New Delhi:

India docked two satellites in space on Thursday, a key milestone for the country’s ambitions of a space station and manned Moon mission. “India docked its name in space history,” said the Indian Space Research Organisation (ISRO) on X. ISRO shared a behind-the-scenes video today to showcase the lead-up to the historic feat – dubbed as SpaDeX, or Space Docking Experiment.

The video shows a packed mission control room for the coverage of the orbital docking.

A man was heard explaining the whole process: “The mission director will be giving a go-ahead for the subsequent motion of spacecraft from 3 meters till docking. The command will be given for the subsequent phase wherein the spacecraft starts at three meters. With a constant velocity of 10 mm per second, it is approaching other spacecraft for docking to take place.”

ISRO successfully completed docking of two SPADEX satellites (SDX-01 & SDX-02) in the early hours of 16 January, 2025.#SPADEX #ISRO pic.twitter.com/UJrWpMLxmh

— ISRO (@isro) January 17, 2025

The satellites, weighing 220 kilograms each, blasted off on December 30, last year, on a single rocket from Andhra Pradesh’s Sriharikota launch site. Later they separated.

The two satellites were manoeuvred back together on Thursday in a “precision” process resulting in a “successful spacecraft capture”.

Back at the control room, the man announced, amid a round of applause, “The capture event is nominal… Both the spacecraft are captured. the capture has been completed.”

Congratulating everyone involved in the mission for accomplishing the “historic docking for the first time in the country”, ISRO chairman V Narayanan said, “During the last 15 days, excellent dedicated activities were carried out and today we have got a historic docking and on this occasion, let me congratulate each one of you. Today, we are a proud nation carrying this technology with us which is required for our future missions, including Chandrayaan-4, crewed mission to moon. This is the first stepping stone towards those important activities”.

The docking experiment is crucial for the smooth conduct of the country’s ambitious future missions, including Chandrayaan-4, Gaganyaan, setting up a space station and landing an astronaut on the moon. Last October, the government announced that India will have its own Space Station by 2035, known as the “Bharatiya Antriksh Station”.

The PSLV C60 rocket carrying two small satellites, SDX01 (Chaser) and SDX02 (Target), along with 24 payloads, had lifted off from the first launchpad of the Satish Dhawan Space Centre, and about 15 minutes after liftoff, the two small spacecraft weighing about 220 kg each were launched into a 475-km circular orbit as intended.

India has become the fourth country to achieve the milestone after Russia, the United States and China.

Two earlier docking attempts by ISRO were postponed due to technical issues.

New Delhi:

India’s first attempt to dock two live satellites in space has not been abandoned and the docking could actually take place in the next few days, ISRO Chairman Dr S Somanath has confirmed.

“Space crafts are at a distance of 1.5 km and on hold mode. Further drift to 500 m is planned to be achieved by tomorrow morning,” the Indian Space Research Organization or ISRO said in a statement.

The choreographed dance of satellites in space as part of India’s first Space Docking Experiment after initial hiccups is now progressing well and the ISRO is hopeful that the docking, or mating of the satellites, in space could happen soon enough.

India made two attempts for docking on January 7 and 9 but glitches in the process made scientists at the space agency abandon the attempts and many feared that India’s big experiment in the New Year, of mating two Indian space crafts in outer space flying at 470 kilometers above Earth, could well be abandoned. But now Dr Somanath has given confidence that things could well be back on track.

“The satellites are in very good health and safe and if all goes well docking will be attempted in the next few days,” Dr Somanath said  speaking to Akashvani News.

“The space docking experiment is our first attempt to try out the docking and every first attempt has its own challenges. We are learning our baby steps now, some of the attempts we did not materialize into final docking. But we have learnt all the lessons, did all the corrections and once again the satellites are coming closer. In the coming days we will decide to do the docking. We are finalizing some of the trimming maneuvers and programs that will help us to do the docking safely. We need to do many corrections and amends to do all of the planned things, also to make sure that nothing untoward happens,” Mr Somanath said, underscoring that “our satellites are in very good health and the docking will happen in a few days from now”.

On being asked if the SpaDeX mission has been a success so far, Dr Somanath added: “The success … the ultimate goal though is docking, but every step we learnt through this process is a journey and through that we learnt many things. Formation flying is another that we have, keeping them at a known distance and fly them is another critical knowledge we need since a combination of propulsion and sensors and up to this it has worked very-very well. Up to now, it is going very smoothly.”

The first attempt on January 7 was abandoned as an ‘abort scenario’ needed more simulation and then the docking scheduled for January 9 was called off as the satellites had drifted far apart’. Scientists at the ISRO are hopeful that the docking could well be attempted soon.

