ISRO called the second success a “milestone,” which will help further refine docking and undocking technologies critical for future missions, including Gaganyaan, lunar sample return, and the establishment of the Bhartiya Antriksh Station (BAS), India’s ambitious space station.
According to space experts, the achievement signals maturity in critical technologies required for advanced missions.
“The ability to dock and undock enables a modular approach to building complex space structures like a space station,” said Aloke Kumar, associate professor at the Indian Institute of Science (IISc), who is also developing space bricks from lunar soil simulants.
He added that mastering docking technology is just one part of the puzzle. The other critical technology India must develop is advanced Environmental Control and Life Support Systems (ECLSS) to ensure human safety in orbit. These systems regulate oxygen levels, pressure, waste, fire suppression, and more.
OrbitAID Aerospace, a Chennai-based startup working on satellite refuelling, said the success of SpaDeX boosts confidence in on-orbit servicing (OOS). The founder, Sakthikumar R, said that by repeating the experiment, ISRO is aiming to perfect the technique.
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“That’s how you scale to larger modules and eventually to human spaceflight missions.” Sakthikumar highlighted that docking needs deep knowledge of guidance, navigation, and control systems for such operations.ISRO said it had quite a few learnings from the first docking attempt on January 16. In this second experiment, the docking was performed fully autonomously from an inter-satellite distance of 15 meters, while the first involved a manual pause at 3 meters before final docking, it said.
Union minister of state for science and technology Jitendra Singh on Monday said more experiments are scheduled over the next two weeks. Experts believe these could include repeatedly maintaining a structural lock, ensuring that the docked satellites can function as a single stable unit in orbit, a key requirement for in-space assembly.
The space agency on Monday announced the second docking of two satellites — Chaser and Target — under its SpaDeX mission.
ISRO demonstrated the docking for the second time on April 20, 2025, at 08:20 pm. “Subsequently, power transfer from SDX 02 to SDX 01 satellite as well as vice versa was also exercised and accomplished on 21st April, 2025,” the space agency said in a statement.
The SpaDex mission was launched on December 30, 2024, onboard PSLV C60.