Powered Descent Trajectory Design and Guidance Algorithms for Chandrayaan-3 Lunar Landing Mission

On 23rd August 2023, India achieved a historic milestone by becoming the fourth nation to successfully perform a soft landing on the lunar surface, and the first to land near the Moon’s south pole region. This paper presents the powered descent trajectory design and the onboard guidance technologies developed for Chandrayaan-3, formulated to satisfy several critical criteria including fuel optimality, robustness, acceleration continuity, real-time retargeting capability, and mission salvage. Pre-flight simulations conducted to evaluate the robustness of the guidance algorithms and trajectory design are discussed, and the corresponding flight performance of the Guidance, Navigation, and Control system is also presented