27 research outputs found
Model of Double Asteroid Redirection Test Impact Ejecta Plume Observations
The Double Asteroid Redirection Test (DART) spacecraft will impact the moon Dimorphos of the [65803]
Didymos binary in order to demonstrate asteroid deflection by a kinetic impactor. DART will measure the
deflection by using ground-based telescopic observations of the orbital period change of Didymos and will carry
the Light Italian CubeSat for Imaging of Asteroids (LICIACube) cubesat, which will perform a flyby of Didymos
about 167 s after the DART impact, obtaining images of the DART impact ejecta plume. LICIACube images
showing the ejecta plume spatial structure and temporal evolution will help determine the vector momentum
transfer from the DART impact. A model is developed for the impact ejecta plume optical depth, using a pointsource scaling model of the DART impact. The model is applied to expected LICIACube plume images and shows
how plume images enable characterization of the ejecta mass versus velocity distribution. The ejecta plume
structure, as it evolves over time, is determined by the amount of ejecta that has reached a given altitude at a given
time. The evolution of the plume optical depth profiles determined from LICIACube images can distinguish
between strength-controlled and gravity-controlled impacts, by distinguishing the respective mass versus velocity
distributions. LICIACube plume images discriminate the differences in plume structure and evolution that result
from different target physical properties, mainly the strength and porosity, thereby allowing inference of these
properties to improve the determination of DART impact momentum transfer
Effects of Impact and Target Parameters on the Results of a Kinetic Impactor: Predictions for the Double Asteroid Redirection Test (DART) Mission
The Double Asteroid Redirection Test (DART) spacecraft will impact into the asteroid Dimorphos on 2022 September 26 as a test of the kinetic impactor technique for planetary defense. The efficiency of the deflection following a kinetic impactor can be represented using the momentum enhancement factor, ÎČ, which is dependent on factors such as impact geometry and the specific target material properties. Currently, very little is known about Dimorphos and its material properties, which introduces uncertainty in the results of the deflection efficiency observables, including crater formation, ejecta distribution, and ÎČ. The DART Impact Modeling Working Group (IWG) is responsible for using impact simulations to better understand the results of the DART impact. Pre-impact simulation studies also provide considerable insight into how different properties and impact scenarios affect momentum enhancement following a kinetic impact. This insight provides a basis for predicting the effects of the DART impact and the first understanding of how to interpret results following the encounter. Following the DART impact, the knowledge gained from these studies will inform the initial simulations that will recreate the impact conditions, including providing estimates for potential material properties of Dimorphos and ÎČ resulting from DARTâs impact. This paper summarizes, at a high level, what has been learned from the IWG simulations and experiments in preparation for the DART impact. While unknown, estimates for reasonable potential material properties of Dimorphos provide predictions for ÎČ of 1â5, depending on end-member cases in the strength regime
The Dimorphos ejecta plume properties revealed by LICIACube
The Double Asteroid Redirection Test (DART) had an impact with Dimorphos (a satellite of the asteroid Didymos) on 26 September 20221. Ground-based observations showed that the Didymos system brightened by a factor of 8.3 after the impact because of ejecta, returning to the pre-impact brightness 23.7âdays afterwards2. Hubble Space Telescope observations made from 15âminutes after impact to 18.5âdays after, with a spatial resolution of 2.1âkilometres per pixel, showed a complex evolution of the ejecta3, consistent with other asteroid impact events. The momentum enhancement factor, determined using the measured binary period change4, ranges between 2.2 and 4.9, depending on the assumptions about the mass and density of Dimorphos5. Here we report observations from the LUKE and LEIA instruments on the LICIACube cube satellite, which was deployed 15âdays in advance of the impact of DART. Data were taken from 71âseconds before the impact until 320âseconds