Chandrayaan 3: ISRO's lunar mission inches closer to landing; What lies ahead in upcoming week

India is on the verge of making history as its Chandrayaan 3 spacecraft prepares to land on the moon's surface on August 23, 2023. If successful, India will become the fourth nation to achieve a soft landing on the moon, after the US, the former Soviet Union and China. The mission also aims to explore the uncharted territory of the lunar south pole, where water ice and other resources may be present.

What is Chandrayaan 3?

Chandrayaan 3 is India's third lunar mission, following Chandrayaan 1 and Chandrayaan 2. The mission consists of a lander and a rover, which will separate from the orbiter after reaching the moon's orbit. The lander will carry the rover to a designated landing site near the south pole, where it will deploy the rover and conduct scientific experiments. The rover will move around the landing site and collect data using its instruments.

The mission objectives of Chandrayaan 3 are:

- To demonstrate India's capability to perform a soft landing on the moon and operate a robotic rover on the lunar surface.

- To study the topography, mineralogy, surface chemical composition and thermo-physical characteristics of the lunar south polar region.

- To assess the abundance and distribution of water ice and other volatiles in the lunar south polar region.

- To enhance our understanding of the origin and evolution of the moon.

What are the challenges of landing on the moon?

Landing on the moon is not an easy task, as it involves many technical and environmental challenges. Some of these are:

- The moon has no atmosphere, which means there is no air resistance or drag to slow down the spacecraft. The spacecraft has to rely on its own propulsion system to decelerate and maneuver during descent.

- The moon has a highly irregular surface, with craters, hills, valleys and rocks. The spacecraft has to avoid these obstacles and find a safe and flat landing site.

- The moon has a variable gravity field, which affects the trajectory and velocity of the spacecraft. The spacecraft has to account for these variations and adjust its thrust accordingly.

- The moon has extreme temperature variations, ranging from -173°C to 127°C. The spacecraft has to withstand these thermal fluctuations and protect its sensitive components from damage.

- The moon has a long day-night cycle, lasting about 29.5 Earth days. The spacecraft has to operate in both sunlight and darkness, and manage its power and thermal systems accordingly.

How will Chandrayaan 3 land on the moon?

Chandrayaan 3 will follow a similar landing strategy as Chandrayaan 2, which attempted a soft landing on September 7, 2019 but failed due to a loss of communication with the lander. Chandrayaan 3 will use four main phases to land on the moon:

- Rough braking phase: This phase will start when the lander is about 30 km above the lunar surface. The lander will fire its engines to reduce its speed from about 1.6 km/s to about 100 m/s. This phase will last for about 10 minutes.

- Absolute navigation phase: This phase will start when the lander is about 7.4 km above the lunar surface. The lander will use its onboard cameras and sensors to identify its location and orientation with respect to the landing site. This phase will last for about 38 seconds.

- Fine braking phase: This phase will start when the lander is about 5 km above the lunar surface. The lander will fire its engines again to reduce its speed from about 100 m/s to about 2 m/s. This phase will last for about 96 seconds.

- Terminal descent phase: This phase will start when the lander is about 400 m above the lunar surface. The lander will hover for a few seconds and then slowly descend towards the landing site. The lander will touch down with a speed of less than 2 m/s. This phase will last for about 15 seconds.

What lies ahead in upcoming week?

Chandrayaan 3 is currently in lunar orbit, undergoing orbital adjustments and fine-tuning its trajectory for landing. According to ISRO, Chandrayaan 3 is expected to land on August 23 or August 24 (depending on local time zones) at around 1:30 AM IST (8:00 PM GMT). The landing site is located at latitude -70.9° and longitude -22.4° near Shackleton crater in the south polar region.

The landing event will be broadcast live by ISRO and other media outlets. Millions of people around the world will be watching with anticipation and excitement as India attempts this historic feat.

If Chandrayaan 3 succeeds in landing safely and deploying its rover, it will mark a new milestone for India's space program and a proud moment for the nation. It will also open up new avenues for scientific exploration and discovery on the moon, especially in the south polar region, which holds many secrets and mysteries.

We wish Chandrayaan 3 all the best and hope it will achieve its mission objectives and make India proud. Jai Hind! 🇮🇳

Source: 

(1) Chandrayaan 3: ISRO's lunar mission inches closer to landing; What lies .... https://www.livemint.com/news/world/chandrayaan-3-isros-lunar-mission-inches-closer-to-landing-what-lies-ahead-in-upcoming-week-11692087283353.html.

(2) Chandrayaan-3: Indian spacecraft enters lunar orbit in step closer to .... https://www.cnn.com/2023/08/07/india/india-chandrayaan-3-moon-mission-lunar-orbit-intl-hnk/index.html.

(3) Chandrayaan-3: Historic India Moon mission sends new photos of lunar .... https://www.bbc.com/news/world-asia-india-66425524.

(4) Chandrayaan-3: Timeline of ISRO's moon missions - CNBCTV18. https://www.cnbctv18.com/science/chandrayaan-3-timeline-of-isros-moon-missions-17482661.htm.

(5) Chandrayaan-3: How ISRO's Third Lunar Mission Differs From Chandrayaan-2. https://www.gadgets360.com/chandrayaan/news/chandrayaan-3-launch-isro-2-difference-third-lunar-mission-4200343.