Chandrayaan-3: India's Lunar Mission Continues : Daily News Analysis

Date : 18/07/2023

Relevance – GS Paper 3 – Developments and Achievements in Science and Technology

Keywords – ISRO, LVM-3, Lunar Missions, Laser, PSLV, GSLV, SSLV

Context –

The Indian Space Research Organization (ISRO) launched its Chandrayaan-3 mission using the LVM-3 (Launch Vehicle Mark-3) on July 14, 2023.

Objectives – According to ISRO, the Chandrayaan-3 mission has three major objectives:

Demonstrate safe and soft landing on the surface of the Moon,
Conduct rover operations on the Moon, and
Conduct on-site experiments on the Lunar surface.

Anticipation for Chandrayaan-3's Lunar Mission

During moonlit nights from now until the end of August, people in India will eagerly search the sky, hoping to catch a glimpse of a spacecraft traveling towards Earth's closest neighbor, the Moon. India's third lunar mission, Chandrayaan-3, was launched from the Satish Dhawan Space Centre in Sriharikota and has captured the public's imagination, much like its predecessors. The mission aims to build upon the achievements of Chandrayaan-2, which unfortunately experienced a setback when its lander, 'Vikram,' crash-landed on the lunar surface in 2019.

Overview of Chandrayaan-3 Mission and Launch Details

Chandrayaan-3, launched using the powerful Launch Vehicle Mark-3 (LVM3), is designed to overcome the challenges of a robotic moon landing near the Moon's south pole. After reaching a 100-kilometer circular polar orbit around the Moon, the Propulsion Module will carry the Lander-Rover configuration. This time, the mission is better equipped to safely soft-land the Lander and deploy the six-wheeled Rover. Both the Lander and Rover are equipped with scientific payloads that will contribute to our understanding of Earth's solitary natural satellite, a celestial body that has captivated the imaginations of countless generations throughout history.

Scientific Payloads of the Lander (Vikram) and Rover (Pragyan)

YOU MUST KNOW THIS –

The Indian Space Research Organisation (ISRO) retained the names of the Chandrayaan-2 lander and rover for their Chandrayaan-3 equivalents as well.
This means, the Chandrayaan-3 lander name is ‘Vikram’ (after Vikram Sarabhai, the father of the Indian space programme) and the rover, ‘Pragyan’.
Much to its disappointment, the ISRO had lost the Chandrayaan-2 lander-rover configuration and the payloads aboard them after ‘Vikram’ crashed on the lunar surface while attempting a soft landing.

The Lander of the Chandrayaan-3 mission carries four scientific payloads.
The first is ChaSTE, which is designed to measure the thermal properties of the lunar regolith (the layer of loose rocky material) near the polar region.
The second payload is RAMBHA, a Langmuir Probe that will measure the density of near-surface plasma and how it changes over time.
The third payload is the Instrument for Lunar Seismic Activity (ILSA), which will measure seismic activity on the Moon.
Lastly, there is the LASER Retroreflector Array (LRA), a passive experiment that will help understand the dynamics of the Moon.

On board the Rover, there are two scientific payloads. The first is the LASER Induced Breakdown Spectroscope (LIBS), which will study the chemical and mineralogical composition of the lunar surface.

The second payload is the Alpha Particle X-ray Spectrometer (APXS), which will measure the elemental composition of the lunar soil and rocks in the vicinity of the landing site.

Propulsion Module Payload and Exoplanet Research

The Propulsion Module, on the other hand, carries one payload called SHAPE (Spectro-polarimetry of HAbitable Planet Earth). This payload will study Earth from lunar orbit, providing valuable data for exoplanet research.

Successful Launch and Orbital Journey of Chandrayaan-3

After a successful launch from the Sriharikota Range, the Chandrayaan-3 spacecraft has embarked on its journey to the Moon, located approximately 384,000 kilometers away. The tension in the Mission Control Centre began to ease, and smiles appeared on the faces of the team members. Chairman of ISRO, Mr. Somanath, expressed his joy and announced that Chandrayaan-3 had started its journey towards the Moon after being placed into a precise orbit around the Earth by the LVM3 launch vehicle.

