A simulated global GM estimate of the asteroid 469219 Kamo‘oalewa for China’s future asteroid mission

Jin, Weitong; Li, F; Yan, Jianguo; Andert, T. P.; Ye, M; Ye, Xuan; Hao, Weifeng; Barriot, Jean‐Pierre

doi:10.1093/mnras/staa384

Cited by 29 publications

(13 citation statements)

References 19 publications

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“…We have strictly validated LUGREAS software with the well‐known planetary spacecraft POD and dynamical parameters software GEODYN II (Pavlis, 2001; Ye et al., 2016). It has been extended to analyze orbital tracking data from various missions targeting different planetary bodies such as Mars (e.g., Yan, Yang, Ye et al., 2018), Mercury (e.g., J. Yan et al., 2019), asteroids (e.g., Jin et al., 2020) and Saturn (e.g., Liu, Kong et al., 2020). In this study, we will first use LUGREAS to process the radio tracking data from the Chang’e 1 to the Chang’e 4 together.…”

Section: Pod Settingsmentioning

confidence: 99%

Review of the Precise Orbit Determination for Chinese Lunar Exploration Projects

Liu

Yan

Cao

et al. 2021

Earth and Space Science

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Section: Pod Settingsmentioning

confidence: 99%

Review of the Precise Orbit Determination for Chinese Lunar Exploration Projects

Liu

Yan

Cao

et al. 2021

Earth and Space Science

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“…In addition to the nominal accuracy, the observation scheduling also repeats that of the A48, page 5 of 13 A&A 644, A48 (2020) All the POD simulations were performed using a stable version of Wuhan University Deep space Orbit determination and Gravity recovery System (WUDOGS), an in-house developed software. It has been used in Moon (Yan et al 2020;Liu et al 2020), Mars (Yan et al 2018;Yang et al 2019), Mercury , and asteroid missions (Jin et al 2020).…”

Section: Concept and Significance Of A Pod Simulationmentioning

confidence: 99%

Possible approach to detecting the mysterious Saturnian convective dynamo through gravitational sounding

Liu

Kong

Yan

2020

A&A

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Context. Planetary dynamo research is mathematically and numerically difficult. Forward calculations are numerically expensive and subject to much uncertainty in key magnetohydrodynamics parameters. For a gaseous planet such as Saturn, even the precise location of its dynamo and typical convective strength are unknown, which further complicates studies. Aims. We test the idea of inversely probing Saturnian convective dynamo through gravitational sounding, based on the principle that the convective fluid motion can distort the internal density distribution and hence induce the gravitational anomaly. Methods. The Cassini Grand Finale mission has reported unprecedentedly accurate measurements of the gravitational field of Saturn. An unexplained nonaxisymmetric component of the gravitational field was detected in the data. By performing precise orbit determination (POD) simulations, we studied the possibility that the Cassini spacecraft might sense the dynamo-related nonaxisymmetric gravitational signature in the Grand Finale phase. In addition, further extensively simulated missions of various orbit configurations were carried out in order to explore promising mission strategies that might fulfill the objective of detecting the Saturnian convective dynamo. Results. Our POD simulations show that the gravity science carried out in the Cassini Grand Finale mission is insufficient to determine weak nonaxisymmetric gravitational moments because good subspacecraft-point coverage is lacking. The origin of the unexplained Saturnian gravity remains a puzzle. However, it is positively indicated by our simulations that future gravitational sounding is probably able to detect dynamo-related gravity when the subspacecraft-point coverage of a mission is sufficient. We suggest that the mission orbits be purposely designed into a near-polar orientation with a height of about 6000 km at periapsis and a moderate eccentricity of 0.5. A total POD tracking time of five months would enable the detection of the secular nonaxisymmetric gravitational moments that are caused by the deep convective dynamo of Saturn. The orbit strategy can facilitate engineering implementation by keeping the spacecraft marginally away from the Saturn radiation belt throughout the mission.

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“…Most recently, in 2020, OSIRIS-Rex obtained a sample from 101955 Bennu (6). The continuation of this trend is clear as several missions are planned for this decade such as Hera (7), ZhengHe (8) and Psyche (9). Sampling and surveying asteroids and comets provide unique opportunities to study the history and development of the solar system (10)(11)(12).…”

Section: Introductionmentioning

confidence: 98%

Geodesy of irregular small bodies via neural density fields: geodesyNets

Izzo¹,

Gómez²

2021

Preprint

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Asteroids' and comets' geodesy is of increasing interest in a wide range of fields ranging from astronomy to potential future mining prospects, as well as being essential to successful proximity operations of spacecraft. However, the problem of inferring the internal density distribution of irregular bodies from gravity measurements is challenging and ill posed, with the added difficulty of finding compact representations of the gravitational field surrounding them. We present a novel approach based on artificial neural networks, socalled geodesyNets, and present compelling evidence of their ability to serve as accurate geodetic models of highly irregular bodies using minimal prior information on the body. The approach does not rely on the body shape information but, if available, can harness it. GeodesyNets learn a three-dimensional, differentiable, function representing the body density, which we call neural density field. The body shape, as well as other geodetic properties, can easily be recov-1

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A simulated global GM estimate of the asteroid 469219 Kamo‘oalewa for China’s future asteroid mission

Cited by 29 publications

References 19 publications

Review of the Precise Orbit Determination for Chinese Lunar Exploration Projects

Review of the Precise Orbit Determination for Chinese Lunar Exploration Projects

Possible approach to detecting the mysterious Saturnian convective dynamo through gravitational sounding

Geodesy of irregular small bodies via neural density fields: geodesyNets

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