendicular half-angles of 69 deg and 51 deg and a rotation of ? = 12° around its axis. The apex of the cone is located near the center of Dimorphos within 15 m. The intersection of the cone and the surface of Dimorphos (surface enclosed by the cone) would correspond to a crater with a maximum radius of about 65 m. The characterization of the cone axis is directly related to the computation of the momentum enhancement factor (?) of the impact, and it hence proves the crucial need of studying impacts in the context of planetary defence scenarios. The results of this work could potentially be used to constrain whether the impact took place in a strength-dominated or a gravity-dominated regime. This work shows the important scientific return of the LICIACube CubeSat in the context of planetary defence.
2023, Poster, ENG
K. Langner , F. Marzari, A. Rossi, G. Zanotti, S. Raducan, A. Campo Bagatin
The European Space Agency spacecraft Hera is the European contribution to the Asteroid Impact Deflection Assessment (AIDA) international cooperation. Hera is scheduled to launch in October 2024 and to rendezvous with the binary asteroid system Didymos-Dimorphos in 2026. Hera will perform close-up measurements of the effects of the NASA/APL DART probe impact, also releasing two dedicated cubestas. As observed by the Italian Space Agency LICIACube and from space and ground telescopes, the impact generated a massive ejecta cone of particles, with observed sizes ranging from microns to meters. Most of the small particles left the binary system due both to the large ejection velocities and to the push exerted by the solar radiation pressure. Nonetheless, there is the possibility that part of the huge ejecta population, especially in low velocity tail, remains trapped within the binary system due to a number of dynamical interactions [6] (e.g., note that post-impact Hubble Space Telescope images revealed the presence of many m-sized boulders within the system). These trapped particles, if present in the system at the time of Hera arrival, could represent a hazard to the probes, especially if they are below the sensitivity thresholds of the probes instruments. Therefore it is important to understand if and where these particles might be found.
2023, Articolo in rivista, ENG
Moreno, Fernando; Bagatin, Adriano Campo; Tancredi, Gonzalo; Li, Jian-Yang; Rossi, Alessandro; Ferrari, Fabio; Hirabayashi, Masatoshi; Fahnestock, Eugene; Maury, Alain; Sandness, Robert; Rivkin, Andrew S.; Cheng, Andy; Farnham, Tony L.; Soldini, Stefania; Giordano, Carmine; Merisio, Gianmario; Panicucci, Paolo; Pugliatti, Mattia; Castro-Tirado, Alberto J.; Fernandez-Garcia, Emilio; Perez-Garcia, Ignacio; Ivanovski, Stavro; Penttila, Antti; Kolokolova, Ludmilla; Licandro, Javier; Munoz, Olga; Gray, Zuri; Ortiz, Jose L.; Lin, Zhong-Yi
The NASA Double Asteroid Redirection Test (DART) spacecraft successfully crashed on Dimorphos, the secondary component of the binary (65803) Didymos system. Following the impact, a large dust cloud was released, and a long-lasting dust tail developed. We have extensively monitored the dust tail from the ground and the Hubble Space Telescope. We provide a characterization of the ejecta dust properties, i.e., particle size distribution and ejection speeds, ejection geometric parameters, and mass, by combining both observational data sets and using Monte Carlo models of the observed dust tail. The size distribution function that best fits the imaging data is a broken power law having a power index of -2.5 for particles of r & LE; 3 mm and -3.7 for larger particles. The particles range in size from 1 & mu;m up to 5 cm. The ejecta is characterized by two components, depending on velocity and ejection direction. The northern component of the double tail, observed since 2022 October 8, might be associated with a secondary ejection event from impacting debris on Didymos, although is also possible that this feature results from the binary system dynamics alone. The lower limit to the total dust mass ejected is estimated at & SIM;6 x 10(6) kg, half of this mass being ejected to interplanetary space.
