Chandrayaan-3’s Propulsion Module Moved to Earth’s Orbit, Demonstrates Successful Experiment: ISRO
Bengaluru: The Indian Space Research Organisation (ISRO) has announced that the Propulsion Module (PM) of Chandrayaan-3 has been successfully moved from an orbit around the Moon to an orbit around Earth. Describing the operation as a unique experiment, ISRO stated that the primary objective of the Chandrayaan-3 mission was to demonstrate a soft landing near the lunar south polar region and perform experiments using the instruments on the ‘Vikram’ lander and the ‘Pragyan’ rover.
The spacecraft was launched on July 14, 2023, aboard the LVM3-M4 vehicle from the Satish Dhawan Space Centre (SDSC-SHAR). On August 23, the Vikram lander made its historic touchdown on the Moon and subsequently, the Pragyan rover was deployed. The scientific instruments in the lander and rover were operated continuously for one lunar day as per the defined mission life.
“The mission objectives of Chandrayaan-3 have been completely met,” ISRO said in a statement. The space agency also revealed that the initial plan was to operate the Spectro-polarimetry of HAbitable Planet Earth (SHAPE) payload in the PM for about three months. However, after over one month of operations in the lunar orbit, over 100 kg of fuel was still available in the PM. Therefore, it was decided to use the additional fuel to derive additional information for future lunar missions and demonstrate mission operation strategies for a sample return mission.
To continue the SHAPE payload for earth observation, ISRO decided to re-orbit the PM to a suitable earth orbit. This mission plan was worked out considering collision avoidance to prevent the PM from crashing onto the Moon’s surface or entering into the Earth’s Geosynchronous Equatorial Orbit (GEO) belt, among other factors.
Following successful maneuvers, the PM is now orbiting Earth and has crossed its first perigee on November 22 with an altitude of 1.54 lakh km. “Hence as per current orbit prediction, there is no threat of close approach with any operational Earth-orbiting satellites,” ISRO assured.
The main outcomes of the return maneuvers carried out on the PM related to future missions include the planning and execution of trajectory and maneuvers to return from the Moon to Earth, development of a software module to plan such a maneuver, and the planning and execution of a gravity-assisted fly-by across a planet or celestial body.
ISRO’s flight dynamics team developed an analysis tool for this operation, which is being validated through the return maneuvers carried out for the Chandrayaan-3 PM. The successful movement of the Propulsion Module to Earth’s orbit is a significant achievement for ISRO and paves the way for future lunar missions.