设计了一种用于深空探测的新型宽视场多光谱降落相机，通过两档切换，实现了1.5 m~+∞以及30 cm两档成像范围的目标探测.在1.5 m~+∞档，能实现着陆器下降过程中对被测星体表面的全色成像；在30 cm档，采用蓝绿、红色以及近红外三个独立的发光二极管光源阵列分别对着陆后近距离目标进行照明，通过对采集到的多光谱图像进行处理，可实现目标组成成分的鉴定.取降落相机设计谱段420~900 nm，方形视场49.5°×49.5°，F数5.4，当目标距离为1.5m~+∞时，焦距f′1为12.9 mm；目标距离30 cm时，焦距f′2为12.5 mm.系统中第一镜采用近似无光焦度的前置弯月透镜，利用镜片的开合完成不同成像范围的档位切换，使系统焦距在两档切换时变化不大，目标不易丢失.分析可知，镜头在35 lp/mm处，系统调制传递函数均达到0.6以上，成像质量接近衍射极限；全视场畸变优于1.2%；第一镜倾斜、偏心公差设计合理.该设计解决了以往定焦降落相机在着陆后无法对近距离目标清晰成像的问题.

A new descent camera which used for deep space explorartion was designed. This camera can explore different distance targets by opening and closing the first optical lens. With the first optical lens in the optical path, the objective was focused for objects at distances ranging from 1.5 m to infinity. In this mode, the camera can take full-color pictures (spectral bandwidth 420~900 nm) of the cytaster surface. With it removed, the camera was focused at an object distance of 30 cm. In this mode, three lights of different wavelengths which were blue-green, red, and NIR were used independently to illuminate the close range objects and the camera can take multispectral pictures of the explored objects. This camera have a focal ratio f/5.4 and project a square field of view 49.5°×49.5° on the CCD. When at the infinity mode (with the first optical lens), the focal length is 12.9 mm and when at the close-up mode (without the first optical lens), the focal lenth is 12.5 mm. The first optical lens of the descent camera is a meniscus lens and it almost have no focal power. So the system focal changes lightly no matter with or without this lens. By this way, the drawback of a traditional two-way switch system that detected objects easily be lost when modes shift can be easily overcome. The design result show that the Modulation Transfer Function is higher than 0.6 in full-field at 35 lp/mm. The distortion of the system in full-field is better than 1.2%. Tilt and decenter tolerance of the first lens also have a reasonable result.