2023, Articolo in rivista, ENG
Li J.-Y.; Hirabayashi M.; Farnham T.L.; Sunshine J.M.; Knight M.M.; Tancredi G.; Moreno F.; Murphy B.; Opitom C.; Chesley S.; Scheeres D.J.; Thomas C.A.; Fahnestock E.G.; Cheng A.F.; Dressel L.; Ernst C.M.; Ferrari F.; Fitzsimmons A.; Ieva S.; Ivanovski S.L.; Kareta T.; Kolokolova L.; Lister T.; Raducan S.D.; Rivkin A.S.; Rossi A.; Soldini S.; Stickle A.M.; Vick A.; Vincent J.-B.; Weaver H.A.; Bagnulo S.; Bannister M.T.; Cambioni S.; Campo Bagatin A.; Chabot N.L.; Cremonese G.; Daly R.T.; Dotto E.; Glenar D.A.; Granvik M.; Hasselmann P.H.; Herreros I.; Jacobson S.; Jutzi M.; Kohout T.; La Forgia F.; Lazzarin M.; Lin Z.-Y.; Lolachi R.; Lucchetti A.; Makadia R.; Mazzotta Epifani E.; Michel P.; Migliorini A.; Moskovitz N.A.; Ormo J.; Pajola M.; Sanchez P.; Schwartz S.R.; Snodgrass C.; Steckloff J.; Stubbs T.J.; Trigo-Rodriguez J.M.
Some active asteroids have been proposed to be formed as a result of impact events. Because active asteroids are generally discovered by chance only after their tails have fully formed, the process of how impact ejecta evolve into a tail has, to our knowledge, not been directly observed. The Double Asteroid Redirection Test (DART) mission of NASA, in addition to having successfully changed the orbital period of Dimorphos, demonstrated the activation process of an asteroid resulting from an impact under precisely known conditions. Here we report the observations of the DART impact ejecta with the Hubble Space Telescope from impact time T + 15 min to T + 18.5 days at spatial resolutions of around 2.1 km per pixel. Our observations reveal the complex evolution of the ejecta, which are first dominated by the gravitational interaction between the Didymos binary system and the ejected dust and subsequently by solar radiation pressure. The lowest-speed ejecta dispersed through a sustained tail that had a consistent morphology with previously observed asteroid tails thought to be produced by an impact. The evolution of the ejecta after the controlled impact experiment of DART thus provides a framework for understanding the fundamental mechanisms that act on asteroids disrupted by a natural impact.
2023, Articolo in rivista, ENG
Cheng A.F.; Agrusa H.F.; Barbee B.W.; Meyer A.J.; Farnham T.L.; Raducan S.D.; Richardson D.C.; Dotto E.; Zinzi A.; Della Corte V.; Statler T.S.; Chesley S.; Naidu S.P.; Hirabayashi M.; Li J.-Y.; Eggl S.; Barnouin O.S.; Chabot N.L.; Chocron S.; Collins G.S.; Daly R.T.; Davison T.M.; DeCoster M.E.; Ernst C.M.; Ferrari F.; Graninger D.M.; Jacobson S.A.; Jutzi M.; Kumamoto K.M.; Luther R.; Lyzhoft J.R.; Michel P.; Murdoch N.; Nakano R.; Palmer E.; Rivkin A.S.; Scheeres D.J.; Stickle A.M.; Sunshine J.M.; Trigo-Rodriguez J.M.; Vincent J.-B.; Walker J.D.; Wunnemann K.; Zhang Y.; Amoroso M.; Bertini I.; Brucato J.R.; Capannolo A.; Cremonese G.; Dall'Ora M.; Deshapriya P.J.D.; Gai I.; Hasselmann P.H.; Ieva S.; Impresario G.; Ivanovski S.L.; Lavagna M.; Lucchetti A.; Epifani E.M.; Modenini D.; Pajola M.; Palumbo P.; Perna D.; Pirrotta S.; Poggiali G.; Rossi A.; Tortora P.; Zannoni M.; Zanotti G.
The NASA Double Asteroid Redirection Test (DART) mission performed a kinetic impact on asteroid Dimorphos, the satellite of the binary asteroid (65803) Didymos, at 23:14 UTC on 26 September 2022 as a planetary defence test. DART was the first hypervelocity impact experiment on an asteroid at size and velocity scales relevant to planetary defence, intended to validate kinetic impact as a means of asteroid deflection. Here we report a determination of the momentum transferred to an asteroid by kinetic impact. On the basis of the change in the binary orbit period, we find an instantaneous reduction in Dimorphos's along-track orbital velocity component of 2.70 ± 0.10 mm s, indicating enhanced momentum transfer due to recoil from ejecta streams produced by the impact. For a Dimorphos bulk density range of 1,500 to 3,300 kg m, we find that the expected value of the momentum enhancement factor, ?, ranges between 2.2 and 4.9, depending on the mass of Dimorphos. If Dimorphos and Didymos are assumed to have equal densities of 2,400 kg m, ?=3.61-0.25+0.19(1?). These ? values indicate that substantially more momentum was transferred to Dimorphos from the escaping impact ejecta than was incident with DART. Therefore, the DART kinetic impact was highly effective in deflecting the asteroid Dimorphos.
