SPADEX: ANOTHER FEATHER IN ISRO'S CAP

SpaDEx is key to achieving India's long-term space exploration goals, including manned spaceflight, spacecraft maintenance, and the construction of the Bharat Antariksha Station (BAS)

- AIR VICE MARSHAL SANJAY BHATNAGAR (RETD)

Never ever in the recent history of space exploration have the space agencies across the globe, the media and a nation of 1.43 billion people watched the events unfold in space with so much of excitement and awe as the Space Docking Experiment (SpaDEx) by Indian Space Research Organisation (ISRO). This is one event that has gathered as much attention of the nation as the Moon landing by Chandrayaan-3 on August 23, 2023.

ISRO announced on January 16, 2025 that they have successfully completed docking with smooth precision, making India the fourth space faring nation to achieve this significant milestone.

Space Docking is a controlled mechanical process for spacecraft orbital mating. It begins with the initial approach of the spacecraft and its first contact. It is performed with a docking system that includes control avionics and mechanical docking assemblies. Methods for the design, simulation and testing different docking systems have been researched and reviewed since 1984. The initial conditions for docking are provided by a rendezvous system and the docking assemblies themselves actually perform the mechanical process of spacecraft mating.

This process is a long drawn one and comprises of various stages, takes tens of hours depending upon various factors. Docking involves aligning the spacecraft docking adaptor with the target docking point and then controlling the spacecraft so that it docks with zero relative velocity (both angular and linear), zero angular error and zero position error. It is a sixdegrees-of-freedom (6DOF) problem.

DOCKING IN SPACE A NICHE TECHNOLOGY