After being detached from the Vikram lander the past August, the Indian Space Research Organization (ISRO) confirmed the successful return of the Chandrayaan-3 propulsion module to an high-Earth orbit.
Chandrayaan-3 Mission:— ISRO (@isro) December 5, 2023
Ch-3's Propulsion Module (PM) takes a successful detour!
In another unique experiment, the PM is brought from Lunar orbit to Earth’s orbit.
An orbit-raising maneuver and a Trans-Earth injection maneuver placed PM in an Earth-bound orbit.… pic.twitter.com/qGNBhXrwff
Initially designed to operate for only 3 months in moon orbit, the module will now use its onboard Spectro-polarimetry of HAbitable Planet Earth (SHAPE) payload for Earth observation, thanks to the precise orbit injection by the LVM3 rocket that allowed in saving more than 100 kg of fuel in over one month of operations in the lunar orbit.
Furthermore, this successful attempt assumes an important meaning because it demonstrates the capability of ISRO to perform a possible future sample return mission from the Moon.
The Moon-Earth transfer
As said, on August 23, 2023, the Vikram Lander touched the surface of the Moon for the first time, deploying the Pragyan rover and making India the fourth country to have successfully achieved a soft land, after the Soviet Union (Interkosmos), the United States (NASA), and China (CNSA).
First, on October 9, the apolune (the farthest point of the spacecraft from the Moon) was increased from 150km to 5112 km, the module was then ready to perform a trans-Earth injection maneuver on October 13. This maneuver, along with four moon fly-bys, allowed the propulsion module of Chandrayaan-3 to leave the Moon’s sphere of influence on November 10.
The spacecraft is currently placed in a high Earth orbit with a 13-day period and an inclination of nearly 27 degrees.
The propulsion module
The main goal of the module was to carry the Vikram Lander and the Pragyan rover to a 100-kilometer lunar orbit. It was equipped with two radioisotope heating units, maintaining the spacecraft to its operational temperature, and providing the necessary electrical energy along with the solar panels.
Onboard the propulsion module there is the SHAPE experimental payload. It operates within the near-infrared (NIR) wavelength range of 1.0 to 1.7 μm, dedicated to studying spectro-polarimetric signatures of Earth. Notably, SHAPE stands out as the sole scientific payload situated on the Propulsion Module (PM) of the Chandrayaan-3 mission.