2023, Abstract in atti di convegno, ENG
S. Soldini, F. Ferrari, J-Y Li, S. Raducan, M. Jutzi, Y. Zhang, A. Rossi, F. Marzari, F. Moreno, A. Campo-Bagatin, A. Cheng, D. Hamilton, S. Ivanovski, G. Fahnestock, O. S Barnouin, R. T. Daly, C. M. Ernst, E. Palmer, A. S. Rivkin, N. L. Chabot and the DART Investigation Team
On 26th September 2022, the NASA's DART spacecraft intentionally impacted Dimorphos, the secondary member of the Didymos system, successfully demonstrating the first planetary defense test in space . ESA's Hera mission will then visit the Didymos system in late 2026 for a thorough evaluation of the aftermath of NASA's DART impact . DART's impact exceeded the expectations of the kinetic-impactor technique, showing that the ejecta generated from the impact enhanced the momentum exchange, making this technique an effective deflection method for rubble-pile asteroids . Extensively observed by the Italian CubeSat (LICIACube) and several ground-based telescopes , the tail has lasted for several months. On the basis of observations made on December 28th, 2022 , it appears to have started to fade. In this study, the N-Body planetary code goNEAR is used to simulate the ejecta dynamics. The tail's morphology and geometry are highly dependent on the acceleration effects of Solar-Radiation Pressure (SRP).
2023, Abstract in atti di convegno, ENG
S. D. Raducan, M. Jutzi, Y. Zhang, A. F. Cheng, G. S. Collins, T. M. Davison, T. Farnham, F. Ferrari, M. Hirabayashi, J-Y. Li, P. Michel, J. Ormö, O. Barnouin, R. T. Daly, C. M. Ernst, A. Lucchetti, N. Murdoch, M. Pajola, P. Sánchez, E. Dotto, E. Fahnestock, P. H. Hasselmann, I. Herreros, S. L. Ivanovski, R. Luther, R. Nakano, A. S. Rivkin, A. Rossi, S. Soldini, F. Tusberti, K. Wünnemann and the DART Investigation Team.
On September 26, 2022, NASA's Double Asteroid Redirection Test (DART) mission successfully impacted the small moon of asteroid Didymos . The primary goal of the mission was to test the feasibility of using a kinetic impactor to change the orbit of an asteroid in space. The impact was highly effective, resulting in a change in Dimorphos' orbit around Didymos by ~33 minutes . Large amounts of ejecta were observed from ground- and space-based telescopes, and from the LICIACube spacecraft , which was deployed from DART before its impact. The deflection efficiency of an asteroid can be quantified in terms of a parameter called ?, which is the ratio of the momentum of the impactor to the recoil momentum of the target. The impact outcome strongly depends on the surface, subsurface and internal properties . In order to better understand the target properties and structure of Dimorphos, we used empirical scaling relationships based on laboratory experiments and previous numerical simulations as well as new numerical simulations using the Bern SPH shock physics code to model the impact outcome and compare it with observations.
2023, Abstract in atti di convegno, ENG
Poggiali G., Brucato J.R., Caporali S., Deshapriya J.D.P., Hasselmann, P., Ieva S., Bertini I., Dotto E., Ivanovski, S.L., Rossi A., Della Corte, V., Zinzi A., Mazzotta Epifani E., Dall'Ora M., Pajola M., Lucchetti A., Amororso M., Barnouin O., Capannolo, A., Ceresoli, M., Chabot, N.L., Cheng, A.F., Cremonese, G., Fahnestock E.G., Gai, I., Glenar, D., Gomez Casajus L., Gramigna E., Impresario G., Lasagni Manghi R., Lavagna, M., Li, J.-Y., Lolachi, R., Lombardo M., Modenini, D., Palumbo, P., Perna, D., Pirrotta, S., Rivkin, A.S., Sánchez, P., Stubbs, T., Tortora, P., Trigo-Rodríguez, J.M., Tusberti F., Zannoni, M., Zanotti, G.
