After several weather-related postponements, Japan’s Moon-lander mission, called SLIM, finally took off Thursday morning. A successful landing on the Moon by the SLIM spacecraft would make Japan only the fifth country in the world to do so. SLIM, or Smart Lander for Investigating Moon, is taking a uniquely long route to the Moon and is scheduled to make a landing in four to six months. If successful, SLIM would be the smallest and lightest spacecraft to land on the Moon. Indian Space Research Organisation (ISRO) sent its greetings to Japan Aerospace Exploration Agency (JAXA) on the successful launch. “Congratulations JAXA on the successful launch of the SLIM lander to the moon. Best wishes for another successful lunar endeavour by the global space community,” ISRO said. The H-IIA rocket that took the SLIM in space also carried an X-Ray Imaging and Spectroscopy Mission (XRISM), a satellite meant for astronomical observations. XRISM was separated from the rocket 14 minutes after the launch and deployed in its intended orbit. XRISM will perform high-resolution X-ray spectroscopic observations of the hot gas plasma wind that blows through the galaxies, and its studies would focus on determining mass-energy flows, composition and evolution of celestial objects. The SLIM spacecraft was detached from the rocket 47 minutes after the launch and deposited in an Earth-orbit where it will perform orbit-raising manoeuvres over the next few days just like Chandrayaan-3 did in its initial phase. This is the first Moon-landing attempt being made by Japan Aerospace Exploration Agency (JAXA). An earlier attempt made by a private Japanese company in May this year had ended in a failure. SLIM is a pretty small spacecraft, weighing just about 200 kg. In comparison, Chandrayaan-3 lander module weighed about 1,750 kg. The main objective of SLIM is to demonstrate precision landing, within 100 metres of the chosen site. The mission is being pitched as one that would demonstrate that it was possible to land on the Moon “where we want, not just where it is easy to land”. JAXA said “pinpoint” landing technology was essential to ensure that a spacecraft was close enough to scientifically-interesting sites on the Moon, accessible by a rover. The chosen landing site for SLIM is near a small crater named Shioli in the equatorial region of the Moon. “Because the landing site is located near a crater, the surrounding area is sloped to approximately 15 degrees. Therefore, the method of landing safely on such a slope becomes important,” JAXA said. “As science and exploration objectives become more sophisticated, landing on such sloping area will be increasingly required in the future. Especially for the case of a SLIM-scale spacecraft, the "two-step landing method", in which the main landing gear first touches the ground and then rotates forward to stabilize, has shown excellent reliable landing results through simulation,” it said.
