Visible and Near-infrared Imaging Spectrometer (VNIS) for Chang'E-3

To analyze the composition of lunar surface minerals, one of the scientific payloads of the Chang'E 3 Yutu rover, the Visible and Near-infrared Imaging Spectrometer (VNIS), was developed to detect lunar surface objects and to obtain their reflectance spectra and geometric images. The VNIS, which uses acousto-optic tunable filters as dispersive components, consists of a VIS/NIR imaging spectrometer (0.45-0.95 mu m), a shortwave IR spectrometer (0.9-2.4 mu m), and a calibration unit with dust-proofing functionality. It is capable of synchronously acquiring the full spectra of lunar surface objects and performing in-situ calibration. After landing successfully on the Moon, the VNIS performed several explorations and calibrations, and obtained several spectral images and spectral reflectance curves of the lunar soil in the Imbrium region. This paper introduces the VNIS, including its working principle, implementation, operation, and major specifications, as well as the initial scientific achievement of lunar surface exploration.