NASA's DART mission successfully demonstrated the first test of planetary defense through the kinetic impactor technique on 26th September 2022. The primary target of the mission was Dimorphos, which is the ~151 meters wide satellite in the binary system (65803) Didymos. The ASI CubeSat LICIACube , separated from the DART spacecraft 15 days before the impact, acquired more than 400 images during a fly-by, before and after the moment of DART impact, to witness the success of the mission and acquire images for the analysis of the surface of the two asteroids and the plume produced by the impact. LICIACube close approach [CA] to Dimorphos was about 58 km. One of the LICIACube payloads, the LUKE (LICIACube Unit Key Explorer) camera, was equipped with an RGB Bayer filter for acquiring color data . As a result of the impact, the secondary asteroid Dimorphos decreased its orbital period around the primary Didymos by about 33 minutes with a large amount of ejected material observed by both LICIACube and ground- and space-based telescopes.
2023, Abstract in atti di convegno, ENG
M. Pajola, F. Tusberti, A. Lucchetti, O. Barnouin, C.M. Ernst, E. Dotto, R.T. Daly, G. Poggiali,, M. Hirabayashi, E. Mazzotta Epifani, N. L. Chabot, V. Della Corte, H. Agrusa,, R.-L. Ballouz, N. Murdoch, C. Robin, A. Rossi, S.R. Schwartz, S. Ieva, S. Ivanovski, A. Campo-Bagatin, L. Parro,, P. Benavidez, J.B. Vincent, F. Ferrari, G. Tancredi, J.M. Trigo-Rodriguez, S. Raducan, J. Sunshine, T. Farnham, E. Asphaug, A. Rivkin, J.D.P. Deshapriya, P.H.A. Hasselmann, J.R. Brucato, A. Zinzi,, M. Amoroso, S. Pirrotta, G. Impresario, S. Cambioni, P. Michel, A. Cheng, I. Bertini, A. Capannolo, S. Caporali, M. Ceresoli, B. Cotugno, G. Cremonese, M. Dall'Ora, V. Di Tana, I. Gai, M. Lavagna, F. Miglioretti, D. Modenini, P. Palumbo, D. Perna, S. Simonetti, P. Tortora, M. Zannoni, G. Zanotti.
On 26 September 2022, the Double Asteroid Redirection Test (DART) spacecraft impacted the surface of Dimorphos, the ~150 m size satellite of the near-Earth binary asteroid (NEA) (65803) Didymos (~760 m-size, ). Numerical models of asteroid disruption, the analyses of asteroids' shapes, and in-situ observations, support the interpretation that small asteroids (0.2-10 km size range) are reaccumulated remnants from disrupted parent bodies, also called rubble-piles. Surface boulders on rubble piles, therefore, represent directly the fragments of those parent-body disruptions followed by some evolutionary process such as cratering and thermal breakdown, followed by the size-sorting and migration of granular materials when an asteroid's regolith is mobilized. Hence, the observed size- frequency distribution (SFD) of boulders on the surface of a NEA and the corresponding fitting indices is a powerful tool for understanding the initial formation of boulders and their subsequent evolution. The boulder SFD is also important in understanding the conditions of the surface for any kinetic deflection experiment such as DART.