afterwards. The ejecta plume was a cone with an aperture angle of 140â±â4 degrees. The inner region of the plume was blue, becoming redder with increasing distance from Dimorphos. The ejecta plume exhibited a complex and inhomogeneous structure, characterized by filaments, dust grains and single or clustered boulders. The ejecta velocities ranged from a few tens of metres per second to about 500âmetres per second.This work was supported by the Italian Space Agency (ASI) in the LICIACube project (ASI-INAF agreement AC no. 2019-31-HH.0) and by the DART mission, NASA contract 80MSFC20D0004. M.Z. acknowledges Caltech and the Jet Propulsion Laboratory for granting the University of Bologna a licence to an executable version of MONTE Project Edition software. M.Z. is grateful to D. Lubey, M. Smith, D. Mages, C. Hollenberg and S. Bhaskaran of NASA/JPL for the discussions and suggestions regarding the operational navigation of LICIACube. G.P. acknowledges financial support from the Centre national dâĂ©tudes spatiales (CNES, France). A.C.B. acknowledges funding by the NEO-MAPP project (grant agreement 870377, EC H2020-SPACE-2019) and by the Ministerio de Ciencia InnovaciĂłn (PGC 2018) RTI2018-099464-B-I00. F.F. acknowledges funding from the Swiss National Science Foundation (SNSF) Ambizione (grant no. 193346). J.-Y.L. acknowledges the support from the NASA DART Participating Scientist Program (grant no. 80NSSC21K1131). S.D.R. and M.J. acknowledge support from the Swiss National Science Foundation (project no. 200021_207359)
After DART: Using the First Full-scale Test of a Kinetic Impactor to Inform a Future Planetary Defense Mission
NASAâs Double Asteroid Redirection Test (DART) is the first full-scale test of an asteroid deflection technology. Results from the hypervelocity kinetic impact and Earth-based observations, coupled with LICIACube and the later Hera mission, will result in measurement of the momentum transfer efficiency accurate to âŒ10% and characterization of the Didymos binary system. But DART is a single experiment; how could these results be used in a future planetary defense necessity involving a different asteroid? We examine what aspects of Dimorphosâs response to kinetic impact will be constrained by DART results; how these constraints will help refine knowledge of the physical properties of asteroidal materials and predictive power of impact simulations; what information about a potential Earth impactor could be acquired before a deflection effort; and how design of a deflection mission should be informed by this understanding. We generalize the momentum enhancement factor ÎČ, showing that a particular direction-specific ÎČ will be directly determined by the DART results, and that a related direction-specific ÎČ is a figure of merit for a kinetic impact mission. The DART ÎČ determination constrains the ejecta momentum vector, which, with hydrodynamic simulations, constrains the physical properties of Dimorphosâs near-surface. In a hypothetical planetary defense exigency, extrapolating these constraints to a newly discovered asteroid will require Earth-based observations and benefit from in situ reconnaissance. We show representative predictions for momentum transfer based on different levels of reconnaissance and discuss strategic targeting to optimize the deflection and reduce the risk of a counterproductive deflection in the wrong direction
After DART: Using the first full-scale test of a kinetic impactor to inform a future planetary defense mission
NASA's Double Asteroid Redirection Test (DART) is the first full-scale test
of an asteroid deflection technology. Results from the hypervelocity kinetic
impact and Earth-based observations, coupled with LICIACube and the later Hera
mission, will result in measurement of the momentum transfer efficiency
accurate to ~10% and characterization of the Didymos binary system. But DART is
a single experiment; how could these results be used in a future planetary
defense necessity involving a different asteroid? We examine what aspects of
Dimorphos's response to kinetic impact will be constrained by DART results; how
these constraints will help refine knowledge of the physical properties of
asteroidal materials and predictive power of impact simulations; what
information about a potential Earth impactor could be acquired before a
deflection effort; and how design of a deflection mission should be informed by
this understanding. We generalize the momentum enhancement factor ,
showing that a particular direction-specific will be directly
