中文摘要：

针对嫦娥二号小行星再拓展试验任务，根据嫦娥二号探测器以及图塔蒂斯小行星轨道参数和太阳光线入射方向计算拍照时的光照条件，基于计算结果建议采用飞越后拍照的策略，并在J2000．0地球平赤道坐标系中给出相机光轴的指向为（118．02°，22．03°）．基于国外雷达数据确定的图塔蒂斯形状模型，计算了交会时刻小行星在惯性空间中的指向．利用Oren—Nayar漫反射模型与太阳、小行星和探测器之间的相对位置，采用建议的相机指向，在星空背景下分别对飞越后探测器距离小行星300km、500km和1000km时刻的成像情况进行了仿真．仿真结果为任务中获得的图塔蒂斯光学图像所验证．

英文摘要：

For the flyby mission of Toutatis by the Chang＇e 2 detector, the light condi- tions for imaging are calculated in this paper based on the orbital parameters of both the detector and the asteroid and the viewing angle. On the basis of the result, it＇s suggested to take the picture during the out-bound track, and the proposed orientation for the optical axis in the mean equator and equinox of J2000.0 coordinate system is represented to be （118.02°, 22.03°）. Based on the shape model determined by radar data, the Oren-Nayar reflection model is used for imaging simulation according to the position relation among the sun, the asteroid, and the detector. The simulations are done at the distances of 300 km, 500 km, and 1000 km respectively from the asteroid after flyby, and the results are certificated by the optical images obtained in the mission.