2023, Abstract in atti di convegno, ENG
A. Lucchetti, O.S. Barnouin, M. Pajola, S. Cambioni, K.T. Ramesh, R. Nakano, T. Kohout, C.M. Ernst, T. Daly, E. Dotto, R.-L. Ballouz, L. Parro, A. Campo Bagatin, T. Hirabayashi, G. Poggiali, T. Farnham, E. Mazzotta Epifani, N. Chabot, N. Murdoch, J. Steckloff, J.B Vincent, S. Schwartz, J. Sunshine, F. Ferrari, S. Raducan, J. M. T. Rodriguez, P. Michel, S. Eggl, B. Mondal, A. Cheng, M. Amoroso, I. Bertini, J.R. Brucato, A. Capannolo, S. Caporali, M. Ceresoli, B. Cotugno, G. Cremonese, M. Dall'Ora, V. Della Corte, J.D.P. Deshapriya, V. Di Tana, I. Gai, P.H.A. Hasselmann, S. Ieva, G. Impresario, S. Ivanovski, M. Lavagna, F. Miglioretti, D. Modenini, P. Palumbo, D. Perna, S. Pirrotta, A. Rossi, S. Simonetti, P. Tortora, F. Tusberti, M. Zannoni, G. Zanotti, A. Zinzi
On 26 September 2022, the Double Asteroid Redirection Test (DART) spacecraft impacted the surface of Dimorphos, the ~150 m-size moonlet of the binary system (65803) Didymos (~780 m-size, ), allowing detailed surface characterization. Both DART and the Light Italian Cubesat for Imaging of Asteroids (LICIACube, ) provided direct observations of geological features, including lineaments, rocks' fractures and/or cracks, boulders, craters and signs of mass movements. Here we study both boulders' fractures and mass movements in order to constrain their formation processes and to investigate the formation and evolution of the Didymos system. Specifically, boulders cracks analysis is pivotal to constrain the internal structure and history of the body and the occurrence of mass movements provide crucial insights on the mechanical behavior of the binary system's constitutive material.
2023, Abstract in atti di convegno, ENG
Jian-Yang Li, M. Hirabayashi, T.L. Farnham, J.M. Sunshine, M.M. Knight, G. Tancredi, F. Moreno, B. Murphy, C. Opitom, S. Chesley, H.A. Weaver, D.J. Scheeres, C.A. Thomas, E.G. Fahnestock, A.F. Cheng, A.S. Rivkin, F. Ferrari, A. Rossi, J.M. Trigo-Rodríguez, and the DART Investigation Team
On September 26, 2022, NASA's first planetary defense experiment, the Double Asteroid Redirection Test (DART) mission, successfully performed an impact experiment on Dimorphos, the secondary asteroid, of the Didymos binary asteroid system . With a spacecraft mass of 579 kg impacting the 151 m equivalent diameter asteroid at a speed of 6.14 km/s, this impact is comparable to the natural impacts occurring on asteroids, providing us with a unique opportunity to study the asteroidal impact process and the fate of the ejecta. As part of the worldwide observing campaign to monitor the impact, we imaged the ejecta with the Hubble Space Telescope (HST) starting one hour before the DART impact with observations continuing for the next 18.5 days at pixel scales of ~2.1 km at the asteroid. The data revealed a complex and unique dynamic evolution of the ejected dust under the gravitational interaction with the binary system and solar radiation pressure (SRP), ultimately forming a dust tail similar to the tails observed to evolve from active asteroids thought to be triggered by natural impacts (e.g., ).
2023, Abstract in atti di convegno, ENG
R. Lolachi, D. A. Glenar, T. J. Stubbs, L. Kolokolova, P. H. Hasselmann, G. Poggiali, J-Y. Li, E. Dotto, A. Rossi, V. Della Corte and A. Zinzi
The Double Asteroid Redirection Test (DART) mission was the world's first planetary defense mission. After reaching the binary (65803) Didymos-Dimorphos asteroid system it hit the 160 m diameter secondary, Dimorphos, on September . Impacting at a speed of approximately 6 km s-1 it successfully demonstrated the kinetic impact deflection technique changing Dimorphos' orbital period about Didymos by about 0 min and creating a complex impact ejecta plume with filamentary structures in the process . These events were observed both from Earth and by DART's ride-along companion CubeSat, LICIACube. These observations will be used to determine and understand the momentum transfer efficiency of the impact . Calculating ejecta mass is critical to understanding momentum transfer. This requires an accurate knowledge of scattering properties including the ejecta particle size distribution. Analysis of LUKE brightness measurements at widely separated phase angles and in multiple colors comprise nearly independent measures for constraining the effective size of scattering particles. We have used LUKE RGB data to examine the spatial and temporal variation of effective particle size within the ejecta plume structure and filaments, as outlined below.
