India becomes fourth country to conduct key docking test in Earth orbit

Friday 17th January 2025 04:45 AM

Key information

ISRO has successfully completed an in-orbit docking test, which is a significant milestone in India’s space plans.
The experiment, called SpaDeX, involved two identical spacecraft that were launched into orbit and then docked with each other using indigenous low-impact docking technology.
This achievement elevates India to the ranks of only four nations – the United States, the Soviet Union/Russia and China – that have demonstrated orbital docking capabilities.

India has successfully completed an in-orbit docking test, representing a significant milestone in its ambitious space plans. The experiment, called SpaDeX, involved two identical spacecraft, SDX01 and SDX02, each weighing 220 kilograms. Launched from the Satish Dhawan Space Center on December 30 aboard a PSLV rocket, the satellites were placed into orbit at an altitude of about 475 kilometers above the Earth.

Docking was initially planned for around January 7, but unplanned orbital shifts caused delays. Amid fears that the attempt would have to be postponed until March, ISRO successfully completed the docking procedure on January 15 Eastern Time. The Indian Space Research Organization (ISRO) announced the successful capture of the spacecraft via X, highlighting the precision maneuvers executed in the process.

Signification

This feat elevates India to the rank of only four nations – the United States, the Soviet Union/Russia and China – that have successfully demonstrated docking capabilities in orbit. Prime Minister Narendra Modi, who was present at the ISRO headquarters in Bangalore to witness the event, expressed his congratulations on X.com, hailing the scientists and the entire space fraternity for their achievement. He highlighted its importance as a crucial stepping stone for India’s future space missions.

Dr V. Narayanan, who took over as director of ISRO on January 13, also extended his congratulations to the team after the successful docking. The mission is part of India’s efforts to become the fourth nation to independently develop human spaceflight capabilities through its Gaganyaan program. A crewed flight is currently planned for 2026, and uncrewed test flights are planned for 2025. In addition, India aims to establish the Bharatiya Antariksha station in orbit by 2035 and achieve a crewed moon landing. by 2040.

Future missions and capabilities

Docking technology will also be crucial for India’s Chandrayaan-4 mission, which aims to collect samples from the Moon’s south pole around 2027 or 2028. Docking will be essential for transferring collected samples to the surface from a vehicle d ascension to a service module capable of returning to Earth. The SpaDeX mission integrates an indigenous low-impact docking system with an approach speed of approximately 10 millimeters per second, as well as advanced sensors such as a laser rangefinder (LRF), Corner Cube retro-reflectors, and others to facilitate precise maneuvers. A GNSS-based Relative Orbit Determination and Propagation (RODP) processor ensures precise relative positioning.

India is targeting a record year for launches in 2023, with 10 orbital missions planned, including the first flight of Skyroot Aerospace’s Vikram-1 rocket. The next launch is expected to be a GSLV mission carrying the NVS-02 navigation satellite from Sriharikota, no earlier than January 26. On January 16, the Indian cabinet approved the construction of a third launch pad (TLP) at the Satish Dhawan Space Center in Sriharikota. This platform will accommodate new generation launchers and increase India’s launch capacity. India also plans to develop a reusable next-generation launch vehicle.

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