Hayabusa2’s superior solar conjunction mission operations: planning and post-operation results

Soldini, Stefania; Takeuchi, Hiroshi; Taniguchi, Sho; Kikuchi, Shota; Takei, Yuto; Ono, Go; Nakano, Masaya; Ohnishi, Takafumi; Saiki, Takanao; Tsuda, Yuichi; Terui, Fuyuto; Ogawa, Naoko; Mimasu, Yuya; Takahashi, T.; Fujii, Atsushi; Nakazawa, Shozo; Yoshikawa, Kunihiko; Oki, Yusuke; Hirose, Chikako; Sawada, Hirotaka; Yamaguchi, Tomohiro; Yoshikawa, Makoto

doi:10.1007/s42064-020-0076-7

Cited by 10 publications

(3 citation statements)

References 14 publications

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“…(goNEAR) is an N-body planetary propagator originally developed for the Hayabusa2 trajectory design, used for the prediction of Hayabusa2ʼs ejecta after the SCI impact (Saiki et al 2017;Soldini et al 2020a) and validated with real-time data during Hayabusa2ʼs superior solar conjunction phase (Soldini et al 2020b(Soldini et al , 2020c. 2.…”

Section: The Gravitational Orbits Near Earth Asteroid Regionsmentioning

confidence: 99%

Pre-encounter Predictions of DART Impact Ejecta Behavior and Observability

et al. 2022

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We overview various efforts within the DART Investigation Team’s Ejecta Working Group to predict the characteristics, quantity, dynamical behavior, and observability of DART impact ejecta. We discuss various methodologies for simulation of the impact/cratering process with their advantages and drawbacks in relation to initializing ejecta for subsequent dynamical propagation through and away from the Didymos system. We discuss the most relevant forces acting on ejecta once decoupled from Dimorphos’s surface and highlight various software packages we have developed and used to dynamically simulate ejecta under the action of those forces. With some additional software packages, we explore the influence of additional perturbing effects, such as interparticle collisions within true N-body codes and nonspherical and rotating particles’ interplay with solar radiation pressure. We find that early-timescale and close-proximity ejecta evolution is highly sensitive to some of these effects (e.g., collisions) while relatively insensitive to other factors. We present a methodology for turning the time-evolving size- and spatially discretized number density field output from ejecta simulations into synthetic images for multiple platforms/cameras over wide-ranging vantage points and timescales. We present such simulated images and apply preliminary analyses to them for nominal and off-nominal cases bracketing realistic total mass of ejecta and ejecta cumulative size–frequency distribution slope. Our analyses foreshadow the information content we may be able to extract from the actual images taken during and after the DART encounter by both LICIACube and Earth-vicinity telescopes.

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Section: The Gravitational Orbits Near Earth Asteroid Regionsmentioning

confidence: 99%

Pre-encounter Predictions of DART Impact Ejecta Behavior and Observability

et al. 2022

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“…We simulate the dynamics of the ejecta during this phase using the GONEAR tool, an N-body planetary propagator written in J2000 equatorial coordinates with a reference frame centered at either asteroid Dimorphos (labeled as A 2 in the equations) or Didymos (labeled as A 1 in the equations). The GONEAR tool was developed and validated in real time for the Hayabusa2 mission (Soldini et al 2020b(Soldini et al , 2020c and is here extended to the case of a binary asteroid system. The new version of the code has been fully validated for the binary asteroid case scenario using available kernels of the trajectory of Hera's Milani cubesat (Ferrari et al 2021b).…”

Section: Ballistic Phasementioning

confidence: 99%

Ejecta Formation, Early Collisional Processes, and Dynamical Evolution after the DART Impact on Dimorphos

et al. 2022

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NASA’s DART spacecraft is planned to reach and impact asteroid Dimorphos, the small moon of binary asteroid (65803) Didymos, at a velocity of 6 km s−1 in late 2022 September. DART will be the first mission to test the “kinetic impactor” technique, aimed at deflecting the orbital path of a potentially hazardous asteroid. The success and effectiveness of this technique resides in the efficiency of momentum exchange between the spacecraft and the impacted target. This depends on many factors, including the cratering process, the formation of ejecta, and their fate, as they remain in the system or escape from it, carrying momentum away. Here we provide an overview of the cratering process, including ejecta formation and their subsequent dynamical evolution. We use different methodologies to model the physics of the problem, including smoothed particle hydrodynamics to model the cratering and ejecta formation process after the hypervelocity impact, N-body granular simulations to model early collisional processes between ejecta fragments right after cratering, and high-fidelity planetary propagation to model the dynamical evolution of ejecta during their purely ballistic phase. We highlight the key features of each phase and their role in defining the dynamical fate of ejecta. We investigate the effect of surface cohesion in the impacted target and identify the qualitative behavior of ejecta particles as a function of the key parameters of the problem. We provide quantitative estimates for the specific case study related to the DART–Dimorphos scenario and a selected range of target properties.

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“…The hopping probes have been demonstrated to be feasible instruments for in‐situ exploration (Ulamec et al., 2011). For example, the rovers, named MINERVA‐II‐1A, MINERVA‐1B, and the lander Mobile Small body Surface Scout (MASCOT) have been successfully deployed by Hayabusa 2 (Scholten et al., 2019; Soldini et al., 2020; Yoshikawa et al., 2020). They landed on the surfaces of the small body 162173 Ryugu, sent back the pictures and videos of the rocky surfaces, examined the surface mechanical properties, and implemented a series of scientific missions, such as investigating the multispectral reflectance, the thermal characteristics, and the magnetic properties (Ho et al., 2021).…”

Section: Introductionmentioning

confidence: 99%

Influence of the Lander Size and Shape on the Ballistic Landing Motion

Zeng

Wen

et al. 2022

Earth and Space Science

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This article investigates the ballistic landing motion and final distribution of the landers in different sizes or shapes near the small celestial body. Three typical shapes, including cubic, cuboid, and cylindrical, are considered for the landers deployed to a tri‐axial ellipsoid model. The Polygonal Contact Model (PCM) is used to detect the contact/collision, where the Hertz model is applied to calculate the continuous contact force. Different‐sized cubic landers (in the edge length of 20, 30, 40, and 50 cm) are numerically simulated to examine how the lander size influences its dynamics. The landing motion of the cuboid‐ and the cylinder‐shaped landers are then analyzed in the same technique. The heights of these asymmetrical landers are assumed to be 25, 30, and 35 cm, respectively, to illustrate the shape effect. Monte Carlo simulations are implemented for various landers to account for the surface motion randomness. The final dispersion, the outgoing velocity after the collision, the horizontal transfer distance, and the settling time are taken to be critical indicators for discussing the landing behavior, which can provide implications for the probe design of future missions.

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Hayabusa2’s superior solar conjunction mission operations: planning and post-operation results

Cited by 10 publications

References 14 publications

Pre-encounter Predictions of DART Impact Ejecta Behavior and Observability

Pre-encounter Predictions of DART Impact Ejecta Behavior and Observability

Ejecta Formation, Early Collisional Processes, and Dynamical Evolution after the DART Impact on Dimorphos

Influence of the Lander Size and Shape on the Ballistic Landing Motion

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