determined by the DART results, and that a related direction-specific
is a figure of merit for a kinetic impact mission. The DART
determination constrains the ejecta momentum vector, which, with hydrodynamic
simulations, constrains the physical properties of Dimorphos's near-surface. In
a hypothetical planetary defense exigency, extrapolating these constraints to a
newly discovered asteroid will require Earth-based observations and benefit
from in-situ reconnaissance. We show representative predictions for momentum
transfer based on different levels of reconnaissance and discuss strategic
targeting to optimize the deflection and reduce the risk of a counterproductive
deflection in the wrong direction
After DART: Using the First Full-scale Test of a Kinetic Impactor to Inform a Future Planetary Defense Mission
After DART: Using the First Full-scale Test of a Kinetic Impactor to Inform a Future
Planetary Defense Mission
Thomas S. Statler 1 , Sabina D. Raducan 2 , Olivier S. Barnouin 3 , Mallory E. DeCoster 3 , Steven R. Chesley 4 ,
Brent Barbee 5
, Harrison F. Agrusa 6 , Saverio Cambioni 7 , Andrew F. Cheng 3 , Elisabetta Dotto 8
, Siegfried Eggl9 ,
Eugene G. Fahnestock 4
, Fabio Ferrari 2 , Dawn Graninger 3 , Alain Herique 10
, Isabel Herreros 11
, Masatoshi Hirabayashi 12,13 ,
Stavro Ivanovski 14
, Martin Jutzi 2
, ĂzgĂŒr Karatekin 15
, Alice Lucchetti 16
, Robert Luther 17 , Rahil Makadia 9 ,
Francesco Marzari 18 , Patrick Michel 19 , Naomi Murdoch 20
, Ryota Nakano13 , Jens Ormö 11 , Maurizio Pajola 16 ,
Andrew S. Rivkin3 , Alessandro Rossi 21 , Paul SĂĄnchez 22 , Stephen R. Schwartz 23
, Stefania Soldini 24
, Damya Souami 19
,
Angela Stickle 3 , Paolo Tortora 25
, Josep M. Trigo-RodrĂguez 26,27 , Flaviane Venditti 28 , Jean-Baptiste Vincent 29
, and
Kai WĂŒnnemann 17,30
1 Planetary Defense Coordination Office and Planetary Science Division, NASA Headquarters, 300 Hidden Figures Way SW, Washington, DC 20546, USA
[email protected]
2 Space Research and Planetary Sciences, Physics Institute, University of Bern, Bern, 3012, Switzerland
3 Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
4 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
5 NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
6 Department of Astronomy, University of Maryland, College Park, MD 20742, USA
7 Department of Earth, Atmospheric & Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
8 INAF-Osservatorio Astronomico di Roma, Rome, I-00078, Italy
9 Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
10 Univ. Grenoble Alpes, CNRS, CNES, IPAG, F-38000 Grenoble, France
11 Centro de AstrobiologĂa CSIC-INTA, Instituto Nacional de TĂ©cnica Aeroespacial, E-28850 TorrejĂłn de Ardoz, Spain
12 Department of Geosciences, Auburn University, Auburn, AL 36849, USA
13 Department of Aerospace Engineering, Auburn University, Auburn, AL 36849, USA
14 INAF- Osservatorio Astronomico di Trieste, Trieste I-34143, Italy
15 Royal Observatory of Belgium, Belgium
16 INAF-Astronomical Observatory of Padova, Padova I-35122, Italy
17 Museum fĂŒr NaturkundeâLeibniz Institute for Evolution and Biodiversity Science, Germany
18 University of Padova, Padova, Italy
19 UniversitĂ© CĂŽte dâAzur, Observatoire de la CĂŽte dâAzur, CNRS, Laboratoire Lagrange, Nice F-06304, France
20 Institut SupĂ©rieur de lâAĂ©ronautique et de lâEspace (ISAE-SUPAERO), UniversitĂ© de Toulouse, Toulouse, France
21 IFAC-CNR, Sesto Fiorentino I-50019, Italy
22 Colorado Center for Astrodynamics Research, University of Colorado Boulder, Boulder, CO 80303, USA
23 Planetary Science Institute, Tucson, AZ 85719, USA
24 Department of Mechanical, Materials and Aerospace Engineering, University of Liverpool, Liverpool, UK
25 Alma Mater StudiorumâUniversitĂ di Bologna, Department of Industrial Engineering, Interdepartmental Center for Industrial Research in Aerospace, Via
Fontanelle 40âForlĂŹ (FC)âI-47121, Italy
26 Institute of Space Sciences (ICE, CSIC), Cerdanyola del VallĂšs, E-08193 Barcelona, Catalonia, Spain
27 Institut dâEstudis Espacials de Catalunya (IEEC), Ed. Nexus, E-08034 Barcelona, Catalonia, Spain
28 Arecibo Observatory, University of Central Florida, HC-3 Box 53995, Arecibo, PR 00612, USA
29 German Aerospace Center, DLR Berlin, Germany
30 Freie UniversitÀt Berlin, Germany
Received 2022 August 9; revised 2022 September 18; accepted 2022 September 22; published 2022 October 28
Abstract
NASAâs Double Asteroid Redirection Test (DART) is the first full-scale test of an asteroid deflection technology.
