Exploring the Unknowns of the lunar south pole: Importance of Chandrayaan 3 and Luna 25 mission

8 min readAug 17, 2023

In 2023, a new chapter in lunar exploration is unfolding as Russia’s Luna-25 and India’s Chandrayaan 3 missions race to explore the lunar south pole. Both missions are aimed at studying the unique geological features of the region and searching for water ice deposits. Despite their shared objectives, these missions differ significantly in their strategies, timelines, and research goals. While Chandrayaan 3 is equipped with more scientific instruments, Luna-25 has a longer mission duration. In this article, an overview of the Chandrayaan 3 and Luna-25 missions will be provided, their scientific objectives, and the importance of exploring the lunar south pole. Also comparing the scientific instruments on board the two missions and discuss their significance in the exploration of the Moon in detail.

The lunar south pole has become a prime target for exploration missions due to its unique characteristics and potential for scientific discoveries. Here are some reasons why the lunar south pole is being targeted:

Water Ice Deposits: Permanently shadowed areas around the lunar south pole are believed to contain water ice. Water is a crucial resource for future human missions, as it can be used for drinking, growing plants, and producing rocket fuel. Exploring these ice deposits can provide valuable insights into the Moon’s history and the potential for sustaining human presence.
Fossil Record of the Early Solar System: The craters in the lunar south pole region, which are in perpetual darkness, act as cold traps. These craters have preserved a fossil record of hydrogen, water ice, and other volatiles dating back to the early Solar System. Studying these materials can offer valuable information about the formation and evolution of the Moon and the Solar System.
Scientific Exploration: The lunar south pole region offers unique scientific opportunities. It has been thoroughly investigated by various spacecraft, such as the Lunar Reconnaissance Orbiter (LRO), which has been mapping the region and studying its radiation and thermophysical properties. The data collected from these missions helps scientists understand the lunar environment and prepare for future exploration.
Potential for Human Outpost: The lunar south pole has been identified as a possible location for a future human outpost. Its proximity to potential water resources and the availability of sunlight for power generation make it an attractive site for sustained human presence. Exploring the region will provide valuable information for planning and designing future lunar habitats.

Both the Chandrayaan 3 and Luna 25 missions are racing to land on the lunar south pole, aiming to be the first to explore this intriguing region. The nation that achieves this feat will make significant strides in lunar exploration and pave the way for future missions. The competition between these missions highlights the importance and excitement surrounding the exploration of the lunar south pole.

Chandrayaan 3:

Chandrayaan 3 is the third lunar exploration mission by the Indian Space Research Organisation (ISRO), which aims to explore the lunar south pole. The mission is a follow-on to the Chandrayaan-2 mission and will consist of a lander and a rover configuration. Unlike its predecessor, Chandrayaan 3 will not have an orbiter. The mission aims to demonstrate India’s proficiency in safely landing on and exploring the lunar surface, thereby deepening our understanding of the Moon’s geological features and potential for water ice deposits. Here is an overview of the scientific objectives of the Chandrayaan 3 mission:

Safe Landing: The primary objective of Chandrayaan 3 is to achieve a safe landing on the lunar surface near the south pole. The mission will use advanced imaging and navigation systems to select a suitable landing site.
Lunar Surface Exploration: The mission will deploy a rover to traverse the lunar terrain, collect data, and conduct scientific experiments to study the composition and characteristics of the lunar surface. The rover is equipped with several scientific instruments, including a terrain mapping camera, a synthetic aperture radar, and an alpha particle X-ray spectrometer.
Technology Demonstration: Chandrayaan 3 aims to demonstrate crucial capabilities and technologies required for future lunar and planetary exploration missions. The mission will test advanced landing and mobility systems, as well as communication and power systems.
Payload Operations: The lander of Chandrayaan 3 carries a scientific payload called Spectro-polarimetry of Habitable Planet Earth (SHAPE). This payload will study the spectral and polarimetric measurements of Earth from the lunar orbit, providing valuable data for Earth observation and scientific research.

This mission consists of lander Vikram and rover Pragyan. Each has its own set of scientific instruments which are stated below,

Lander Segment (Vikram) :

Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere (RAMBHA)

To measure the near surface plasma (ions and electrons) density and its changes with time.

2. Chandra’s Surface Thermo physical Experiment (ChaSTE)

To carry out the measurements of thermal properties of lunar surface near polar region.

3. Instrument for Lunar Seismic Activity (ILSA)

To measure seismicity around the landing site and delineating the structure of the lunar crust and mantle.

4. Laser Retroreflector Array (LRA)

It is a passive experiment to understand the dynamics of Moon system.

