Context:

On January 17, 2025, India achieved a major milestone in space exploration, becoming the fourth country in the world to successfully perform space docking. This remarkable feat was carried out using two small spacecraft, SDX01 (Chaser) and SDX02 (Target), as part of ISRO’s Space Docking Experiment (SpaDeX) mission.

About Space Docking:

• Space docking refers to the precise process of joining two fast-moving satellites in space.
• India's Space Docking Mission Details: The SpaDeX mission involved two spacecraft — SDX01 (Chaser) and SDX02 (Target) — which successfully docked in orbit. This technology is crucial for future space missions and satellite servicing.
• The US, Russia, and China are the only other countries to have performed successful space docking before India. By joining this elite group, India strengthens its position in the global space exploration community.

About the SpaDeX Mission

Mission Background

• SpaDeX and its 24 PS4-Orbital Experiment Module (POEM-4) payloads were launched by ISRO via the PSLV-C60 rocket from the Sriharikota space centre in December 2024.
• Mission Purpose: The main objective was to develop and demonstrate autonomous rendezvous and docking technology using two small spacecraft.

Mission Goals

• Rendezvous and Docking: Develop technology for the rendezvous and autonomous docking of SDX01 (Chaser) and SDX02 (Target).
• Controllability Evaluation: Once docked, the system’s ability to maneuver and maintain stability as a single unit will be assessed.
• Power Transfer: The mission will also test the power transfer between the docked spacecraft.
• Life Extension: The potential for extending the operational life of the target spacecraft will be explored.
• Mission Duration: The mission is expected to last up to two years post-docking operations.

Indigenous Technologies Developed for SpaDeX

Key Technologies Used

• Inter-Satellite Communication Link (ISL): Facilitates autonomous communication between the two spacecraft.
• GNSS-Based RODP Processor: This system determines the relative position and velocity of the spacecraft, crucial for precise docking.
• Other Indigenous Technologies:
• Docking Mechanism: Enables the joining of two spacecraft.
• Sensor Suite: Provides critical data for autonomous docking operations.
• Autonomous Rendezvous Strategy: Ensures the spacecraft approach and dock without manual intervention.

Significance of the SpaDeX Mission

Strategic Importance for India’s Space Ambitions

• Support for Future Missions: SpaDeX technology will support India’s long-term space objectives, such as sample return from the Moon and the development of the Bharatiya Antariksh Station (BAS).
• Satellite Servicing: Docking technology allows for the servicing and refueling of satellites, which can extend their operational lifespans and reduce the cost of satellite maintenance.

Benefits for Future Space Exploration

• Multiple Rocket Launches: The technology helps in situations where multiple launches are needed to achieve a single mission goal, such as constructing a space station or conducting a large-scale space experiment.
• Potential Applications:
• In-Space Robotics: Technology for robotic repairs and satellite servicing.
• Natural Resource Monitoring: Enhanced capacity for environmental and resource monitoring, including vegetation studies.