In a moment of immense pride for India, the Indian Space Research Organisation (ISRO) made history in the early hours of Thursday, January 16, 2025, by successfully executing the SpaDeX docking experiment. This accomplishment places India among an elite group of nations — the USA, Russia, and China — capable of performing such advanced space maneuvers.

ISRO SpaDeX Docking Experiment

The Space Docking Experiment (SpaDeX) involved two satellites, SDX01 (Chaser) and SDX02 (Target), which were launched aboard the PSLV C60 rocket on December 30, 2024. After weeks of preparation and multiple trials, the satellites successfully docked in space under the watchful eyes of ISRO’s Mission Operations Complex (MOX) at the ISRO Telemetry, Tracking, and Command Network (ISTRAC).

Announcing the achievement, ISRO shared on X (formerly Twitter):

“Docking Success Spacecraft docking successfully completed! A historic moment. Let’s walk through the SpaDeX docking process: Manoeuvre from 15m to 3m hold point completed. Docking initiated with precision, leading to successful spacecraft capture. Retraction completed smoothly, followed by rigidisation for stability. Docking successfully completed. India became the 4th country to achieve successful Space Docking. Congratulations to the entire team! Congratulations to India!”

The post further detailed that control of the two satellites as a single object was achieved following the docking. Subsequent undocking and power transfer checks are slated for the coming days, marking the next critical milestones in the mission.

ISRO Trial Runs and Challenges

Earlier in the week, ISRO conducted trial attempts by moving the satellites within three meters of each other and then returning them to a safe distance. This exercise was crucial in validating the procedure before the actual docking.

The SpaDeX docking was originally scheduled for January 7, 2025, but was postponed due to the need for further validation based on ground simulations. ISRO cited an abort scenario identified on January 6 as the reason for the delay. The experiment was rescheduled for January 9 but faced another postponement due to a higher-than-expected drift between the satellites. However, ISRO quickly addressed the drift issue, setting the stage for Thursday’s successful docking.

Significance of SpaDeX Mission

The SpaDeX mission is a landmark project for ISRO, aimed at developing and demonstrating technologies crucial for future space exploration. These include:

Rendezvous, Docking, and Undocking: This technology is essential for assembling spacecraft in orbit and conducting advanced space missions.

Power Transfer Demonstration: Post-docking, the mission will showcase the transfer of electrical power between the docked spacecraft, a critical capability for in-space robotics and other applications.

ISRO emphasized the broader implications of the SpaDeX mission, stating: “After successful docking and rigidization, electrical power transfer between the two satellites will be demonstrated before undocking and separation of the two satellites to start the operation of their respective payloads for the expected mission life of up to two years.”

Additionally, the mission’s focus on electric power transfer opens up avenues for innovations in composite spacecraft control, payload operations, and robotic systems.

The SpaDeX journey began with the launch of the two satellites on December 30, 2024, from the Satish Dhawan Space Centre in Sriharikota. Weighing approximately 220 kg each, the satellites were placed in a 475-km circular orbit. The meticulous planning and execution by ISRO’s scientists exemplify India’s growing prowess in space technology.

This accomplishment highlights ISRO’s dedication to pushing the boundaries of space exploration and underscores India’s emergence as a major player in the global space arena.

The successful SpaDeX docking experiment marks a new chapter in India’s space journey. By mastering complex technologies like spacecraft docking, ISRO has paved the way for future missions that will expand humanity’s reach into space. With each milestone, India’s position as a global leader in space exploration is further solidified, inspiring countless dreams and ambitions for generations to come.