Scientific challenges of CHANDRAYAAN-1: the Indian lunar polar orbiter mission

Abstract

The Indian Space Research Organisation is planning to send a polar orbiting satellite called CHANDRAYAAN-1 to the Moon, for remote sensing of the lunar surface. The scientific objectives of the proposed mission are simultaneous geochemical, mineralogical and photogeological studies of the whole lunar surface. The payloads include hyperspectral imager for mineralogical mapping, X-ray fluorescence spectrometer for elemental mapping, low energy gamma-ray spectrometer for mapping some radioactive elements, a terrain mapping camera and a laser altimeter, leaving a provision for some additional instruments, which may enhance the capability of this mission in achieving its objectives. A plausible launch scenario using the Polar Satellite Launch Vehicle (PSLV) suggests that a lunarcraft (dry weight 440 kg), carrying about 60 kg of payloads can be inserted in a 100 km altitude polar orbit around the Moon with adequate fuel (about 80 kg) for orbit maintenance to sustain it for two years of observations for complete coverage of the lunar surface. Here we describe the scientific reasons for undertaking such a mission and some of the major scientific challenges. The purpose of this article is to involve the scientific community of the country in formulating the best possible objectives and participating in the mission.