2023, Abstract in atti di convegno, ENG
M. Hirabayashi, T. L. Farnham, J. D. P. Deshapriya, J.-Y. Li, E. Dotto, P. H. Hasselmann3, A. Rossi, S. L. Ivanovski, O. S. Barnouin, R. T. Daly, I. Gai, H. Nair, E. E. Palmer, A. Zinzi, H. F. Agrusa,, B. W. Barbee, N. L. Chabot, A. F. Cheng, E. G. Fahnestock, A. J. Meyer, A. S. Rivkin, M. E. DeCoster, V. Della Corte, C. M. Ernst, K. M. Kumamoto, A. Lucchetti, E. Mazzotta Epifani, M. Pajola, S. D. Raducan, D. C. Richardson, T. S. Statler, A. M. Stickle, the DART Investigation Team, and the LICIACube Team
NASA's Double Asteroid Redirection Test (DART) successfully impacted Dimorphos, the satellite of the binary system (65803) Didymos. After the DART impact at 23:14:24.183±0.004 UTC on September 26, 2022, the resulting ejecta plume immediately grew, and was captured in detail by ground- and space-based telescopes and LICIACube, the Italian CubeSat released from DART before the impact. The impact reduced Dimorphos's orbital velocity, leading to an orbital period change of 33.0±1.0 (3?) minutes and thus a momentum enhancement (?) factor of 2.2-4.9, depending on its unknown mass. This ? (>1) factor indicates the critical role of the DART impact-driven ejecta in kinetic deflection. Here, we apply image processing and statistical estimation techniques to show that the ejecta cone has a skewed geometry, stretched along Dimorphos's short axis. Given both Hubble Space Telescope (HST) and LICIACube LUKE images taken at an early stage of the ejecta formation, our preliminary solution prefers a cone opening angle of ~145 deg along the short axis and that of ~95 deg along the equatorial plane.
2023, Abstract in atti di convegno, ENG
P. H. Hasselmann, E. Dotto, J.D.P. Deshapriya, G. Poggiali, A. Rossi, I. Bertini, G. Zanotti, S. Ieva, S. Ivanovski, E. Mazzotta-Epifani, V. Della Corte, J. Sunshine, A. Zinzi, J-Y. Li, L. Kolokolova, D. Glenar, R. Lolachi, T. Stubbs, M. Amoroso, O. Barnouin, J.R. Brucato, N. Chabot, A. Cheng, A. Capannolo, S. Caporali, M. Ceresoli, B. Cotugno, G. Cremonese, T. R. Daly, M. Dall'Ora, V. Di Tana, C.M. Ernst, E.G. Fahnestock, T. Farnham, F. Ferrari, I. Gai, G. Impresario, D. P. Sanchez-Lana, M. Lavagna, A. Lucchetti, F. Miglioretti, D. Modenini, M. Pajola, S. Pirrotta, P. Palumbo, D. Perna, S.D. Raducan, A. Rivkin, S.R. Schwartz, S. Simonetti, P. Tortora, J.M. Trigo-Rodríguez, M. Zannoni
The NASA/DART mission successfully accomplished the first planetary defense test on the 26th September 2022 when it impacted Dimorphos, the secondary object of the (65803) Didymos binary system. DART demonstrated the capabilities of the kinetic redirection technique. Dimorphos was hit by DART with velocity of 6.1 km/s, which produced a complex ejecta plume composed of filamentary streams extending roughly 10 km from the surface just hundreds of seconds after impact. Before the impact, DRACO imager onboard DART provided near-real-time images during the fast approach phase, unveiling the surface of Dimorphos at very small spatial resolution in a single phase angle of 59°. The first seconds to minutes into the event were witnessed by the LEIA and LUKE instruments of the Italian Space Agency CubeSat LICIACube . Both cameras captured hundreds of images during the fly-by maneuver, with the closest approach of about 57 km from Dimorphos. The disk-resolved data obtained has the largest phase angle coverage, ranging from 43° to 118°.
