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This study investigates the orbit determination of the Mars-crossing asteroids (MCAs) with a focus on the possibility of detecting their Yarkovsky signals. We analyze the influences of force model uncertainties on MCA orbits, including the uncertainty of the main asteroid belt, and the uncertainty of the major planets’ ephemeris. The main asteroid belt is modeled using 343 asteroids and a ring structure. The Yarkovsky effect’s quadratic nature allows it to dominate over extended observation periods. To address dynamical errors and potential interactions with the main asteroid belt, we employ not only a traditional seven-dimensional differential corrector but also a nine-dimensional differential corrector that considers radial, vertical, and transversal forces. Comparison shows that the latter approach enhances the fit to observational data. However, the reliability of the Yarkovsky parameter is not enhanced because the estimation of the radial component is physically unacceptable. Despite incorporating precise Gaia data, our analysis does not conclusively detect a Yarkovsky effect on MCAs due to uncertainties in the force model. Nevertheless, our research advances our understanding of MCA dynamics, identifying five potential candidates whose Yarkovsky effect may be observable.

Asteroid detection is now a hot spot of solar system exploration. The understanding of the evolution of asteroids has a great benefit on researches to the origin of the solar system. An important topic of the evolution research is the evolution of inner structures of asteroids, in other words, asteroids' evolution of shapes and structures under multiple mechanisms. A common method to simulate the dynamical evolution of asteroids is Discrete Element Method (DEM) under the assumption that asteroids are in rubble-pile structures. Some teams have developed several kinds of softwares for DEM simulations. The basics, realization, algorithms of our software "Multi-particle system simulation software based on DEM algorithm" are introduced in this article, and the software is verified using two body collision, sound wave propagation, inner stress of asteroid, and asteroid spin disruption setups. [ABSTRACT FROM AUTHOR]

A comprehensive study on the autonomous orbit determination (AOD) performance of satellite pairs in halo orbits and distant retrograde orbits (DROs) is carried out. A factor called dynamic and geometric dilution of precision (DAGDOP) is proposed to simultaneously incorporate influences from the dynamics and geometry of satellite pairs. Based on the DAGDOP, the effect of different observation arcs on the AOD accuracy is investigated. Next, the AOD accuracy of three different types of satellite pairs—halo+halo, DRO+DRO, and halo+DRO—is systematically analyzed. The hybrid halo+DRO type shows the best overall accuracy. Finally, the AOD performance of the hybrid type is verified in a realistic model. Our studies find that the average AOD accuracy of the halo orbit is about 170 meters, and that of the DRO is about 190 meters. The relative time synchronization error of two satellites is less than 30 nanoseconds.

A novel algorithm based on the Lindstedt–Poincaré method is proposed to construct an analytical solution of the lunar orbit. Based on the analytical solution, a numerical fitting algorithm is proposed to improve the coefficients of the analytical solution so that its accuracy can reach the level of a few kilometers within 20 yr. By fitting our solution to the long-term JPL ephemerides, we are able to recover the receding speed of the Moon from the Earth due to tidal effects. The proposed algorithm also provides a general way to treat the third-body perturbation in rectangular coordinates.

The Yarkovsky effect causes the semimajor axis drift of near-Earth asteroids. The drift can be detected by a precise orbit determination process. Using the proposed algorithm, 2233 out of 27,078 near-Earth asteroids are chosen as the initial candidates. Out of these initial candidates, 769 have a measurable Yarkovsky effect with a signal-to-noise ratio (S/N) larger than 1, and 166 have a measurable Yarkovsky effect with an S/N larger than 3. The ratio between retrograde and prograde near-Earth asteroids is plotted with respect to their size. An average ratio of 2 is found for asteroids with an absolute magnitude between 14 and 21. The measurement work is carried out based on orbit determination software developed by the authors that considers a high-precision dynamical model.

The ghost dust clouds in the vicinity of Earth-Moon triangular libration points are known as the “Kordylewski clouds” (KDCs). Objects in the KDCs may give hints to the physical, chemical, and dynamical properties of the solar system. As a result, in situ exploration of the KDCs can help us understand the evolution of our solar system. This paper first summarizes the observation history of the KDCs. Based on the properties of the KDCs, a ground- and space-based observation concept is proposed, using the CAST 100 platform developed by DFH and ground stations. Some details of the concept are exploited.