Space debris spectrum detection optical system

The invention particularly relates to a space debris spectrum detection optical system, which is used for solving the problems of small entrance pupil diameter and narrow light spectrum range of a large view field during spectrum detection in the existing optical system. The space debris spectrum detection optical system comprises an aperture diaphragm, a first reflecting mirror, a second reflecting mirror, a third reflecting mirror and a light splitting substrate which are sequentially arranged in the light propagation direction, wherein the first reflecting mirror, the second reflecting mirror and the third reflecting mirror are all secondary aspheric surfaces; the aperture diaphragm is located on a system optical axis. The optical system provided by the invention adopts a total reflection type structure and is wide in system spectral range; the light splitting assembly is located in front of the focal plane in the system and is small in size and light in weight; a primary image plane of the system is not i