Optimal Guidance in Soft-Landing of Chandrayaan-3
Radhakant Padhi
HAG Professor, HAL Chair
Dept. of Aerospace Engineering
Indian Institute of Science, Bangalore
Abstract
High-precision autonomous soft-landing is increasingly becoming an essential requirement for various inter-planetary missions and also missions of unmanned aerial vehicles. A good soft-landing algorithm must fulfill various conditions, such as high terminal position, velocity and acceleration accuracy, continuity between phases, recovery from path perturbations, and prevention of altitude excursion. Moreover, autonomous soft-landing in space missions needs to be carried out with the limited capability of onboard processors, thereby necessitating a closed-form expression of the guidance law. A powerful Jerk-minimizing optimal guidance incorporating all these features, developed and published by Prof. Padhi and his research team, will be discussed in this talk, a milder version of which was used in the Chandrayaan-3 mission due to system limitations. The talk will also include the drone soft-landing experiments carried out by Prof. Padhi’s team in the outdoor environment for confidence building prior to the Chandrayaan-3 mission. For completeness, this talk will also include some of the lessons learnt from the unsuccessful attempt of Chandrayaan-2 and the improvements carried out subsequently that led to the success of the Chandrayaan-3 mission.
Biography
Prof. Radhakant Padhi, a Ph.D. from the Missouri University of Science and Technology, Rolla, USA, is currently the HAL Chair Professor at the Department of Aerospace engineering in the Indian Institute of Science, Bangalore; and also an Associate Faculty at its Centre for Cyber-Physical Systems. He is a Fellow of Indian National Academy of Engineering (INAE), Astronautical Society of India (ASI), Aeronautical Society of India (AeSI), Institution of Electronics and Telecommunication Engineers (IETE), and Institute of Engineers (India). He is an Associate Fellow of AIAA and a Senior Member of Institute of IEEE. He is the Director of Operations of the Automatic Control and Dynamic Optimization Society, which is the national member organization of the International Federation of Automatic Control (IFAC) in India. He is an Associate Editor of Unmanned Systems journal, and has been an associated editor of two more journals in the past in the control and automation field.
Prof. Padhi’s research interest is in optimal and nonlinear control synthesis algorithms and their applications to challenging practical problems in aerospace, biomedical and mechanical engineering. He has co-authored 93 journal papers and 200 conference papers, and also a book on Satellite Formation Flying (2021). Three more books are going to be published soon, on Intelligent Adaptive Control with System Constraints, on Applied Optimal Control and State Estimation, and on Flight Mechanics and Control. He is also a co-author of the motivational book for young minds The Gap Year Advantage: Efforts are in your hands, Results are not, published recently in 2025.
Prof. Padhi is a member of technical review committees for several missions of Indian Space Research Organisation (ISRO) and Defence R&D Organisation of India. Recently, Prof. Padhi has floated two deep-tech start-ups through which he intends to utilize his research output for the benefit of the society.