On December 30, ISRO’s workhorse, the Polar Satellite Launch Vehicle (PSLV), lifted off with twin 220-kg satellites for space and released in a 470-km circular orbit.

Docking is a complex maneuver perfected only by China, the US, and Russia.

ISRO’s SpaDeX mission involved two satellites separated by 20 km in a 470 km circular orbit. A chaser and target satellite move at a speed of 28,800 kmph, or 10 times the speed of a bullet, but they appear to be stationary due to zero relative velocity.

When the docking process begins, the satellites will be brought closer. The chaser will approach the target with progressively reduced inter-satellite distances of 5 km, 1.5 km, 500 m, 225 m, 15 m, and 3 m, ultimately leading to the precise docking of the two spacecraft.

When the docking happens, the chaser will move closer to the target at a speed of 10 mm per second and hold onto the target.

The system developed indigenously, is named Bhartiya Docking System. Incidentally, the ISRO has taken a patent for this technology. The mission’s success is crucial for completing future programmes such as Chandrayaan 4 and making the Bhartiya Antariksh Station and Gaganyaan.

New:

The skies over Sriharikota, Andhra Pradesh, were lit up at 10 pm today with the 62nd launch of the PSLV. The 25-hour countdown which started on Sunday, ended with the rocket lifting off from the First Launch Pad at this spaceport, exuding blinding orange fumes that streaked through the night sky. Within 15 minutes, it placed the twin space docking satellites into space. 

Amid much applause, Dr S Somanath, chairman of ISRO (Indian Space Research Organisation) announced that they have got the “right orbit”. 

The last stage of the launch vehicle was continuing to work to lower its orbit for the POEM (PS4-Orbital Experiment Module), which would conduct tests in the vacuum of space. 

ISRO has announced that the space docking experiment will most likely take place on January 7. The two satellites will be mated in space when they would be travelling at ten times the velocity of a bullet. 

The Spacecraft A (SDX01) or the ‘Chaser’ and Spacecraft B (SDX02) or the ‘Target’ would be merged together at an altitude of about 470 km after travelling at the same speed and distance.

A successful docking and undocking would make India the world’s fourth nation to have space docking technology, ISRO has said.

Explaining the process, Dr Somnath, in an exclusive interview to NDTV, said: “When you have multiple objects in space that need to be brought together for a specific purpose, a mechanism called docking is required. Docking is the process by which two space objects come together and connect”. 

This, he said, can be done using various approaches — soft mechanisms, hard mechanisms, or pressurised compartments for human transfer. 

“For example, on the International Space Station, crew modules dock at the station, equalise pressure, and transfer people,” he told NDTV.

This was the 99th rocket launch from the Satish Dhawan Centre of Sriharikota and it had a glorious lift off, placing SpaDeX satellites in the best orbit. 

The next steps — docking and the 24 experiments — will be conducted over the next few weeks.

With this, ISRO, which had started 2024 with a PSLV launch on Jan 1, ends it on a high note as well.

New Delhi:

Only three countries in the world – United States, Russia, and China – have the ability to carry out docking of two spacecraft or satellites in outer space. India is now on the cusp of achieving that feat as ISRO’s last mission of 2024 – named SpaDeX – lift-off from Andhra Pradesh’s Sriharikota at 2200 hrs (10 pm) IST.

SpaDex is short for Space Docking Experiment. This involves an experimental docking, subsequent interlocking and pressure checks, and undocking of two satellites. The mission is important for ISRO’s future moon missions, including Chandrayaan 4. It is also particularly important for India’s plan to set up its own space station.

In October this year, the government had announced that India will have its own Space Station called the Bharatiya Antriksh Station by 2035.

ISRO’s PSLV-C60 carrying SpaDeX and its payloads, lifts off from the first launch pad at Satish Dhawan Space Centre, in Sriharikota

So far, there are two other space stations – the International Space Station, built by the United States (NASA) and Russia (Roscosmos). The US side of the ISS is built by NASA and European Space Agency or ESA. The second space station is being built by China, and is called the Tiangong Space Station. India aims to set up the third.

Every time astronauts or cosmonauts are sent to space, especially the International Space Station, the shuttle or capsule they travel in needs to perform a docking manoeuvre. Only after the docking procedure is complete, and the two objects are securely interlocked, can the astronauts get into the pressurised cabin of the space station.

