On August 17, Chandrayaan-3 embarked on the final phase of its mission, executing a meticulously controlled detachment of the lander and rover payloads from the propulsion module.
The Indian Space Research Organisation (ISRO) conveyed through a post on the microblogging platform X (formerly Twitter) that at approximately 1:15 pm on August 17, the lander, named Vikram, and the rover, known as Pragyan, effectively separated from the spacecraft's propulsion module. This pivotal separation event marked the initiation of the mission's most critical phase.
The Moon mission, which commenced its journey from the Satish Dhawan Space Centre in Sriharikota on July 14, aims to achieve significant objectives as defined by the space agency. These objectives encompass showcasing a secure and gentle landing on the lunar surface, alongside a demonstration of the Pragyan rover's ability to amass essential lunar data for the execution of on-site scientific experiments.
Vikram Lander's Payloads and Communication
In the Chandrayaan-3 mission, the lander module, Vikram, boasts three significant scientific payloads - RAMBHA-LP, ChaSTE, and ILSA. The upcoming phase of the mission revolves around the activation and verification of the instruments embedded within these crucial payloads. Additionally, Vikram is enhanced with a passive Laser Retroreflector Array, provided by NASA, which plays a vital role in facilitating lunar laser ranging studies.
Vikram's role extends beyond its scientific contributions. It will serve as a communication link between the Pragyan rover and the Indian Deep Sea Network (IDSN), ensuring a seamless flow of data and information throughout the mission.
In Chandrayaan-3's initial phase, the first orbital maneuver will position Vikram in a circular orbit, situated at an altitude of 100x100 km above the Moon. A subsequent maneuver will then situate the lander in its ultimate orbit, drawing it closer to the lunar surface at a height of 100x30 km. This strategic orbital configuration will serve as a pivotal starting point for Vikram's impending descent on August 23.
One of the scientific payloads, RAMBHA-LP (Radio Anatomy of Moon Bound Hypersensitive Ionosphere and Atmosphere - Langmuir probe), will focus on gauging the density of near-surface plasma (comprising ions and electrons) and monitoring its fluctuations over time. The ChaSTE (Chandra’s Surface Thermophysical Experiment) payload, meanwhile, is tasked with analyzing and quantifying the thermal characteristics of the Moon's surface in the vicinity of its poles.
The ILSA (Instrument for Lunar Seismic Activity) holds the role of assessing seismic activity at the landing site, unveiling the composition of the lunar crust and mantle's structure. Lastly, the Lunar Retroreflector Array (LRA), a passive experiment, will contribute to comprehending the dynamics of the Moon's system.
Chandrayaan-2, launched by ISRO on July 22, 2019, encountered an unsuccessful attempt at achieving a gentle lunar landing. Communication with the Vikram lander was severed when it was only around 2.1 km away from the lunar surface.