On December 30, 2024, the Indian Space Research Organisation (ISRO) launched the SpaDeX Mission, a significant advancement in space docking technology. This mission involves two small spacecraft, each weighing approximately 220 kilograms, deployed at an altitude of 470 kilometers above Earth using the PSLV-C60 rocket from Sriharikota.
The mission features a chaser satellite (SDX01) and a target satellite (SDX02), both orbiting Earth at the same speed and altitude. The primary objectives include demonstrating successful docking, energy transfer between the docked spacecraft, and operational payload management post-undocking.
ISRO successfully conducted a docking trial on January 7, 2025, bringing the two satellites within a distance of 3 meters after initially setting a distance of 15 meters. The data from this docking trial is currently under analysis.
Former ISRO scientist Vinod Kumar Srivastava explained that docking refers to the process of connecting two spacecraft, while undocking is their separation. This procedure is critical due to the high velocity of the spacecraft, which can exceed 28,800 kilometers per hour, posing risks of collision.
With the successful completion of the SpaDeX Mission, India joins the ranks of the United States, Russia, and China as the fourth nation to possess space docking technology. The spacecraft achieved speeds ten times faster than a bullet, reaching approximately 29,000 kilometers per hour.
The mission employs advanced technologies, including laser range finders for precise distance measurement during docking maneuvers. Successful docking will allow for electrical power transfer between the spacecraft, with valuable data expected to be gathered over the next two years.
If successful, the SpaDeX Mission could pave the way for India's Chandrayaan-4 mission, aimed at bringing lunar soil samples back to Earth, anticipated for launch in 2028.
SDX01 is equipped with a high-resolution camera capable of monitoring natural resources, while SDX02 includes a radiation monitor for future space science studies.