Isro, India’s space agency, is working on its next ambitious lunar mission, Chandrayaan-4, which aims to bring back samples from the moon’s surface. The mission will involve complex maneuvers and technologies that Isro is planning to test and demonstrate in the coming years.
Chandrayaan-4 will be a follow-up to Chandrayaan-3, which made history by successfully landing on the moon on August 23, 2023. Chandrayaan-3 also performed a lunar hop experiment, where the lander Vikram reignited its engines and lifted off from the landing site to another location. This showed Isro’s capability to launch a spacecraft from the lunar surface and reach a lunar orbit.
Another milestone achieved by Chandrayaan-3 was the return of the propulsion module, which carried the lander rover to the moon, to an Earth orbit. The propulsion module used a gravity assist flyby technique, where it used the moon’s gravity to slingshot itself towards Earth. This was the first time Isro demonstrated this technique and also brought back a spacecraft from the moon.
The propulsion module experiment, which began on October 9, 2023, helped Isro plan and execute a trajectory back to Earth. The propulsion module will remain in orbit around the Earth for a year. This experiment also avoided the risk of the propulsion module crashing into the moon or colliding with other satellites in the geostationary orbit.
These achievements have given Isro confidence and experience for the Chandrayaan-4 mission, which will be much more challenging. Chandrayaan-4 will require the spacecraft to collect samples from the moon and place them in a canister, which will then return to the unit that will take off from the moon and reach a lunar orbit. There, it will dock with another spacecraft that will return to Earth’s orbit. After that, the canister will separate and dock with another spacecraft in Earth’s orbit, which will eventually make a re-entry and land on Earth.
To test the docking technology, which is essential for the sample return mission, Isro has planned the Space Docking Experiment (SPADEX). SPADEX will launch a satellite with two components, which will separate and then dock again. This will also provide data on space rendezvous technology, which is crucial for future missions involving a space station and human exploration of the moon.
Isro chairman S Somanath told The Times of India that SPADEX is expected to be launched by the end of 2024. He also said that Isro is working with Japan on the Lunar Polar Exploration (Lupex) mission, which will explore the water-ice deposits on the moon’s poles.
Isro’s lunar missions are part of its long-term vision to establish India as a leading space-faring nation. The Prime Minister’s Office recently announced a roadmap for Isro, which includes a space station by 2035 and humans on the moon by 20401
Read More:1: Chandrayaan 4: Isro gears up to bring Lunar samples; Key docking experiment in 2024