Only three countries have successfully landed a spacecraft on the moon

One of the main objectives of the Chandrayaan-3 mission is to demonstrate end-to-end capability in safe landing and roving on the lunar surface. According to space experts, soft landing on the moon will come with its whole set of challenges.

ISRO Chairman S Somanath has expressed confidence about the soft landing of the Chandrayaan-3 mission and the space fraternity is hoping that the mission successfully achieves it. Recent moon landing missions have been met with mixed success. While China has successfully landed on the moon, other missions, including those by India and two private companies, have crashed. This suggests that there are still challenges to overcome in order to safely land on the moon.

“Despite the recent setback of iSpace's HAKUTO-R mission, which crashed on the moon on April 25, there are still a number of upcoming moon landing missions scheduled for the second half of this year. These missions, which are being undertaken by both public and private entities, represent a renewed commitment to lunar exploration and offer the potential for new scientific discoveries,” Girish Linganna, space and aerospace expert said.

India is set to launch its third lunar mission, Chandrayaan-3, this month. The country's previous attempt, Chandrayaan-2, faced a major setback when the Vikram lander crashed during its descent to the moon in July 2019. However, India is determined to succeed in its lunar exploration efforts, and Chandrayaan-3 is a significant step towards that goal. Interestingly till date, only three countries have successfully landed a spacecraft on the moon: the United States, Russia, and China. All of these missions were government sponsored, and they represent the culmination of decades of research and development.

In 2019, two private companies experienced setbacks in their lunar landing missions. In April, SpaceIL's Beresheet lander crashed onto the moon's surface, and in July, India's Chandrayaan-2 lander failed to land safely. These failures highlight the challenges of landing on the moon, but they also demonstrate the growing interest in lunar exploration.

“Despite the setbacks of previous missions, several organisations are still planning to land on the moon in the near future. India's Chandrayaan-3 mission is scheduled to launch in July, and iSpace has announced plans for more attempts in the coming months. Two US companies, Astrobotic and Intuitive Machines, are also firming up plans to land on the moon in 2023. This renewed interest in lunar exploration is an exciting development, and it suggests that we may be on the cusp of a new era of space exploration,” added Linganna.

Despite the recent setbacks, ISRO is confident that it has learned from these experiences and is well-prepared for its upcoming Chandrayaan-3 mission. Chandrayaan-3 is a follow-up mission to Chandrayaan-2, and it will demonstrate India's end-to-end capabilities in safe landing and roving on the lunar surface. The mission will consist of a lander and a rover, and it will be launched by the GSLV Mk III or LVM3 from the Satish Dhawan Space Centre. The propulsion module will carry the lander and rover configuration to a 100-kilometre lunar orbit.

The Chandrayaan-3 mission has three main objectives: to safely land on the lunar surface, to deploy a rover, and to conduct scientific experiments. The propulsion module will carry the lander and rover to the moon, and the lander payload will be responsible for the safe landing. The rover will then be deployed to explore the lunar surface, and the scientific experiments will be conducted to learn more about the moon.

The propulsion module of the Chandrayaan-3 mission also carries the Spectro-polarimetry of Habitable Planet Earth (SHAPE) payload, which will study the spectral and polarimetric measurements of earth from the lunar orbit. This will help scientists to better understand the earth's atmosphere and climate, and to identify potential habitable planets beyond our own.

The lander payload of the Chandrayaan-3 mission consists of three instruments namely Chandra's Surface Thermophysical Experiment (ChaSTE) to measure the thermal conductivity and temperature of the lunar surface. Instrument for Lunar Seismic Activity (ILSA) to measure the seismicity around the landing site and Langmuir Probe (LP) to estimate the plasma density and its variations.

The lander payload also includes a passive Laser Retroreflector Array(LRA) from NASA, which will be used for lunar laser ranging studies. The rover payload of the Chandrayaan-3 mission consists of two instruments including Alpha Particle X-ray Spectrometer (APXS) to derive the elemental composition of the lunar surface by analysing the X-rays and gamma rays emitted by the elements.

Laser Induced Breakdown Spectroscopy (LIBS) to derive the elemental composition of the lunar surface by analyzing the light emitted when a laser is fired at the surface.

“Japan and UAE had joined forces for the historic Lunar Mission iSpace's Hakuto-R lunar lander, named after the Moon-dwelling white rabbit of Japanese folklore, which crashed near the Atlas crater on April 25, 2023. The spacecraft was launched by SpaceX from Cape Canaveral, Florida, on December 11, 2022. The UAE's Rashid rover (HOPE) was one of the payloads on iSpace's Hakuto-R lunar lander. The rover, which weighed just 10 kilograms, was designed to roam the lunar surface for two weeks and send back valuable images. However, the lander crashed on April 25, 2023, dashing UAE's hopes of a successful mission,” explained Linganna.

Recently Syed Maqbool Ahmed, principal payload scientist at XDLINX Labs, a space startup, had pointed out that landing on the moon is a complex maneuver that takes a week or so, even with powerful rockets. The lander must be slowed down from its orbital speed of 5,000 to 7,000 kilometres per hour to a complete stop. This is done by firing retro-rocket engines, as there is no atmosphere on the moon to slow the lander down with a parachute. This is a challenging task that has been the downfall of many recent human attempts to land on the moon.

Due to the setback of Chandrayaan-2, ISRO had embarked on an exhaustive analysis of the mission, meticulously scrutinising every aspect to identify areas for improvement. The goal was not only to rectify the issues that led to the previous failure but also to enhance their technologies to significantly increase the chances of a successful soft landing with Chandrayaan-3.

“One critical aspect that received considerable attention was the software systems. Advanced algorithms and simulations were developed to optimise the onboard software, enabling precise navigation, control, and coordination. These enhancements allowed the team to simulate numerous landing scenarios, ensuring preparedness for various contingencies and enhancing the mission's overall resilience. However, software improvements were just the beginning. The lander itself underwent substantial modifications to augment its capabilities and increase the chances of a successful touchdown. Engineers conducted meticulous studies on the lander's legs, fortifying them to withstand the harsh lunar terrain and minimising the risk of damage upon landing. Extensive upgrades were also made to the lander's sensors, equipping it with state-of-the-art technology to ensure safe and accurate navigation during the descent,” remarked Srimathy Kesan, founder and CEO of Space Kidz India, which is into design, fabrication and launch of small satellites, spacecraft and ground systems.

Explaining further, Kesan said that another critical area of focus was the power system. The lander and rover now rely on advanced solar power technology, featuring larger and more efficient solar panels. This upgrade guarantees a stable power supply throughout the mission, enabling extended exploration and seamless data collection on the lunar surface.

“Despite these advancements, the challenge of achieving a soft landing on the Moon remains immensely daunting. The lunar South Pole, the intended destination for Chandrayaan-3, presents its own unique set of difficulties. Its rugged and uneven terrain, coupled with the presence of craters and boulders, demands an extraordinary level of precision. Even the slightest miscalculation or unforeseen obstacle could jeopardize the mission's success,” added Kesan.