India’s Chandrayaan-3 mission, a trailblazing endeavor to explore the lunar frontier, has reached a pivotal juncture in its trajectory. Recent developments this week have highlighted the mission’s progress and the Indian Space Research Organisation’s (ISRO) adept handling of its intricate components. These developments encompass the successful separation of the Lander Module from the Propulsion Module on Thursday, followed by a triumphant deboosting operation on Friday. Additionally, ISRO has outlined plans for another deboosting maneuver for the Vikram lander on 20 August.
What is the Meaning of Deboosting?
Deboosting, in the context of space exploration, refers to the deliberate reduction of a spacecraft’s orbital velocity. This controlled maneuver is executed with the intention of altering the spacecraft’s orbital parameters, specifically its altitude and velocity, in order to achieve a desired trajectory or position within its orbital path.
In the case of the Chandrayaan-3 mission, the objective of deboosting is to position the spacecraft, including the Vikram lander and Pragyan rover, for a soft landing on the Moon’s surface. By slowing down the spacecraft and modifying its orbit, it is maneuvered to approach the Moon with specific parameters. The mentioned parameters of 30 km for the closest point to the Moon (Perilune) and 100 km for the farthest point (Apolune) represent the desired elliptical shape of the spacecraft’s lunar orbit.
Subsequent Steps in Chandrayaan-3’s Mission Progression:
Following the successful deboosting operation on Saturday, Chandrayaan-3’s mission trajectory is poised to advance through a series of strategic maneuvers, all of which have been meticulously planned to ensure a safe and precise landing on the Moon’s surface on the 23rd of August. As per the information provided by the ISRO Chairman, the upcoming steps include:
Reorientation of Vikram Lander:
The Vikram lander will undergo a critical reorientation, adjusting its position to an angle of 90 degrees. This realignment is crucial for preparing the lander’s descent trajectory for the upcoming stages of the landing sequence.
At an altitude of approximately 100 meters above the lunar surface, the Vikram lander will initiate an essential scanning process. This scanning operation serves to identify any potential complications or hazards that could impede the safe landing of the lander and rover.
Gradual Descent and Thruster Firings:
In the absence of identified complications during the scanning phase, the Vikram lander will begin its gradual descent toward the lunar surface. Throughout this phase, the lander’s thrusters will be engaged, finely controlling its descent velocity. The precise control over the thrusters’ firing plays a pivotal role in ensuring a gentle touchdown.
As the Vikram lander continues its descent, it will utilize its thrusters to maintain a controlled speed. This controlled descent aims to mitigate any potential impact forces and ensure a soft landing on the Moon’s surface. The culmination of this meticulously planned sequence is the anticipated touchdown of the Vikram lander and deployment of the Pragyan rover onto the lunar terrain.
Challenges in Achieving a Successful Soft Landing for Chandrayaan-3:
The endeavor to achieve a successful soft landing on the lunar surface with Chandrayaan-3 is underscored by several intricate challenges. These challenges, while formidable, exemplify the complexity and precision required for such a mission. The following four significant challenges represent key obstacles that must be navigated for the mission’s triumphant conclusion:
Lack of Lunar Atmosphere at 100 km Altitude:
The absence of a substantial atmosphere on the Moon at an altitude of 100 km eliminates the feasibility of utilizing parachutes to facilitate a gradual descent. Unlike Earth, where parachutes can effectively slow down spacecraft, the Moon’s negligible atmosphere renders this method ineffective. Consequently, alternative strategies must be employed to ensure a controlled descent.
Altitude Range of 30 km to 100 Meters:
Within the altitude range of 30 km to 100 meters lies a pivotal phase where Chandrayaan-2 encountered a setback. The proximity to the Moon’s surface during this phase presents challenges in managing speed, altitude, and navigation. A software glitch in Chandrayaan-2 led to an unsuccessful landing attempt as the lander’s speed control mechanisms failed to operate as intended.
Sudden Terrain Changes at 100 Meters Altitude:
During the final stages of descent, at an altitude of 100 meters, the Vikram lander may encounter unexpected and rapid variations in lunar terrain. Such abrupt changes could potentially trigger software glitches or errors in altitude sensing systems. Managing these unpredictable variations is crucial for ensuring a smooth landing.
Lunar Dust and Sensor Interference:
The lunar environment introduces a unique challenge involving the presence of lunar dust. As the lander approaches the surface, the disturbance caused by its descent can result in the elevation of lunar dust. This dust poses a risk of interfering with sensors and cameras, potentially causing erroneous readings. Additionally, the dust can lead to the premature shutdown of thrusters due to sensor obstructions.
Chandrayaan-3: Advancing Lunar Exploration Through Demonstrative Objectives
Chandrayaan-3 represents a logical progression from its predecessor, Chandrayaan-2, aimed at showcasing comprehensive capabilities in secure lunar landing and rover mobility. This mission embarks on a transformative journey to validate key elements of lunar exploration. Its objectives are threefold: to successfully execute a gentle landing on the lunar surface, to conduct rover-based exploration, and to conduct on-site scientific investigations. The synergy of these objectives accentuates Chandrayaan-3’s significance in lunar research and technology advancement.
Demonstrating Secure and Gentle Lunar Landing:
At the core of Chandrayaan-3’s objectives lies the ambition to manifest the proficiency of executing a soft and secure landing on the lunar terrain. This feat underscores India’s capabilities in meticulously planning and executing precision maneuvers in an environment bereft of Earth-like atmosphere. The successful landing will validate essential technologies for lunar exploration and lay the foundation for more intricate missions.
Mobility Through Rover Roving:
A pivotal milestone of Chandrayaan-3 involves showcasing the viability of mobility on the Moon’s surface through rover roving. The rover, designated as Pragyan, will traverse the lunar landscape, symbolizing a leap forward in the exploration of extraterrestrial terrains. By maneuvering across the Moon, Pragyan will extend human understanding of the lunar geology and environment, transcending the static nature of earlier missions.
In-situ Scientific Experiments:
Chandrayaan-3 amplifies its significance by serving as a platform for conducting in-situ scientific experiments. The rover’s capabilities enable on-the-spot chemical analyses of the Moon’s surface. This endeavor will facilitate the acquisition of valuable insights into the lunar composition, mineralogy, and geological characteristics, bolstering global lunar research efforts and contributing to humanity’s understanding of celestial bodies’ origins and evolution.