ISRO satellites on SpaDex mission shook hands! What space docking means for India?

Chaser and Target have finally “shook hands”. The two satellites launched by the Indian Space Research Organisation (ISRO) successfully docked in space. The Indian space agency had anticipated an “exciting handshake” earlier in January. The milestone was achieved early Thursday, January 16.

This historic feat made India the fourth country in the world — after Russia, the United States and China — and part of the “elite club of nations” with space-docking capabilities.

Prime Minister Narendra Modi called “the successful demonstration of space docking of satellites” a “significant stepping stone for India’s ambitious space missions in the years to come.”

What is ISRO SpaDex mission?

ISRO launched the Space Docking Experiment (SPADEX) mission aboard PSLV-C60 and innovative payloads in late December. The mission consists of two small spacecraft (about 220 kg each).

The mission aimed to develop and demonstrate the technology needed for spacecraft rendezvous, docking, and undocking of two small spacecraft.

The ISRO also wanted to showcase “controllability in docked conditions to extend the life of target spacecraft and test power transfer between docked satellites.”

The docking process involved controlling two satellites—Chaser and Target—as a single object in space. “Post docking, control of two satellites as a single object is successful. Undocking and power transfer checks to follow in coming days,” ISRO tweeted while announcing the historic feat.

Earlier, docking attempts by ISRO were postponed due to technical issues.

What is docking?

ISRO said that docking technology is essential when multiple rocket launches are required to achieve common space mission objectives.

“When you have multiple objects in space, and we need to bring them together for a specific purpose, we need a mechanism called docking,” former ISRO Chairman Somanath explained earlier.

Somanath said that initially, a mechanism comes and connects, and later, a sealed connection is established.

“Suppose you want to build a space station. Not everything is launched in one go. Modules go one after the other. They are connected to each other to build a long, big, complex space station,” he had explained in an interview with NDTV.

Somanath then cited the United States International Space Station as an example. He said, “For example, at the International Space Station, when a crew module connects to the station, you equalise the pressure and transfer people.”

The Indian space agency said the SPADEX “is a pivotal project designed to develop and demonstrate the technology needed for spacecraft rendezvous, docking, and undocking using two small satellites”.

Meanwhile, the National Aeronautics and Space Administration (NASA)defined docking as “mating operations where an active vehicle flies into the mating interface under its own power”.

Science Direct also explained that Spacecraft docking has significant applications, such as ferrying supplies to manned space stations, refuelling space vehicles, and recovering daughter spacecraft separated from mother spacecraft.

What does ‘docking in space’ mean for India?

Docking is a “groundbreaking technology” which will prove to be a game-changer for several space missions lined up for the ISRO in future.

Union Minister of Science & Technology Jitendra Singh said this docking capability paves the way for the smooth conduct of ambitious future missions, including the Bharatiya Antriksha Station, Gaganyaan and Chandrayaan 4. The mechanism will also help during human space missions — sending an Indian astronaut to the Moon.

India is hoping to send an Indian astronaut to the Moon by 2040, establish the Bharatiya Antariksh Station (BAS) by 2035 and launch the Chandrayaan-4 mission to bring back lunar samples by 2027. Space docking will also be useful in future Gaganyaan missions.

“SPADEX will serve as a milestone in advancing India’s capabilities in space docking, a critical technology for future space missions including satellite servicing, space station operations, and interplanetary missions,” ISRO said.

It added, “By mastering rendezvous and docking technologies, ISRO is set to enhance its operational flexibility and expand its mission horizons.”