ISRO’S AMBITIOUS CHANDRAYAAN-4 MISSION

Er Mayadhar Swain

The Indian Space Research Organisation (ISRO) after its historic success with the Chandrayaan-3 mission is already gearing up for the next lunar mission named Chandrayaan-4. In fact India is one of the few countries which has achieved success in lunar exploration. India carried out chandrayaan-1 mission in 2008 with an orbiter and a probe. In this mission water was detected for the first time in Moon. The second mission Chandrayaan-2 was launched in 2019 with an orbiter, a lander and a rover. After separating from the orbiter, the lander and rover descended on lunar surface, but due to some software problem they crash landed on the lunar surface instead of soft landing. As a result, the lander and the rover did not work, but the orbiter is still working.

The Chandrayaan-3 was launched in 2023 with a propulsion module, one lander and one rover. The lander Vikram and rover Pragyan successfully soft landed on the surface of the Moon on August 23, 2023 and worked for 14 days (one lunar day). The mission conducted several in-situ scientific experiments on the lunar surface. On August 30, the Laser-Induced Breakdown Spectroscope instrument onboard ‘Pragyan’ rover of Chandrayaan-3 ‘unambiguously confirmed’ the presence of sulphur in the lunar surface near south pole. Other elements like Aluminum, Calcium, Iron, Chromium, Titanium, Manganese, Silicon, and Oxygen were also detected.

Chandrayaan – 4

With the success ofChandrayaan-3 ISRO has planned the next lunar mission Chandrayaan-4 and is scheduled to be launched in 2028. This time the aim is to collect rocks and soils from the surface of the Moon and bring them to India so that these can be tested in Indian laboratories.

Speaking at the National Space Science Symposium in the first week of March this year, ISRO chief S Somanath revealed the proposal about the mission.

CHANDRAYAAN-4 COMPONENETS

While Chandrayaan-3 consisted of three main components – lander, rover and the propulsion module, the Chandrayaan-4 mission will have two more additional components tasked to return the samples from the Moon and drop them on Earth.

The Chandrayaan-4 components will consist of five spacecraft modules. The five modules will be as follows.

* Propulsion Module: Similar to Chandrayaan-3, the propulsion module will guide Chandrayaan-4 in lunar orbit, before separating.

* Descender Module: This module will make the lunar landing, similar to the Vikram lander on Chandrayaan-3.

* Ascender Module: Once the samples are collected and stored, the ascender module will eject from the lander and begin returning to Earth.

* Transfer Module: It will be responsible for grabbing the ascender module and getting it out of lunar orbit. It will journey back to Earth before the capsule with the rock and soil samples detach.

* Re-entry Module: This will be the capsule carrying the lunar soil that will land on Earth after a return journey from the Moon.

TWO SEPARATE LAUNCHES

The mission will not be launched in a single phase like its predecessor, instead, two separate launches will push vehicles that will not only land on the Moon but also return rocks and soils from the lunar surface to India.

The five components of the Chandrayaan-4 mission will not be launched together. According to ISRO Chief, India’s heaviest launch vehicle LVM-3 will launch with three components, which will include the Propulsion Module, the Descender Module and the Ascender Module. This will be a similar launch to the Chandrayaan-3 mission in 2023. The Transfer Module and the Re-entry Module will be launched aboard a Polar Satellite Launch Vehicle (PSLV). This will, however, be the first such mission involving two launch vehicles aimed at completing a single mission.

Working of the Mission

The propulsion Module will carry the Descender Module and Ascender Module to the Moon and insert them to the lunar orbit.The Descender Module will detach from the Propulsion Module and land on the lunar surface, carrying a robotic arm  and a drill to collect samples. The Ascender Module will also detach from the Propulsion Module and dock with the Descender Module on the surface, transfer the samples to a container. The Ascender Module then lift off from the surface and rendezvous with the Propulsion Module in orbit.

The Transfer Module will carry the Re-entry Module to the Moon and dock with the Propulsion Module in orbit. The Transfer Module will then transfer the sample container from the Ascender Module to the Re-entry Module. The Re-entry Module will separate from the Transfer Module and return to Earth, carrying the samples. The Re-entry Module will enter the Earth’s atmosphere and land safely using parachutes.

Challenges

The Chandrayaan-4 mission will be a major milestone for India’s space program, as it will demonstrate India’s capabilities in various aspects of lunar exploration, such as landing, ascent, docking, transfer, and return. But there are many challenges to be overcome for the mission. It will be the first time for ISRO to collect and bring back the rock and soil from the Moon to the Earth. Some of the challenges identified by the ISRO are given below.

1. There is a need for multiple launchers for this mission. The Chandrayaan- 3 mission was launched in a single phase. But now there are five modules and these will be launched in two phases by two separate launching vehicles. The mission has to demonstrate return and re-entry to Earth for sample delivery.
2. The team “must have docking capability either on Earth orbit or on the Moon’s orbit. Failure in docking mission can make a mission to fail.
3. We must have the robotic capability to operate a drill, select a sample and load it in compartments to keep the samples very safe.
4. One of the objectives of the mission is to demonstrate the transfer of samples from one module to the other. This is a difficult task.
5. There are also challenges on the technical capabilities. ISRO first started with remote sensing and then in-situ observations and experiments were done. The third phase is to bring lunar samples back to Earth for greater laboratory observations and analysis. So there must be greater challenge here.

Conclusion

Chandrayaan-4 aims to build on the accomplishments of the recently concluded Chandrayaan-3 mission while attempting more complex objectives. Only three countries have achieved lunar sample return so far: the United States, the Soviet Union, and China. The successful execution of Chandrayaan-4 would position India as the fourth nation globally to achieve the capability of bringing back samples from the lunar surface. This ambitious venture underlines ISRO’s continuous efforts to push the boundaries of space exploration and enhance India’s standing in space research and technology. The mission will also contribute to the global efforts of lunar exploration and cooperation, and advance the scientific and technological knowledge of humanity.