ISRO’S DOCKING EXPERIMENT EXPLAINED WITH THE HELP OF ‘INTERSTELLAR’

Docking in space is one of the most difficult and complicated procedures – the slightest of errors can lead to a catastrophe – an example of which was shown in the epic sci-fi movie Interstellar – where Cooper and the crew had to navigate a near-impossible and heart-pounding docking scenario after a minuscule error by Dr Mann sends the Endurance space station into an uncontrolled spin due to a catastrophic decompression. The scene highlights a complex docking manoeuvre.

Just like in the movie, where there was a Lander spacecraft and a Courier spacecraft, ISRO’s mission has two spaceships – the Chaser (SDX01) and the Target (SDX02), each weighing 220 kilograms. As the names suggest, the aim of the mission will be for the chaser to chase the target while both are orbiting Earth at a high speed and dock with it expeditiously.

ALL ABOUT ISRO’S SPADEX MISSION

The SpaDex mission lift-off at 2200 hrs (10 pm) IST on December 30 from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh.

ISRO’s launch was onboard the workhorse PSLV-C60 rocket, which put the two spacecraft in low-Earth orbit, roughly 475 km above the Earth’s surface. The inclination of the two spacecraft will be at 55 degrees facing the Earth. After being deployed in a circular orbit, the two spacecraft will grow apart by around 20 kilometers over 24 hours. The scientists will first carry out several other experiments under the POEM-4 mission – a parallel mission to SpaDex (explained below).

The scientists sitting at ISRO’s mission control in Bengaluru are expected to initiate the intricate and precise docking and undocking manoeuvre in the later half of the first week of January. If successful, India will create history by becoming only the fourth nation in the world to possess such technological ability.

According to ISRO, the main objectives of the SpaDeX mission include:

• To develop and demonstrate the technology needed for rendezvous, docking, and undocking of two small spacecraft.
• The demonstration of the transfer of electric power between the docked spacecraft, which is essential for future applications such as in-space robotics.
• Composite spacecraft control, including remotely controlling it both in space and from mission control.
• Payload operations after undocking.

This mission is crucial for India’s ability to set up its own Space Station. It will also give India’s RLV or Reusable Launch Vehicle – India’s variant of NASA’s iconic space shuttle – docking capability in future.

India’s Reusable Launch Vehicle or RLV

HOW THE INTERNATIONAL SPACE STATION WAS BUILT

Among other key missions, NASA’s space shuttle was used by the United States to construct the US side of the International Space Station. Russia too used their own space shuttle to build the Russian side of the International Space Station. While NASA had a series of space shuttles, starting with Columbia and evolving into Challenger, Discovery, Atlantis, and Endeavour, Russian space agency Roscosmos named their space shuttle Buran.

NASA’s Space Shuttle (L) and Russia’s Space Shuttle (R)

Here is a insightful video of how the International Space Station – the largest man-made space object – was built by the US and Russian space shuttles using the docking mechanism and robotic arms in addition to astronauts and cosmonauts:

ISRO’S POEM-4 MISSION – AND EXPERIMENT WITH MICROGRAVITY

Besides the space docking manoeuvre, there is another key mission objective. ISRO plans to experiment with microgravity during the PSLV rocket’s fourth-stage. ISRO aims to use the spent fourth stage, which it has termed POEM-4 or PSLV Orbital Experimental Module 4, as a platform for carrying our experiments with microgravity.

According to the space agency, it provides an opportunity for the scientific community to carry out certain in-orbit microgravity experiments for an extended duration of up to three months using the POEM platform, which otherwise would end up as space debris immediately after the mission objective of injecting the primary payloads of the mission.

A total of 24 payloads are part of the POEM-4 mission, of which 14 payloads are from ISRO/DOS centres and 10 payloads are from various Non-Government Entities (NGEs) comprising Academia and Start-ups that have been received through IN-SPACe.

One of the fourteen payloads by ISRO is of a robotic arm – again a crucial element to constructing India’s own space station in future. For now the experiment will involve a robotic arm to demonstrate the capturing of tethered debris.
 

New Delhi:

Only three countries in the world – United States, Russia, and China – have the ability to carry out docking of two spacecraft or satellites in outer space. India is now on the cusp of achieving that feat as ISRO’s last mission of 2024 – named SpaDeX – lift-off from Andhra Pradesh’s Sriharikota at 2200 hrs (10 pm) IST.

SpaDex is short for Space Docking Experiment. This involves an experimental docking, subsequent interlocking and pressure checks, and undocking of two satellites. The mission is important for ISRO’s future moon missions, including Chandrayaan 4. It is also particularly important for India’s plan to set up its own space station.

In October this year, the government had announced that India will have its own Space Station called the Bharatiya Antriksh Station by 2035.

