India's ISRO carries out 'historic' space docking mission

India on Thursday became the fourth nation in the world to achieve space docking, a technological milestone that underscores its ambitions to expand its share in the rapidly growing $400 billion global space market.

The US, Russia, and China were the other countries to have mastered the docking technology. "Docking Success Spacecraft docking successfully completed! A historic moment," ISRO shared in a post on social media platform X.

"Docking successfully completed. India became the 4th country to achieve successful Space Docking. Congratulations to the entire team! Congratulations to India!" it added.

Dr. V. Narayanan, Secretary DOS, Chairman of Space Commission, and Chairman ISRO, congratulated the team ISRO.

At around 9 am IST (0330 GMT), the Indian Space Research Organisation (ISRO) carried out the highly anticipated Space Docking Experiment (SpaDeX), a spokesperson for the agency said.

Two ISRO satellites, Target and Chaser – each roughly the size of a large refrigerator – successfully latched onto each other and unlatched after a series of complex orbital manoeuvres.

The indigenous technology, crucial for satellite servicing, space station operations, and interplanetary missions, positions India to play a significant role in the commercial and exploratory frontiers of space.

Dr. V. Narayanan

"India has ambitious missions planned and to achieve those this is an important technology we have to have. Various missions like building a space station need assembly in space, which is not possible without space docking," Indian astrophysicist Jayant Murthy said.

The mission was postponed twice earlier – first because the docking process needed further validation through ground simulations, and later because of an issue arising from excess drift between the satellites.

SpaDeX, launched on Dec. 30 from India's main spaceport, used an Indian-made rocket to deploy the satellites into orbit. Among various payloads and experiments were eight cowpea seeds ISRO had sent to space onboard the rocket to study plant growth in microgravity conditions, which germinated within four days of the launch of the mission.

On Sunday, the two satellites came as close as three metres in a trial attempt for space docking up to 15m. It later moved back to a safe distance.

But now, "manoeuvre from 15m to 3m hold point completed," ISRO said while noting that the docking was achieved "with precision, leading to successful spacecraft capture".

"Retraction completed smoothly, followed by rigidisation for stability".

The docking technology was indigenously developed and has been named the 'Bharatiya Docking System'.

It includes a docking mechanism, a suite of four rendezvous and docking sensors, power transfer technology, indigenous novel autonomous rendezvous and docking strategy, and an inter-satellite communication link (ISL) for autonomous communication between spacecraft, incorporated with inbuilt intelligence to know the states of the other spacecraft, among others.

ISRO believes the SpaDeX mission will help establish India's capability in orbital docking -- a key technology for future human spaceflight and satellite servicing missions.

In addition to joining the elite club of spacefaring nations, docking technology is also key to India's impending space missions including the Moon mission, setting up the Indian space station, and lunar missions like Chandrayaan-4 without the support of GNSS from Earth.

Transfer of electric power

The mission will also demonstrate the transfer of electric power between docked spacecraft, a capability vital for applications like in-space robotics, composite spacecraft control and payload operations post-undocking.

Such technologies are essential for missions requiring multiple rocket launches to achieve shared objectives.

Space exploration and commercialisation is a key part of Indian Prime Minister Narendra Modi's efforts to position the country as a global superpower.

The successful SpaDeX mission "is a significant stepping stone for India’s ambitious space missions in the years to come," Modi said on X on Thursday.

ISRO is focused on deep-space exploration and enabling private companies to commercialise the sector, with projects that include solar studies, orbital astronaut missions and planetary defence, in collaboration with NASA.

The stakes are significant. While the global commercial space market is expected to reach $1 trillion by 2030, India's current share is just 2%, or $8 billion. The government aims to grow this to $44 billion by 2040.

Agencies