Rover Segment (Pragyan):

LASER Induced Breakdown Spectroscope (LIBS):

Qualitative and quantitative elemental analysis & To derive the chemical Composition and infer mineralogical composition to further our understanding of Lunar-surface.

2. Alpha Particle X-ray Spectrometer (APXS):

To determine the elemental composition (Mg, Al, Si, K, Ca, Ti, Fe) of Lunar soil and rocks around the lunar landing site.

Propulsion Module :

Spectro-polarimetry of HAbitable Planet Earth (SHAPE):

Future discoveries of smaller planets in reflected light would allow us to probe into variety of Exo-planets which would qualify for habitability (or for presence of life).

Luna 25

Russia’s Luna 25 mission, launched on August 10, 2023, is a lunar lander mission by Roscosmos. It is the first lunar mission by Russia in nearly 50 years and is designed to land near the moon’s south pole. The mission was initially called Luna-Glob lander but was renamed to Luna 25 to emphasize the continuity of the Soviet Luna program from the 1970s. The spacecraft will land at the Boguslavsky crater, near the lunar south pole. The mission aims to explore resources at the moon’s south pole and to study the lunar environment. The scientific team has already started processing the first measurement data on the flight to the Moon. The Luna 25 mission is part of what was at one point conceptualized as the Luna-Glob lunar exploration program.

Lander Segment:

The Lander Segment consists of eight payloads mainly to study the soil composition, dust particles in the polar exosphere, and most importantly, detect surface water.

ADRON-LR, active neutron and gamma-ray analysis of regolith
ARIES-L, measurement of plasma in the exosphere
LASMA-LR, laser mass-spectrometer
LIS-TV-RPM, infrared spectrometry of minerals and imaging
PmL, measurement of dust and micro-meteorites
THERMO-L, measurement of the thermal properties of regolith
STS-L, panoramic and local imaging
Laser retroreflector, Moon libration and ranging experiments

Trajectory

The trajectory of Chandrayaan-3 involves a series of maneuvers and burns to gradually raise its orbit and synchronize with the Moon. Here is a breakdown of the trajectory based on the available information:

Earth-Bound Maneuvers: Chandrayaan-3 employs a series of Earth-bound maneuvers to gradually raise its orbit. These maneuvers invlove using the spacecraft’s propulsion system to increase its velocity and gradually move it away from earth.
Lunar Orbit Insertion Burns: Once the spacecraft reaches a certain distance from Earth, it performs lunar orbit insertion burns. hese burns are designed to reduce the spacecraft’s velocity and allow it to enter the Moon’s gravitational field.
Orbit Reduction Maneuvers: After entering the Moon’s gravitational field, Chandrayaan-3 performs orbit reduction maneuvers. These maneuvers are performed to gradually decrease the spacecraft’s altitude and bring it closer to the Moon’s surface.
Lunar Landing : The ultimate goal of Chandrayaan-3 is to achieve a soft landing on the Moon’s surface near the lunar south pole. The trajectory is carefully calculated to ensure a precise landing and maximize the scientific data collected during the mission.

The trajectory of luna 25 includes,

Launch: Luna-25 will be launched from the Vostochny Cosmodrome in Russia.
Trans-Lunar Injection: After launch, the spacecraft will perform a trans-lunar injection maneuver to leave Earth’s orbit and travel towards the Moon.
Circumlunar Trajectory: Luna-25 will follow a circumlunar trajectory, which takes the spacecraft from Earth, around the far side of the Moon, and back to the Moon using only gravity once the initial trajectory is set.
Lunar Orbit Insertion: Once the spacecraft reaches the Moon, it will perform a lunar orbit insertion maneuver to enter into a circular near-polar orbit around the Moon, maintaining an altitude of 100 km for three days.
Lunar Landing: After three days in orbit, Luna-25 will perform a series of maneuvers to reduce its altitude and land on the Moon’s surface near the lunar south pole

India’s Chandrayaan-3 and Russia’s Luna-25 missions are both racing to explore the lunar south pole and carry scientific payloads to gather data and conduct experiments on the Moon. Investigating this region will yield valuable insights, contributing to our understanding of the Moon’s history and evolution. Each mission holds the potential to expand our technological capabilities and expertise in space exploration. Luna-25 consists of a lander with eight payloads, while Chandrayaan-3 includes a lander module called Vikram, which successfully separated from the spacecraft on August 17. The two missions differ in terms of methodology, route, and experiments. The focus of these missions is to expand our knowledge of the Moon’s south pole and contribute to our understanding of lunar science and exploration. The data and insights gathered from these scientific payloads will help scientists and researchers uncover more about the Moon’s composition, geology, and potential resources.