ISRO’s PSLV-C60 carrying SpaDeX and its payloads, lifts off from the first launch pad at Satish Dhawan Space Centre, in Sriharikota

So far, there are two other space stations – the International Space Station, built by the United States (NASA) and Russia (Roscosmos). The US side of the ISS is built by NASA and European Space Agency or ESA. The second space station is being built by China, and is called the Tiangong Space Station. India aims to set up the third.

Every time astronauts or cosmonauts are sent to space, especially the International Space Station, the shuttle or capsule they travel in needs to perform a docking manoeuvre. Only after the docking procedure is complete, and the two objects are securely interlocked, can the astronauts get into the pressurised cabin of the space station.

ISRO’S DOCKING EXPERIMENT EXPLAINED WITH THE HELP OF ‘INTERSTELLAR’

Docking in space is one of the most difficult and complicated procedures – the slightest of errors can lead to a catastrophe – an example of which was shown in the epic sci-fi movie Interstellar – where Cooper and the crew had to navigate a near-impossible and heart-pounding docking scenario after a minuscule error by Dr Mann sends the Endurance space station into an uncontrolled spin due to a catastrophic decompression. The scene highlights a complex docking manoeuvre.

Just like in the movie, where there was a Lander spacecraft and a Courier spacecraft, ISRO’s mission has two spaceships – the Chaser (SDX01) and the Target (SDX02), each weighing 220 kilograms. As the names suggest, the aim of the mission will be for the chaser to chase the target while both are orbiting Earth at a high speed and dock with it expeditiously.

ALL ABOUT ISRO’S SPADEX MISSION

The SpaDex mission lift-off at 2200 hrs (10 pm) IST on December 30 from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh.

ISRO’s launch was onboard the workhorse PSLV-C60 rocket, which put the two spacecraft in low-Earth orbit, roughly 475 km above the Earth’s surface. The inclination of the two spacecraft will be at 55 degrees facing the Earth. After being deployed in a circular orbit, the two spacecraft will grow apart by around 20 kilometers over 24 hours. The scientists will first carry out several other experiments under the POEM-4 mission – a parallel mission to SpaDex (explained below).

The scientists sitting at ISRO’s mission control in Bengaluru are expected to initiate the intricate and precise docking and undocking manoeuvre in the later half of the first week of January. If successful, India will create history by becoming only the fourth nation in the world to possess such technological ability.

According to ISRO, the main objectives of the SpaDeX mission include:

• To develop and demonstrate the technology needed for rendezvous, docking, and undocking of two small spacecraft.
• The demonstration of the transfer of electric power between the docked spacecraft, which is essential for future applications such as in-space robotics.
• Composite spacecraft control, including remotely controlling it both in space and from mission control.
• Payload operations after undocking.

This mission is crucial for India’s ability to set up its own Space Station. It will also give India’s RLV or Reusable Launch Vehicle – India’s variant of NASA’s iconic space shuttle – docking capability in future.

India’s Reusable Launch Vehicle or RLV

HOW THE INTERNATIONAL SPACE STATION WAS BUILT

Among other key missions, NASA’s space shuttle was used by the United States to construct the US side of the International Space Station. Russia too used their own space shuttle to build the Russian side of the International Space Station. While NASA had a series of space shuttles, starting with Columbia and evolving into Challenger, Discovery, Atlantis, and Endeavour, Russian space agency Roscosmos named their space shuttle Buran.

NASA’s Space Shuttle (L) and Russia’s Space Shuttle (R)

Here is a insightful video of how the International Space Station – the largest man-made space object – was built by the US and Russian space shuttles using the docking mechanism and robotic arms in addition to astronauts and cosmonauts:

ISRO’S POEM-4 MISSION – AND EXPERIMENT WITH MICROGRAVITY

Besides the space docking manoeuvre, there is another key mission objective. ISRO plans to experiment with microgravity during the PSLV rocket’s fourth-stage. ISRO aims to use the spent fourth stage, which it has termed POEM-4 or PSLV Orbital Experimental Module 4, as a platform for carrying our experiments with microgravity.

According to the space agency, it provides an opportunity for the scientific community to carry out certain in-orbit microgravity experiments for an extended duration of up to three months using the POEM platform, which otherwise would end up as space debris immediately after the mission objective of injecting the primary payloads of the mission.

A total of 24 payloads are part of the POEM-4 mission, of which 14 payloads are from ISRO/DOS centres and 10 payloads are from various Non-Government Entities (NGEs) comprising Academia and Start-ups that have been received through IN-SPACe.

