ISRO to launch Chandrayaan-4 in two parts, assemble modules in space while in orbit: Chief Somanath

ISRO Chairman S. Somanath, has stated that at the moment, ISRO is working on at least 1500 new pieces of tech to power India's space missions. Image Credit: File

The Indian Space Research Organisation (ISRO) is gearing up for its ambitious Chandrayaan-4 mission, which aims to bring back samples from the Moon. However, unlike previous missions, the Chandrayaan-4 mission has some unique challenges. To start with, it will involve the most powerful rocket system that India has ever used.

And to make things even more challenging, the mission involves multiple launches, after which, the modules will be assembled in space, as per a report by The Indian Express.

A technical marvel on its own

Unlike previous missions, Chandrayaan-4 will be launched in multiple parts and assembled in space before heading to the Moon, ISRO Chairman S. Somanath revealed on Wednesday.

This innovative approach is necessary because the spacecraft's size exceeds the carrying capacity of ISRO's most powerful rocket.

Assembling spacecraft parts in orbit is not new—it's how the International Space Station was built. However, this will be the first time a lunar mission follows this method, potentially setting a new precedent in space exploration.

Somanath explained that Chandrayaan-4’s configuration involves multiple launches due to the current limitations of ISRO’s rockets. "Our rockets aren't strong enough to handle the entire spacecraft at once," he said at an event in Delhi. To achieve this, ISRO is developing new docking capabilities that will allow the spacecraft parts to join together in both Earth and Moon orbits. This capability will be tested later this year with a mission called Spadex.

Docking in space: A novel concept

In lunar missions, docking is a common manoeuvre. Typically, part of the spacecraft lands on the Moon while the other part stays in orbit. After collecting samples, the lander returns and docks with the orbiting module, forming a single unit again.

However, assembling modules in Earth orbit for a lunar journey is a novel concept. Somanath mentioned that while ISRO doesn't claim to be the first to attempt this, it’s an unprecedented move in space exploration.

The upcoming Spadex mission will be ISRO’s first to demonstrate in-space docking. Somanath noted that a detailed study and internal review for the Chandrayaan-4 mission are complete, and the cost estimate will soon be submitted to the government for approval. This mission is part of ISRO’s Vision 2047, which includes plans for India’s own space station by 2035 and sending humans to the Moon by 2040.

The need to dock modules while in space

India’s future space station, Bharatiya Antariksh Station (BAS), will also be assembled in space through multiple launches. The first segment of BAS will be launched using the current LVM3 rocket, with the goal of having the first launch by 2028. A proposal detailing the construction, required technologies, timeline, and costs is being prepared for government approval.

Somanath added that additional BAS modules will be developed over time. The station will have a five-module configuration, with multiple committees working on their development. Future modules may be launched using an upgraded LVM3 or the Next Generation Launch Vehicle (NGLV), a heavy rocket currently under development. The design and production plan for NGLV is ready and will be submitted to the government for approval.

To accommodate the NGLV, ISRO is creating a new launch complex, as the current facilities are inadequate for the 4,000-ton rocket. This new facility will be crucial for handling and processing the NGLV, enabling ISRO to undertake larger and more complex missions.

Through these innovative strategies and missions, ISRO continues to push the boundaries of space exploration, positioning India as a significant player on the global stage.