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In this work, we investigate the rotational dynamics of the ginger-shapednear-Earth asteroid 4179 Toutatis, which was closely observed by Chang'e-2 at adistance of $770\pm120~$ meters from the asteroid's surface during the outboundflyby \citep{Huang2013} on 13 December 2012. A sequence of high-resolutionimages was acquired during the flyby mission. In combination with ground-basedradar observations collected over the last two decades, we analyze these flybyimages and determine the orientation of the asteroid at the flyby epoch. The3-1-3 Euler angles of the conversion matrix from the J2000 ecliptic coordinatesystem to the body-fixed frame are evaluated to be $-20.1^\circ\pm1^\circ$,$27.6^\circ\pm1^\circ$ and $42.2^\circ\pm1^\circ$, respectively. Theleast-squares method is utilized to determine the rotational parameters andspin state of Toutatis. The characteristics of the spin-state parameters andangular momentum variations are extensively studied using numericalsimulations, which confirm those reported by \citet{Takahashi2013}. The largeamplitude of Toutatis' precession is assumed to be responsible for its tumblingattitude as observed from Earth. Toutatis' angular momentum orientation isdetermined to be described by $\lambda_{H}=180.2^{+0.2^\circ}_{-0.3^\circ}$ and$\beta_{H}=-54.75^{+0.15^\circ}_{-0.10^\circ}$, implying that it has remainednearly unchanged for two decades. Furthermore, using Fourier analysis toexplore the change in the orientation of Toutatis' axes, we reveal that the tworotational periods are 5.38 and 7.40 days, respectively, consistent with theresults of the former investigation. Hence, our investigation provides a clearunderstanding of the state of the rotational dynamics of Toutatis.

Orientation and Rotational Parameters of Asteroid 4179 Toutatis: New Insights from Chang'e-2's Close Flyby