One of the fourteen payloads by ISRO is of a robotic arm – again a crucial element to constructing India’s own space station in future. For now the experiment will involve a robotic arm to demonstrate the capturing of tethered debris.
 

New Delhi:

Only three countries in the world – United States, Russia, and China – have the ability to carry out docking of two spacecraft or satellites in outer space. India is now on the cusp of joining that elite global space club with the last mission of 2024 named SpaDeX scheduled for lift-off on December 30.

SpaDex is short for Space Docking Experiment.

Every time astronauts or cosmonauts are sent to space, especially the space station, the space shuttle they travel in needs to dock with a spacecraft or space station. Only after docking is complete and secured can the astronauts get into the pressurised space station.

Docking in space is one of the most difficult and complicated procedures – the slightest of errors can lead to a massive catastrophe – an example of which was shown in the epic sci-fi movie Interstellar – where Cooper and the crew had to navigate a near-impossible and heart-pounding docking scenario after a minuscule error by Dr Mann sends the Endurance space station into an uncontrolled spin due to a catastrophic decompression. The scene highlights a complex docking manoeuvre.

Just like in the movie, where there was a Lander spacecraft and a Courier spacecraft, ISRO’s mission on December 30 will also have two spaceships – the Chaser (SDX01) and the Target (SDX02), each weighing 220 kilograms. As the names suggest, the aim of the mission will be for the chaser to chase the target while both are orbiting Earth at a high speed and dock with it expeditiously.

ALL ABOUT ISRO’S SPADEX MISSION

The SpaDex mission is scheduled for lift-off at 2158 hrs (9:58 pm) IST on December 30 from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh.

ISRO’s launch will be onboard the workhorse PSLV-C60 rocket, which will put the two spacecraft in low-Earth orbit, roughly 470 km above the Earth’s surface. The inclination of the two spacecraft will be at 55 degrees facing the Earth. After being deployed in a circular orbit, the two spacecraft will grow apart by around 20 kilometers over 24 hours. The scientists sitting at ISRO’s mission control in Bengaluru will then initiate the intricate and precise docking and undocking manoeuvre.

According to ISRO, the main objectives of the mission will include:

• To develop and demonstrate the technology needed for rendezvous, docking, and undocking of two small spacecraft.
• The demonstration of the transfer of electric power between the docked spacecraft, which is essential for future applications such as in-space robotics.
• Composite spacecraft control, including remotely controlling it both in space and from mission control.
• Payload operations after undocking.

A successful docking and undocking would catapult India in the league of a select few in space technology.

This mission is crucial for India’s ability to set up its own Space Station. It will also give India’s RLV or Reusable Launch Vehicle – India’s variant of NASA’s iconic space shuttle – docking capability in future.

India’s Reusable Launch Vehicle or RLV

US AND RUSSIA – RIVALS ON EARTH, UNITED IN SPACE

Among other key missions, NASA’s space shuttle was used by the United States to construct the US side of the International Space Station. Russia too used their own space shuttle to build the Russian side of the International Space Station. While NASA had a series of space shuttles, starting with Columbia and evolving into Challenger, Discovery, Atlantis, and Endeavour, Russian space agency Roscosmos named their space shuttle Buran.

NASA’s Space Shuttle (L) and Russia’s Space Shuttle (R)

Here is a insightful video of how the International Space Station – the largest man-made space object – was built by the US and Russian space shuttles using the docking mechanism and robotic arms in addition to astronauts and cosmonauts:

ISRO’S EXPERIMENT WITH MICROGRAVITY

Besides the space docking manoeuvre, there is another key mission objective. ISRO plans to experiment with microgravity during the PSLV rocket’s fourth-stage. ISRO aims to use the spent fourth stage, which it has termed POEM-4 or PSLV Orbital Experimental Module 4, as a platform for carrying our experiments with microgravity.

According to the space agency, it provides an opportunity for the scientific community to carry out certain in-orbit microgravity experiments for an extended duration of up to three months using the POEM platform, which otherwise would end up as space debris immediately after the mission objective of injecting the primary payloads of the mission.

A total of 24 payloads will be flown in this POEM-4 mission, of which 14 payloads are from ISRO/DOS centres and 10 payloads are from various Non-Government Entities (NGEs) comprising Academia and Start-ups that have been received through IN-SPACe.

One of the fourteen payloads by ISRO is of a robotic arm – again a crucial element to constructing India’s own space station in future. For now the experiment will involve a robotic arm to demonstrate the capturing of tethered debris.

As India and the rest of the world prepare to ‘have a blast’ on New Years’ Eve, Scientists at ISRO are readying themselves for the blast-off (lift-off) which will help India enter a new era in space technology.