India is set to make a significant leap in space technology with the upcoming launch of the Space Docking Experiment (SpaDEX) on December 30, 2024. The Indian Space Research Organisation (ISRO) will utilize the Polar Satellite Launch Vehicle (PSLV-C60) to deploy two satellites, Chaser and Target, into a 470 km orbit, marking a crucial milestone in the country's space ambitions.
The primary goal of the SpaDEX mission is to demonstrate in-space docking capabilities, an essential technology for India's future space endeavors, including its space station and lunar missions. With this mission, ISRO will become one of the few space agencies in the world to achieve advanced docking technology.
Mission Overview: Docking in Space
The SpaDEX mission will involve the deployment of two identical satellites, Chaser (SDX01) and Target (SDX02), both weighing around 220 kg. These satellites will be placed in a low-Earth circular orbit with an inclination of 55°. The mission’s objectives include:
Demonstrating precise maneuvers for rendezvousing and docking the satellites. Validating the transfer of electrical power between the docked spacecraft. Operating payloads after undocking, with a mission life of up to two years.The PSLV-C60 vehicle has already been fully integrated and moved to the First Launch Pad at the Satish Dhawan Space Centre in Sriharikota for final checks before the mission.
A Step Toward India's Space Station
The SpaDEX mission is a crucial step for India's space exploration goals, positioning the country to become the fourth nation globally to master advanced docking technology. This capability is essential for future missions that involve multiple spacecraft working together, such as satellite servicing, formation flying, and building large space structures like the proposed Bharatiya Antariksh Station (BAS).
According to an ISRO official, the mission will significantly enhance India’s space station ambitions and broaden the scope for interplanetary exploration.
Innovative Microgravity Experiments
The PSLV's fourth stage, known as POEM-4 (PSLV Orbital Experimental Module), will serve as a platform for conducting microgravity experiments. Twenty-four payloads, contributed by academic institutions and startups, will be onboard for this purpose. This unique use of the PSLV’s spent stage further demonstrates ISRO's innovative approach to space research.
Execution and Docking Process
In the mission, the Chaser and Target satellites will be deployed independently but simultaneously into orbit. With precise maneuvering, the Target will gradually create a separation of 10-20 km from the Chaser, known as the Far Rendezvous phase. The Chaser will then approach the Target in stages, reducing the distance progressively from 5 km to as close as 3 meters, where docking will occur.
After docking, the spacecraft will transfer electrical power between each other before undocking for payload operations.
The Bigger Picture: Why SpaDEX Matters
SpaDEX is more than just a technological demonstration—it is a stepping stone toward ISRO's broader goals. The ability to dock spacecraft is vital for future missions involving lunar sample returns, interplanetary exploration, and establishing a sustained human presence in space.
By mastering this technology, India will join the ranks of the United States, Russia, and China, the only other countries that have achieved successful space docking. SpaDEX underscores ISRO’s commitment to developing advanced, cost-effective space capabilities and bolstering India's position in the global space community.
As the countdown to the launch begins, the SpaDEX mission promises to unlock new opportunities for scientific research and international collaboration, reaffirming India’s growing role in global space exploration.