The Journey To Moon: Here's Why Chandrayaan-3 Took 40 Days To Reach The Moon

The Chandrayaan-3 spacecraft covered approximately 3,84,000 kilometers distance in nearly 40 days.

Led by Ritu Karidhal, also regarded as the 'Rocket Woman of India', Chandrayaan-3 has landed safely on south pole of Moon on 23rd August. With this historic landing, the very first kind by any nation, the scientific community is currently waiting for the findings of this mission. Chandrayaan-3's aim is to demonstrate soft-landing safely on the Moon surface, roving on the Moon, alomg with conducting scientific experiments to understand geology and atmosphere of moon. However, this spacecraft will not return back to the Earth as it is designed to stay forever there. NASA's Apollo 11 landed on the lunar surface in only 4 days. Netizens were confused over the longer time period taken by this spacecraft than others. To clarify why this approach is taken, here's the article for you.

The science behind:

A senior ISRO official told, "The slingshot is aimed at ensuring that the spacecraft uses Earth's gravity to increase its velocity travelling towards the Moon. It's a complex dynamic of astronomy and physics. While it is cost-effective and fuel efficient compared to Apollo missions, it does consume a significant amount of fuel for the burns to happen in order to raise the orbits."

Let's discuss the science in details.

The Trajectory:

NASA's Apollo missions followed a direct trajectory path, a system "Translunar Injection" while reaching the Moon. Apollo spacecraft used the powerful Saturn V launch vehicle, propelling from Earth orbit, enabled a swift journey within 4 days. This mission used single engine burn technology to reach moon.

However, Chandrayaan-3 followed a different trajectory, a number of Earth orbits and 'engine burns' to eventually raise the speed of the spacecraft. ISRO used a comparatively less powerful launch vehicle, the 'Geosynchronous Satellite Launch Vehicle (GSLV) Mark-III'. This vehicle doesn't carry the similar payload capacity of Saturn V. As a result, ISRO opted for a gradual trajectory to optimize the mission.

How ISRO utilitied limiting factor as success strategy?

ISRO used an intelligent strategy to overpower the limitations by following an elliptical path around Earth. In this strategy, Chandrayaan-3 attained the highest speed while crossing through the perigee or the closest distant to Earth.

"Each time the spacecraft approaches the perigee, the engines fired to increase its speed. A series of these firings in every orbit pushed the module into higher and more elongated orbits. With each burn, the module spiralled outward, gaining momentum and energy," an ISRO official told about the strategy.

How Chandrayaan-3 Escaped Earth's Gravitational Field:

The velocity need to attain to escape from earth's gravitational field is known as escape velocity. With continous journey, the module eventually reached this point. After this stage, the propulsion module's orbit got elongated, eventually setting its smooth journey towards the Moon.

"The timing of the Chandrayaan-3 module's entry into the Lunar Transfer Trajectory (LTT) was meticulously planned to align with the Moon's position in its own orbit, ensuring proximity to the Moon's trajectory at the desired moment," ISRO shared in their website.

How Chandrayaan-3 entered Lunar orbit?

Once the propulsion module reached the selected zone in the LTT, a maneuver called 'lunar orbit insertion' was executed. This led to reduction of the speed of the Chandrayaan-3. This crucial step allowed the gravitational field of Moon to slowly pull the spacecraft into a stable lunar orbit.

The perfect 'soft-landing':

Following lunar orbit insertion, the propulsion module started orbiting the earth's natural satellite in an elliptical pathway.

Then, a number of maneuvers are completed to gradually decrease the propulsion module's altitude. The plan was to place the lander and rover in a near circular orbit around 100 km above the moon surface. After this step, propulsion module separated from the lander and rover.

"Chandrayaan-3 Mission: 'India, I reached my destination and you too!': Chandrayaan-3

Chandrayaan-3 has successfully

soft-landed on the moon! Congratulations, India!" ISRO tweeted after successful soft-landing yesterday.