Chennai, August 23: In a historic achievement, India’s moon lander executed a soft and successful touchdown on lunar soil, marking the nation’s entry into an exclusive club of lunar explorers. The event unfolded as planned, with the spacecraft’s four legs gently making contact with the moon’s surface, positioning it near the South Pole. This achievement solidifies a significant part of the Rs 600 crore Chandrayaan-3 mission. The next phase of the mission involves the moon rover descending from the lander, embarking on its journey, and conducting programmed experiments.
The Chandrayaan-3 mission consists of three components: a propulsion module (weighing 2,148 kg), a lander (1,723.89 kg), and a rover (26 kg). The rover is equipped with advanced instruments, including the Alpha Particle X-ray Spectrometer (APXS) and Laser Induced Breakdown Spectroscope (LIBS) for analyzing the elemental composition in its vicinity.
The lander, too, carries a suite of payloads to fulfill its mission objectives. These include Chandra’s Surface Thermophysical Experiment (ChaSTE) for measuring thermal conductivity and temperature, the Instrument for Lunar Seismic Activity (ILSA) for assessing seismic activity, and the Langmuir Probe (LP) to estimate plasma density and variations. Additionally, a passive Laser Retroreflector Array from NASA is onboard for lunar laser ranging studies.
Both the lander and rover are designed to operate for one lunar day, equivalent to 14 Earth days, as stated by ISRO.
The propulsion module, which separated from the lander, carries the Spectro-polarimetry of Habitable Planet Earth (SHAPE) payload to conduct spectral and polarimetric measurements of Earth from lunar orbit. This payload has a lifespan of three to six months.
The nail-biting 19-minute descent and landing process commenced at 5.45 p.m. as scheduled and concluded at 6.05 p.m. during which the lander safely touched down on the lunar surface. This achievement follows the unsuccessful attempt with the Vikram lander during the Chandrayaan-2 mission.
A soft landing on the moon is an intricate operation involving a series of complex maneuvers, including rough and fine braking. Imaging of the landing site region was performed before the descent to identify safe and hazard-free zones.
The descent of the lander began horizontally from an altitude of approximately 30 km at around 5.45 p.m. During the rough braking phase, the lander’s speed was reduced from 1,680 meters per second to 358 meters per second, with the altitude decreasing to 7.4 km above the lunar surface. The altitude hold phase followed, bringing the lander down to 6.8 km.
The lander then changed its position to a vertical orientation, hovering 150 meters above the moon’s surface. During this time, it captured images and surveyed the landing zone to select a secure landing spot. The successful landing was executed using two of the four engines.
The primary communication channel for the mission will be the Mission Operations Complex at ISRO Telemetry, Tracking, and Command Network (ISTRAC) in Bengaluru, connecting to the Chandrayaan-3 Propulsion Module, which will relay signals to the lander and rover. Additionally, the moon lander has established communication links with the Chandrayaan-2 mission’s Orbiter, serving as a backup communication channel.
Meanwhile, the Chandrayaan-3’s propulsion module continues to orbit the moon, with its SHAPE payload actively conducting its scientific tasks.
The Chandrayaan-3 mission was successfully launched on July 14 using India’s heavy lift rocket, LVM3. It subsequently completed its Earth orbit phase and commenced its journey towards the moon on August 1. This achievement marks a significant milestone in India’s space exploration endeavors.
