Why in the News?

Nearly two months after the Indian Space Research Organisation (ISRO) successfully demonstrated its docking capability, it disengaged and undocked two satellites.

What’s in Today’s Article?

• SpaDeX Mission (Introduction, Key Features, Significance, Road Ahead, etc.)

Introduction:

• ISRO successfully undocked the SpaDeX (Space Docking Experiment) satellites SDX01 (Chaser) and SDX02 (Target) after nearly two months of testing their docking capabilities.
• The manoeuvre marks India’s significant progress in autonomous docking and undocking technology.
• This accomplishment positions India as the fourth country after the United States, Russia, and China to develop this advanced space docking capability.
• The achievement is critical for future ISRO missions, including human spaceflight, lunar exploration, and the construction of India’s planned space station.

About the SpaDeX Mission:

• SpaDeX is an ambitious ISRO mission designed to test India's ability to autonomously dock and undock satellites in orbit. The experiment involved:
  • Docking: Two 220-kg satellites, SDX01 and SDX02, were maneuvered into the same orbit and progressively brought closer until they were joined on January 16, 2025.
  • Power Sharing: The mission demonstrated power-sharing capabilities, where both satellites operated as a single composite unit.
  • Undocking: On March 14, the capture levers were released, and the satellites were commanded to separate, successfully completing the undocking operation.
• ISRO officials took their time before executing the undocking manoeuvre to ensure every step was thoroughly analysed, as this was the agency’s first attempt at such a mission.

Significance of this Capability:

• Chandrayaan-4 and Lunar Sample Return Missions
  • ISRO plans to launch Chandrayaan-4, a mission aimed at bringing back lunar surface samples. This will require two critical docking operations:
    • In Lunar Orbit: The ascender module carrying Moon samples will dock with a transfer module.
    • In Earth Orbit: The transfer module will dock with a re-entry module, which will carry the samples back to Earth.
• The Bharatiya Antariksha Station (India’s Own Space Station)
• India is working on launching its own space station, the Bharatiya Antariksha Station, by 2035.
• This will consist of five separate modules that must be docked together in space to form the complete station.
• Human Spaceflight and Resupply Missions
  • In future human spaceflight missions, docking and undocking will be crucial for sending astronauts to space stations and facilitating cargo transport, similar to how the International Space Station (ISS) functions.

ISRO’s Indigenous Docking System: A Major Innovation

• One of the highlights of the SpaDeX mission is the development of Bharatiya Docking System, which is:
  • Inspired by International Standards: Similar to the International Docking System Standard used by spacecraft docking with the ISS.
  • Designed with Simplicity: While the ISS docking system has 24 motors, ISRO’s system operates efficiently with just two motors.
  • Androgynous Design: Both the Chaser and Target satellites have identical docking systems, making the process seamless.
• This indigenous innovation strengthens India’s self-reliance in space technologies and paves the way for future deep-space missions.

The Road Ahead: Further Refinements and More Experiments

• ISRO officials stated that they might conduct further docking and undocking experiments to refine the system’s accuracy.
• Exhaustive ground simulations and analysis were key to achieving this milestone in the first attempt itself.
• The organization is now focused on integrating docking systems into upcoming missions, including the Gaganyaan human spaceflight program, future lunar missions, and satellite servicing projects.

Conclusion:

The successful undocking of the SpaDeX satellites is a major milestone for ISRO, showcasing its growing expertise in space docking technology.  This capability is essential for future lunar exploration, space station assembly, and human spaceflight missions.

As ISRO continues its research and experimentation, SpaDeX lays the groundwork for a future where India can independently conduct complex space missions, marking a giant leap toward self-sufficiency in space exploration.