Do YOU KNOW

ISRO operates three classes of launch vehicles:

PSLV (Polar Satellite Launch Vehicle): The PSLV is known as a reliable workhorse with a remarkable success rate. It is capable of launching payloads of up to 3.8 tonnes into Low Earth Orbit (LEO). The PSLV has been instrumental in launching numerous Indian satellites as well as international satellites.
GSLV (Geostationary Satellite Launch Vehicle): The GSLV is designed to launch heavier payloads, including communication satellites, into geostationary orbits. It has multiple configurations, including the GSLV Mk-II and the more powerful GSLV Mk-III. The GSLV Mk-III, also known as LVM-3 (Launch Vehicle Mark-3), is ISRO's most powerful launch vehicle and is capable of placing payloads weighing up to 4 tonnes into Geosynchronous Transfer Orbit (GTO).
SSLV (Small Satellite Launch Vehicle): The SSLV is a dedicated launch vehicle designed to cater to the growing demand for launching small satellites. It is a three-stage launch vehicle that uses solid propulsion for the first three stages and a liquid propulsion-based Velocity Trimming Module (VTM) as the final stage. The SSLV is specifically designed for launching small satellites into a variety of orbits, including Low Earth Orbit (LEO).

LVM-3, which stands for Launch Vehicle Mark-3, is the most powerful configuration of the Geosynchronous Satellite Launch Vehicle (GSLV) developed by ISRO. It is designed to launch heavier payloads into various orbits, including geostationary orbits.

What is LVM-3?

The LVM-3 has three stages:

First stage (S200 Boosters stage): The first stage of LVM-3 consists of two S200 solid rocket boosters attached to the sides of the rocket body. These boosters burn hydroxyl-terminated polybutadiene (HTPB) as a solid propellant. They provide a significant amount of thrust during the initial phase of the launch.
Second stage (Vikas Engines stage): The second stage of LVM-3 is powered by Vikas engines, which use liquid propellants. The engines can burn a combination of nitrogen tetroxide (N2O4) as the oxidizer and unsymmetrical dimethylhydrazine (UDMH) as the fuel. This stage provides additional thrust to propel the rocket further into space.
Third stage (Cryogenic Upper Stage): The uppermost stage of LVM-3 is a cryogenic stage, which means it uses cryogenic propellants that are in a liquid state at extremely low temperatures. It employs a cryogenic engine that burns a combination of liquid hydrogen (LH2) and liquid oxygen (LOX) as propellants. The cryogenic stage provides the final push to place the payload into its intended orbit.

With its powerful configuration, LVM-3 is capable of lifting payloads weighing up to 8 tonnes into Low Earth Orbit (LEO). It has been successfully used for missions such as the Chandrayaan-2 lunar mission and the GSAT-29 communication satellite launch.

Evolution of India's Space Program and Lunar Mission

Reflecting on the progress made by India's space program, it is remarkable to consider that missions to the Moon and Mars were once beyond the imagination of the early visionaries. In the early days of the space program, the focus was on addressing the priorities and anxieties of a young nation. However, the words of Vikram Sarabhai, one of the pioneers of India's space program, highlighted the conviction that advanced technologies should be applied to real problems faced by society and contribute meaningfully both nationally and internationally.

Chandrayaan-1: India's First Lunar Mission

As the Indian space program evolved, it naturally turned its focus towards the Moon and beyond, aligning with the vision and mission conceived by Dr. Vikram Sarabhai. Discussions about an Indian scientific mission to the Moon began in 1999 during a meeting of the Indian Academy of Sciences, followed by further discussions in the Astronautical Society of India in 2000. The feasibility of undertaking a lunar mission was explored through interactions between scientists, engineers, and mission planners.

Chandrayaan-2: Setbacks and Lessons Learned

ISRO established a National Lunar Mission Study Task Force, headed by George Joseph, to study the mission's feasibility. Interestingly, the original name proposed for India's Moon mission was 'Somayana-1.' However, it was eventually named Chandrayaan-1. The plans for Chandrayaan-1 were announced by then Prime Minister Atal Bihari Vajpayee in his Independence Day address on August 15, 2003. The mission was successfully launched on October 22, 2008, aboard the Polar Satellite Launch Vehicle (PSLV-C11) and carried 11 scientific instruments. Chandrayaan-1 made significant discoveries, including the detection of water molecules on the Moon.

