Launched on July 14, 2023, aboard the LVM3-M4 vehicle from Satish Dhawan Space Centre (SDSC), SHAR, Chandrayaan-3's primary mission was to facilitate a soft landing near the lunar south pole and conduct various experiments through the Vikram lander and Pragyan rover. These objectives were successfully met, with both the lander and rover performing as expected for one lunar day, in line with their designated mission life.

The Propulsion Module, originally tasked with delivering the Vikram lander into lunar polar orbit, achieved its primary goal flawlessly. After the separation of the lander, the PM's secondary objective came into focus - the operation of the Spectro-polarimetry of HAbitable Planet Earth (SHAPE) payload, designed for Earth observation.

The mission's efficiency exceeded expectations, leaving over 100 kg of unused fuel in the PM after its lunar operations. This surplus prompted ISRO to repurpose the PM for additional objectives, contributing valuable insights for future lunar missions and demonstrating strategies pertinent to a potential sample return mission.

In a carefully planned maneuver, ISRO repositioned the PM to a suitable Earth orbit, avoiding potential collisions with the Moon or interference with Earth's Geostationary Orbit (GEO) belt. The first maneuver, executed on October 9, 2023, increased the PM's apolune altitude significantly, followed by a Trans-Earth injection maneuver on October 13. These adjustments set the stage for the PM's eventual transition from lunar to Earth orbit.

By November 10, the PM had departed the Moon's sphere of influence, with its first perigee pass around Earth occurring on November 22nd at an altitude of 1.54 lakhs km. The current orbit, with a 27-degree inclination and a period of nearly 13 days, poses no threat of close approaches to operational Earth satellites, as per ISRO's orbit predictions.

Continuing its scientific mission, the SHAPE payload is being operated whenever Earth is within its field of view. Notably, a special operation was conducted during the Solar Eclipse on October 28, 2023. These operations will proceed further, providing valuable Earth observation data.

The UR Rao Satellite Centre, a key division of ISRO, developed a novel analysis tool from first principles specifically for this operation. This tool, currently being validated through the Chandrayaan-3 PM's return maneuvers, marks a significant advancement in ISRO's capabilities for planning and executing complex space missions.

This successful maneuver sequence by Chandrayaan-3's PM not only showcases ISRO's increasing proficiency in space mission management but also sets a precedent for future missions. The outcomes include the ability to plan and execute trajectory changes from the Moon to Earth, the development and preliminary validation of software for such maneuvers, and strategies for gravity-assisted flybys and controlled end-of-life disposal of space assets, thereby adhering to no-debris creation norms.

In conclusion, the Chandrayaan-3 mission, through its extended PM operations, has not only fulfilled its primary scientific objectives but has also ventured into new realms of space mission flexibility and sustainability. This move by ISRO reflects a growing trend in space exploration where maximizing the utility of space assets and ensuring their sustainable end-of-life disposal are becoming increasingly important.

Following are the main outcome from the return maneuvers carried out on CH3 PM related to future missions:

+ Planning and execution of trajectory and maneuvers to return from Moon to Earth.

+ Development of a software module to plan such a maneuver and its preliminary validation.

+ Planning and execution of a gravity assisted flyby across a planets/ celestial body.

+ Avoiding uncontrolled crashing of the PM on the Moon's surface at the end of life of PM thus meeting the requirements of no debris creation.

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