Detection and calibration characteristics of the visible and near-infrared imaging spectrometer in the Chang'e-4

Abstract

Chang'e 4 is a robotic lunar exploration mission operated by the China National Space Administration and was to pull off the first-ever soft landing of space hardware on the mysterious lunar far side. The Visible and Near-IR Imaging Spectrometer (VNIS) is one of the main scientific instruments onboard the Chang'e 4 lunar rover. In order to analyze the lunar surface mineral composition, the VNIS was mounted on the front of the rover and detects lunar objects with a 45° visual angle to obtain spectra and geometry data to make mineralogical and compositional measurements. The VNIS is the same as the one in the Chang'e 3 Yutu rover and consists of a visible and near-infrared imaging spectrometer (0.45-0.95 μm), a shortwave IR spectrometer (0.9-2.4 μm), and a calibration unit with dust-proofing functionality. Here, we describe detection and calibration characteristics of the VNIS, which provides valuable information for scientific data processing and applications.