2023, Abstract in atti di convegno, ENG
T. L. Farnham, M. Hirabayashi, J. D. P. Deshapriya, O. S. Barnouin, M. Bruck-Syal, A. Cheng, V. Della Corte, E. Dotto, E. M. Epifani, E. G. Fahnestock, F. Ferrari, I. Gai, P. H. Hasselmann, S. Ivanovski, J.-Y. Li, F. Marzari, M. Pajola, J. M. Sunshine, K. T. Ramesh, S. Raducan, A. Rossi, A. Zinzi, the DART Investigation Team and the LICIACube Team
NASA's Double Asteroid Redirection Test (DART) was designed to demonstrate the potential for using a kinetic impactor to deflect the trajectory of a potentially hazardous object, and to investigate the momentum enhancement, beyond that of the spacecraft itself, that is produced by the material ejected in the impact. The DART spacecraft impacted asteroid Dimorphos, the secondary component of the binary asteroid system (65803) Didymos, on 26 September 2022, changing its orbital period by 33±1 (1?) minutes. The successful outcome of the experiment proved the feasibility of the kinetic impactor concept, but to fully understand how the momentum imparted by the ejecta contributed to the changes in Dimorphos' orbit, it is necessary to ascertain the net direction in which the material was expelled. DART's companion spacecraft, LICIACube, observed the aftermath of the event during its post-impact flyby, imaging the complex structures formed by the ejected material, and we are using the parallax imparted by the spacecraft's changing viewpoint to map these structures in three dimensions. LICIACube also detected what appear to be clusters, consisting of dozens of boulders, that were launched in preferred directions. These boulders could represent a notable fraction of the ejecta mass, and determining the directions in which they were emitted could inform on the mechanisms that controlled the impact physics. As part of our ejecta mapping efforts, we will determine the relative positions and velocities of these boulders with respect to Dimorphos, and estimate their contributions to the total momentum yield from the DART impact.
2023, Abstract in atti di convegno, ENG
Dotto, E., Zinzi, A., Amoroso, M., Bertini, I., Brucato, J.R., Capannolo, A., Caporali, S., Ceresoli, M., Cremonese, G., Dall'Ora, M., Della Corte, V., Deshapriya J.D.P., Gai, I., Gomez Casajus L., Gramigna E., Hasselmann, P., Ieva, S., Impresario G., Ivanovski, S.L., Lasagni Manghi R., Lavagna, M., Lombardo M., Lucchetti, A., Mazzotta Epifani, E., Modenini, D., Pajola, M., Palumbo, P., Perna, D., Pirrotta, S., Poggiali, G., Rossi, A., Tortora, P., Tusberti F., Zannoni, M., Zanotti, G., Chabot, N.L., Cheng, A.F, Rivkin, A.S. and the DART Investigation Team
"LICIACube - the Light Italian Cubesat for Imaging of Asteroids" is a 6U CubeSat, managed by the Italian Space Agency (ASI), that witnessed in situ the DART impact on Dimorphos. LICIACube was hosted as a piggyback during the interplanetary cruise and was released 15 days before the DART impact, on its autonomous path towards the target. After commissioning phase and braking and correction maneuvers LICIACube approached the target and performed its scientific phase during the asteroid's fly-by. After that, LICIACube downloaded the obtained images to Earth: the Ground Segment was based on the Argotec Mission Control Centre, antennas of the NASA Deep Space Network and data archiving and processing, managed at the ASI Space Science Data Center.
2023, Abstract in atti di convegno, ENG
M. E. DeCoster, O. S. Barnouin, A. Cheng, R. T. Daly, E. Dotto, C. M. Ernst, D. M. Graninger, K. M. Kumamoto, A. Lucchetti, R. Luther, F. Marzari, J. M. Owen, M. Pajola, E. S. G. Rainey, A. Rossi, A. M. Stickle, F. Tisberti, and K. Wunnermann
The use of a kinetic impactor is one strategy to deflect objects that might be on an Earth impact trajectory. NASA's Double Asteroid Redirection Test (DART) is the first planetary defense test mission, which demonstrated a kinetic impactor technology on a non-threatening binary asteroid called (65803) Didymos. At 23:14 UTC on Sept 26, 2022, the 579-kg DART spacecraft impacted the secondary of the Didymos system, Dimorphos, at 6.14 km/s, within 25 m of the center-of-figure [1]. This impact resulted in massive streams of ejecta that contributed to a reduction in the binary orbital period by 33.0 +/- 1.0 (3?) minutes, which was measured via ground-based telescopes and radar [2]. This work explores computing the momentum enhancement factor (?), which is a measurement of the effectiveness of the kinetic impact, and is the ratio of momentum transferred to the target (?PT ) to the impactor momentum (?Pi ).