A Comparison between Chandrayaan-2 and Chandrayaan-3:

1. Design and Soft-Landing:

Chandrayaan-2: During its soft-landing attempt, Chandrayaan-2 failed to reduce its speed to the desired level and crashed on the lunar surface. Problems in software and hardware were later identified.
Chandrayaan-3: Important improvements have been made in the design to avoid a similar accident. The legs of Chandrayaan-3 have been strengthened to ensure landing and stabilization even at a higher speed. Additional fuel has been carried to enable a last-minute change in landing site if required.

2. Solar Panels:

Chandrayaan-2: The Lander had solar panels on two sides.
Chandrayaan-3: The Lander is equipped with solar panels on four sides, ensuring continuous power generation even in unfavorable landing orientations.

3. Navigational and Guidance Instruments:

Chandrayaan-2: Limited navigational and guidance instruments were onboard.
Chandrayaan-3: Additional navigational and guidance instruments, including a Laser Doppler Velocimeter, have been incorporated to continuously monitor the Lander's speed and make necessary corrections. New sensors and cameras have also been added.

4. Software and Algorithm Upgrades:

Chandrayaan-2: The hazard detection and avoidance camera and processing algorithm were upgraded.
Chandrayaan-3: The navigation and guidance software has been updated, and multiple layers of redundancies have been introduced to ensure system functionality even if one component fails.

5. Stress Tests and Experiments:

Chandrayaan-2: The Lander underwent various tests, including simulations, to simulate lunar landing conditions.
Chandrayaan-3: Similar stress tests and experiments have been conducted on Chandrayaan-3, including dropping it from helicopters to ensure its resilience in lunar landing scenarios.

Overall, Chandrayaan-3 has incorporated several improvements and enhancements based on the learnings from Chandrayaan-2's failure. Strengthened legs, increased fuel capacity, updated software, additional instruments, and comprehensive stress testing have been implemented to enhance the chances of a successful soft landing on the lunar surface. These advancements aim to mitigate potential issues faced by Chandrayaan-2, improving the overall reliability and success rate of the mission.

The Challenge of Chandrayaan-3: Ensuring Success and Lunar Landing

After an 11-year gap, India's next lunar mission, Chandrayaan-2, was launched on July 22, 2019, aboard the GSLV MkIII-M1. The spacecraft, comprising the Vikram lander and Pragyan Rover, entered lunar orbit on August 20, 2019. However, during the descent of the Vikram lander, communication with ground stations on Earth was lost at an altitude of 2.1 km.

With the launch of Chandrayaan-3, ISRO scientists face the challenge of ensuring a successful mission and achieving a soft landing on the Moon. Learning from the experiences of Chandrayaan-2, the focus is on making sure that all systems function properly and India successfully lands on the lunar surface.

Conclusion –

With the advancements made in the design, technology, and lessons learned from Chandrayaan-2, Chandrayaan-3 holds great promise for India's lunar exploration. The comprehensive improvements, strengthened legs, upgraded software, and additional instruments demonstrate India's commitment to overcoming challenges and achieving a successful soft landing on the Moon. The mission showcases ISRO's determination to explore new frontiers and contribute to our understanding of the lunar surface. Chandrayaan-3 not only represents India's scientific prowess but also inspires optimism and sets the stage for future lunar missions, furthering our quest for knowledge and exploration in space.

Probable Questions for UPSC Mains Examination–

"Discuss the key objectives and advancements of India's Chandrayaan-3 mission in comparison to its predecessor, Chandrayaan-2. Examine the significance of strengthened legs, additional instruments, and software upgrades in ensuring a successful soft landing on the lunar surface." (10 Marks, 150 Words)
"Analyzing India's lunar missions, Chandrayaan-1, Chandrayaan-2, and the recent launch of Chandrayaan-3, explain the evolution of India's space program and its contributions to lunar exploration. Discuss the challenges faced during Chandrayaan-2 and how Chandrayaan-3 incorporates lessons learned to enhance the success rate of soft landings and on-site experiments." (15 Marks, 250 Words)

Source – The Hindu