The Indian Space Research Organisation (ISRO) is poised to conclude 2024 with an innovative and ambitious mission. The "Space Docking Experiment" (SpaDeX) is scheduled for launch today, December 30, at exactly 10:00:15 PM, from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh.

The SpaDeX mission, carried aboard the PSLV-C60 rocket, marks a significant milestone in India's space exploration journey. This groundbreaking experiment aims to demonstrate India’s ability to achieve orbital docking, a crucial capability for future human spaceflight missions, satellite servicing, and advanced space exploration, including lunar missions.

Key Objectives and Technologies

SpaDeX focuses on developing and validating the technology required for the rendezvous, docking, and undocking of two small spacecraft: SDX01, designated as the Chaser, and SDX02, the Target. Both spacecraft will operate in a low-Earth circular orbit.

Unlike docking larger spacecraft, SpaDeX presents unique challenges due to the smaller size and mass of the satellites. The precision required for the maneuvering is far greater, making this mission a stepping stone for autonomous docking techniques that could be employed in future lunar missions like Chandrayaan-4.

The spacecraft utilize differential GNSS-based Satellite Positioning Systems (SPS) to achieve accurate Position, Navigation, and Timing (PNT) data. A novel Relative Orbit Determination Processor (RODP) has been integrated into the SPS receiver to precisely measure the relative position and velocity of the Chaser and Target. This innovation enhances the accuracy of docking procedures without relying on Earth-based Global Navigation Satellite Systems (GNSS).

Collaborative Development and Operational Control

The SpaDeX spacecraft were designed and developed by ISRO's UR Rao Satellite Centre (URSC) with assistance from several other ISRO centers, including VSSC, LPSC, SAC, IISU, and LEOS. Advanced hardware and software testing were conducted to verify the performance of the RODP and ensure mission success.

Once launched into orbit, the spacecraft will be controlled by ISRO's ISTRAC facility, utilizing a combination of ISRO-operated ground stations and externally hired ground stations.

Significance of SpaDeX

This mission is not only a technical demonstration but also a visionary step for ISRO's future ambitions. It showcases India's growing expertise in space technology and positions the nation as a key player in advanced space operations.