Only three countries in the world – the United States, Russia and China – have the capability to dock two spacecraft or satellites in outer space. India is now on the verge of achieving the feat as ISRO’s last mission of 2024 – named SpaDeX – launches at 2200 hrs (10 pm) IST from Sriharikota in Andhra Pradesh.
Spadex is short for Space Docking Experiment. This involves experimental docking, followed by interlocking and pressure testing and undocking of the two satellites. This mission is important for ISRO’s future Moon missions including Chandrayaan 4. It is also particularly important for India’s plans to set up its own space station.
In October this year, the government had announced that by 2035, India will have its own space station which will be called the Indian Space Station.
ISRO’s PSLV-C60 carrying SpaDeX and its payload lifted off from the first launch pad of the Satish Dhawan Space Center in Sriharikota.
So far, there are two other space stations – the International Space Station, built by the United States (NASA) and Russia (Roskosmos). The American side of the ISS is built by NASA and the European Space Agency, or ESA. The second space station is being built by China, and is called the Tiangong Space Station. India aims to establish the third.
Every time astronauts or cosmonauts are sent into space, especially the International Space Station, the shuttle or capsule in which they travel needs to perform a docking maneuver. Only after the docking process is complete and the two objects are safely connected can astronauts enter the pressurized 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 complex processes – the slightest error can lead to disaster – an example of which was shown in the epic sci-fi film Interstellar – where Cooper and the crew had to navigate the almost impossible and A heartbreaking docking scenario after a small error by Dr. Mann sends the Endurance space station into an uncontrolled spin due to a catastrophic decompression. This view highlights a complex docking maneuver.
Just like the movie, where there was a lander spacecraft and a courier spacecraft, ISRO’s mission has two spacecraft – Chaser (SDX01) and Target (SDX02), each weighing 220 kg. As the name suggests, the objective of the mission will be for the pursuer to pursue the target while both are orbiting the Earth at high speed and will rapidly engage with it.
All about ISRO’s Spadex mission
The Spadex mission lifted off from the Satish Dhawan Space Center in Sriharikota, Andhra Pradesh on December 30 at 2200 hrs IST (10 PM IST).
The launch was on ISRO’s workhorse PSLV-C60 rocket, which placed the two spacecraft into low-Earth orbit, about 475 km above the Earth’s surface. Both spacecraft will be inclined at 55 degrees towards the Earth. After being deployed in a circular orbit, the two spacecraft will be separated by about 20 kilometers in 24 hours. Scientists will first conduct several other experiments under the POEM-4 mission – a parallel mission to Spadex (described below).
Scientists at ISRO’s Mission Control in Bengaluru are expected to begin the complex and precise docking and undocking process in the latter half of the first week of January. If successful, India will create history by becoming the fourth country in the world to have such technological capability.
According to ISRO, the main objectives of the Spadex mission include:
- To develop and demonstrate the technology required for rendezvous, docking and undocking of two small spacecraft.
- Demonstration of the transfer of electrical power between docked spacecraft, which is essential for future applications such as space robotics.
- Overall spacecraft control, which includes controlling it remotely both in space and from mission control.
- Payload operations after undocking.
This mission is critical to India’s ability to establish its own space station. It will also give India RLV or Reusable Launch Vehicle – India’s version of NASA’s iconic Space Shuttle – docking capability in the future.
India’s Reusable Launch Vehicle or RLV
How was the International Space Station built?
Among other major missions, NASA’s Space Shuttle was used by the United States to construct the American side of the International Space Station. Russia also used its 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, the Russian space agency Roscosmos named its space shuttle Buran.
NASA’s Space Shuttle (left) and Russia’s Space Shuttle (right)
Here’s an insightful video of how the International Space Station – the largest man-made space object – was built by American and Russian space shuttles using docking mechanisms and robotic arms in addition to astronauts and cosmonauts:
ISRO’s Kavita-4 mission – and experiments with microgravity
In addition to space docking maneuvers, there is another major mission objective. ISRO plans to experiment with microgravity during the fourth stage of the PSLV rocket. ISRO aims to use the spent fourth stage, which it has called POEM-4 or PSLV Orbital Experimental Module 4, as a platform to further our experiments with microgravity.
According to the space agency, it provides the scientific community an opportunity to conduct some microgravity experiments in orbit for an extended period of up to three months using the POEM platform, which would otherwise end up as space debris soon after the mission objective. Injecting the mission’s primary payload.
A total of 24 payloads are part of the POEM-4 mission, out of which 14 payloads are from ISRO/DOS centers and 10 payloads are from various Non-Government Entities (NGEs) including academics and start-ups received through IN- Are. space.
One of ISRO’s fourteen payloads consists of a robotic arm – a key element for building India’s own space station in the future. For now the experiment will involve a robotic arm to demonstrate capturing tethered debris.