By Vaishali Basu Sharma
Chandrayaan-3, India’s ambitious lunar mission, is scheduled for launch by LVM3 from the Satish Dhawan Space Center in Sriharikota on July 14.
Chandrayaan-3 is essentially a follow-on mission to Chandrayaan-2 to demonstrate end-to-end capability in safe landing and roving on the lunar surface.
It consists of lander and rover configurations. The launch window opened on June 12. If successful, India will become the fourth country to achieve the remarkable feat of landing a spacecraft on the Moon’s surface. As the countdown to the big launch day begins, there is tremendous excitement across India about launching the lunar spacecraft.
S Somnath, head of the Indian Space Research Organization (ISRO), says, “Essentially, Chandrayaan-3 is similar to Chandrayaan-2, with the same scientific architecture and mission objective.” During Chandrayaan 2, India’s previous lunar mission, the lander crash-landed during descent due to a technical failure, ending the mission in disappointment and tears.
Speaking at the India Today conclave, the Chairman of the Indian Space Research Organization explained that to understand the reason for the previous mission’s failure, ISRO underwent a process of cold stimulation.
As a successor to Chandrayaan-2, Chandrayaan-3 has undergone a few changes to increase the robustness of the lander. He said all these modifications have been subject to exhaustive ground tests and simulations through test beds.
While the equatorial front side of the Moon has been studied in great detail, and there is a wealth of information about lunar surface topography, gravity, albedo, and chemical and mineral composition, many gaps remain in our understanding of the Moon. A major gap is related to the lunar polar regions, which the earlier moon missions did not observe.
Is there hydrogen or water ice deposited on the permanently shadowed region of the lunar poles where temperatures can be as low as –230°C? Chandrayaan-1, India’s first orbiter mission to the Moon launched in 2008, was designed to seek answers to such questions. Despite a hard landing that crashed its Moon Impact Probe (MIP) near the Lunar South Pole, Chandrayaan-1 conclusively provided evidence of water molecules on the Moon.
Apart from the MIP, which crashed on landing, all the other experiments part of the Chandrayaan-1 mission were conducted from the orbiting spacecraft, where Chandrayaan-2 marked a big step forward. Launched onboard India’s most powerful rocket, the GSLV Mk-III, the Chandrayaan-2 mission attempted to study the southernmost realm of the far side of the Moon at close quarters with help from lander ‘Vikram’ and robotic rover ‘Pragyan.’
The mission objectives of Chandrayaan-3 are to demonstrate a safe and Ssoft Landing on the lunar surface, rover roving on the Moon, and conducting in-situ scientific experiments.
India hopes to join an elite list of nations that have managed to land on the Moon: the United States, the erstwhile USSR, and China.
The launch vehicle Mark III is a three-stage medium-lift launch vehicle. Christened as the “baahubali” of rockets (the strong-armed), it’s the most powerful rocket ever developed by ISRO.
To launch the Chandrayaan-3 spacecraft, LVM3 consists of two solid-fuel boosters and a liquid-fuel core stage powering it. The solid fuel boosters provide the initial thrust, while the liquid fuel core stage provides the sustained trust to propel the rocket into orbit.
The spacecraft consists of three parts: the lander module, the propulsion module, and a rover. The integrated spacecraft weighs around 3900 kilograms.
The main function of the propulsion module is to carry the lander module from launch vehicle injection to the final lunar 100-km circular polar orbit and separate it. The lander will make a soft landing at a specific site on the Moon and deploy the rover. In turn, the rover will conduct a chemical analysis of the lunar surface. It will move only within a limited range, within the sight of the lander’s cameras.
All data the rover collects will be transmitted to the orbiter and then back to Earth. ISRO is targeting a soft landing sometime in the middle of August. Landing dates are determined based on the availability of sunlight at a particular landing spot.
Sunlight is essential for the lunar lander and rover to utilize their solar panels and generate power. ISRO has designed the Chandrayaan 3 lander rover to function for 14 earth days which amounts to one lunar day. After that, there will be a period of 14 Earth days of darkness at the landing site, so the rover and lander will not be able to recharge their batteries during that period.
Countdown for #Chandrayaan3, India’s third lunar exploration mission to begin today. 26-hour count down to begin at 1:05 pm.
— All India Radio News (@airnewsalerts) July 13, 2023
While there have been several moon landings, Chandrayaan-3 will be the first to land on the Moon’s south pole. A successful landing of Chandrayaan-3 on the Moon’s south pole will demonstrate India’s technical prowess and space-faring ambitions.
The soft landing that is being aimed involves separation from the orbiter through a series of complex maneuvers. This is the more challenging part of the mission. Extreme surface temperature variations because of the length of a lunar day and hostile surface full of craters, rocks, and dust make it difficult to conduct lander and rover operations.
China’s moon mission ‘Chang’e 4’ was the first to land on the lunar far side within the South Pole-Aitken basin. Although both the Chang’e Project and Chandrayaan moon missions are attempting to explore the far side by soft landing, there are some differences in their scientific aims.
Chang’e mission was to expose the lunar mantle, which is the region just below the Moon’s crust but above the core, and understand the questions about the formation of the solar system, whereas Chandrayaan 3’s aim is to study lunar topography and signatures of hydroxyl and water ice.
The Lunar South Pole has long held the interest of scientists and space experts because there is a possibility of water there. The Lunar South Pole region has craters that are cold traps and contain a fossil record crucial for understanding the Solar System’s formation.
Any data and conclusions drawn regarding lunar topography, mineralogy, elemental abundance, the lunar exosphere, and hydroxyl and water ice signatures are set to be studied worldwide.
The future is likely to see greater space exploration by India as consultations on the Space Activities Bill, which aims to channel the activities of the domestic private space industry through national legislation, are in pre-legislative stages.
- Vaishali Basu Sharma is an analyst of strategic and economic affairs. She has worked as a consultant with India’s National Security Council Secretariat (NSCS) for nearly a decade. She is presently associated with the New Delhi-based think tank Policy Perspectives Foundation.
- The author can be reached at postvaishali (at) gmail (dot) com.