Results from the hypervelocity kinetic impact and Earth-based observations, coupled with LICIACube and the later
Hera mission, will result in measurement of the momentum transfer efficiency accurate to âŒ10% and
characterization of the Didymos binary system. But DART is a single experiment; how could these results be used
in a future planetary defense necessity involving a different asteroid? We examine what aspects of Dimorphosâs
response to kinetic impact will be constrained by DART results; how these constraints will help refine knowledge
of the physical properties of asteroidal materials and predictive power of impact simulations; what information
about a potential Earth impactor could be acquired before a deflection effort; and how design of a deflection
mission should be informed by this understanding. We generalize the momentum enhancement factor ÎČ, showing
that a particular direction-specific ÎČ will be directly determined by the DART results, and that a related direction-
specific ÎČ is a figure of merit for a kinetic impact mission. The DART ÎČ determination constrains the ejecta
momentum vector, which, with hydrodynamic simulations, constrains the physical properties of Dimorphosâs near-
surface. In a hypothetical planetary defense exigency, extrapolating these constraints to a newly discovered
asteroid will require Earth-based observations and benefit from in situ reconnaissance. We show representative predictions for momentum transfer based on different levels of reconnaissance and discuss strategic targeting to
optimize the deflection and reduce the risk of a counterproductive deflection in the wrong direction
Achievement of the planetary defense investigations of the Double Asteroid Redirection Test (DART) mission
NASA's Double Asteroid Redirection Test (DART) mission was the first to demonstrate asteroid deflection, and the mission's Level 1 requirements guided its planetary defense investigations. Here, we summarize DART's achievement of those requirements. On 2022 September 26, the DART spacecraft impacted Dimorphos, the secondary member of the Didymos near-Earth asteroid binary system, demonstrating an autonomously navigated kinetic impact into an asteroid with limited prior knowledge for planetary defense. Months of subsequent Earth-based observations showed that the binary orbital period was changed by â33.24 minutes, with two independent analysis methods each reporting a 1Ï uncertainty of 1.4 s. Dynamical models determined that the momentum enhancement factor, ÎČ, resulting from DART's kinetic impact test is between 2.4 and 4.9, depending on the mass of Dimorphos, which remains the largest source of uncertainty. Over five dozen telescopes across the globe and in space, along with the Light Italian CubeSat for Imaging of Asteroids, have contributed to DART's investigations. These combined investigations have addressed topics related to the ejecta, dynamics, impact event, and properties of both asteroids in the binary system. A year following DART's successful impact into Dimorphos, the mission has achieved its planetary defense requirements, although work to further understand DART's kinetic impact test and the Didymos system will continue. In particular, ESA's Hera mission is planned to perform extensive measurements in 2027 during its rendezvous with the DidymosâDimorphos system, building on DART to advance our knowledge and continue the ongoing international collaboration for planetary defense
Effects of impact and target parameters on the results of a kinetic impactor: predictions for the Double Asteroid Redirection Test (DART) mission
The Double Asteroid Redirection Test (DART) spacecraft will impact into the asteroid Dimorphos on September 26, 2022 as a test of the kinetic impactor technique for planetary defense. The efficiency of the deflection following a kinetic impactor can be represented using the momentum enhancement factor, Beta, which is dependent on factors such as impact geometry and the specific target material properties. Currently, very little is known about Dimorphos and its material properties that introduces uncertainty in the results of the deflection efficiency observables, including crater formation, ejecta distribution, and Beta. The DART Impact Modeling Working Group (IWG) is responsible for using impact simulations to better understand the results of the DART impact. Pre-impact simulation studies also provide considerable insight into how different properties and impact scenarios affect momentum enhancement following a kinetic impact. This insight provides a basis for predicting the effects of the DART impact and the first understanding of how to interpret results following the encounter. Following the DART impact, the knowledge gained from these studies will inform the initial simulations that will recreate the impact conditions, including providing estimates for potential material properties of Dimorphos and Beta resulting from DARTs impact. This paper summarizes, at a high level, what has been learned from the IWG simulations and experiments in preparation for the DART impact. While unknown, estimates for reasonable potential material properties of Dimorphos provide predictions for Beta of 1-5, depending on end-member cases in the strength regime.This work was supported by the DART mission, NASA contract No. 80MSFC20D0004. This work has received funding from the European Unionâs Horizon 2020 research and innovation program
under grant agreement No. 870377 (project, NEO-MAPP) and from the French space agency CNES and the CNRS through the MITI interdisciplinary programs. We gratefully acknowledge the developers of iSALE-2D (www.isale-code.de) including Dirk Elbeshausen, Boris Ivanov, and Jay Melosh. This work was supported by the Italian Space Agency (ASI) within the LICIACube project (ASI-INAF agreement AC n.2019-31-HH.0; C.B. and C.M.S. appreciate support by the German Research Foundation (DFG) project 39848852. Alice Lucchetti, Maurizio Pajola, and all other coauthors from the LICIACube team acknowledge financial support from Agenzia Spaziale Italiana (ASI, contract No. 2019-31-HH.0). J.O. and I.H. were supported by the Spanish State Research Agency (AEI) Project No. MDM-2017-0737 Unidad de Excelencia âMarĂa de MaeztuââCentro de AstrobiologĂa (CSIC-INTA). They are also grateful for all logistical support provided by Instituto Nacional de TĂ©cnica Aeroespacial (INTA). Parts of this work were performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. LLNLJRNL-831475. This work was supported in part by a Chick Keller Postdoctoral Fellowship through the Center for Space and Earth Science at Los Alamos National Laboratory. Parts of this work were supported by the Advanced Simulation and Computing (ASC)âThreat Reduction and ASCâPlanetary Defense programs. Los Alamos National Laboratory, an affirmative action/equal opportunity employer, is operated by Triad National Security, LLC, for the National Nuclear Security Administration of the US Department of Energy under contract 89233218NCA000001. LA-UR-22-21164