Chandrayaan moon
Photo: indiatoday

India is going to the Moon. Again. Four years after the Chandrayaan-2 mission ended in part failure, the Indian Space Research Organisation (Isro) is making another attempt to land on the Moon. Later this evening, the Chandrayaan-3 mission’s Vikram lander, currently in orbit around the Moon, will begin a slow, calculated descent on to the lunar surface.

The landing sequence will begin around 5:45 pm and will last for around a quarter of an hour, a period that a former Isro chief has described as “15 minutes of terror”.

If all goes well, Vikram will land in an area near the lunar South Pole. Shortly after, the lander will open its doors to deploy Pragyaan — a six-wheeled rover the size of a coffee table — on the surface of the moon.

This would make India only the fourth country in the world — after the United States, Russia, and China — to operate a rover on the Moon and the first to land near the forbidding South Pole.

AMBITIOUS MISSION

Chandrayaan-3 fundamentally is a “proving mission”, aiming to showcase India’s ability to land and rove on the Moon. The mission was launched on July 14, 2023, on board the Launch Vehicle Mark III. The rocket, dubbed ‘Bahubali’, is the most powerful launch vehicle developed by India and is slated to carry Indians to space as part of the upcoming Gaganyaan mission.

Post-launch, Chandrayaan-3 performed a series of movements around the Earth, accelerating with each completed orbit. After gaining enough speed and power, the spacecraft left Earth’s gravitational influence and set course for the Moon.

Chandrayaan-3’s journey to the Moon

On entering the Moon’s gravitational area, Chandrayaan-3 repeated the orbit movements, this time to slow down around our neighbour. On August 17, the Vikram lander separated from the propulsion module — the ‘mothership’ that had ferried it to the Moon — and began its solo journey to the lunar surface.

On successful landing, Vikram, along with the Pragyaan rover it carries in its belly, will perform a series of experiments. These include:

  • Analysing the Moon’s surface composition and its soil
  • Documenting the heat retained in the lunar polar region
  • Investigating the seismic activity around the landing site
  • Measuring the distance to Earth from near the lunar South Pole

Vikram and Pragyaan’s mission will last 14 days — the amount of time for which sunlight will be available near the lunar South Pole following the landing — after which they are expected to lose power. Meanwhile, the Chandrayaan-3 ‘mothership’ will continue to revolve around the Moon and will perform experiments to study Earth from the lunar orbit.

It is expected that these experiments combined will help further our understanding of the Moon’s ability to support future human exploration of its surface and resources.

Chandrayaan-3

STORIED HISTORY

As the name suggests, Chandrayaan-3 is the third of India’s Moon mission. The first, launched in 2008, placed an orbiter around the Moon and deliberately crashed a probe near the lunar South Pole.

The Moon’s polar region has long been of interest to scientists because of its many permanently shadowed craters. The permanent shadows, a result of the angle at which sunlight hits the areas, were thought to hide regions that could contain water.

And Chandrayaan-1 hit global headlines because of that. An instrument developed by the US space agency Nasa and carried on board the impact probe that crashed into the Moon found traces of water in the polar region. The Chandrayaan-1 mission ended in 2009 after the orbiter stopped communicating. It remained in orbit for 312 days.

A decade later, India launched Chandrayaan-2 — an orbiter-lander-rover combine that aimed to, among others, perform a ‘soft landing’ near the South Pole. The mission, launched in July 2019, was partly successful.

The Chandrayaan-2 orbiter was successfully placed around the Moon, but that was not it. The precise movements with which that was done ensured enough leftover fuel to extend the orbiter’s life to seven years from the original one. In fact, Isro is using the same orbiter for the Chandrayaan-3 mission.

The Chandrayaan-2 mission consisted of an orbiter, a lander, and a rover. The orbiter remains in the lunar orbit and is serving the Chandrayaan-3 mission. (Illustration: Vani Gupta/India Today)

However, the lander-rover combo — also named Vikram and Pragyaan — perished on the way to the Moon. On September 6, 2019, the Vikram lander began its descent and aced most of the landing stages. Towards the end of the treacherous sequence, a few unexpected movements caused Vikram’s engines to push the lander toward the lunar surface instead of slowing it down, resulting in a crash.

The failed attempt provided many learnings that have been factored into Chandrayaan-3’s Vikram to avoid a repeat, several Isro officials have said. Among them is K Sivan, who was the Isro chief during Chandrayaan-2 and who, in 2019, famously coined the phrase “15 minutes of terror” to describe the last moments of a lunar landing attempt.

Will 2023’s version of 15 minutes of terror end in euphoria and scientific advancements or sadness and another bout of learnings? We’ll know soon enough.

Published On:

Aug 23, 2023

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