The Indian Space Research Organisation is set to achieve a significant milestone with the launch of the Space Docking Experiment Mission on December 30, 2024. The mission aims to demonstrate satellite docking capabilities, an important technology for future space missions.
SPADEX
- SpaDeX is a technology demonstration mission developed by ISRO to demonstrate docking technology in space.
- The mission aims to demonstrate the ability of two small spacecraft to rendezvous, dock and undock with each other, marking a significant advance in India’s space capabilities.
- Objective: The primary goal of SpaDeX is to develop docking technology for two small spacecraft, SDX01 (chaser) and SDX02 (target), in low Earth orbit. They will dock autonomously using advanced sensors and propulsion systems. Secondary objectives include testing electrical power transfer and demonstrating spacecraft control.
- Mission duration: Two years
- Mission design: SpaDeX will place two satellites, SDX01 and SDX02, into a 470 km orbit using a Polar Satellite Launch Vehicle (PSLV) rocket, where they will separate and gradually approach each other, eventually reaching a distance of 20 km. Both the satellites are equipped with Indian Docking System (BDS). BDS has identical, low impact (approach velocity is of the order of 10 mm/sec), biconvex (docking system is same for both spacecraft, chaser and target) docking mechanism, which enhances mission flexibility and precision for future tasks like satellite servicing, crew transfer and India’s space station development. SpaDeX will use the fourth stage of PSLV, POEM (PSLV Orbital Experimental Module)-4 to carry 24 payloads from academic institutions and startups. These experiments will take advantage of the microgravity environment in orbit.
- Docking Challenge: Both the satellites (chaser and target) will be orbiting at a speed of 28,800 km/hr. They will have to carefully reduce their relative velocity to 0.036 km/hr before docking.
Space Docking
- Space docking refers to the technology of connecting two spacecraft in space. It is a technology that makes it possible to send humans from one spacecraft to another.
- This capability is important for assembling large structures in space or transferring equipment, crew or supplies.
- For example, the International Space Station (ISS) was built using this technology, with different modules launched separately and installed in space.
- Frequent docking missions keep the ISS operational by delivering supplies, new crew members and modules, and helping old crew members return to Earth.
Why is Space Docking Technology Important for India
- Modular Space Infrastructure: Docking is a prerequisite for building a multi-modular space station. It allows the assembly of structures in space, thereby reducing the size and weight constraints of single launch missions.
- Interplanetary and lunar missions: Docking allows in-orbit refueling and payload exchange, thereby increasing mission flexibility for lunar bases and Mars exploration. It is important for future missions such as Chandrayaan-4, space stations and India’s planned Indian Space Station (BAS).
- Human spaceflight programme: Space docking is important for crew transfer and emergency evacuation during long-duration missions like Gaganyaan and beyond.
- Global collaboration and market potential: Spadex could make India the fourth country after Russia, the US and China to master space docking, strengthen its presence in satellite servicing and enable enhanced international collaboration.
- Satellite servicing: Docking allows servicing, refueling and upgrading of satellites, thereby improving their operational life and performance.