2023, Abstract in atti di convegno, ENG
M. Pajola, F. Tusberti, A. Lucchetti, O. Barnouin, C.M. Ernst, E. Dotto, R.T. Daly, G. Poggiali,, M. Hirabayashi, E. Mazzotta Epifani, N. L. Chabot, V. Della Corte, H. Agrusa,, R.-L. Ballouz, N. Murdoch, C. Robin, A. Rossi, S.R. Schwartz, S. Ieva, S. Ivanovski, A. Campo-Bagatin, L. Parro,, P. Benavidez, J.B. Vincent, F. Ferrari, G. Tancredi, J.M. Trigo-Rodriguez, J. Sunshine, T. Farnham, E. Asphaug, A. Rivkin, J.D.P. Deshapriya, P.H.A. Hasselmann, J.R. Brucato, A. Zinzi,, M. Amoroso, S. Pirrotta, G. Impresario, S. Cambioni, P. Michel, A. Cheng, I. Bertini, A. Capannolo, S. Caporali, M. Ceresoli, B. Cotugno, G. Cremonese, M. Dall'Ora, V. Di Tana, I. Gai, M. Lavagna, F. Miglioretti, D. Modenini, P. Palumbo, D. Perna, S. Simonetti, P. Tortora, M. Zannoni, G. Zanotti
On 26 September 2022, the Double Asteroid Redirection Test (DART) spacecraft impacted the surface of Dimorphos, the ~150 m size satellite of the near-Earth binary asteroid (NEA) (65803) Didymos (~780 m-size, [1]). Numerical models of asteroid disruption, the analyses of asteroids' shapes, and in situ observations, support the interpretation that small asteroids (0.2-10 km size range) are reaccumulated remnants from disrupted parent bodies, also called rubble-piles (e.g. [2, 3]). Surface boulders, therefore, represent directly the fragments of those parent-body disruptions followed by some evolutionary process such as cratering and thermal breakdown, followed by the size-sorting and migration of granular materials when an asteroid's regolith is mobilized. Hence, the observed size-frequency distribution (SFD) of boulders on the surface of a NEA and the corresponding fitting indices is a powerful tool for understanding the initial formation of boulders and their subsequent evolution. The boulder SFD is also important in understanding the conditions of the surface for any kinetic deflection experiment such as DART.
2023, Abstract in atti di convegno, ENG
S. Ieva , E. Mazzotta Epifani , V. Petropoulou, J. D. P. Deshapriya , P. H. Hasselmann , D. Perna , M. Dall'Ora , G. Poggiali ,, J.R. Brucato , M. Pajola , A. Lucchetti , S. Ivanovski , A. Rossi, P. Palumbo ,, V. Della Corte , A. Zinzi ,, C. Thomas, J. de Leon,, A.S. Rivkin, E. Dotto, M. Amoroso, I. Bertini ,, A. Capannolo , S. Caporali , M. Ceresoli , G. Cremonese , I. Gai, L. Gomez Casajus , E. Gramigna , G. Impresario , R. Lasagni Manghi , M. Lavagna , M. Lombardo , D. Modenini , S. Pirrotta , P. Tortora , F. Tusberti , M. Zannoni , G. Zanotti
ear-Earth objects (NEOs), due to their proximity to our planet, represent one of the most accessible bodies in the whole Solar System. Their investigation, other than providing vital information to planetary formation and water delivery, is compelling due to the hazard these bodies pose to human civilization. The DART/LICIACube mission: To this purpose, the NASA Double Asteroid Redirection Test (DART) has been approved to be the first demonstration of kinetic impactor as an asteroid hazard mitigation [1]. The DART spacecraft successfully crashed onto the secondary member of the Didymos system (Dimorphos) on September 26th 2022 at 23:14 UTC. Hosted as a piggyback and released fifteen days before the DART impact there was also the Light Italian Cubesat for Imaging of Asteroids (LICIACube, 2), a 6U cubesat space mission financed by the Italian Space Agency (ASI). LICIACube with its two scientific cameras (LUKE & LEIA) has testified the impact and characterized the system and the ejecta plume in the aftermath of DART event with an incredible level of detail. In addition, the ESA Hera mission, to be launched in 2024, will continue the characterization of the binary system.