The Indian space agency ISRO has succeeded for the first time in performing a docking operation in space by joining two small spacecraft.
This technology is essential to the country's future ambition to build an Indian space station and put a person on the moon.
The mission is called SpaDeX exploded From the Sriharikota launch pad in southern India on December 30. The two spacecraft, launched on a single rocket, separated in space. The docking operation, which was scheduled for January 7, was rescheduled several times.
On Thursday morning, the space agency announced that it had made history by becoming the fourth country in the world to possess such technology after the United States, Russia and China.
Prime Minister Narendra Modi was at the ISRO office in Bangalore where scientists conducted the test.
“It is an important stepping stone for India's ambitious space missions in the coming years,” he later posted on X.
Union Science Minister Jitendra Singh expressed relief that the docking had “finally” taken place.
The two spacecraft on SpaDeX (short for Space Docking Experiment) are called SDX01, or Chaser, and SDX02, or Target. They each weigh about 220 kg (485 lb), and since their launch, they have been traveling through space at a carefully chosen speed.
“They were thrown together into space, but when separated, they were put at a different speed to allow them to build up a distance of 10 to 20 kilometers between them,” said Myla Mitra, a former NASA scientist and co-founder of the Delhi-based NASA. Space education company Stem and Space told the BBC.
She added: “During docking, scientists maneuvered them to close that distance, which allowed them to mate.”
The docking was initially scheduled to take place on January 7, but Isro later delayed it by two days saying they “need to do more tests through simulations” before the actual docking.
The second time, she said that a defect occurred while trying to bring the satellites closer, but she added that The spacecraft were safe.
ISRO said on Sunday that scientists were able to reduce the distance between the pursuer and the target, first to 15 meters and then to 3 metres. They said that after the test attempt, the spacecraft was “returned to a safe distance” and that they are analyzing the data.
S Somanath, who was Isro's president when SpaDeX (short for Space Docking Experiment) was launched and had been monitoring its progress until he retired a few days ago, described docking as a “very complex process” that needs extreme precision and coordination.
Initially, the two spacecraft had to be in the same orbit for the pursuer to begin approaching the target.
On Thursday morning, scientists began gradually reducing the speed of the two spacecraft, bringing them closer together until the distance between them was only 3 meters. Their connectors were then sealed together.
In the next step, the two spacecraft were perfectly stabilized, creating a tight passage for the safe transfer of materials or crew, completing space docking.
An ISRO official told the BBC that the mission will carry out in the next two or three days what is described as one of its most important experiments, which is transferring electrical energy from the pursuer to the target.
Ms. Mitra says this is aimed at proving the possibility of sending a spacecraft for another service in space.
The experiment will then demonstrate “separation and separation of the two satellites.”
Ms. Mitra says the mission will also test India's inter-satellite communication capabilities, as during docking and undocking, the spacecraft will have to communicate with the ground station and also with each other so that they know each other's location and speed.
The spacecraft also carries scientific instruments and cameras that will then be deployed. Over the next two years, they will measure radiation in space and monitor natural resources on Earth.
Isro, known for its mission economy, is also using part of the rocket that carried SpaDeX into space – which under normal circumstances would become space debris – to conduct some important experiments in orbit for three months.
Ode – short for PS4-Orbital Experiment Module – carries 24 payloads and has already carried out two successful experiments.
The first to demonstrate seed germination. Last week, Isro chirp A video clip says, “Cowpea buds revealed their first leaves in space under microgravity.” Microgravity is the state of nearly weightlessness that occurs on board spacecraft.
Scientists say it's great news because it means future astronauts can produce food during long-duration missions.
The second experiment includes the robotic arm, which Ms. Mitra says is among the most important payloads of the missile. A video Isro's X account shows the 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 objects and put them in their correct place.” It will also be useful in Chandrayaan-4, India's next mission to the moon that aims to collect and return samples of lunar soil, she added.
Follow BBC News India on Instagram, YouTube, twitter and Facebook.