The traditional space target detection technology primarily relies on single-mode sensors such as optical telescopes, radar, and LiDAR. However, single-mode detection methods have significant limitations when faced with complex space environments. For instance, optical telescopes are constrained by ambient light conditions, radar detection is susceptible to clutter interference, and the effective range of LiDAR is limited. Additionally, single detection modes struggle to adapt to changing space environments. For example, using only visible optical detection can lead to weak signals in shadowed areas and signal saturation under intense light, all of which affect the effectiveness of space target detection. To address these issues and enhance the environmental adaptability of space target detection systems, this article explores the development of a multi-mode space target sensing system that utilizes aperture and detector multiplexing, leveraging the advantages of different bands and detection modes. This approach aims to provide multi-source space target detection data.This paper designs a highly integrated multi-mode space target sensing system consisting of four detection structures: visible to near-infrared, short-wave infrared, mid-wave infrared long focal length, and zoom (Fig.1). The visible-near infrared system, the short-wave infrared system (Fig.2), and the mid-wave infrared long focal length system (Fig.5) share the front-end optical aperture, while the mid-wave infrared zoom (Fig.7) and mid-wave infrared long focal length system share the infrared detector. Through a clever multi-optical path layout design, this system resolves the conflicting issues between various detection modes of the optical system and limited space.The system uses a 1 920×1 080 detector for the visible to near-infrared band, with a pixel size of 9 μm. The RMS radius of the spot diagram of is less than 1.6 μm, and the MTF across the full field of view at the characteristic frequency of 55.6 lp/mm is greater than 0.6. For the short-wave infrared band, a 1 280×1 024 detector is used, with a pixel size of 10 μm. The system's spot diagram RMS radius is less than 2.5 μm, and the MTF at 50 lp/mm is greater than 0.39. The mid-wave infrared zoom and long focal length system modes use the same detector, with an array size of 1 080×1 024 and a pixel size of 12 μm. In both modes, the optical system's spot diagram is close to the diffraction-limited Airy disk, and the MTF across the full field of view is also near the diffraction limit. In summary, each mode of this multi-mode space target detection system has excellent imaging capabilities.An integrated multi-mode space target sensing system is proposed and designed, which has four detection modes: visible to near-infrared detection system, short-wave detection system, mid-wave infrared long focal length and mid-wave infrared zoom system. The visible to near-infrared detection system, the short-wave detection system, and the mid-wave long focal system employ a common aperture design, while the mid-wave long focal system and the mid-wave zoom system share a common detector. Compared to single-mode space target sensing systems, the highly integrated multi-mode sensing system can obtain multi-source data while maintaining a lightweight design, allowing for high-precision spatial information through data fusion. This system boasts stronger environmental adaptability, thereby enhancing the ability of space-based target sensing systems to detect targets in complex space environments within the constraints of current satellite resources.