ISRO Achieves Historic SpaDeX De-Docking, Advancing Chandrayaan 4, Gaganyaan, and Bharatiya Space Station

The Indian Space Research Organisation (ISRO) has marked another major milestone with the successful undocking of the SpaDeX (Space Docking Experiment) satellites. This achievement is a crucial step toward India’s ambitious space goals, including the development of the Bharatiya Antriksha Station (Indian Space Station), Chandrayaan-4, and the Gaganyaan human spaceflight mission. Following its historic docking feat on January 16, 2025, ISRO has now demonstrated its capability to execute autonomous space docking and undocking, making India the fourth nation to achieve this after the United States, Russia, and China.

Successful SpaDeX Undocking: A Major Achievement

On March 7, 2025, ISRO confirmed the successful de-docking of the SpaDeX satellites in low Earth orbit (LEO). The operation was carried out at an altitude of 460 km with a 45-degree inclination, with both satellites SDX-1 (Chaser) and SDX-2 (Target) now orbiting independently. ISRO reported that their health remains stable, ensuring a smooth progression for future missions.

The key undocking sequences involved:

SDX-2 extension completed successfully

Capture Lever 3 released as planned

Capture Lever in SDX-2 disengaged

Decapture command issued in both SDX-1 and SDX-2

ISRO shared video footage of the separation, showcasing India’s growing expertise in autonomous satellite operations.

Significance of the SpaDeX Mission

The SpaDeX mission, launched on December 30, 2024, using a PSLV-C60 rocket, is a crucial step toward developing in-orbit servicing, space station operations, and deep-space exploration. The primary objective was to test and demonstrate autonomous rendezvous, docking, and undocking technology, a capability that will be instrumental for:

Satellite servicing and refueling

Docking spacecraft for future space stations

Lunar sample return missions like Chandrayaan-4

Interplanetary missions requiring spacecraft docking

This success sets the foundation for upcoming complex missions requiring multiple docking maneuvers in space, including crewed space exploration and long-term space station operations.

Bharatiya Antriksha Station: India’s Space Station Plan

One of the long-term objectives of ISRO is to establish the Bharatiya Antriksha Station, India’s first independent space station, by 2035. The technology demonstrated through SpaDeX will be essential for assembling and maintaining space modules in orbit. With Gaganyaan’s human spaceflight mission scheduled for 2025-26, ISRO is making steady progress toward sustainable human presence in space.

Chandrayaan-4: India’s Lunar Sample Return Mission

Following the success of Chandrayaan-3, ISRO is now preparing for Chandrayaan-4, which is planned for launch in 2028. Unlike its predecessor, this mission will focus on collecting and returning lunar samples to Earth, requiring advanced docking technology for its return module. The SpaDeX experiment serves as a critical testbed for ensuring a successful lunar docking process.

Future Applications and Global Collaboration

ISRO is not only advancing national space capabilities but also engaging in international partnerships. The agency is working with NASA on the NISAR satellite and is also exploring collaborative opportunities for in-orbit servicing and space station docking.

The successful docking and undocking of SpaDeX satellites marks a turning point for India’s space ambitions, bringing the country closer to independent space station operations, interplanetary missions, and long-duration spaceflight.

Conclusion

With the successful completion of SpaDeX docking and undocking, ISRO has achieved another historic milestone, reinforcing India’s position among global space leaders. As the agency moves forward with Gaganyaan, Chandrayaan-4, and Bharatiya Antriksha Station, the successful demonstration of autonomous docking technology will play a vital role in future missions, ensuring India’s self-reliance in space technology and long-term exploration goals.