IsroThe Indian space agency Isro has successfully conducted a space docking for the first time by bringing two small craft together in space.
The technology is essential to the country's future ambition to build an Indian space station and send a man to the moon.
The mission called SpaDeX fired from the Sriharikota launch pad in South India on December 30. The two spacecraft, launched on one rocket, separated in space. The docking process, originally scheduled for January 7, was rescheduled several times.
On Thursday morning, the space agency announced that it had made history by becoming only the fourth country in the world to have such technology, after the United States, Russia and China.
IsroPrime Minister Narendra Modi was at Isro's office in Bangalore as scientists conducted the test.
“This is an important step for India's ambitious space missions in the coming years,” he later posted on X.
Federal Science Minister Jitendra Singh expressed relief that the docking had “finally” happened.
The two spacecraft of SpaDeX (short for Space Docking Experiment) are called SDX01 or Chaser and SDX02 or Target. Each weighs about 220 kg (485 pounds), and since launch they have traveled through space at a carefully chosen speed.
“They were thrown into space together, but at the time of separation they were put at different speeds so that they could build a distance of 10-20 km between each other,” Mila Mitra, a former NASA scientist and co-founder of the Delhi-based company for space education Stem and Space, BBC said.
“During docking, the scientists maneuvered them to reduce this distance, allowing them to mate,” she added.
The docking was initially scheduled for January 7, but Isro later postponed it by two days, saying they “need to carry out more tests through simulations” before the actual docking.
The second time it said there was a problem trying to approach the satellites, but added that the spaceships were safe.
On Sunday, Isro said scientists were able to reduce the distance between Chaser and Target first to 15 meters and then to 3 meters. They said that after the test run, the spacecraft was “moved back to a safe distance” and that they were analyzing data.
isroS Somanath, who was the Isro chief when SpaDeX (short for Space Docking Experiment) was launched and oversaw its progress until his retirement a few days ago, had described docking as a “very complex process” that required extreme precision and coordination.
To begin with, the two spacecraft had to be in the same orbit for the Chaser to begin approaching the target.
On Thursday morning, scientists began by gradually reducing the speed of the two spacecraft – bringing them closer and closer until they were just 3 meters apart. Their connectors were then clipped together.
In the next step, the two spacecraft were bolted together perfectly, creating an airtight passage for the safe transfer of material or crew, completing the docking in space.
An Isro official told the BBC that over the next two to three days, the mission will carry out what is billed as one of its most important experiments – transferring electricity from the Chaser to the Target.
This, according to Ms Mitra, is to demonstrate that a spacecraft can be sent to service another in space.
The experiment will then demonstrate “uncoupling and separation of the two satellites.”
Ms Mitra says the mission will also test India's intersatellite communication capabilities, as during docking and undocking the spacecraft will need to communicate with the ground station and also with each other so that they know the position and speed of the other.
IsroThe spacecraft is also carrying science instruments and cameras that will then be deployed. Over the next two years, they will measure radiation in space and monitor Earth's natural resources.
Isro, known for the economy of its missions, also used part of the rocket that carried SpaDeX into space – which under normal circumstances would have turned into space debris – to conduct some important experiments in orbit for three months.
Poem – short for PS4-Orbital Experiment Module – carries 24 payloads and has already performed two successful experiments.
The first demonstrated seed germination. Last week, Isro tweeted video that says “cowpea sprouts have revealed their first leaves in space in microgravity.” Microgravity is a nearly weightless state aboard a spacecraft.
Scientists say this is great news because it means future astronauts can produce food during long-duration missions.
The second experiment involves the robotic arm, which Ms. Mitra says is among the rocket's most important payloads. A video in Isro's X account shows a robotic arm moving to grab a piece of space debris.
Ms Mitra says this arm will play a “crucial role during the construction of the space station as it can be used to pick up and place things”. It will also be useful in Chandrayaan-4, India's next mission to the moon, which will aim to collect and return lunar soil samples, she added.
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